Biology For Class X - Chapter No. 8 - Biotechnology - Question Answers

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CHAPTER 8: BIOTECHNOLOGY
Questions Answers

By Mrs. Ayesha Arif
Vice Principal
(Jauhar Progressive School)
Q.1: Define biotechnology?
Ans: BIOTECHNOLOGY:
Introduction:
The term "Biotechnology" was used before the twentieth century for traditional activities such as making dairy products like cheese and curds, as well as bread, wine, beer, etc. In 1919, a Hungarian agriculture engineer called Karl Ereky coined the word Biotechnology.
Definitions:
There are several definitions for biotechnology.
1. Simple Definition is that:

"It is the commercialization of cell and molecular biology."

2. Classical Or Modern Biotechnology: According to the National Science Academy of United:

"Biotechnology is the controlled use of biological agents like cells or cellular components for beneficial use".

It covers both classical as well as modern biotechnology.

3. General Definition: Generally, biotechnology can be defined as:

"The use of living organisms, cells or cellular components  for the production of compounds or precise genetic improvement of living things for the benefit of man"

Old Biotechnology:
Even though biotechnology has been in practice for thousands of years  but credit goes to Indo Aryan civilizations, which first practised biotechnology in 5000 BC to produced fermented foods, medicines and to keep the environment clean.

Q.2: What is genetic engineering? Write down the role of genetic engineering in biotechnology OR
Why genetic engineering is considered as modern biotechnology. Explain?
Ans: GENETIC ENGINEERING:
Definition:
Genetic engineering is considered as modern biotechnology. It has been defined as:

"The artificial manipulation, modification, and recombination of DNA or other nucleic acid molecules in order to modify an organism or population of organisms. It refers to any process in which an organism’s genome is intentionally altered."

Explanation:
ROLE OF GENETIC ENGINEERING IN BIOTECHNOLOGY:
Genetic engineering play important role in biotechnology. Such as:
1. Cloning:
Genetic engineering does not encompass traditional breeding techniques because it requires manipulation of an organism’s genes through cloning or transformation via the addition of foreign DNA.
For example: a DNA fragment may be isolated from one organism spliced to other DNA fragments, and put into a bacterium or another organism. This process is called cloning because many identical copies can be made of the original DNA fragment.

2. Production Of insulin:
In 1970s, the scientists were able to alter the DNA of the organisms and in 1978 the first genetically engineered drug, human insulin was produced by bacteria.

3. Vitro Mutagenic Methods.
In another example of genetic engineering, a stretch of DNA, often an entire gene, may be isolated and its nucleotide sequence determined, or its nucleotide sequence may be altered by in vitro mutagenic methods.
There are several ways that DNA can be cut, spliced or otherwise altered. But engineered DNA by itself is a static molecule. To be anything more than the end of a laboratory exercise, the molecule must be integrated into a system of production; to have an impact on society at large; it must become a component of an industrial or otherwise useful process.

Basic: Objectives Of Genetic Engineering Activities
 The related activities in genetic engineering have two basic objectives:

1. To learn more about the ways nature works, and
2. To make use of this knowledge for practical purposes.

Benefits Of Fermentation In Genetic Engineering:
A useful genetic approach to increase the efficiency of production. The fermentation was useful in its production and genetic engineering promises to make the fermentation process economically competitive.

Q.3: What is HGP? Write down its objectives?
Ans: HGP Or Human Genome Project:
In 1990, The Human Genome Project was launched to map all the genes of the human cell. The complete draft of the human genome sequence was published in 2002.
OBJECTIVES:
It has following objectives:

• Determining the human DNA sequence.
• Understanding the function of the human genetic code
• Identifying all of the genes.
• Determining their functions Understanding how and when genes are turned on and off throughout the lifetime of an individual.

Q.4: What are the scope and importance of biotechnology?
Ans: Scope and importance of Biotechnology:
Biotechnology is controlled use of biological agents for beneficial use. It is integrated use of biochemistry, molecular biology, microbiology to achieve technological application of the capabilities of biological agents. Therefore, biotechnology has emerged as a science with immense potential for human health to environmental protection.
The following are the areas of the application of biotechnology:

1. Biotechnology in medicine:
In the field of medicine biotechnology has been extremely helpful in the production of large number of vaccines and antibodies. The major achievements include:

• Production of a monoclonal antibody, DNA, RNA probes for diagnosis of various diseases.
• Valuable drugs like insulin and interferon have been synthesized by bacteria for the treatment of human diseases.
• DNA fingerprinting is utilized for identification of parents and criminals.
• Development of recombinant vaccines like human hepatitis B etc. by genetically engineered microbes.
  

2. Biotechnology in Agriculture:
Biotechnology has been beneficial in the field of agriculture in the following ways:

• Plant cell, tissue, and organ culture are used for rapid and economic clonal multiplication of fruit and forest trees.
• They are also used for the production of virus-free genetic stocks and planting material as well as in the creation of novel genetic variations through somaclonal variation.
• Genetic engineering techniques are utilized to produce transgenic plants with desirable genes like disease resistance, herbicide resistance, an increased shelf life of fruits etc.
• Molecular breeding to hasten the process of crop improvement.

3. Biotechnology in Industry:
Biotechnology is helpful in industries as:

• Industrial biotechnology is an area with which biotechnology is initiated for large scale production of alcohol and of antibiotics by microorganisms.
• A variety of pharmaceutical drugs and chemicals like lactic acid, glycerine etc. are being produced by genetic engineering for better quality and quantity.
• Fermented foods like pickles and yogurt are produced
• Malted foods like powdered milk are being produced
• Dairy products and vitamins are produced.

4. Biotechnology in the environment:
Environmental problems like pollution control, depletion of natural resources for nonrenewable energy, conservation of biodiversity etc. are being dealt with using biotechnology. For example:

• Bacteria are being utilized:
  * for detoxification of industrial effluents.
  * in combats oil spills for treatment of sewage.
  * for biogas production.
• Bio-pesticides give an environmentally safer alternative to chemical pesticides for control of insects, pest and diseases.

Q.5: What is fermentation? Describe the types of fermentation?
Ans: FERMENTATION:
The classical biotechnology that emerged during the early twentieth century was basically a microbial-based fermentation process in which the principles of biochemical engineering have been applied to change it into an industrial process.
Definition: Fermentation is an alternative term for Anaerobic respiration. It can be defined as:

"Fermentation is the process by which living organism such as yeast or bacteria are employed to produce useful compounds or products."
Or
"An important way of making ATP without oxygen is called fermentation."

TYPES OF FERMENTATION:
There are two major types:

1. Lactic acid fermentation
2. Alcoholic fermentation

1. LACTIC ACID FERMENTATION:
In lactic acid fermentation,  pyruvic acid from glycolysis changes to lactic acid. In this process, NAD⁺ forms NADH. The NAD⁺ cycles back to allow glycolysis to continue so more ATP is made. Each cycle represents as carbon atom.
Cause:
This type of fermentation is carried out by the bacteria Streptococcus and Lactobacillus species.
Uses:

• With the help of bacteria, this fermentation is used for souring milk into yogurt and production of various types of cheese.
• It is also used by our own muscle cells when we work them hard and fast.

2. ALCOHOL FERMENTATION:
In alcoholic fermentation, pyruvic acid is converted to alcohol and carbon dioxide. It produces ethanol and NAD⁺ from NADH. The NAD⁺ allows glycolysis to continue making ATP.
Ethanol fermentation converts two pyruvate molecules, the products of glycolysis into two molecules of ethanol and two molecules of carbon dioxide.
Cause:
This type of fermentation is carried out by yeast Saccharomyces cerevisiae and some bacteria.
Uses:

• It is used to make bread, wine, and biofuels.
• It also causes the rising of dough in breads. The yeast produces carbon dioxide gas in the dough using alcoholic fermentation. The gas forms bubbles which makes the dough rise and expand. The bubbles leave small holes in the bread after baking which makes the bread light and fluffy.

Q.6: Why fermentation can be referred to as industrial biotechnology?
Ans: Fermentation or Industrial Biotechnology:
Fermentation can be referred to as industrial biotechnology because it refers to the growth of microorganisms forming on food under either aerobic or anaerobic conditions. The industrial microorganisms are grown under controlled conditions with the aim of optimizing the growth of organism for the production of targeted microbial products such as food (cheese, yogurt, fermented pickles and sausages, soy sauce), beverages (beers, wines) and spirit.

Q.7: Write down the applications of fermentation?
Ans: APPLICATIONS OF FERMENTATION:

• Fermentation changes the chemical environment of a food.
• Fermentation is an important process in the preparation of food for human consumption. 
• Many plants undergo a fermentation process in order to produce the final products.
• Pre-sterilized (pasteurized) materials assembled into packages and aseptically filled (Aseptic packaging) for grocery shelf.
• Fermentation helps preserve the food and lower the need of refrigerator.

APPLICATION IN THE FOOD INDUSTRY
Fermentation as a food preservative technique:
Fermented foods are foods that have been prepared in a way so that the bacteria naturally found within them starts to ferment.
Lacto-fermentation, is a chemical process in which bacteria and other microorganisms break down starch and sugars within the foods, possibly making them easier to digest, and resulting in a product that is filled with helpful organisms and enzymes. This process of fermentation is a natural preservative, which means that fermented foods can last a long time.

Q.8: Write down products of fermentation?
Ans: PRODUCTS OF FERMENTATION:
Food products:
Foods that undergo fermentation are:

• Dairy products: Yogurt, cheese
• Cereal products: bread ,cakes
• Fruit and vegetable products: flavorings , candy, fruit juice, silage
• Beverages: beer, wine, cider
• Pickling:involves fermentation that are frequently pickled include beans, onions, cauliflower, cucumber, tomatoes cabbage.
• Microbial cells:
  * Yeast cells used in the baking industry.
  * Single-cell protein used as food material.

Non Food Products:
Non-food items that undergo fermentation include: 

• Laundry detergents
• Cellulose:
  * It is also used to produce bio-surfactant, polymers production such as bacterial cellulose production.
• Compost
• Chemicals
• Transformation products
  * Biofuels production (biodiesels, bioethanol, butanol, biohydrogen, bioplastic etc).
  * Bioremediation products involving microbes or their isolated enzymes for soils and waste water treatments (Wastewater, aromatics, toxic dyes etc.)

Medicine Products:

• Antibiotics
• Insulin
• Monoclonal antibodies
• Vaccines
• Medicines to dissolve tumors and to clot blood
• r DNA products:
  * Growth hormones
  * Interferon
• Enzymes:
  * Bacterial: amylase, protease, lipase.
  * Fungal: amylase, protease, pectinase.
• Metabolites:
  * Primary metabolites are proteins, vitamins, lipids, carbohydrates.
  * Secondary metabolites are enzymes, antimicrobial compounds, growth promoters.

Q.8: What is fermentor and its advantages?
Ans: FERMENTOR:
Definition:
In general term, as its name suggests:

"Fermentors are containers used to grow bacteria and fungi on large scale."

The general idea behind:

"The fermentor is to provide a stable and optimal environment for microorganisms to reproduce and interact with substrate for required product."

Advantages Of Fermentor:

1. Controlled Environment: For each biotechnological process, the environment provide to the organisms must be monitored and controlled. Such controlled environment is provided by fermentors.
2. Optimize Growth Of Organisms: A fermentor optimizes growth of organisms by controlling many factors like nutrients, oxygen, growth inhibitors pH and temperature.
3. Production in Bulk: A fermentor may hold several thousand liters of growth medium. So, fermentors allow the production of material in bulk quantities.
4. Production of Medicines: Massive amounts of medicines, insulin, human growth hormone and others protein are being produced in fermentors and thus production proves much inexpensive.
5. Minimized Wastage Of Materials: Wastage of materials in handling is minimized by fermentors. They can be installed with ease and take up very little space.

Q.9: What is genetic engineering? Write down its uses?
Ans: GENETIC ENGINEERING:
Genetic engineering is the cornerstone of modern biotechnology. It is based on scientific tools, developed in recent decades.
Uses:
It enable the researchers to:

• Identify the gene that produces the protein of interest.
• Cut the DNA sequence that contains the gene from a sample of DNA.
• Place the gene into a vector, such as a plasmid or a bacteriophage.
• Use the vector to carry the gene into the DNA of the host cells, such as escherichia coli (E coli) or mammalian cells grown in culture.
• Induce the cells to activate the gene and produce the desired protein.
• Extract and purify the protein for therapeutic use.

Q.10: Describe genetic engineering tools?
Ans: GENETIC ENGINEERING TOOLS
To manipulate cells and DNA, scientists use tools that are borrowed from nature. These include:

• Restriction enzymes:
  These naturally occurring enzymes are used as a defense by bacteria to cut up DNA from viruses. There are hundreds of specific restriction enzymes that researchers use like scissors to snip specific genes from DNA.
  
  
• DNA Ligase:
  This enzyme is used in nature to repair broken DNA. It can also be used to paste new genes into DNA.
  
  
• DNA vector:
  In molecular cloning, a vector is a DNA molecule used as a vehicle to artificially carry foreign genetic material into another cell, where it can be replicated. They include:
  a) Plasmids:
  They are mostly circular units of DNA. They can be engineered to carry genes of interest.
  b) Bacteriophages (also known as phages):
  These are viruses that can enter or infect bacteria. Bacteriophage can be engineered to carry recombinant DNA.
  
  
• Recombinant DNA technology:
  When segments of DNA are cut and pasted together to form new sequences, the result is known as recombinant DNA. When recombinant DNA is inserted into cells, the cells use this modified blueprint and their own cellular machinery to make the protein encoded by a recombinant DNA.
  
  
• Transgenic Cells:
  Cells that have recombinant DNA are known as Genetically Modified Organism (GMO) or transgenic cells. The GMO contains genes of interest and manufactures the desired products.

Q.11: Describe the major achievements of genetic engineering?
Ans: MAJOR ACHIEVEMENTS OF GENETIC ENGINEERING:
Genetic engineering means making changes to DNA in order to change the way living things work. So many things have been made through genetic engineering such as; Vaccines, Monoclonal antibodies, Gene therapy, Interferons, Interleukins, Recombinant human proteins, Human growth hormones, Clotting factors and Erythropoietins.

1. Vaccine against foot and mouth disease:
   The creation of new synthetic vaccine for foot and mouth diseases (a highly contagious viral disease that infects cattle, sheep, and other animals.) is strange and impressive achievement. The trick was to carve up the virus genome to make a DNA copy that codes only for the three capsid proteins.
   
   
2. Vaccine against coccidiosis:
   Coccidiosis is a disease of both invertebrates and vertebrates caused by parasitic protozoa which invade the epithelial cells lining the alimentary tract and the cells of associated glands. A vaccine made against coccidiosis by using avian protein to immunize chicken against avian coccidia.
   
   
3. Treatment of Trypanosomiasis:
   Sleeping sickness (trypanosomiasis) is caused by a parasite called Trypanosoma brucei. The availability of a genetic transformation made possible the treatment of this disease.
   
   
4. Genetic therapy:
   Molecular biology has introduced in modern medicine a new way to cure diseases, namely genetic therapy, direct intervention in the genetic makeup of an individual. Gene therapy can be somatic or germ line. It is being used to treat genetic disorders of the blood (e.g. thalassaemia).
   
   
5. Cloning Humans:
   In the second half of the 20th century, as dramatic advances were taking place in genetic knowledge, as well as in the genetic technology. Some proposals suggested that persons of great intellectual or artistic achievement or of great virtue be cloned.
   
   
6. Herbicides: Genetically modified (GM) foods possess specific traits such as tolerance to herbicides or resistance to insects or viruses.
   
   
7. Insect Killing Bacteria: Adding a gene from insect-killing bacteria to cotton so that insects, eat cotton will be poisoned!
   
   
8. Treatment Of Lung disease: Genetic engineering also includes insertion of human genes into sheep so that they secrete alpha-1 antitrypsin in their milk - a useful substance in treating some cases of lung disease.
   
   
9. Human insulin:
   By inserting a gene for human insulin into an E. coli bacterium, the E. coli will make a lots of insulin, which scientists and doctors can collect and use.
   
   
10. Cancer treatment: Scientists have found a gene called p-53 which normally keeps cells under control and works best to suppress cancer cells.
    

Q.12:What is single cell protein? Write down its uses?
Ans: Introduction:
When there were shortage in proteins and vitamins in the diet, the Germans produced yeast and a moulds (Geotrichum candidum) in some quantity for food, this led to the idea to produce edible proteins on a large scale by means of microorganisms.

Single-cell protein:
Single-Cell Protein (SCP) is a term coined at Massachusetts Institute of Technology by Prof. C. L. Wilson (1966) and represents microbial cells (primary) grown in mass culture harvested for use as protein sources in food or animal feeds.
Definition:

“The isolated protein or the total cell material from microorganisms like bacteria, yeast, filamentous fungi and algae contains carbohydrates, lipids, nucleic acid, mineral salts and vitamins, used as food or feed is called single-cell protein (SCP).”

Production OF SCP:

• Carbon substrates: Major substrates used in commercial SCP production are alcohol, n-alkanes, molasses, sulphite, liquor and whey.
• Substitute for protein-rich food: SCP is a protein is a protein extracted from cultured algae, yeasts, or bacteria and used as a substitute for protein rich food, especially in animal feeds or as dietary supplement.
• 60-80% dry cell weight: Many types of animal feeds contain single cell protein. 60-80% dry cell weight; contains nucleic acid, fats, CHO, vitamins, and minerals rich in essential amino acids (Lys-Met).
• Microbes: can be used to ferment some of the vast amount of waste materials, such as:
  * Straws
  * Wood and wood processing wastes
  * Food cannery and food processing wastes
  * Residues from alcohol production
  * From human and animal excreta

Q.13: Give reason?
(i) Did you ever run a race and notice that your muscles feel tired and sore afterwards. why?
Ans: This is because our muscle cells used lactic acid fermentation for energy. This causes lactic acid to build up in the muscles. It is the buildup of lactic acid that makes the muscles feel tired and sore.

(ii) Why small holes are formed in the sliced of bread?
Ans: The small holes are formed in the sliced of bread by bubbles of carbon dioxide gas. The gas was produced by alcoholic fermentation carried out by yeast.


Source: Special Thanks To Sir Syed Arif Ali

Biology For Class X - Chapter No. 8 - Biotechnology - Review Exercise From Text Book

GO TO INDEX
CHAPTER 8: BIOTECHNOLOGY
Review Exercise From Text Book

By Mrs. Ayesha Arif
Vice Principal
(Jauhar Progressive School)

A. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:
i. The artificial manipulation, medication and recombination of DNA:
(a) Genetic engineering ✓
(b) Biotechnology
(c) Molecular Biology
(d) Genetics

ii. The earlier biotechnologist were:
(a) Biologist
(b) Agriculturist
(c) Genetist
(d) Farmers ✓

iii. The complete graph of human genome was studied by:
(a) PCR
(b) HGP (Human Genome project) ✓
(c) Medicine
(d) soma-clonal

iv. Alcohol and antibiotics on large scale production by organism is an area of:
(a) Environmental biotechnology
(b) Fermentation
(c) Biotechnology in industry ✓
(d) Medicinal biotechnology

v. Most of the living things use O₂ to produce:
(a) ATP ✓
(b) Alcohol
(c) Organic acid
(d) Ecological pyramid

vi. In acidic formulation lactic acid produced from:
(a) Pyruvic acid ✓
(b) Acetic acid
(c) Citric acid
(d) Glyceric acid

vii. The bread dough rises during alcoholic fermentation is due to:
(a)Methyl alcohol
(b) CO₂ ✓
(c) Ethyl alcohol
(d) H₂O

viii. The container use to grow bacteria on large scale are called:
(a) Chillers
(b) Sterilizers
(c) Fermenters (Fermentor) ✓
(d) Ferments

ix. Naturally occurring enzyme used as a defense chemical by bacteria:
(a) Defense protein
(b) Restriction enzyme ✓
(c) Hydrolytic enzyme
(d) ligase enzyme

x. Extra circular DNA which use as vector of gene is:
(a) Genome
(b) Plasmid ✓
(c) Pilli
(d) Ligase

B. ANSWER THE FOLLOWING QUESTIONS:
Q.No.1: What kind of enzymes allows scientists to cut and paste pieces of DNA together to form recombinant DNA?
Ans: The following are the enzymes which allow scientists to cut and paste pieces of DNA together to form recombinant DNA:

1. Restriction enzymes:
   Restriction enzymes are DNA-cutting enzymes which occur naturally. They are used by bacteria as a defense to cut up DNA from Viruses. Scientists used hundreds of these restriction enzymes to snip specific gene from DNA.
   
   
2. DNA Ligase:
   DNA ligase is a DNA-joining enzyme. This enzyme is used to repair broken DNA. If two pieces of DNA have matching ends, ligase can link them to form a single, unbroken molecule of DNA. It can also be used to paste new genes into DNA.

Q.No.2: Explain how making human tissue plasminogen activator (t-PA) in Chinese hamster ovary (CHO) cells is an example of genetic engineering.
Ans: Plasminogen Activator (t-PA):
To produce t-PA for therapeutic use, researchers genetically engineered mammalian cell of Chinese hamster ovary cells. The ovary cells are grown into culture and given a segment of human DNA with the genetic instructions to make the human t-PA enzyme.
Chinese Hamster Ovary (CHO) cells:
are the most commonly used host system for the expression of high quality recombinant proteins. However, the development of stable, high-yielding CHO cell lines is a major bottleneck in the industrial manufacturing of therapeutic proteins. Therefore, different strategies such as the generation of more efficient expression vectors and establishment of genetically engineered host cells have been employed to increase the efficiency of cell line development. In order to examine the possibility of generating improved CHO host cells, cell line engineering approaches were developed making use of Biotechnology.
Result:
The results obtained in this study indicate successful development of the improved CHO host cells.
Aim:
The aim of this study was to improve the recombinant protein productivity of CHO cells. Genetic modification of the host cells has proven to be a promising strategy to eliminate or reduce the bottlenecks in recombinant protein expression.

Q.No.3: How do organisms obtain energy? How does fermentation work?
Ans: Organism Obtains Energy From ATP:
Living organisms use organic food (substrate) such as carbohydrates for generation of energy. During process of respiration, these carbohydrates react with oxygen to produce CO₂, H₂O and energy. This energy is usually in the form of ATPs. This process take place in the mitochondria of the cell. Most living organisms use oxygen to make ATP from glucose.

Many living things can make ATP without oxygen as well. Some plants, fungi and many bacteria use aerobic respiration when oxygen is present but in the absence of oxygen they use anaerobic respiration.
During photosynthesis, plants (producers)  captures the light energy by chlorophyll and transform this energy into the chemical potential energy such as glucose. The consumption of plants by animals allows the energy of glucose to be used in various function.
An important way of making ATP without oxygen is Fermentation.

FERMENTATION:
Fermentation is a metabolic process in which an organism converts a carbohydrate into an alcohol or lactic acid to obtain energy.
Definition: Fermentation is an alternative term for Anaerobic respiration. It can be defined as:

"Fermentation is the process by which living organism such as yeast or bacteria are employed to produce useful compounds or products."
Or
"An important way of making ATP without oxygen is called fermentation."

TYPES OF FERMENTATION:
There are two major types:

1. Lactic acid fermentation
2. Alcoholic fermentation

1. LACTIC ACID FERMENTATION:
In lactic acid fermentation,  pyruvic acid from glycolysis changes to lactic acid. In this process, NAD⁺ forms NADH. The NAD⁺ cycles back to allow glycolysis to continue so more ATP is made. Each cycle represents as carbon atom.

2. ALCOHOL FERMENTATION:
In alcoholic fermentation, pyruvic acid is converted to alcohol and carbon dioxide. It produces ethanol and NAD⁺ from NADH. The NAD⁺ allows glycolysis to continue making ATP.
Ethanol fermentation converts two pyruvate molecules, the products of glycolysis into two molecules of ethanol and two molecules of carbon dioxide.

Q.No.4: What types of microorganisms cause fermentation to occur?
Ans: Microorganisms Cause Fermentation:
Fermentation occurs in the absence of oxygen (anaerobic conditions), and in the presence of beneficial microorganisms. Some beneficial microorganisms for fermentation are yeasts, molds, and bacteria that obtain their energy through fermentation.

Similarly the lactic acid fermentation is carried out by the bacteria Streptococcus and Lactobacillus, which can produce lactic acid from carbohydrates. They help in souring milk for yogurt and is also helpful in production of various types of cheese.

The alcoholic fermentation uses Saccharomyces cerevisiae, a type of yeast to make bread and wine etc.

Q.No.5: What food and non food products are created by fermentation?
Ans: Food Products Created By Fermentation:

• Dairy products: Yogurt, cheese
• Cereal products: bread, cakes
• Fruit and vegetable products: flavorings , candy, fruit juice, silage
• Beverages: beer, wine, cider
• Pickling: pickling of beans, onions, cauliflower, cucumber, tomatoes, cabbage
• Microbial cells:
  * Yeast cells used in the baking industry.
  * Single-cell protein used as food material.

Non Food Products Created By Fermentation:

• Laundry detergents
• Cellulose:
  * It is also used to produce bio-surfactant, polymers production such as bacterial cellulose production.
• Compost
• Chemicals
• Transformation products
  * Biofuels production (biodiesels, bioethanol, butanol, biohydrogen, bioplastic etc).
  * Bioremediation products involving microbes or their isolated enzymes for soils and waste water treatments (Wastewater, aromatics, toxic dyes etc.)

Medicine Products:

• Antibiotics
• Insulin
• Monoclonal antibodies
• Vaccines
• Medicines to dissolve tumors and to clot blood
• r DNA products:
  * Growth hormones
  * Interferon
• Enzymes:
  * Bacterial: amylase, protease, lipase.
  * Fungal: amylase, protease, pectinase.
• Metabolites:
  * Primary metabolites are proteins, vitamins, lipids, carbohydrates.
  * Secondary metabolites are enzymes, antimicrobial compounds, growth promoters.

Q.No.6: What are some advantages and disadvantages of fermentation?
Ans: ADVANTAGES:

1. Makes our food more digestible.
2. Yeast is used to prepare bread from wheat.
3. Milk is converted to curd (yogurt) by bacteria.
4. Preparation of cheese and other dairy products.
5. Production of lactic acid, propionic acid, and butanol. Addition of lactic and acetic acids prevent foods from spoilage and also give sour flavours to yogurt, cheese and pickles.
6. Acetone is also formed as a by-product.
7. It helps restore proper bacteria balance in the intestines.
8. It improves heart health.
9. It improves the immune system.
10. It is the source of ethyl alcohol in beverages.

DISADVANTAGES:

1. It is linked with the development of gastric cancer.
2. Antibiotic resistance.
3. Temporary increase in gas and bloating.
4. Lose beneficial bacteria.
5. Fermentation is a slow and inefficient process. This means it carries a higher cost of production and requires more energy and resources.
6. It is vulnerable to contamination.

Q.No.7: What factors can affect the fermentation process?
Ans: Factors Affect Fermentation Process:
There are several factors which affect the process and progression of both alcoholic and lactic acid fermentation. These include:

• Fermentation time
• pH
• Presence of air
• Temperature
• Salt
• Water
• Concentration of substrate (sugar)
• Contaminating organisms

Q.No.8: Define biotechnology.
Ans: BIOTECHNOLOGY:
Introduction:
The term "Biotechnology" was used before the twentieth century for traditional activities such as making dairy products like cheese and curds, as well as bread, wine, beer, etc. In 1919, a Hungarian agriculture engineer called Karl Ereky coined the word Biotechnology.
Definitions:
There are several definitions for biotechnology.
1. Simple Definition is that:

"It is the commercialization of cell and molecular biology."

2. Classical Or Modern Biotechnology: According to the National Science Academy of United States:

"Biotechnology is the controlled use of biological agents like cells or cellular components for beneficial use".

It covers both classical as well as modern biotechnology.

3. General Definition: Generally, biotechnology can be defined as:

"The use of living organisms, cells or cellular components  for the production of compounds or precise genetic improvement of living things for the benefit of man"

Old Biotechnology:
Even though biotechnology has been in practice for thousands of years  but credit goes to Indo Aryan civilizations, which first practised biotechnology in 5000 BC to produced fermented foods, medicines and to keep the environment clean.

Q.No.9: What is classical biotechnology?
Ans: CLASSICAL BIOTECHNOLOGY:
The second phase of evolution and development of biotechnology can be called 'Classical Biotechnology'. According to the National Science Academy of United:

"Biotechnology is the controlled use of biological agents like cells or cellular components for beneficial use".

It covers both classical as well as modern biotechnology.
Scientists use classical biotechnology techniques to alter the genetic makeup (genotype) of microorganisms, plants and animals for the purpose of changing their physical characteristics (phenotype).

Q.No.10: What is your justification in considering biotechnology an old technology?
Ans: Biotechnology Is Considered An Old Technology:
In 1919, a Hungarian agriculture engineer called Karl Ereky coined the word Biotechnology.
There is no doubt about the fact that biotechnology is an old technology. As with the passage of time man made discoveries and developments were seen in almost every field. Food, clothes, and shelter are the most important basic needs of human beings irrespective of whether they lived in the ancient period or the modern period. The only factor that has changed is their types and origins.

Biotechnology In Old Civilization:
Biotechnology has been in practice for thousands of years, but credit goes to Indus and Indo-Aryan civilizations, which first practiced biotechnology in 5000 BC to produce fermented foods, medicines and to keep the environment clean.

Farmers Were Earliest Biotechnologist:
The earliest biotechnologists were farmers who developed, improved species of plants and animals using cross-pollination or cross-breeding techniques. The use of these techniques to manufacture products intended to improve the quality of human life.
One of the oldest examples of crossbreeding for the benefit of humans is mule. Mule is an offspring of a male donkey and a female horse. People started using mules for transportation, carrying loads, and farming, when there were no tractors or trucks.

Food Production In Early time:
The term "Biotechnology" was used before the twentieth century for traditional activities such as making dairy products like cheese and curd, as well as bread, wine, beer, etc.

Fermentation Process:
The classical biotechnology that emerged during the early twentieth century was basically a microbial-based fermentation process in which the principles of biochemical engineering have been applied to change it into an industrial process.
Based on all these facts we can consider biotechnology a very old technology.

Q.No.11: Describe the contribution of Louis Pasteur toward development of classical biotechnology?
Ans: Contribution Of Louis Pasteur:
Louis Pasteur is best known for inventing the process that bears his name, pasteurization. He also has other contributions as well towards biotechnology. They are as follows:

Fermentation:
In the mid-1850s, he started a series of studies on alcoholic fermentation. He learned about many aspects of fermentation, including the compounds that cause milk to sour. In 1857 he presented evidence that all type of fermentation is caused by microorganisms and that specific microorganisms cause specific kinds of fermentation.

Pasteurization:
Using his work with fermentation, Pasteur was able to devise a process, now known as pasteurization, to kill microbes and preserve certain products. Pasteurization prevents fermentation and spoilage in beer, milk, and other goods. In his work with silkworms, Pasteur developed practices that are still used today for preventing disease in silkworm eggs.

Germ theory:
Pasteur’s work with microorganisms in fermentation and pasteurization led to a much better understanding of germ theory - that certain diseases are caused by the attack of microorganisms on healthy body of living organisms. Before Pasteur’s theory, most people, including scientists, believed that all disease came from inside the body rather than from outside. Pasteur’s findings eventually led to improvements in sterilizing and cleaning in medical practices and antiseptic methods in surgery.

Produce Vaccines:
Pasteur was the first scientist to create vaccines for fowl cholera, anthrax, a major liver stock disease and rabies.

Q.No.12: What are different types of fermentation?
Ans: TYPES OF FERMENTATION:
There are two major types:

1. Lactic acid fermentation
2. Alcoholic fermentation

1. LACTIC ACID FERMENTATION:
In lactic acid fermentation,  pyruvic acid from glycolysis changes to lactic acid. In this process, NAD⁺ forms NADH. The NAD⁺ cycles back to allow glycolysis to continue so more ATP is made. Each cycle represents as carbon atom.
Cause:
This type of fermentation is carried out by the bacteria Streptococcus and Lactobacillus species.
Uses:

• With the help of bacteria, this fermentation is used for souring milk into yogurt and production of various types of cheese.
• It is also used by our own muscle cells when we work them hard and fast.

2. ALCOHOL FERMENTATION:
In alcoholic fermentation, pyruvic acid is converted to alcohol and carbon dioxide. It produces ethanol and NAD⁺ from NADH. The NAD⁺ allows glycolysis to continue making ATP.
Ethanol fermentation converts two pyruvate molecules, the products of glycolysis into two molecules of ethanol and two molecules of carbon dioxide.
Cause:
This type of fermentation is carried out by yeast Saccharomyces cerevisiae and some bacteria.
Uses:

• It is used to make bread, wine, and biofuels.
• It also causes the rising of dough in breads. The yeast produces carbon dioxide gas in the dough using alcoholic fermentation. The gas forms bubbles which makes the dough rise and expand. The bubbles leave small holes in the bread after baking which makes the bread light and fluffy.

Q.No.13: What is lactic acid bacillus? Explain its role in fermentation of curd ?
Ans: LACTIC ACID BACILLUS:
Lactic acid bacillus are inactivated bacteria that are good the gut and normally found in the human digestive and urinary tracts. They prevent the growth of the other pathogenic bacteria that cause diarrhea or other bacterial infections. Thus, it helps in treating bacterial infections.

ROLE OF  LACTIC ACID BACILLUS IN FERMENTATION OF CURD:

• Lactobacillus can help the body to break down food, absorb nutrients and fight off harmful organisms that might cause diseases.
• Lactic acid bacillus is very helpful in formation of curd. When it is added to milk the bacterium uses enzymes to produce energy (ATP) from lactose. The lactic acid curdles the milk that then separates to form curds, which are used to produce cheese and whey.
• In lactic acid fermentation, pyruvic acid from glycolysis changes to lactic acid. This type of fermentation is carried out by the bacteria Streptococcus and Lactobacillus species for souring milk into yogurt and production of various cheese.

Q.No.14: Name some of the fermented food products of Pakistan.
Ans: Fermented Food Products Of Pakistan
The fermented food products available in Pakistan are:

• Dairy products: Yogurt, cheese
• Cereal products: bread, cakes
• Fruit and vegetable products: flavorings , candy, fruit juice, silage
• Beverages: beer, wine, cider
• Pickling: pickling of beans , onions, cauliflower, cucumber, tomatoes cabbage

OR

Fermentation products:
The following are the most consumed fermentation products used worldwide and in Pakistan:
1. Alcohol:
Alcohol is made as a result of the fermentation of a natural source of sugar with a catalyst, which is usually yeast. During fermentation, carbohydrates (starch and sugars) are the main source that is converted into carbon dioxide and ethyl alcohol. Alcohol is widely used in medicines.

2. Yogurt:
Yogurt is lactic acid-containing milk fermented by bacteria. Lactose present in milk is converted to lactic acid during fermentation.

3. Bread:
Wheat dough is fermented to make bread. Fermentation plays an important role in softening the bread and is also responsible for its aroma. This fermentation is mainly carried out by yeast and sometimes by bacteria.

4. Cheese:
Cheese is formed when bacteria convert milk lactose into lactic acid due to which milk proteins are also coagulated. In this way, the milk changes into cheese.

Q.No.15: Name four recombinant DNA products available on the market?
Ans: Recombinant DNA Products:
Biochemical products of recombinant DNA technology in medicine and research include:

• Human recombinant insulin
• Growth hormone
• Blood clotting factors
• Vaccines (e.g. Hepatitis B vaccine)

Source: Special Thanks To Sir Syed Arif Ali

Biology For Class X - Chapter No. 8 - Biotechnology - Multiple Choice Questions And Fill In The Blanks By Sir Saeed Sarang

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CHAPTER 8: BIOTECHNOLOGY
Multiple Choice Questions And Fill In The Blanks

Special Thanks To Sir Saeed Sarang (Sindh Text Book Board)
Contact # 03023006727
Youtube Channel # Shafquat Ali YouTube

A. MULTIPLE CHOICE QUESTIONS
Choose the correct answer:
i. The artificial manipulation, medication and recombination of DNA:
(a) Genetic engineering ✓
(b) Biotechnology
(c) Molecular Biology
(d) Genetics

ii. The earlier biotechnologist were:
(a) Biologist
(b) Agriculturist
(c) Genetist
(d) Farmers ✓

iii. The complete graph of human genome was studied by:
(a) PCR
(b) HGP (Human Genome project) ✓
(c) Medicine
(d) soma-clonal

iv. Alcohol and antibiotics on large scale production by organism is an area of:
(a) Environmental biotechnology
(b) Fermentation
(c) Biotechnology in industry ✓
(d) Medicinal biotechnology

v. Most of the living things use O₂ to produce:
(a) ATP ✓
(b) Alcohol
(c) Organic acid
(d) Ecological pyramid

vi. In acidic formulation lactic acid produced from:
(a) Pyruvic acid ✓
(b) Acetic acid
(c) Citric acid
(d) Glyceric acid

vii. The bread dough rises during alcoholic fermentation is due to:
(a)Methyl alcohol
(b) CO₂ ✓
(c) Ethyl alcohol
(d) H₂O

viii. The container use to grow bacteria on large scale are called:
(a) Chillers
(b) Sterilizers
(c) Fermenters (Fermentor) ✓
(d) Ferments

ix. Naturally occurring enzyme used as a defense chemical by bacteria:
(a) Defense protein
(b) Restriction enzyme ✓
(c) Hydrolytic enzyme
(d) ligase enzyme

x. Extra circular DNA which use as vector of gene is:
(a) Genome
(b) Plasmid ✓
(c) Pilli
(d) Ligase

11. The first genetically engineered drug produced by bacteria in 1978.
(a) antibiotic
(b) antigen
(c) human insulin ✓
(d) None of these

12. The Human Genome Project was launched to map all the genes of the human cell in:
(a) 2002
(b) 1990 ✓
(c) 1978
(d) 1970

13. The complete draft of the human genome sequence was published in:
(a) 2002 ✓
(b) 1990
(c) 1978
(d) 1970

14. It is controlled use of biological agents for beneficial use.
(a) Genetic engineering
(b) Biotechnology ✓
(c) Molecular biology
(d) Genetic

15. The classical biotechnology that emerged during the early twentieth century was a microbial-based:
(a) genetics
(b) molecular biology
(c) pharmacology
(d) fermentation ✓

16. This type of fermentation is carried out by the bacteria Streptococcus and Lactobacillus species souring milk into yogurt and production of cheese.
(a) Lactic Acid Fermentation ✓
(b) Alcoholic Fermentation
(c) Both 'a' & 'b'
(d) None of these

17. It is used by your muscle cells when you work them hard and fast.
(a) Lactic Acid Fermentation ✓
(b) Alcoholic Fermentation
(c) Both 'a' & 'b'
(d) None of these

18. In alcoholic fermentation, pyruvic acid changes to alcohol and:
(a) O₂
(b) H₂O
(c) CO₂ ✓
(d) lactic acid

19. This is used in nature to repair broken DNA.
(a) Defense protein
(b) Restriction enzyme
(c) Hydrolytic enzyme
(d) Ligase enzyme ✓

20. It can also be used to paste new genes into DNA.
(a) Defense protein
(b) Restriction enzyme
(c) Hydrolytic enzyme
(d) Ligase enzyme ✓

21. These are viruses that infect bacteria.
(a) Genome
(b) Plasmids
(c) Phages ✓
(d) Ligase

22. When segments of DNA are cut and pasted together to form new sequences, the result is known as:
(a) recombine DNA
(b) recombinant DNA ✓
(c) genetically modified organism
(d) transgenic cells

23. Cells that have recombinant DNA are known as:
(a) genetically modified organism
(b) transgenic cells
(c) Both 'a' & 'b' ✓
(d) None of these

24. An important way of making ATP without oxygen is called:
(a) Fermentation ✓
(b) ligase
(c) fermenter
(d) phages

25. It is the commercialization of cell and molecular biology.
(a) Genetics
(b) Inheritance
(c) Biotechnology ✓
(d) Heredity

26. It is controlled use of biological agents for beneficial use.
(a) Genetics
(b) Inheritance
(c) Biology
(d) Biotechnology ✓

FILL IN THE BLANKS:
1. Biotechnology can be defined as "the use of living organisms, cells or cellular components for the production of compounds or precise genetic improvement of living things for the benefit of man".
2. Biotechnology is integrated use of biochemistry, molecular biology, microbiology to achieve technological application of the capabilities of biological agents.
3. An important way of making ATP without oxygen is called fermentation.
4. There are two major types of anaerobic fermentation: lactic acid fermentation and ethanol fermentation.
5. Fermentation is carried out by the bacteria Streptococcus and Lactobacillus species for souring milk into yogurt and production of various types of cheese.
6. Yeasts in bread dough use alcoholic fermentation and produce carbon dioxide gas.
7. The carbon dioxide gas forms bubbles in the yeast dough, which cause the dough to expand.
8. The process of fermentation is a natural preservative, which means that fermented foods can last a long time.
9. The fermentor is to provide a stable and optimal environment for microorganisms to reproduce and interact with substrate for required product.
10. To manipulate cells and DNA, scientists use tools.
11. Restriction enzymes are naturally occurring enzymes and are used to cut up DNA use like scissors to snip specific genes from DNA.
12. DNA ligase enzyme is used in nature to repair broken DNA.
13. Plasmids are circular units of DNA.
14. Plasmids can be engineered to carry genes of interest.
15. Single-Cell Protein (SCP) is a term represents microbial cells (primary) grown in mass culture and harvested for use as protein sources in foods or animal feeds.
16. Single Cell Protein (SCP) is not a pure protein but refers to whole cells of bacteria, yeasts, filamentous fungi or algae.
17. Many types of animal feeds contain single cell proteins.
18. 60-80%  dry cell weight; contains nucleic acids, fats, CHO, vitamins, and minerals rich in essential amino acids (Lys-Met).
19. Hungarian agriculture engineer called Karl Ereky coined the word Biotechnolgy.
20. Genetic engineering refers to any process in which an organism's genome is intentionally altered.
21. A DNA fragment may be isolated from one organism, spliced to other DNA fragments, and put into a bacterium or another organism. This process is called cloning.
22. In 1978, the first genetically engineered drug, human insulin was produced by bacteria.
23. DNA fingerprints is utilized for identification of parents and criminals.
24. Fermentation is the process by which living organism such as yeast and bacteria are employed to produce useful compounds or products.
25. Lactic acid fermentation is also used by your own muscles when you work then hard and fast.
26. Alcoholic fermentation is carried out by yeast saccharomyces cerevisiae and some bacteria.
27. Alcoholic fermentation is used to make bread, wine, and biofuels.
28. Fermentation changes the chemical environment of a food.
29. Fermentation is an important process in the preparation of food for human consumption.
30. E coli stands for Escherichia coli.
31. Bacteriophages is also known as phages.
32. Bacteriophages are virus that infect bacteria.
33. Cells that have recombinant DNA are known as genetically modified organism (GMO) or transgenic cells.
34. Sleeping sickness (trypanosomiasis) is caused by a parasite called Trypanosoma brucei.
35. A gene called p-53 which normally keeps cells under control and work best to suppress cancer cells.

Biology For Class X - Chapter No. 6 - Inheritance - Notes By FAW Group Of Education

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CHAPTER 6: INHERITANCE

Notes By FAW Group Of Education

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Turning Effect Of Forces - Physics For Class IX (Science Group) - Numericals

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Physics For Class IX (Science Group)
UNIT 4: TURNING EFFECT OF FORCES
Numericals

Worked Example 1

1. Find the resultant of three forces 15 N along x-axis, 10 N making an angle of 30° with x- axis and 10 N along y-axis.
Solution:
Step 1: Write the Known quantities and choose a suitable scale.
Here,

• F₁ = 15 N along x-axis
• F₂ = 10 N 30° with x-axis
• F₃ = 10 N along Y-axis.
• Scale 2 N = 1 cm.

Step 2: Draw the representative vectors for the forces F₁, F₂, F₃ according to the scale in the given directions.

Step 3: Take F₁ as first vector and draw F₂ and F₃ in such away that the tail of next vector coincides with the headof the previous vector.

Step 4: Join the tail of the F₁ with the head of F₃ with a straight-line F with an arrow pointing towards F₃.
According to head to tail rule, Force F represents the resultant force.

Step 5: Measure the length of F with a ruler and multiply it with 2 Ncm^-1 that is the magnitude of resultant. Measure the angle with protector that F makes with F₁. This gives the direction of resultant Force.

Worked Example 2

2. A man is pushing a wheelbarrow on a horizontal ground with a force of 300 N making an angle of 60° with ground. Find the horizontal and vertical components of the force.
Solution:
Step 1: Write the known quantities and point out the quantities to be found.

• F = 200 N
• θ = 60° with horizontal.
• F_x = ?
• F_y =?

Step 2: Write the formula and rearrange if necessary.

• F_x = F cos θ
• F_y = F sin θ

Step 3: Put the values in the formula and calculate.

F_x = F cos 60°
F_x = 300 N x cos 60°
F_x = 300 N x 0.5
F_x = 150 N

F_y = F sin 60°
F_y = 300 N x sin 60°
F_y = 300 N x 0.8660
F_y = 259.8N

Ans: Therefore, horizontal and vertical components of pushing force are 150 N and 259.8 N respectively.

Worked Example 3

3. A car driver tightens the nut of wheel using 20 cm long spanner by exerting a force of 300N. Find the torque.
Solution:
Step 1: Write the known quantities and point out the quantity to be found.

• F = 300 N
• L = 20 cm = 0.20 m
• τ = ?

Step 2: Write the formula and rearrange if necessary.

τ = F × L

Step 3: Put the values in formula and calculate

τ = 300 N × 0.20 m = 60 Nm

Ans: Thus, torque of 60 Nm is used to tighten the nut.

Worked Example 4

4. Consider a meter rod supported at mid-point O as shown in figure. The block of 20 N is suspended at point A 30 cm from O. Find the weight of the block that balances it at point B, 20 cm from O.
Solution:
Step 1: write known quantities and point out unknown quantities.

• W₁ = 20 N
• Moment arm of W₁ = OA = 30 cm = 0.30 m
• Moment arm of W₂ = OB = 20 cm
• W₂ = ?

Worked Example 5

5. A uniform rod of length 2.0 m is placed on a wedge at 0.5 m from its one end. A force of 150 N is applied at one of its ends near the wedge to keep it horizontal. Find the weight of the rod and the reaction of the wedge.
Solution:
Step 1: Write the known quantities and point out unknown.

• F = 150 N
• OA = 0.5 m
• AG = BG = 1.0 m
• OG =AG – AO =1.0 m - 0.5 m = 0.5 m
• W = ?
• R = ?

Step 2: Write formula and substitute values. For W applying second condition of equilibrium, taking torques about O.

Σ𝜏 = 0

F x AO + R x 0 + W x OG = 0

150 x 0.5 - W x 0.5 = 0 or

W x 0.5 m = 150 x 0.5 m

Numericals (Self Assessment Question)

Q.8: What will be moment of force? When 500 N force is applied on a 40 cm long spanner to tighten a nut.
Solution:
Data:

• F = 500 N
• L = 40 cm = 40/ 100 = 0.40 m
• τ = ?

Formula:

τ = F × L

Calculation:

τ = 500 × 0.40 =200 Nm.

Ans. Thus, the moment of force will be 200 Nm.

Q.12: If two forces 5 N each form a couple and the moment arm is 0.5 m .Then what will be torque of the couple?
Solution:
Data:

• F = 5 N
• d = 0.5 cm
• τ = ?

Formula:

τ = F x d

Calculation:

τ = 50 x 0.5 = 2.5 Nm

Ans: Thus, The torque of the couple will be 2.5 Nm.

Numericals (Text Book exercise)

Section (B) Structured Questions
Forces on bodies:
1. b) A pair of like parallel forces 15 N each are acting on a body. Find their resultant.
Ans: SOLUTION:
Data:

• F₁ = 15 N
• F₂ = 15 N
• F = ?

Formula:

F = F₁ + F₂

Calculation:

F = 15 + 15 = 30 N

Ans. Their resultant force is 30 N.

1. c) Two unlike parallel forces 10 N each acting along same line. Find their resultant.
Ans: SOLUTION:
Data:

• F₁ = 10 N
• F₂ = 10 N
• F = ?

Formula:

F = F₁ - F₂

Calculation:

F = 10 - 10 = 0 N

Ans. Their resultant force is Zero.

Addition of forces
2. b) Three forces 12 N along x-axis, 8 N making an angle of 45° with x-axis and 8 N along y-axis.
i) Find their resultant
ii) Find the direction of resultant
Ans: SOLUTION:
Data:

• F₁ = 12 N along x-axis
• F₂ = 8 N making an angle of 45° with x-axis
• F₃ = 8 N along y-axis

Graphical Representation:
Scale: 1 N = 1 square (You can also take 2 N = 1 square)

Ans:

1. Magnitude of Resultant of Force: Measuring the length of F with ruler, it is found that force is 22.322 N.
2. Direction of resultant: Measuring the angle with the protector (Dee) that F makes with F₁, it is found 37.72°

Resolution of forces
3. b) A gardener is driving a lawnmower with a force o of 80 N that makes an angle of 40° with the ground.
i) Find its horizontal component
ii) Find its vertical component
Ans: Solution
Data:

• Force F = 80 N
• Angle = θ = 40°
• Horizontal Component = F_x = ?
• Vertical Component = F_y = ?

Formula:

1. F_x = F cos θ
2. F_y = F sin θ

Calculation:

F_x = F cos θ

F_x = (80) cos 40°

F_x = (80) x (0.766)

F_x = 61.28 N

F_y = F sin θ

F_y = (80) sin 40°

F_y = (80) x (0.642)

F_y = 51.36 N

Ans: Therefore, Horizontal and vertical components of the force are 61.28 N and 51.36 N respectively.

4. b) Horizontal and vertical components of a force are 4 N and 3 N respectively. Find
i) Resultant force
ii) Direction of resultant
Ans: Solution
Data:

• Horizontal Component = F_x = 4 N
• Vertical Component = F_y = 3 N
• Resultant Force = F = ?
• Direction of Resultant = θ

Moment of force
5. b) A spanner of 0.3 m length can produce a torque of 300 Nm.
i) determine the force applied on it.
ii) What should be the length of the spanner if torque is to be increased to 500 Nm with same applied force.
Ans: Solution:
(i) Applied Force
Data:

• Length of the Spanner = L = 0.3 m
• Torque = 𝜏 = 300 Nm
• Applied Force = F = ?

Formula:

𝜏 = F x L

Calculation:

300 = F x 0.3 or

Applied force = F = 1000 N

(ii) Length of spanner
Data:

• Applied Force = F = 1000 N
• Torque = 𝜏 = 500 Nm
• Length of the Spanner = L = ?

Formula:

𝜏 = F x L

Calculation:

500 = 1000 x L or

Length of Spanner = L = 0.5 m

Ans: Therefore,

1. The applied force on the spanner is 1000 N. and
2. The length of the spanner will be 0.5 m.

Principle of moments
6. b) A uniform meter rule is supported at its center is balanced by two forces 12 N and 20 N
i) if 20 N force is placed at a distance of 3 m from pivot find the position of 12 N force on the other side of pivot
ii) if the 20 N force is moved to 4 cm from pivot then find force to replace 12 N force.
Ans: Solution:
(i) Position Of Force
Data:

• 1^st force = F₁ = 20 N
• 2^nd force = F₂ = 12 N
• Moment of arm of F₁ = d₁ = 3 m
• Moment of arm of F₂ = d₂ = ?

Formula:

Clockwise Moment = Anticlockwise Moment

F₁ x d₁ = F₂ x d₂

Calculation:

20 x 3 = 12 x d₂

60 = 12 x d₂

60 = 12d₂

Ans: Therefore, The position or the moment arm of force F₂ on the other side of the pivot is 5 m.

(i) 2^nd Force
Data:

• 1^st force = F₁ = 20 N
• 2^nd force = F₂ = ?
• Moment of arm of F₁ = d₁ = 4 m
• Moment of arm of F₂ = d₂ = 5 m

Formula:

Clockwise Moment = Anticlockwise Moment

F₁ x d₁ = F₂ x d₂

Calculation:

20 x 4 = F₂ x 5

80 = F₂ x 5

80 = 5F₂

Ans: Therefore, if the 20 N force is moved to 4 cm from pivot then the 12 N force would be replaced by 16 N force.

Couple
8. b) A mechanic uses a double arm spanner to turn a nut. He applies a force of 15 N at each end of the spanner and produces a torque of 60 Nm. What is the length of the moment arm of the couple?
Ans: Solution:
Data:

• Applied Force = F = 15 N
• Torque produced = 𝜏 = 60 Nm
• Length of the moment arm of the couple = d = ?

Formula:

𝜏 = F x d

Calculation:

60 = 15 x d

d =   ⁶⁰/₁₅  = 4 m

Ans: Therefore, the length of the moment arm of the couple is 4 m.

8. c) If he wants to produce a torque of 80 Nm with same spanner then how much force he should apply?
Ans: Solution:
Data:

• Applied Force = F = ?
• Torque produced = 𝜏 = 80 Nm
• Length of the moment arm of the couple = d = 4 m (Calculated in Q.8. b above)

Formula:

𝜏 = F x d

Calculation:

80 = F x 4

F =  ⁸⁰/₄   = 20 N

Ans: Therefore, If he wants to produce a torque of 80 Nm with same spanner then he should apply 20 N force.

Equilibrium
9. b) A uniform metre rule is balanced at the 30 cm mark when a load of 0.80 N is hung at the zero mark.
i) At what point on the rule is the Centre of gravity of the rule?
ii) calculate the weight of the rule?
Ans: Solution:
(i) Data:
Load = 0.80 N

• Moment arm of F = OA = 30 cm = ³⁰/₁₀₀ = 0.3 m
• Length of the rule = L = 1 m
• The Centre of gravity of the rule = ?

(ii) Data:

• Load = 0.80 N
• Moment arm of F = OA = 30 cm = ³⁰/₁₀₀ = 0.3 m
• Weight of the rule = W = ?
• Moment arm of W = OG = 20 cm = ²⁰/₁₀₀ = 0.20 m

Formula:

∑𝜏 = 0

Calculation:

F x OA + R x 0 - W x OG = 0

0.8 x 0.3 + 0 - W x 0.20 = 0

0.24 - W x 0.20 = 0

W x 0.20 = 0.24

W =   ^0.24/_0.20  = 1.2 N

Ans: Therefore, The weight of the rule is 1.2 N.

More Numericals

10) A telephone pole of mass 300 kg is 30 m long. Its center of gravity is 10 m from the thick end. What force must be applied at the thin end to maintain the pole in horizontal position when it is supported at its mid point?
Ans: Solution:
Data:

• Mass of the pole = 300 kg
• Length of the pole = 30 m
• Center of gravity = 10 m
• Weight of the pole = W = mg = 300 x 9.8 = 2940 N

Required Data:

• Force = F = ?

Formula:

∑𝜏 = 0

Calculation:
Forces acting on the pole are shown in the figure where W represents the weight of the pole and F represents the force applied to the thin end to maintain the pole in a horizontal position when it is supported at its mid point.
From figure we have,

• AB = 30 m,
• AC = 15 m,
• BC = 15 m,
• DC = 5m

Now, According to 2nd condition of equilibrium about C, we have

∑𝜏 = 0

W x DC - F x BC = 0

2940 x 5 - F x 15 = 0

14700 - 15F = 0

15F = 14700

F =  ¹⁴⁷⁰⁰/₁₅

F = 980 N

Ans: Therefore, To maintain the pole in horizontal position 980 N force must be applied at the thin end.

11) A uniform rod 10 meters long and weighing 30 N is supported in a horizontal position on a fulcrum with weight of 40 N and 50 N suspended from its ends as shown in the figure. Find the position of the fulcrum.
Ans: Solution:
Data:

• The length of rod = AB = 10 m
• The weight of point C = W_c = 30 N
• The weight of point A = W_a = 4 0N
• The weight of point B = W_g = 50 N
• The length of rod between A and C = 5 m

Required Data:

• Position of fulcrum = x = ?

Formula:
(i) 1^st condition of equilibrium:
F = F_x + F_y Or
F - F_x - F_y = 0
(ii) According to 2^nd condition of Equilibrium
∑𝜏 = 0

Calculation:
The weight of the uniform rod acts at “C”. Let D be the fulcrum and F be the upward force at the fulcrum. Suppose x is the position of the fulcrum with respect to A. The rod is in equilibrium.
(i) Now by applying 1^st condition of equilibrium:

∑F_x = 0

∑F_y = 0

Now,

F - 40 - 30 - 50 = 0

F - 120 = 0

F = 120 N

(ii) Now by applying 2^nd condition of Equilibrium

∑𝜏 = 0

F x AD - W x AC - 50 x AB = 0

120 x X -30 x 5 - 50 x 10 = 0

120X - 650 = 0

120X = 650

X = ⁶⁵⁰/₁₂₀

X = 5.41 m

Ans: Therefore, the position of the fulcrum is 5.41 cm.

12) A force of 25 N acts on a body. If moment of arm is 2 m, find the value of torque?
Ans: Solution:
Data:

• Force = F = 25 N
• Moment of arm = d = 2 m

Required Data:

• Torque = 𝜏 = ?

Formula:

𝜏 = F x d

Calculation:

𝜏 = 25 x 2

𝜏 = 50 Nm

Ans: Therefore, the value of torque is 50 Nm.

13) A force is applied perpendicularly on a door 4 meters wide which requires a torque of 120 Nm to open it. What will be minimum force required?
Ans: Solution:
Data:

• Moment of arm = d = 4 m
• 𝜏 = 120 Nm

Required Data:

• Force = F = ?

Formula:

𝜏 = F x d

Calculation:

120 = F x 4

120 = 4F

F =  ¹²⁰/₄  = 30 N

Ans: Therefore, minimum force required is 30 N.

14) What is the moment of the couple of 10 N acting at the extremities of a rod 5 m long as shown in figure. How can this couple be balanced?
Ans: Solution:
Data:

• Force = F = 10 N Couple arm
• = d = 5 m

Required Data:

• Moment of couple or torque = 𝜏 = ?

Formula:

𝜏 = F x d

Calculation:

𝜏 = 10 x 5 = 50 Nm

Ans: Therefore, the moment of the couple or torque is 50 Nm.