cloning and biotechnology

Question 1

clones

Answer 1

Clones are genetically identical copies.
Can apply to cells or whole organism.
Clones are produced by asexual reproduction
Nucleus is divided by mitosis

Question 2

examples of natural cloning in nature

Answer 2

single- celled yeast reproduce by budding
Bacteria reproduce by binary fission.
Both processes involve exact replication of DNA

Question 3

Advantages of natural cloning

Answer 3

If the conditions for growth are good for the parent then they will be good for the offspring.

Cloning is relatively rapid- can increase population and take advantage of suitable environmental conditions

Able to reproduce if only one parent or if sexual reproduction not possible.

Question 4

Disadvantages of natural cloning

Answer 4

The offspring may become overcrowded
There will be no genetic diversity
If environment changes to be less advantageous the whole population is susceptible.

Question 5

Horticulture

Answer 5

The practice of garden cultivation and management. Improving quality.

Natural cloning methods are often used by horticulture gardeners to increase the number of plants.

Question 6

Natural cloning in plants involves a process called vegetative propagation

Answer 6

Process of asexual reproduction from non-reproductive tissues such as stems and leaves to produce genetically identical copies.

Question 7

Method of vegetative propagation:

Rhizomes

Answer 7

Stem structures that grow horizontally, underground, away from parent plant. Contain nodes from which new shoots and roots can grow.
E.g. Bamboo

Question 8

Method of vegetative propagation:

Runners

Answer 8

Stem structures that grow horizontally, above ground on the surface of the soil. New shoots and roots can develop from nodes or the end of the runner. e.g. strawberries

Question 9

Method of vegetative propagation:

Tubers

Answer 9

Large underground food store used by the plant. ‘Eye’ cells use this food to produce energy for cell division. These cells then grow and develop into new plants.
e.g. potatoes

Question 10

Method of vegetative propagation:

Suckers

Answer 10

New stems grow from the root of parent plant.

e.g elms

Question 11

Natural cloning in animals

Answer 11

Mammals clone when identical twins are formed. This occurs when a fertilised egg divides as normal. But then the two daughter cells then split to become two separate cells. Each cell grows and develops into a new individual.

Question 12

Artificial cloning in plants: cutting

Answer 12

Stem:
Cut stem between two nodes
Dip cut stem in rooting powder(auxin)
Stem planted in damp compost

Leaf: Score the large veins of the lower surface of a leaf.
Place broken veins downwards on the growth medium.

Scion cutting: dormant woody twigs

Put in a clear plastic bag- creates moist and warm conditions

Question 13

Artificial cloning in plants: Tissue culture

Answer 13

Used to clone plants that don’t readily reproduce
The cloned plants come from one individual

cells from original plant are taken
Cells from root and stem are taken as they contain meristem cells which can differentiate
Cells are sterilised to kill microorganisms that will compete for nutrients.
Cells are placed on a growth medium containing nutrients and growth hormones.
When the cells have divided and grown into small plants they are planted in soil.
Plants are genetically identical to the original plant.

Question 14

Artificial cloning in plants: Micro propagation

Answer 14

To produce lots of cloned plants very quickly
Involves taking cells from developing cloned plants and sub culturing them in new fresh growth medium.
Involves same steps as tissue culture( sterilise, growth hormones)
Produces a large number of cloned plants.
An extension of tissue culture.

Question 15

Biotechnology

Answer 15

The use of living organisms or parts of living organisms in industrial processes

Question 16

Biotechnology products: Food

Answer 16

Mycoprotein
Uses a fungus protein to produce vegetarian food

Lactobacillus bacteria- use lactic acid to produce yoghurt and cheese

Question 17

Biotechnology products: pharmaceutical drugs

Answer 17

Penicilin
Uses fungus penicilium
In times of stress, fungi from penicilium produce penicillin, an antibiotic, to stop bacteria growing and competing for resources. Most common used antibiotic in medicine.

Question 18

Biotechnology products: enzymes

Answer 18

Lactase- to make lactose free milk
Amylase- to digest starch to sugar to make syrups which are used for sweeteners
Protease- used to pre-digest proteins for use in baby food
use of bacteria to produce - protease and lipase- use in washing detergents to break down stains (containing lipids and proteins) into water-soluble substances.

Question 19

Biotechnology products: bioremediation

Answer 19

use of various bacteria and fungi to clean waste water
Removing pollutants like oil and pesticides from contaminated sites. These bacteria break down the pollutants into less harmful products.

Question 20

Biotechnology products: the protein hormone insulin

Answer 20

Insulin is a hormone that’s crucial for treating people with type 1 diabetes. Insulin is made by genetically modified bacteria, which have had the gene for human insulin production inserted into their DNA.

Question 21

Advantages of using microorganisms in biotechnology

Answer 21

Microorganisms are relatively cheap and easy to grow.
The production takes place at lower temperatures than would be required to make molecules via chemical engineering. Saves fuel and reduces cost.
Production may take place at normal atmospheric pressure. In comparison to chemical reactions that require high pressure.
microorganisms have a short life cycle and reproduce quickly. Means a large population can be grown inside reaction vessel.
Fewer ethical issues to consider.

Question 22

Biotechnology: food production: Yoghurt

Answer 22

Yoghurt is milk that has undergone fermentation
Bacteria lactobacillus converts lactose to lactic acid.
The acidity denatures the milk protein causing it to coagulate

Question 23

Biotechnology: food production: Cheese

Answer 23

Lactobacillus is added to milk to produce lactic acid from lactose
This acidifies the milk
Rennen is added to the milk which contains the enzyme chymosin
Rennet coagulates the milk protein
The resulting solid, the curd, is separated from the liquid, the whey.

Question 24

Biotechnology: food production: baking

Answer 24

Bread uses yeast.
The dough is left in a warm place while the yeast (contains a fungus) anaerobically respires.
This produces CO2 which causes the bread to rise.
The ethanol evaporates.

Question 25

Biotechnology: food production: brewing i.e. making beer

Answer 25

Alcoholic beverages are made by anaerobic respiration of yeast. The yeast uses glucose from grapes e.g. to respire producing CO2 and ethanol. This is called fermentation.

Question 26

Biotechnology: food production: advantages

Answer 26

Production of protein may be many times faster than that of animal or plant protein.

The biomass produced has high protein content: 45-85%

Production can be increased or decreased according to demand.

Contains no animal fat or cholesterol.

Microorganisms can be genetically modified to adjust amino acid content of protein.

Question 27

Biotechnology: food production: disadvantages

Answer 27

Some people may not want to eat fungal protein that has been grown on waste.

The conditions needed for microorganism growth are also optimum for pathogenic growth. Need to be careful culture is not infected.

Palatability: fungal protein lacks texture and taste f animal protein.

Amino acid profile altered- deficient in methionine.

Question 28

Aseptic technique

Answer 28

Use of sterile conditions in culturing and manipulating microorganisms.
Used to prevent contamination of unwanted microorganisms which would reduce yield by:
competing for space and nutrients
spoil the products
produce chemicals that are toxic
In processes of food or medicinal products: products that are contaminated must be discarded which is economically bad.

Question 29

serial dilutions: A sequence of dilutions used to reduce the concentration of a solution

Answer 29

The number of individual microorganisms in a broth can be high. If broth used to inoculate agar plate, there will be too many colonies which make counting impossible, as they merge together. In order to measure rate of growth you need to reduce the population density i.e. concentration. Achieved by serial dilution.

Question 30

The standard growth curve of a closed culture

Answer 30

Closed cultures follow a standard growth curve. The vessel is isolated from the external environment. No extra nutrients are added. Waste products are not removed.

Question 31

lag phase

Answer 31

The population size increases slowly. reproduction rate is slow.
Organisms are adjusting to their environment
They have to synthesise proteins (enzymes)
Cell growth
Activate certain genes

Question 32

Log phase (exponential)

Answer 32

Organisms have adjusted to their environment.
Culture conditions are optimal
Enough nutrients and space - little competition
The population size doubles for each generation

Question 33

Stationary stage

Answer 33

Eventually, increasing amounts of waste products build up
The rate of population growth declines
Nutrients are running out
Reproduction rate equals death rate

Question 34

Death (decline) stage

Answer 34

The population size declines
Nutrients run out
Concentration of waste products become lethal

Question 35

primary metabolite

Answer 35

any product produced during the normal activities (growth, reproduction) of microorganisms
Produced during the log phase

Question 36

Secondary metabolite

Answer 36

any product produced that are not directly involved in the normal growth/ reproduction of microorganisms
occurs in stationary stage.

Question 37

Immobilised enzymes

Answer 37

some biotechnological processes can be simplified by taking the enzymes out of microorganisms. Enzymes act on substrates to generate products. The isolated enzymes are mixed into the reaction product. This means the product must then be separated from the mixture containing enzyme. which is costly and complicated.
and so enzymes are immobilised so they can’t become mixed with product. they are attached to an insoluble surface. immobilised enzyme: an enzyme that is held in place and not free to diffuse through the solution.

Question 38

advantages of immobilised enzymes

Answer 38

Enzymes do not mix with products, so extraction costs are lower.
The enzymes can be re-used

Question 39

method of immobilising enzymes

ADSORPTION

Answer 39

adsorption:
enzymes are bound to a porous, insoluble support such as clay, by hydrophobic and ionic bonds.
The enzyme is bound with the active site exposed and accessible to substrates.

upon binding the active site may become distorted, reducing activity.
The bonding forces are not that strong so the enzyme may become detach and enter reaction mixture

Question 40

method of immobilising enzymes

COVALENT BONDING

Answer 40

enzymes are bound to a porous, insoluble support such as clay, by strong covalent bonds. Cross linking agents are used to link them in a chain. The enzyme is bound with its active site exposed and accessible to substrate.

upon binding the active site may become distorted, reducing activity.
Covalent bonds are a lot stronger and so, less likely to become detached.
Production of covalent bonds are expensive.

Question 41

method of immobilising enzymes

ENTRAPMENT

Answer 41

enzymes molecules are trapped inside a silica gel matrix which does not allow free movement.

the active site is not distorted by process of entrapment and so remains active.

matrix provides protection against extreme conditions- so high temperatures and ph do not denature.

substrate molecules must diffuse in and out of gel matrix. so, only suitable for substrate molecules which are relatively small.

Question 42

Industrial uses of immobilised enzymes

GLUCOSE ISOMERASE

Answer 42

converts glucose to fructose
fructose is much sweeter than glucose
It is used in diet foods - less sugar is needed to obtain the same level of sweetness
Fructose is cheaper than sucrose and so used in food industry

Question 43

Industrial uses of immobilised enzymes

PENICILIN ACYLASE

Answer 43

Some bacteria have become penicillin resistant
semi- synthetic penicillins have been produced which are effective against penicillin resistant organisms yet retain antibiotic properties of penicillin. catalysed by the enzyme peniclin acylase.

Question 44

Industrial uses of immobilised enzymes

LACTASE

Answer 44

Converts lactose into glucose and galactose by hydrolysis
used to produce lactose- free milk
fresh milk can be passed over immobilised enzyme lactase to produce lactose free milk, without mixing lactase into mixture.

important- milk important source of calcium
needed for strong teeth and bones
without milk likely to develop osteoporosis.