Biology (English) - Theory And Practical - For Class SSC - Part 1 (Science Group) - Solved Model papers 2020 -2021- AS PER CONDENSED SYLLABUS

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Biology (English)
For Class SSC - Part 1 (Science Groups)
Solved Model papers 2021
As Per condensed Syllabus

Special Thanks To Sir Waseem Ahmed Qureshi
(BS Zoology UOK)
# 0315 - 0226373

Answer of  MCQs No.1: Paleontology

SECTION "B" (SHORT ANSWER QUESTIONS)  (18)

Note: Answer any Six 06 Questions from this section. Each carries 03 marks.
Q. 2 Write three differences between Prokaryotic cell and Eukaryotic cell.

S.NO.	PROKARYOTIC CELL	EUKARYOTIC CELL
1.	Prokaryotic cells do not have a well-defined nucleus.	Eukaryotic cells have a - well- defined nucleus.
2.	Nuclear membrane is absent.	Nuclear membrane is present.
3.	They do not have membrane bound structures.	They have membrane bound structures.

Q. 3 Define Immunology, Exocytosis and Apoptosis?
Ans: Immunology:
Immunology is the study of the immune system includes all physical, chemical and biological reactions of the organism against the foreign substances.

Apoptosis or Self - Destruction (Autophagy):
"Program change which lead to sequence of physiological changes in cell by which cell commit suicide collectively called Apoptosis".

Exocytosis:
Exocytosis is a form of active transport and bulk transport in which a cell transports molecule out of the cell by secreting them through an energy-dependent process.

Q.4: Draw a labelled diagram of smooth muscles?

Smooth muscle

Q.5: Define any three types of chromosomes depending upon position of centromere.
Ans: The chromosomes are of different types, depending upon position of centromere.
These types are:
Metacentric: Chromosomes with equal arms.
Sub-meta centric: Chromosomes with unequal aims
Acrocentric or sub-telocentric: Rod like chromosomes with one arm very small and other very long. The centromere is subterminal.

Q. 6 Why meiosis is called reduction division? Name different stages of Prophase of meiosis.
Ans: The first division is called the reduction division — or meiosis I - because it reduce the number of chromosomes from 46 chromosomes or 2n to 23 chromosomes or n (n describes a single chromosome set).

Meiosis I (First Meiotic Division):
Prophase I:
It consists of the longest phase of meiosis. It can be subdivided into following stages:

1. Leptotene
2. Zygotene
3. Pachytyne
4. Diplotene
5. Diakinesis

Q.7: Define Anaerobic and Aerobic respiration. Write down chemical equation of aerobic respiration?
Ans: i) Anaerobic Respiration or Fermentation:
The primitive type of respiration which takes place in the absence of O₂ (Oxygen) or without O₂ is called anaerobic respiration or fermentation.

ii) Aerobic Respiration:
Type of respiration where food breakdown occurs in the presence of oxygen to produce energy. It is a method of respiration found in majority of organisms. It takes place in the presence of free oxycen, oxidizing the food and releasing maximum amount of energy i.e. 2827 KJ / mole of glucose or 36 ATP molecules / glucose. The end products of aerobic respiration are CO₂ and O₂.

Glucose + Oxygen → Carbon dioxide + water + Energy (36 ATP)

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + 36 ATP

Q.8: What is Nutrition? Define Autotrophic nutrition and Hetrotrophic nutrition?
Ans: Nutrition:
Process by which organisms obtain and use the nutrients required for maintaining, life is called nutrition.

Autotrophic :
The term 'autotroph' is derived from two Greek words-autos (self) and trophe (nutrition).It is the mode of nutrition in which an organism makes its own food from the simple inorganic materials like carbon dioxide, water and minerals present in the surrounding (with the help of energy). The processes are photosynthesis or either chemosynthesis.

Heterotrophic nutrition:
The word 'heterotroph' is derived from two Greek words-heteros (other) and trophe (nutrition). It is the mode of nutrition in which an organism can't make its organic material but depends on other organisms for its food and use it for growth and energy. As heterotrophs depend on other organisms for their food, they are also called consumers.

Q. 9 Draw a flowchart showing different types of plant tissues.

Plant tissue

Q. 10 Define parasitology, Developmental Biology, Paleontology and Pharmacology?
Ans:
Parasitology (Gr. para; up): The study of parasites.
Developmental Biology (Gr. embryon; embryo, logos, discourse): The study of formation and development of embryo.
Paleontology (Gr. palaios; ancient, ontos; being, logos: discourse): The study of remote past organic life, with the help of fossils.
Pharmacology (Gr. pharmakon, drug;). The study about action of drugs.

SECTION "C" (DETAILED ANSWER QUESTIONS) (12)

NOTE: Attempt any Two 02 questions from this section. Each question carries 06 marks.
Q. 11 Draw a neat and Labelled diagram of L.S. (internal structure) of Human Heart.

Human Heart (internal and external L S. of heart)

Q. 12 Write a detailed note on animal tissues. (Diagram is not necessary)
Ans: Animal tissue:
Humans and other large multicellular animals are made up of four basic types tissue:

1. Epithelial tissue
2. Connective tissue
3. Muscular tissue and
4. Nervous tissue.

i. Epithelial tissue:
Epithelial tissue covers the surface of the body, lines the spaces inside the body and forms glands. For instance, the outer layer of our skin is an epithelial tissue and the lining of small intestine are made up of epithelial tissues.

ii. Connective tissue:
This tissue which connects or bind the different types of cells called connective tissues. They also bind other tissues of the body with each other. Connective tissue holds structures in the body together, such as tendons.

iii. Muscle tissues:
Muscle tissue contains the cells that are responsible for the contraction of muscles.

iv. Nervous tissues:
Nervous tissue is composed of neurons, which transmit information to other cells. Nervous tissue is found in the brain, spinal cord, and nerves.

Q. 13 What are enzymes? Describe any five characteristics of Enzymes.
Ans: Enzyme:
The molecules which facilitate biochemical reaction by reducing activation energy called enzymes. Enzymes are biocatalyst made up of mostly proteins and therefore are three dimensionally folded chains of amino acids with a specific shape.

Characteristics of Enzymes:

• Enzymes are biocatalyst, made up of mostly proteins and therefore three dimensionally folded chains of amino acids with a specific shape.
• When an enzyme starts a chemical reaction, catalyzes reaction hence does not utilized itself which means even a single or little amount of enzyme can start a reaction and catalyze fastly.
• Their presence does not affect the nature or properties of end products.
• Reactants of enzyme are called substrate.
• They are very specific in their action: a single enzyme catalyzes only a single chemical reaction or a group of related reaction.

Q. 14 What is transpiration? Where it occurs? Write five significance of transpiration?
Ans: Transpiration:
Loss of internal water of plant in the form of vapours from aerial part of plant called transpiration. Transpiration mainly takes place through special pores guarded by specialized guard cells called stomata (sing: stoma).

Significance of Transpiration:

• By active transpiration, transpiration pull is created which helps in the ascent of sap.
• Transpiration also increases the rate of absorption because the loss at one end increases demand on other end.
• Transpiration gets rid of the excess amount of water from plant.
• Transpiration helps in maintaining the temperature of plant for its metabolism and survival because evaporation causes cooling.
• Opening and closing of stomata is also regulated by transpiration, which indirectly influences upon the rate of photosynthesis and respiration.