Biology For Class IX - Chapter No.7 - BIOENERGETICS - Text Book Exercise and Short Question Answers

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CHAPTER 7
BIOENERGETICS

By Mrs. Ayesha Arif
(Jauhar Progressive School)

Review Questions

1. Encircle the correct answer:
i) In an oxidation process 14135 KJ energy is release, how many moles of glucose consume during this process.
(a) 1
(b) 3
(c) 5 ✔
(d) 10

(ii) Stage of aerobic respiration takes place at the cristae of mitochondria called:
(a) Electron transport chain ✔
(b) Glycolysis
(c) Kreb's cycle
(d) C3 cycle

(iii) In a process of cellular respiration 180 ATP molecules are produced, how many moles of glucose consume during this process.
(a) 2
(b) 5 ✔
(c) 8
(d) 10

(iv) Loss of electron and proton is called:
(I) Oxidation reaction
(II) Reduction reaction
(III) Redox reaction
(a) I only ✔
(b) I and II
(c) II and III
(d) I, II and III

(v) Each mole of ATP store energy:
(a) 7.3 kcal/mole ✔
(b) 7.3 kj/mole
(c) 17.3 kcal/mole
(d) 17.3kj/mole

(vi) Fundamental molecule produced during photosynthesis is:
(a) Glucose ✔
(b) Amino acid
(c) Fatty acid
(d) Nucleotide

(vii) Light dependent reaction takes place in:
(a) Stroma
(b) Thylakoid ✔
(c) Cristae
(d) Cisternae

(viii) Reaction in which solar energy is transferred to glucose from ATP and NADPH₂ , takes place in stroma called:
(I) Light reaction
(II) Dark reaction (III) Light dependent reaction
(a) I only
(b) II only ✔
(c) I and II
(d) II and III

(ix) Splitting of water in presence of light called:
(a) Hydrolysis
(b) Glycolysis
(c) Photolysis ✔
(d) None of these

(x) Splitting of glucose (glycolysis) release small amount of energy which is enough to generate:
(a) 2 ATP ✔
(b) 5 ATP
(c) 18 ATP
(d) 36 ATP

2. Fill in the blanks:
(i) The only source of energy on earth is Sun.
(ii) Conversion of free energy into different forms by living organisms is called bioenergetics.
(iii) In living organisms energy is stored in a special molecule called ATP.
(iv) Plant utilizes simple inorganic molecules (CO₂ and H₂O) to prepare glucose and oxygen.
(v) Feeding sequences and relationships are called food chains.
(vi) Photosynthesis is the only process which produces free O₂ by splitting water.
(vii) Chloroplast is double membrane bounded organelle have semifluid protein containing membrane called stroma.
(viii) In chloroplast different pigments absorb light of different wavelength.
(ix) The breakdown of food molecules to release energy is called respiration.
(x) Each mole of glucose produce maximum energy i.e.2827 Kj.

3. Define the following terms:

1. Bioenergetics
2. Energy
3. Oxidation reaction
4. Food chain
5. Granum
6. Photolysis
7. Fermentation
8. Stroma
9. Aerobic respiration
10. Pyruvic acid

Ans: (i) BIOENERGETICS:

"The study about conversion of free energy into different forms by living organisms is called Bioenergetics."

Bioenergetics can also be defined as:

"The study of energy relationships, energy transformation and transmission in living organisms."

It is the part of biology, Physics and chemistry concerned with the energy involved in making and breaking of chemical bonds found in the molecules of organisms.

(ii) ENERGY:
Energy is the capacity for doing work. The only source of energy on earth is Sun. Energy can neither be created nor be destroyed but it can change from one form to another form. It may exist in potential, kinetic, thermal, electrical, chemical, nuclear, or other various forms.

(iii) The Oxidation Reactions:
are those reactions in which loss of electron (e^-) and proton (H⁺) occurs. These electrons carry energy from the molecules from where they release to the molecules where they added. e.g.
Iron reacts with oxygen to form a chemical called rust, in this reaction iron (Fe) loses some e- which transfer to oxygen. In this reaction Fe is oxidized and it transfers its energy to oxygen through electrons.

(iv) Food chain:
In ecology, food chain is the sequence of transfers of matter and energy in the form of food from organism to organism. In other words, the feeding sequences and relationship are called food chains.

OR

A food chain is a linear sequence of organisms through which nutrients and energy pass as one organism eats another. Therefore these feeding sequences and relationships are called food chain.

(v) Granum (pl. grana):
It is a stack of plate-like bodies (thylakoids), many of which are found in plant chloroplasts (each chloroplast contains about 50 grana). Grana bear the light receptive pigment chlorophyll and contain the enzymes responsible for the light-dependent reactions of photosynthesis.

OR

It is a stacked membranous structure within the chloroplasts of plants and green algae that contain the chlorophyll and are the site of the light reactions of photosynthesis. The sac like membranes that make up grana are known as thylakoids.

(vi) Photolysis:
Some of the light is utilized to split water into oxygen and H⁺ with e^- (electron), this splitting of water is called Photolysis. Oxygen which is produced during photolysis is released in the environment where as H⁺ together with CO₂ are used in building glucose.

(vii) Fermentation:
Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes and breaks down into a simpler substance.
In biochemistry, it is narrowly defined as:
The primitive type of respiration which takes place in the absence of O₂ or without O₂ is called anaerobic respiration or fermentation. There are special conditions where O₂ is not available so the organisms adapt themselves to break down their food without oxygen which is called anaerobic respiration or fermentation.
Example:
It takes place in some bacteria, fungi, endoparasite and sometimes in animal.

(viii) Stroma:
Chloroplast have semi-fluid proteins containing medium called Stroma, which surrounding thylakoids and grana. Initially, the stroma was thought to simply provide support for the pigmented thylakoids. However it is now known that the stroma contains starch, chloroplast DNA and ribosomes, as well as all the enzymes required to carry light independent reactions of photosynthesis, also called Calvin-Benson cycle.

(ix) Aerobic Respiration:
Type of respiration where food breakdown occurs in the presence of oxygen to produce energy, is called aerobic respiration.
It takes place in the presence of free oxygen, oxidizing the food and releasing the maximum amount of energy i.e. 2827 kj / mole of glucose or 36 ATP molecules/glucose.
Example:
It is a method of respiration found in majority of organisms.
Equation:
The end products of aerobic respiration are CO₂ and H₂O.

Glucose + oxygen → Carbon dioxide + water + Energy (36 ATP)
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 36 ATP

(x) Pyruvic Acid:
Pyruvic acid, (CH₃COCOOH), is an organic acid that probably occurs in all living cells. It ionizes to give a hydrogen ion and anion, termed pyruvate. Pyruvic acid can be made from glucose through glycolysis. It can also be used to construct the amino acid alanine and can be converted into ethanol or lactic acid via fermentation.

4. Distinguish between the following in tabulated form:
(i) Respiration and photosynthesis
(ii) Light reaction and Dark reaction
(iii) Aerobic respiration and anaerobic respiration
(i) Difference Between Photosynthesis & Respiration

S.No.	Photosynthesis	Respiration
1.	Photosynthesis is the process where light energy converted in chemical energy.	Respiration is the process where chemical energy converted into energy of ATP.
2.	It occurs only in chlorophyll containing organisms.  OR  It takes place in green part i.e. chlorophyll of the cells of plants only.	It occurs in all organisms. OR  It takes place in all living cells of plants and animals.
3.	It requires light sources i.e occur only in the presence of light. (i.e. during day time only)	It does not requires light source so occurs throughout the life. (i.e. during day and night like.)
4.	It occurs in chloroplast.	It occurs in mitochondria.
5.	The reactants are Carbon dioxide and water.	Reactants are carbohydrates and oxygen usually.
6.	The end products are glucose (simple carbohydrate) and oxygen.	The end products are carbon dioxide and water in the case of aerobic respiration
7.	It is an anabolic process i.e. compounds are formed.	It is a catabolic process i.e. compounds are broken down.
8.	Energy is used in this process and it is stored in the form of food material.	In respiration energy is released from food materials.
9.	During this process carbon dioxide enters in the plant body and oxygen is given out.	During this process oxygen is entered in the body and carbon dioxide releases.
10.	The chemical equation for this process is: 6CO2 + 6H2O → C6H12O6 + 6O2	The chemical equation for this process is: C6H12O6 + 6O2 → 6CO2 + 6H2O + Energy
11.	During the breakdown of one glucose, 38 ATP molecules are formed.	During the formation of one glucose, 18 ATP molecules are utilized.

OR

Difference Between Light Reaction And Dark Reaction

S.No.	Light Reaction	Dark Reaction
1.	It take place only in the presences of light	It takes place only in presence or absence of sunlight.
2.	It is a photo-chemical phase.	It is a biochemical phase.
3.	It takes place in the grana of the chloroplast	It takes place in the stroma of the chloroplast.
4.	NADP utilizes H+ ions to form NADPH.	The hydrogen of NADPH combines with CO2.
5.	The end products are ATP and NADPH2.	Glucose is the end product. ATP and NADPH2 help in the formation of glucose.
6.	The water molecules split into hydrogen and oxygen.	Glucose is produce. CO2 is utilized in the dark reaction.
7.	Photolysis occurs.	Photolysis does not occur.

Difference Between Aerobic Respiration And Anaerobic Respiration

S.No.	Aerobic Respiration	Anaerobic Respiration
1.	It is that type of respiration in which oxygen is necessary.	It takes place in the absence of oxygen.
2.	It oxidizes the food completely.	It oxidizes the food partially.
3.	During this process large amount of energy is released i.e. 2827 KJ.	In this process, small amount of energy is released i.e. 210 KJ (in bacteria 8 fungi) and 150 KJ (in animals).
4.	Carbon dioxide and water are the end products of this process.	The end products are lactic acid (in animals), Ethanol and carbon dioxide (in bacteria and fungi).

OR

5. Write short answers of following questions:
(i) How CO₂ maintain the temperature of earth?
Ans: CO₂ has a property to absorb heat of sun. If its quantity increases in the environment, there will be increase in an environmental temperature on earth called Global warning. Photosynthesis keeps the quantity of CO₂ maintained in environment i.e. indirectly keeping the concentration of CO₂ to maintain the temperature of earth.

OR

Carbon dioxide controls temperature because it has a property to absorb infra red radiation of the sun. When the carbon dioxide concentration goes up, temperature goes up. When the carbon dioxide concentration goes down, temperature goes down.

(ii) Why second phase of photosynthesis is called dark reaction?
Ans: The second phase of photosynthesis or Calvin cycle is also called the dark reactions or light-independent reactions because it's the part that doesn't need energy from the sun to happen. This cycle uses ATP and NADPH₂ synthesized in the light-dependent reactions to drive its reactions forward.

OR

The second phase in photosynthesis is called dark reaction because it does not require light energy. Instead, dark reaction uses ATP and NADPH₂ which is prepared in light reaction, to produce energy molecules. No photosystem is required. Photolysis of water does not occur.

(iii) How respiration is different from breathing?
Ans: Breathing is the biophysical and voluntary process of inhaling the oxygen and exhaling the carbon dioxide by the lungs, while respiration is the biochemical process performed by each cell by using oxygen and glucose to produce energy in the form of ATP and used by the other organelles to carry various imperative cellular work.
Breathing occurs outside the cells through respiratory organs like the nose, lungs and so it is an extracellular process, but respiration is an intracellular process as it takes place inside the cells especially in cell organelles like mitochondria, etc.

OR

Ans: Respiration is the chemical reaction takes place in cells to release energy from food while the breathing is movement of air in and out of the organism to supply O₂ and CO₂. We use another term for breathing called Ventilation. Breathing allows the process of gaseous exchange at surface of cells and tissues. So the terms breathing, gaseous exchange and respiration are different from one another but linked together to make possible energy production at cellular level.

OR

DIFFERENCE BETWEEN BREATHING AND RESPIRATION OR CELLULAR RESPIRATION:

S.No	Breathing	Cellular Respiration
1.	Breathing is a physical process in which O2 is taken in CO2 is given out.	Respiration is a biochemical process in which food is oxidized into CO2 and H2O.
2.	It occurs outside the cells through respiratory organs like nose, lungs and so on.	It occurs inside the cells, especially in cell organelles i.e. mitochondria.
3.	There is gradual and step wise release of energy.	There is no release of energy.
4.	Enzymes are not involved.	Enzymes are involved.
5.	Oxygen is necessary in this process	Oxygen is not necessary in anaerobic respiration.

(iv) Why acidic fermentation is harmful?
Ans: Ans: Acidic fermentation is harmful because the lactic acid which accumulates in human may cause fatigue and pain during anaerobic respiration.

OR

Acidic fermentation is harmful as it powers the athlete's muscles during start time of sprint. As a result the person experiences pain, this condition of pain is called Muscle fatigue. The lactic acid is produced in muscles and blood stream.

(v) How glucose form secondary products in plants?
Ans: Glucose utilizes in most of the metabolism of plant to produce secondary products like starch and other polysaccharides. Plants also use carbohydrates to form fats, proteins and other chemical like Nucleic Acids. This glucose is also used in respiration as reactant to produce energy for the metabolism of living organisms.

6. Write detailed answers of the following questions:
(i) What is energy currency of cell? Describe chemical process of energy transmission.
Ans: Energy Currency in living organism:
The major energy currency of all cells of living organism is a nucleotide called adenosine triphosphate (ATP) because it acts as the main energy source for majority of the cellular functions.

Formation Of Adenosine Tri-Phosphate (ATP):
As all living organisms have system to store energy. This energy is stored in a special molecule called Adenosine Tri-Phosphate (ATP). In organisms, energy is liberated during any oxidation reaction; this energy is utilized by molecules called Adenosine Di-Phosphate (ADP) to form a bond with phosphate (P). As a result the ADP become ATP, energy of oxidation is now stored in ATP.

Use Of Energy Stored In ATP:
The amount of energy stored is 7.3 Kcal / mole, this stored energy in ATP will be utilized by living organism for performing any type of work e.g. transport of molecules against the concentration gradient. The energy is now become free (liberated) by breaking ATP molecule.

ATP → ADP + P + Energy (7.3 K Cal / mole)

So the formation of ATP is endergonic (energy intake) process and breakdown of ATP is exergonic (energy liberating) process.

CHEMICAL PROCESS OF ENERGY TRANSMISSION:
In living organisms the energy is transferred through gain or loss of electrons during formation and breaking of chemical bonds. There are two chemical processes where it occurs, known with the name of oxidation and reduction.

The Oxidation Reactions:
are those reactions in which loss of electron (e^-) and proton (H⁺) occurs. These electrons carry energy from the molecules from where they release to the molecules where they added. e.g.
Iron reacts with oxygen to form a chemical called rust, in this reaction iron (Fe) loses some e- which transfer to oxygen. In this reaction Fe is oxidized and it transfers its energy to oxygen through electrons.

The Reduction Reactions:
are those reaction in which gain of e^- and H⁺ occur. This gain of e^- also brings energy which is stored in it.

Redox Reaction:
In living organisms these oxidation - reduction (Redox) reactions occur continuously to transfer energy from one molecule to other molecule, without these reactions energy transfer becomes impossible in living system.

(ii) Describe phases of photosynthesis with suitable diagram.
Ans: >PHASES OF PHOTOSYNTHESIS:
Processes of Photosynthesis involves number of chemical reactions which are catalyzed by number of enzymes, either in non cyclic or cyclic ways. Each reaction occurs at different site in chloroplast. It is mainly divided into phases or reactions.

1. Light Reaction or Light Dependent reaction
2. Dark Reaction or Light Independent reaction

1. Light Reaction or Light Dependent Reaction:
Definition:
Reaction in which light energy converted into chemical energy and stored in ATP (Adenosine Triphosphate) and NADPH₂ (reduced Nicotine amide Adenosine Dinucleotide Phosphate). This conversion occurs at thylakoid membrane where solar energy is captured by pigments located in harvesting complex. This phase of photosynthesis is called Light Dependent reaction Or Light Reaction.
It is non Cyclic process coupled with breakdown of H₂O molecules i.e. photolysis, takes place also at thylakoid membrane.
Explanation:
The term light reaction or light dependent reaction is used due to the reason that during this phase of photosynthesis light energy is captured and converted into chemical energy.
Photolysis:
Some of the light is utilized to split water into oxygen and H with e^- (electrons), this splitting of water is called Photolysis. Oxygen which is produced during photolysis is released in the environment where as H⁺ together with CO₂ are used in building Glucose.
Photosystem I & II:
In chloroplast, different pigments absorb light of different wave lengths. Among them chlorophyll is the main light capturing molecules in thylakoid membrane which absorbs violet, blue and red light but reflects green therefore it appears green. In the thylakoid membrane other pigments and electron carrier molecules form highly organized assemblies in a series called photosystems. Each thylakoid contains thousands of copies of two different kind of photosystems called photosystems I and II. Each consists of two major parts:

• A light harvesting complex and
• An electron transport system.

The conversion of light energy takes places when the chlorophyll of reaction center receives energy. One of the electrons from chlorophyll “a” molecule leaves and jump over the electron transport system. This energized electron moves from one carrier to next. The electron releases energy, when it comes down, this energy drives reactions and produces two energy rich compounds. These are:

1. ATP (Adenosine Triphosphate)
2. NADPH₂ (Reduced Nicotinamide Adenosine Dinucleotide Phosphate)

Phosphorylation:
ADP is the compound which is already present in cell. It combines with phosphate by using energy of photon released from when moving through e- carriers in photosynthesis. The formation of ATP from ADP by using light energy called phosphorylation

Reduction Of NADP:
NADP also present in chloroplast is reduced into NADPH₂ by accepting Hydrogen ions (H⁺, released from splitting of water.

ATP and NADPH₂ formed, both are energy rich compounds which are utilized in dark reaction.

2. Dark Reaction or Light Independent reaction:
Definition:
Reaction in which captured solar energy transferred to glucose from ATP and NADPH₂. It takes place in stroma, in cyclic manner. This phase of photosynthesis is called Light Independent reaction Or Dark Reaction.
During this phase fixation of atmospheric CO₂ also takes place to form organic molecules.

Explanation:
This phase of photosynthesis does not require energy of photon but it also takes place in day simultaneously with the light reaction.
Calvin-Benson Cycle:
The ATP and NADPH₂ synthesized during the light dependent reaction are dissolved in stroma where, they provide energy to power the synthesis of Glucose from CO₂ and H₂O (i.e. H⁺ and e^- of water).
This Phase occurs independently, without light as long as ATP and NADPH₂ are available. This phase of photosynthesis is cyclic phase. This phase occurs in set of reactions also called Calvin – Benson Cycle due to it's discoverer or the C₃ (three Carbon Containing Compounds formed initially) Cycle.
The C₃ Cycle requires:

1. CO₂ - normally from air some of it also comes from respiration.
2. CO₂ Capturing Sugar - a Pentose Sugar.
3. Enzymes to catalyze all the reactions.
4. Energy from ATP and NADPH₂ come from light dependent reaction.

(iii) Describe aerobic respiration in living system.
Ans: (ii) AEROBIC RESPIRATION:
Definition:
Type of respiration where food breakdown occurs in the presence of oxygen to produce energy, is called aerobic respiration.
It takes place in the presence of free oxygen, oxidizing the food and releasing the maximum amount of energy i.e. 2827 kj / mole of glucose or 36 ATP molecules/glucose.
Example:
It is a method of respiration found in majority of organisms.
Equation:
The end products of aerobic respiration are CO₂ and H₂O.

Glucose + oxygen → Carbon dioxide + water + Energy (36 ATP)
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 36 ATP

MECHANISM OF AEROBIC RESPIRATION:
Aerobic Respiration takes place in 3 steps at different places in the cell.

• Glycolysis
• Kreb's or Citric acid Cycle
• Electron Transport Chain

(a) Glycolysis (Gr. Glyco = Sugar, Lysis = Break down):
First stage is that stage where a molecule of glucose (Six carbon sugar) is broken down into two molecules of pyruvic acid (three carbon acid). It does not require oxygen. It takes place in both aerobic and anaerobic respiration. This splitting of glucose releases small amount of energy of glucose which is enough to generate 2 molecules of ATP. Glycolysis is a complex sequence of reaction all occur in cytosol.

(b) Kreb's or Citric acid Cycle:
The second stage of aerobic respiration in which pyruvic acid produced during glycolysis enters the mitochondria where O₂ available. Cellular respiration uses this O₂ to break pyruvic acid completely into CO₂ and H₂O in a cyclic manner. During Kreb's Cycle some ATP produce and some coenzymes like NAD and FAD are reduced to NADH₂ and FADH₂ . It takes place in matrix of mitochondria.

(c) Electron Transport Chain:
The last stage of aerobic respiration in which NADH₂ (Nicotinamide Adenosine Di-nucleotide) and FADH₂ (Flavinamide Adenosine Di- nucleotide) are oxidized to produce ATP and H₂O. It takes place at the cristae of mitochondria.

Importance Of Anaerobic Respiration:

1. Anaerobic respiration is the emergency arrangement of energy which has an advantage that organisms can survive without O₂ or can work with same pace for short period.
2. The other products of anaerobic respiration are acids. Vinegars are also organic acids that are produced commercially by acidic formulations.
3. Anaerobic respiration also produces ethyl alcohol. This process is commercially utilized by making alcoholic products like beer, wines and other beverages.
4. Baking industry is also based on it because anaerobic respiration also produces CO₂ which gives fluffy and soft shapes to cakes and breads also break down of starch into complex sugar to form bread and pizza.

MORE SHORT QUESTIONS:

Q.1: What is an ADP? How is it formed?
Ans: ADP: ADP is an abbreviation of Adenosine diphosphate. Each ADP compound consists of: Adenine, ribose and two phosphate groups. Formation: When the terminal bond is broken the ATP is converted into ADP by enzyme ATP ase releasing a phosphate and liberating 30.6 Kj (7.3 Kcal) of energy. An ADP is like a discharged battery. When the energy is made available by oxidation of food. ADP takes this energy to be converted to ATP that is to say that it becomes charged once again.

Q.2 How anaerobic respiration help to power athelete's muscles and what is muscle fatigue?
Ans: In animals when aerobic respiration is not enough to produced required energy they start anaerobic respiration. During this process glucose breaks down into a substance called lactic acid.

Glucose → Lactic acid + Some energy

C₆H₁₂O₆ → 2C₃H₆O₃

A limited amount of energy is produced as compared to aerobic respiration but this is enough to power the athlete's muscles during start time of sprint. He experiences pain, this condition of pain is called Muscle fatigue. The lactic acid is produced in his muscles and blood stream.

Source: Special Thanks To Sir Syed Arif Ali

Biology For Class IX - Chapter No.7 - BIOENERGETICS - MCQs and Fill In the Blanks

GO TO INDEX
CHAPTER 7
BIOENERGETICS

By Mrs. Ayesha Arif
(Jauhar Progressive School)

1. Encircle the correct answer:
i) In an oxidation process 14135 KJ energy is release, how many moles of glucose consume during this process.
(a) 1
(b) 3
(c) 5 ✔
(d) 10

(ii) Stage of aerobic respiration takes place at the cristae of mitochondria called:
(a) Electron transport chain ✔
(b) Glycolysis
(c) Kreb's cycle
(d) C3 cycle

(iii) In a process of cellular respiration 180 ATP molecules are produced, how many moles of glucose consume during this process.
(a) 2
(b) 5 ✔
(c) 8
(d) 10

(iv) Loss of electron and proton is called:
(I) Oxidation reaction
(II) Reduction reaction
(III) Redox reaction
(a) I only ✔
(b) I and II
(c) II and III
(d) I, II and III

(v) Each mole of ATP store energy:
(a) 7.3 kcal/mole ✔
(b) 7.3 kj/mole
(c) 17.3 kcal/mole
(d) 17.3kj/mole

(vi) Fundamental molecule produced during photosynthesis is:
(a) Glucose ✔
(b) Amino acid
(c) Fatty acid
(d) Nucleotide

(vii) Light dependent reaction takes place in:
(a) Stroma
(b) Thylakoid ✔
(c) Cristae
(d) Cisternae

(viii) Reaction in which solar energy is transferred to glucose from ATP and NADPH₂ , takes place in stroma called:
(I) Light reaction
(II) Dark reaction (III) Light dependent reaction
(a) I only
(b) II only ✔
(c) I and II
(d) II and III

(ix) Splitting of water in presence of light called:
(a) Hydrolysis
(b) Glycolysis
(c) Photolysis ✔
(d) None of these

(x) Splitting of glucose (glycolysis) release small amount of energy which is enough to generate:
(a) 2 ATP ✔
(b) 5 ATP
(c) 18 ATP
(d) 36 ATP

2. Fill in the blanks:
(i) The only source of energy on earth is Sun.
(ii) Conversion of free energy into different forms by living organisms is called bioenergetics.
(iii) In living organisms energy is stored in a special molecule called ATP.
(iv) Plant utilizes simple inorganic molecules (CO₂ and H₂O) to prepare glucose and oxygen.
(v) Feeding sequences and relationships are called food chains.
(vi) Photosynthesis is the only process which produces free O₂ by splitting water.
(vii) Chloroplast is double membrane bounded organelle have semifluid protein containing membrane called stroma.
(viii) In chloroplast different pigments absorb light of different wavelength.
(ix) The breakdown of food molecules to release energy is called respiration.
(x) Each mole of glucose produce maximum energy i.e.2827 Kj.

Source: Special Thanks To Sir Syed Arif Ali

Geography Of Pakistan -II (For Foreigners only) - For Class X Or SSC - Part 2 (Science Group) - Model papers 2020 -2021- AS PER CONDENSED SYLLABUS

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Geography Of Pakistan -II (For Foreigners only)
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Physics (urdu)
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Q.07: A body starting from rest acquires a velocity of 10 m/s in 5 seconds. Calculate
a) the acceleration
b) the distance covered by the body in 5 seconds.
Solution:

Q.08) Calculate the length of second's pendulum. (g = 9.8 m/s².
Solution:

Q.09: The potential difference applied to the terminals of a portable radio is 9.0 volts. Find the resistance of the radio if a current of 25 mA is flowing through it.
Solution:

Q.10: How much work done to displace horizontally a body 400 cm by a force of 200 N, whose angle with the horizontal is 30°.
Solution:-
Data:-
W = ?
F = 200 N
S = 400 cm = ⁴⁰⁰ / ₁₀₀ = 4 m
θ = 30°

Formula:-
W = F. S cos θ

Calculation:-
W = (200) . (4) cos 30°
W = 800 cos 30°
W = 800 (0.86)

Result:- W = 688 Joules Ans.

Q.11: 0.5 Kg of copper needs 1905 J of hest to raise its temperature through 10°C. Calculate the heat Capacity of the sample.
Solution:

 Click Here For Physic Formulas For Numerical

Special thanks to Sir Sajjad Akber chandio

Physics (Theory And Practicals) - For Class SSC - Part 2 (Science Group) - Solved Model papers 2020 -2021- AS PER CONDENSED SYLLABUS

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Physics
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Solved Model papers 2020 -2021
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Solution Of Numerical

Q.07: A body starting from rest acquires a velocity of 10 m/s in 5 seconds. Calculate
a) the acceleration
b) the distance covered by the body in 5 seconds.
Solution:

Q.08) Calculate the length of second's pendulum. (g = 9.8 m/s².
Solution:

Q.09: The potential difference applied to the terminals of a portable radio is 9.0 volts. Find the resistance of the radio if a current of 25 mA is flowing through it.
Solution:

Q.10: How much work done to displace horizontally a body 400 cm by a force of 200 N, whose angle with the horizontal is 30°.
Solution:-
Data:-
W = ?
F = 200 N
S = 400 cm = ⁴⁰⁰ / ₁₀₀ = 4 m
θ = 30°

Formula:-
W = F. S cos θ

Calculation:-
W = (200) . (4) cos 30°
W = 800 cos 30°
W = 800 (0.86)

Result:- W = 688 Joules Ans.

Q.11: 0.5 Kg of copper needs 1905 J of hest to raise its temperature through 10°C. Calculate the heat Capacity of the sample.
Solution:

Click Here For Physics formulas For Numerical

Special thanks to Sir Sajjad Akber chandio

Braille (Theory And Practical) - For Class X Or SSC - Part 2 (Arts / General Group) - Model papers 2020 -2021- AS PER CONDENSED SYLLABUS

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Braille (Theory And Practical)
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Biology For Class IX - Chapter No.8 - NUTRITION - Review Questions From Text Book

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CHAPTER 8
NUTRITION
Review Questions From Text Book

1. Encircle the correct answer:
(i) Select the mismatched
(a) Protein → Amino acid
(b) Carbohydrate → Glucose
(c) Fats → Starch ✔
(d) Nucleic acid → Nucleotide

(ii) Deficiency of vitamin-k cause
(a) Rickets
(b) Anemia ✔
(c) Scurvy
(d) Beriberi

(iii) Period of rapid growth and development called:
(a) Childhood
(b) Adult hood
(c) Adolescence
(d) Both “a” and “c” ✔

(iv) Deficiency of dietary protein, causes an imbalance in the gastrointestinal system:
(a) Marasmus
(b) Edema
(c) Diarrhea
(d) Kwashiorkor ✔

(v) An animal that migrates great distances would obtain the greatest benefit from storing its energy as:
(a) Fats ✔
(b) Carbohydrates
(c) Protein
(d) Minerals

(vi) Which of the following vitamins is correctly associated with its use?
(a) Vitamin K → Production of white blood cells
(b) Vitamin C → Curing rickets
(c) Vitamin E → Protection of skin from cancer
(d) Vitamin A → Incorporated into the visual pigment of the eye ✔

(vii) Which of the following statements describes pepsin?
(a) It is manufactured by the pancreas.
b) It helps stabilize fat-water emulsions.
(c) It splits maltose into monosaccharides.
(d) It begins the hydrolysis of proteins in the stomach. ✔

(viii) Which of the following is true about bile salts?
(a) They are enzymes
(b) They are manufactured by the pancreas
(c) They emulsify fats in the duodenum ✔
(d) They increase the efficiency of pepsin action.

(ix) In human digestive system trachea and oesophagus both connect to the:
(a) Large intestine
(b) Stomach
(c) Pharynx ✔
(d) Rectum

(x) All are sources of calcium except:
(a) Red meat ✔
(b) Green leafy vegetables
(c) Broccoli
(d) Nuts

2. Fill in the blanks:
(i) Sea food is an excellent source of protein because it's usually low in fats.
(ii) Iron deficiency is associated with decreased cognitive abilities and resistance to diseases.
(iii) Wave of rhythmic movements of muscle contraction and relaxation called peristalsis.
(iv) Liquid secreted by the pancreas, which contains a variety of enzymes.
(v) Living organisms which derive their food from dead and decaying organic materials called saprotrophs or saprotrophic organisms.
(vi) Nutrients that are needed in the highest concentration called macronutrients.
(vii) Fertilizers are substances containing chemical elements such as manure or mixture of nitrates.
(viii) High solubility of fertilizers also degrades ecosystem through eutrophication.
(ix) Carbohydrates which digested quickly are called starch or simple carbohydrates.
(x) Each gram fat supplies the body with about 9 calories.

3. Define the following terms:
(i) Vitamins
(ii) Malnutrition
(iii) Goiter
(iv) Anemia
(v) Constipation
(vi) Obesity
(vii) Starvation
(viii) Ingestion
(ix) Chyme
(x) Ulcer
Ans: (i) VITAMINS:
A vitamin is an organic molecule (or related set of molecules), an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. They are for maintaining normal health and development. Lack of vitamins can cause several diseases.
They are divided into two types:
Fat Soluble Vitamins are vitaimns A, D, E and K)
Water Soluble Vitamins are vitamins B and C.
Source Of Vitamins:
Milk, Fruits and Vegetables.

(ii) MALNUTRITION:
Problems related to nutrition are grouped as malnutrition. The malnutrition is a condition that occurs when a body does not get enough nutrients. Malnutrition results from a poor diet or a lack of food. It happens when the intake of nutrients or energy is too high, too low, or poorly balanced. Consuming less than 2100 calories a day, one is considered to be under-nourished and suffering from hunger.
There are two types of malnutrition:

• Chronic malnutrition
• Acute malnutrition

OR

Malnutrition is a serious condition that happens when the diet does not contain the right amount of nutrients. It means "poor nutrition" and can refer to undernutrition – not getting enough nutrients.
There are two types of malnutrition

• Chronic malnutrition
• Acute malnutrition

(iii) GOITER:
Goiter is a condition in which thyroid gland becomes enlarged and it results in swelling in neck. Goiter is caused by an insufficient amount of “Iodine” in diet. Iodine is used by thyroid gland to produce hormones that control the body's normal functioning and growth.

OR

A goiter is an enlargement of the thyroid gland which results in the swelling of neck. Goiter is caused by an insufficient amount of “Iodine” in diet. Iodine is used by thyroid gland to produce hormones that control the body's normal functioning and growth.

(iv) ANEMIA:
The term anemia literally means “a lack of blood”. The condition is caused when number of red blood cells reduced to a level lower than normal. Haemoglobin molecule contains four atom of iron. If body fails to receive sufficient amount of iron, an adequate number of haemoglobin will not be formed. So, there are not enough functioning red blood cells. A person becomes weak and there is shortage of oxygen supply to body's cells.

OR

The term anemia literally means “a lack of blood”. Anemia is a condition in which the body lacks enough healthy red blood cells to carry adequate oxygen to the body's tissues. Having anemia can make one feel tired and weak. There are many forms of anemia, each with its own cause. Anemia can be temporary or long term, and it can range from mild to severe.

(v) CONSTIPATION:
Constipation is a condition, where a person experiences hard faeces that are difficult to eliminate. The main causes of constipation are hardening of faeces due to excessive absorption of water through colon, insufficient intake of dietary fibre, dehydration, use of medicine (e.g. those containing iron, calcium and aluminum) and tumors in rectum or anus.

(vi) OBESITY:
It is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. Obesity is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. Obesity is known as mother disease and may lead to heart problems, hypertension, diabetes etc.

OR

Obesity is defined as abnormal or excessive fat accumulation that presents a risk to health. Obesity is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. Obesity is known as mother disease and may lead to heart problems, hypertension, diabetes etc.

(vii) STARVATION:
It is a severe deficiency in caloric energy intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death.

(viii) INGESTION:
Food enters the digestive system through the mouth. This process is called ingestion. Once in the mouth, food is chewed to form a ball of food called a bolus. This passes down the oesophagus and into the stomach.

(ix) CHYME:
In stomach food is partially digested and further broken apart through a churning process. The churning action also produces heat which helps to melt the lipid contents of the food. By the time food is ready to leave the stomach, it has been processed into a thick paste like liquid called chyme.
The pylorus keeps chyme in the stomach until it reaches the right consistency to pass into the small intestine. Chyme is then squirted down into the small intestine, where digestion of food continues.

OR

Chyme, is a thick semifluid mass of partially digested food and digestive secretions that is formed in the stomach and intestine during digestion. In the stomach, gastric juice is formed by the gastric glands, these secretions include the enzyme pepsin, which breaks down proteins, and hydrochloric acid.
Food is further broken apart through a process called churning. The walls of stomach contract and relax and these movements help in mixing of the gastric juice and food. The churning action also produces heat which helps to melt the lipid contents of the food.

(x) ULCER:
It is a sore in gut lining and can be different organs such as; ulcer of stomach is called “gastric ulcer”, Ulcer of duodenum is called “duodenal ulcer”, ulcer of oesophagus is called “esophageal ulcer” and breakdown of tissues by acidic gastric juice. It can be due to the long term use of anti-inflammatory medicine (e.g. aspirin), smoking, drinking coffee, colas and eating spicy food.

OR

Ulcer is an open sore on an external or internal surface of the body, caused by a break in the skin or mucous membrane which fails to heal. Ulcers range from small, painful sores in the mouth to bedsores and serious lesions of the stomach or intestine. It can be due to the long term use of anti-inflammatory medicine (e.g. aspirin), smoking, drinking coffee, colas and eating spicy food.

4. Distinguish between the following in tabulated form.
(i) Fat-soluble vitamins and water soluble vitamins

-	Water soluble vitamins	Fat-soluble vitamins
Vitamins	B, C	A, D, E, K
Site of Absorption	Small intestines	Small intestines
Dietary Intake	Excess intake usually detected and excreted by the kidneys	Excess intake tends to be stored in fat-storage sites
Solubility	Hydrophilic	Hydrophobic
Capitalize	Easily absorbed the blood, travels freely in the bloodstream	Absorbed into the lymphatic system, many require protein carriers to travel in the blood
Body storage	Not generally	Yes
Deficiency	Deficiency symptoms appear relatively quickly	Deficiency symptoms are slow to develop
Toxicity	Low risk	Higher risk
Need for daily consumption	Yes	No

(ii) Marasmus and kwashiorkor

S.No	Kwashiorkor	Marasmus
1.	The deficiency of protein in the body of children upto three years leads to the kwashiorkor.	The deficiency of calories and other nutrition in the children of upto one year leads to Maramus
2.	It occurs due to deficiency of proteins.	It occurs due to deficiency of calories, proteins and other nutrients.
3.	Acute illness, trauma, infections, measles, Sepsis are some of the causes of the kwashiorkor.	Chronic infections, prolonged starvation, recurring infections are some of the significant causes of Marasmus.
4.	Muscles and limbs get thin.	Limbs get thin.
5.	Oedema (when an excess of watery fluid is accumulated in the tissues or cavity of the body) is present.	Oedema is absent.
6.	Subcutaneous fat (harmless fat present under the skin and protect against some pathogens and disease) is present.	Subcutaneous fat is absent
7.	Typical weight loss is observed.	There is severe weight loss
8.	Enlargement in fatty liver cells	No such enlargement is observed
9.	Appetite is prodigious.	Appetite is poor.
10.	Cracky skin appears	Wrinkled and dry skin appears
11.	No prominent ribs	Prominent ribs.
12.	High mortality	Low mortality, until the condition, is severe.

OR

-	Kwashiorkor	Marasmus
Causes	Deficiency of proteins.	Deficiency of both proteins and calories.
Age factor	Between the age of 6 months and 3 years of age.	Between the age of 6 months and 1 year of age.
Oedema	Present.	Absent.
Subcutaneous fat	Present.	Absent.
Weight loss	There is some weight loss.	There is severe weight loss.
Symptoms	The thinning of muscles and limbs.	The thinning of limbs.
Fatty liver cells	There is an enlargement in the fatty liver cells.	There is no enlargement in the fatty liver cells.
Appetite	Voracious feeder	Poor appetite.
The texture of the skin	Flaky paint appearance on the skin.	Dry and wrinkled skin.
Requirement of Nutrition	Adequate amounts of proteins.	Adequate amounts of proteins, carbohydrates and fats.

(iii) Chemical digestion and mechanical digestion

S.No	Mechanical digestion	Chemical digestion
1.	Mechanical digestion refers to the breakdown of food into digestible particles, mainly by teeth.	Chemical digestion refers to the process by which compounds with a high molecular weight in the food are broken down into small substances that can be absorbed by the body.
2.	It occurs from the mouth to the stomach.	It occurs from the mouth to the intestine
3.	A major part of mechanical digestion occurs in the mouth	A major part of chemical digestion occurs in the stomach.
4.	It is driven by teeth.	It is driven by enzymes
5.	It increases the surface area for the ‘enzymatic reactions in the chemical digestion	It enhances the absorption of the nutrients by breaking down them into small molecules.

OR

-	Chemical digestion	Mechanical digestion
Definition	It breaks down the food chemically into the form that can be used by the cells.	It breaks down food into small pieces physically.
Beginning	Begins in mouth when food mixes with saliva	Begins in mouth as food is chewed.
Occurrence	Mouth to the intestine	Mouth to stomach.
Materials involved	Enzymes,bile and acids etc	Teeth, tongue and muscles etc
Main activity	Hydrolysis by enzymes	Chewing and grinding.
Importance	Chemically digestion	Mechanical digestion
Facilitates	absorption of nutrients.	facilitates chemical digestion

(iv) Autotrophic nutrition and Heterotrophic nutrition

S.No	Autotrophic nutrition	Heterotrophic nutrition
1.	Autotrophic nutrition is a mode of nutrition in which an organism prepares its own food with the help of simple inorganic materials like water and carbon dioxide from the surrounding.	Heterotrophic nutrition is a mode of nutrition in which an organism cannot prepare its own food and depend upon other organisms for its food.
2.	For autotrophic nutrition, presence of chlorophyll (green pigment) and sunlight are necessary. Autotrophic nutrition takes place during day time.	No green pigment and sunlight is required for heterotrophic nutrition.
3.	All green plants synthesizing their own food through the biological process are referred to as photosynthesis are examples of autatrophs.	Animals including herbivores, omnivores and carnivores are examples of Heterotrophs.
4.	In the food chain, autotrophs are the primary producers.	Heterotrophs are consumers; they are place at secondary or tertiary level.
5.	Types of autotrophic mode of nutrition include: phototrophic and chemotrophic.	Types of heterotrophic mode of nutrition include: holozoic, saprophytic, parasitic and symbiotic association.
6.	Autotrophs are independent of any organisms.	Heterotrophs rely on other organisms for their food.
7.	Autotrophs are capable of storing sunlight and chemical energy.	Heterotrophs are not capable of storing energy.
8.	Heterotrophs can move from one place to another in search of food.	Autotrophs cannot move from one place to another.
9.	In autotrophs, the process of digestions is absent	Heterotrophs, the process of digestion is required to convert complex molecules into simpler molecules.

OR

BASIS OF COMPARISON	HETEROTROPHIC NUTRITION	AUTOTROPHIC NUTRITION
Description	Autotrophic nutrition is a mode of nutrition in which an organism prepares its own food with the help of simple inorganic materials like water and carbon dioxide from the surrounding.	Heterotrophic nutrition is a mode of nutrition in which an organism cannot prepare its own food and depend upon other organisms for its food.
Requirement	For autotrophic nutrition, presence of chlorophyll (green pigment) and sunlight are necessary. Autotrophic nutrition takes place during day time.	No green pigment and sunlight is required for heterotrophic nutrition.
Examples	All green plants synthesizing their own food through the biological process are referred to as photosynthesis are examples of autotrophs.	Animals including herbivores, omnivores and carnivores are examples of heterotrophs.
In food Chain	Autotrophs are the primary producers.	Heterotrophs are consumers; they are place at secondary or tertiary level.
Mode of nutrition	Include: phototrophic and chemotrophic.	Include: holozoic, saprophytic, parasitic and symbiotic association.
Dependency	Autotrophs are independent of any organisms.	Heterotrophs rely on other organisms for their food.
Storage of Energy	Autotrophs are capable of storing sunlight and chemical energy.	Heterotrophs are not capable of storing energy.
Movement	Heterotrophs can move from one place to another in search of food.	Autotrophs cannot move from one place to another.
Digestion	In autotrophs, the process of digestion is absent.	In Heterotrophs, the process of digestion is required to convert complex molecules into simpler molecules.

(v) Inorganic fertilizers and organic fertilizers
(Note: Inorganic fertilizers are also called Chemical fertilizers and Organic fertilizers are also called natural fertilizers)

S.No	Inorganic Fertilizers	Organic Fertilizers
1.	Inorganic fertilizers are rich equally in three essential nutrients that are needed for crops and always ready for immediate supply of nutrients to plants if situation demands.	Adds natural nutrients to soil increases soil organic matter, improves soil structure and tilth, improves water holding capacity, reduces soil crusting problems, reduces erosion from wind and water, Slow and consistent release of nutrients.
2.	Several Inorganic fertilizers have high acid content. They have the ability to burn the skin. Changes soil fertility.	Have slow release capability; distribution of nutrients in organic fertilizers is not equal.
3.	Immediate supply or fast release	Slow release
4.	Inorganic fertilizers are manufactured from synthetic material.	Organic fertilizers are made from materials derived from living things
5.	Artificially prepared	Prepared naturally
6.	Inorganic fertilizer has an equal distribution of three essential nutrients: phosphorous, itrogen, potassium.	Have unequal distribution of essential nutrients.

OR

Basis of Comparison	organic fertilizers	Inorganic fertilizers
Source	Living	Non-living
Type	Natural	Synthetic
Release speed	Slow	Fast
Absorption	Varies depending on the source of the fertilizer	Maximum
Use	Small or medium lands	Big lands
Source materials	Manure, leaves, sticks, fruits, bone, flour, flowers	Rocks, sand, petroleum, air, natural gas, methane

5. Write short answers of following questions.
(i) Why fertilizers are necessary for plant?
Ans: Fertilizers Are Necessary For Plants:

• Fertilizers are substances containing chemical elements such as manure of mixture of nitrates that improves the growth of plants.
• They give nutrition to the crops and produce more fruit, faster growth, more attractive flowers.
• When added to soil or water, plants can develop tolerance against pests like weeds, insects and diseases.
• The use of manure and composts as fertilizers is probably almost as old as agriculture.
• Modern chemical fertilizers include one or more of the three elements that are most important in plant nutrition: nitrogen, phosphorus, and potassium.
• Chemicals fertilizers are simply that nutrients applied to agricultural fields to supplement required elements found naturally in the soil.

OR

Ans: Fertilizers are important for plants because:

• They contain chemical elements mixture of nitrates that improves the growth of plants.
• They give nutrition to the crops and produce more fruits and more attractive flowers.
• When fertilizers are added to soil or water, plants can develop tolerance against pests like weeds, insects and diseases.
• Modern chemical fertilizers include one or more of the three elements, nitrogen, phosphorus, and potassium that are most important in plant nutrition.
• Chemicals fertilizers act as nutrients to plants.

(ii) How stomach linings are protected from acidic environment?
Ans: Our stomach protects itself from being digested by its own enzymes, or burnt by the corrosive hydrochloric acd, by secreting sticky, neutralising mucus that clings to the stomach walls. If this layer becomes damaged in any way it can result in painful and unpleasant stomach ulcers.
The stomach is protected by the epithelial cells, which produce and secrete a bicarbonate rich solution that coats the mucosa. Bicarbonate i alkaline, a base, and neutralizes the acid secreted by the parietal cells, producing water in the process. This continuous supply of bicarbonate is the main way that your stomach protects itself from auto-digestion (the stomach digesting itself) and the overall acidic environment.

OR

Ans: The stomach protects itself from being digested by its own enzymes, or burnt by the corrosive hydrochloric acid, by secreting a sticky, neutralizing mucus that clings to the stomach walls. If this layer becomes damaged in any way it can result in painful and unpleasant stomach ulcers.

(iii) Why nitrogen is essential for plants?
Ans: Ans: Nitrogen is essential for plants to synthesize amino acids, which are the building blocks for protein synthesis and also required for the production of chlorophyll, nucleic acids, and enzymes. For all metabolic elements which plants use from soil, nitrogen needs in the largest amounts.

(iv) Why fats are called most efficient form of food?
Ans: Fats are the slowest source of energy but the most energy-efficient form of food. Each gram of fat supplies the body with about 9 calories, more than twice that supplied by proteins or carbohydrates. Because fats are such an efficient form of energy, the body stores any excess energy as fat. The body deposits excess fat in the abdomen (omental fat) and under the skin (subcutaneous fat) to use when it needs more energy.

(v) Why grinding and lubrication are necessary for swallowing?
Ans: Grinding of food: The second function of oral cavity is the grinding of food by teeth. It is known as chewing or mastication. It is useful because oesophagus can pass only small pieces through it as well as enzymes cannot act on large pieces of food.

Lubrication of food: The third function of the oral cavity is lubrication of food by mixing saliva secreted by saliva. It has two main functions.

• Adds water and mucus to the food.
• Partial digestion of starch by saliva which contains an enzyme salivary amylase.

Than the pieces of food are rolled up by the tongue into small, slippery, spherical mass called bolus.
As chewing continue the food is made softer and warmer, and the enzymes in saliva begin to break down carbohydrates in the food. After chewing, the food (now called a bolus) is swallowed easily.

6. Write detailed answers of the following questions.
(i) Describe environmental hazards related to chemical fertilizers.
Ans: Environmental Hazards Related To Chemical Fertilizers:
An environmental hazard is a condition, which has the potential to threat natural environment or adversely affect people's health, including pollution and natural disasters. The farmers apply fertilizer for better growth of their crops, but on the other side these fertilizers pollute water and soil as well.

1. Soil nutrient holding capacity:
   The massive quantities of inorganic fertilizers affect the soil nutrient holding capacity.
2. Eutrophication:
   The high solubility of fertilizers also degrade ecosystem through eutrophication (means an increase in chemical nutrients typically compounds containing nitrogen or phosphorus in an ecosystem).
3. Emission of greenhouse gas:
   Storage and application of some nitrogen fertilizers may cause emission of greenhouse gas, e.g nitrous oxide.
4. Soil acidity:
   Ammonia gas (NH₃) may be emitted from applied inorganic fertilizers. This extra ammonia can also increase soil acidity.
5. Pest problems:
   Excessive nitrogen fertilizers can lead to pest problem by increasing their reproduction rate.
6. Nutrient balance:
   It is recommended that nutrient content of the soil and nutrient requirement of crop should be carefully balanced with application of inorganic fertilizers. It is critical to apply no more than it is needed; any excess in nutrient will definitely develop pollution of any kind.

(ii) Describe function of stomach and intestine with suitable diagram of human digestive system.
Ans: Function Of Stomach:

• Break Food into small pieces: The stomach muscles churn and mix the food with acids and enzymes, breaking it into much smaller, digestible pieces. An acidic environment is needed for the digestion that takes place in the stomach.
• Gastric Juice: Glands in the stomach lining produce about 3 quarts (2.8 liters) of these digestive juices each day. When food enters into the stomach the gastric juice is secreted by gastric glands found in the stomach wall. It is composed of:
  * Mucous,
  * Hydrochloric acid and
  * Protein digesting enzyme pepsinogen.
  Hydrochloric acid converts the inactive enzyme pepsinogen into active form called pepsin. HCl also kills micro-organisms present in food.
• Mucous Protection: Stomach is protected against the action of acid by mucus.
• Enzyme Pepsinogen (Pepsin): Pepsin partially digests the protein portion of the food into polypeptides and shorter peptide chains.
• Churning Of Food: In stomach food is further broken apart through a process called churning. The walls of stomach contract and relax and these movements help in mixing of the gastric juice and food. The churning action also produces heat which helps to melt the lipid contents of the food.
• Chyme: By the time food is ready to leave the stomach, it has been processed into a thick paste like liquid called chyme. The pylorus keeps chyme in the stomach until it reaches the right consistency to pass into the small intestine. Chyme is then squirted down into the small intestine, where digestion of food continues.

Function Of Intestines:
Function Of Small Intestine:
The small intestine is made up of three parts: Duodenum, Jejonum And Ileum

Duodenum:
It is the first part of small intestine which is about 25 cm (10 inches) long. It is C-shaped part of small intestine.
Function Of Duodenum:
The duodenum receives chyme from the stomach and it is a part of alimentary canal where most of the digestive process occurs. Ducts that enter into the duodenum deliver pancreatic juice and bile from the pancreas and liver, respectively.

• Bile salts have detergent action on particles of dietary fat which causes fat globules to break down or be emulsified into minute, microscopic droplets.
• Pancreatic juice is a liquid secreted by the pancreas, which contains a variety of enzymes, including:
  * Protease like trypsinogen: Coverts proteins (polypeptides) into amino acid.
  * Pancreatic lipase: Converts fats into fatty acid and glycerol.
  * Amylase: Converts carbohydrates into glucose (simple sugar).
• Intestinal juices produced from the small intestine contain enzymes and pancreatic juice break down all four groups of molecules found in food (polysaccharides, proteins, fats, and nucleic acids) into their component molecules.

Function Of Jejonum:
It is coiled shaped mid section of small intestine.

Ileum:
It is the final section of small intestine which leads into the large intestine.
Function Of Ileum (Absorption):
The inner wall of the small intestine is covered with millions of microscopic, finger-like projections called villi (singular, villus). Each villus is connected and richly supplied with blood capillaries and lymphatic vessels, i.e lacteal. The villi are the vehicles through which nutrients can be absorbed into the body. They increase the surface area over which absorption and digestion occur. These specialized cells help absorbed materials (simple sugars, amino acids and nucleosides) cross the intestinal lining into the bloodstream.
From the small intestine,the undigested food travels to the large intestine through a muscular ring, that prevents food from returning to the small intestine.

Large Intestine:
The large intestine is made up of three parts:

1. Caecum
2. Colon
3. Rectum

Function Of Large Intestine: The large intestine's main function is to remove water from the undigested matter and form solid waste that can be egested.
1. The Caecum:
is a pouch at the beginning of the large intestine that joins the small intestine to the large intestine. This transition area expands in diameter, allowing food to travel from the small intestine to the large. The appendix, a small, hollow, finger-like pouch, hangs at the end of the caecum. It is no longer appears to be useful to the digestive process.

2. The Colon:
extends from the caecum up the right side of the abdomen, across the upper abdomen, and then down the left side of the abdomen, finally connecting to the rectum. The colon has three parts, the ascending colon, transverse colon and descending colon.
Function: The ascending colon and transverse colon absorb fluids and salts, and the descending colon holds the resulting waste (faeces). Faeces mainly consist of undigested material, large number of bacteria, sloughed off gastrointestinal cells, bile pigments and water. Bacteria in the colon help to digest the remaining food products.

3. Rectum:
is the last part of large intestine. It opens to the outside by anus.
The rectum is where faeces are stored until they leave the digestive system through the anus as a bowel movement.

Human Digestive System

(iii) What are vitamins? Describe types of vitamins
Ans: VITAMINS:
A vitamin is an organic molecule (or related set of molecules), an essential micronutrient that an organism needs in small quantities for the proper functioning of its metabolism. They are for maintaining normal health and development. Lack of vitamins can cause several diseases.
Source Of Vitamins:
Milk, Fruits and Vegetables.

TYPES OF VITAMINS:
They are divided into two types:

1. Fat Soluble Vitamins:
   Vitamin which can soluble in organic solvent are called Fat-soluble vitamins (A, D, E and K) are less excreted from the body as compared to water-soluble vitamins.
2. Water Soluble Vitamins:
   Vitamin which are soluble in H₂O. These are vitamins B and C. Cooking or heating destroys the water soluble vitamins more readily than the fat-soluble vitamins.

Functions, chemical names and deficiencies of important vitamins

Vitamin generic name	Deficiency diseases
Vitamin K	Bleeding disorder
Vitamin D	Rickets and osteomalacia
Vitamin C	Scurvey
Vitamin B	Beriberi
Vitamin A	Night blindness, eye-infection, rough skin, respiratory infections

(iv) Describe mineral deficiency diseases in human.
Ans: Mineral Deficiency Disease:
Diseases resulting from deficiency of a mineral are relatively rare among humans some are given below:
1. Goiter:
Symptoms: Goiter is a condition in which thyroid gland becomes enlarged and it results in swelling in neck.
Cause: Goiter is caused by an insufficient amount of “Iodine” in diet. Iodine is used by thyroid gland to produce hormones that control the body's normal functioning and growth.

2. Anemia (most common of all mineral deficiency diseases):
The term anemia literally means “a lack of blood”.
Cause: The condition is caused when number of red blood cells reduced to a level lower than normal. Haemoglobin molecule contains four atom of iron. If body fails to receive sufficient amount of iron, an adequate number of haemoglobin will not be formed. So, there are not enough functioning red blood cells.
Symptoms: A person becomes weak and there is shortage of oxygen supply to body's cells.

(v) Describe effects of malnutrition on human.
Ans: The Effects Of Malnutrition:
Malnutrition hurts people both mentally and physically. The more malnourished a person is; the more nutrients the person is missing, the more likely person will experience health issues. Some of them are given below:
1. Starvation:
It is a severe deficiency in caloric energy intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death.

2. Heart Diseases:
The term "heart disease" is often used interchangeably with the term "cardiovascular disease." Cardiovascular disease generally refers to conditions that involve narrowed or blocked blood vessels that can lead to a heart attack, chest pain (angina) or stroke. Heart problems occur in those people who take unbalanced diet. Fatty foods increase blood cholesterol level. It obstructs the blood vessels leading to heart diseases.

3. Constipation:
People do not schedule their meals. This irregularity cause many health problems like constipation. It can be well defined, a condition in which there is difficulty in emptying the bowels, usually associated with hardened faeces.

4. Obesity:
It is a medical condition in which excess body fat has accumulated to the extent that it may have a negative effect on health. Obesity is most commonly caused by a combination of excessive food intake, lack of physical activity, and genetic susceptibility. Obesity is known as mother disease and may lead to heart problems, hypertension, diabetes etc.

More Short Questions Answers

1. Differentiate between:
(a) Carnivores and Herbivores
(b) Digestion in stomach and Digestion in intestine
Ans: (a) Difference Between Carnivores and Herbivores

S.No	Carnivores	Herbivores
1.	Those animals which feed upon other animals are called carnivores.	Those animals which use plants for their food are called herbivores.
2.	They have sharp, long strong and pointed canine teeth.	They do not have strong, and pointed canines.
3.	Cat, dog, lion are carnivores.	Horse, Deer and cattle are herbivores.

(b) Difference Between Digestion in stomach and Digestion in intestine

S.No	Digestion In Stomach	Digestion In Intestine
1.	Gastric glands are present in stomach.	Intestinal glands are present in small intestine.
2.	Gastric glands secrete gastric juice.	Intestinal glands secrete intestinal juice.
3.	Food becomes acidic due to the presence of HCl in stomach.	Food is neutralized due to bile and pancreatic juices.
4.	Food is partially digest in stomach.	Food is completely digest in intestine.
5.	No absorption or egestion process occur	Absorption process occur in small intestine and egestion process occur in large intestine.