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:
- 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. - 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:
TYPES OF FERMENTATION:
There are two major types:
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 beneļ¬cial microorganisms. Some beneficial microorganisms for fermentation are yeasts, molds, and bacteria that obtain their energy through fermentation.
ROLE OF LACTIC ACID BACILLUS IN FERMENTATION OF CURD:
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:
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:
Source: Special Thanks To Sir Syed Arif Ali
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."
Or
"An important way of making ATP without oxygen is called fermentation."
TYPES OF FERMENTATION:
There are two major types:
- Lactic acid fermentation
- Alcoholic 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 beneļ¬cial 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:
Non Food Products Created By Fermentation:
Medicine Products:
Q.No.6: What are some advantages and disadvantages of fermentation?
Ans: ADVANTAGES:
DISADVANTAGES:
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:
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:
2. Classical Or Modern Biotechnology: According to the National Science Academy of United States:
3. General Definition: Generally, biotechnology can be defined as:
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:
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:
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:
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:
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.
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:
- Makes our food more digestible.
- Yeast is used to prepare bread from wheat.
- Milk is converted to curd (yogurt) by bacteria.
- Preparation of cheese and other dairy products.
- 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.
- Acetone is also formed as a by-product.
- It helps restore proper bacteria balance in the intestines.
- It improves heart health.
- It improves the immune system.
- It is the source of ethyl alcohol in beverages.
DISADVANTAGES:
- It is linked with the development of gastric cancer.
- Antibiotic resistance.
- Temporary increase in gas and bloating.
- Lose beneficial bacteria.
- Fermentation is a slow and inefficient process. This means it carries a higher cost of production and requires more energy and resources.
- 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:
- Lactic acid fermentation
- Alcoholic 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
thnk u so so much
ReplyDeleteJAZAKALLAH
Delete