Cloning Flashcards
describe the stages in the production of cloned mammals?
- remove the nucleus of a sheep’s egg cell, to create an enucleated cell
- a diploid (full set of paired chromosomes) nucleus is inserted into the enucleated cell (diploid nucleus taken from the udder cell of a different sheep)
- cells are stimulated by an electric shock; starts dividing by mitosis, just like a normal fertilised egg
- the dividing cell is implanted into the uterus of another sheep (the surrogate mother)
what are the ethical issues of cloning?
- the cloned embryo is created solely for destruction
- health risks to the mother
- low success rate meaning loss of large number of embryos and fetuses
- commodification of human life
what are the advantages of cloning?
- all new plants and animals are genetically identical therefore will have the desired characteristics
- organisms that are difficult or slow to breed normally can be reproduced quickly.
what are the disadvantages of cloning?
- if a clone is susceptible to disease or changes in environment, then all the clones will also be susceptible
- it will lead to less variation, and less opportunities to create new varieties in future
what is selective breeding?
in selective breeding humans breed from animals or plants that have desired characteristics that they want
what is natural selection?
in natural selection the organisms that breed are those that are best suited to the environment
what are the steps in selective breeding?
- decide which characteristics are important
- choose parents that show these characteristics
- mate the chosen parents showing the desired characteristics
- select the best offspring (that show these characteristics) from parents to breed the next generation
how can selective breeding be sped up?
- micro propagation of plants
- artificial insemination in animals
- embryo transfer in animals
- cloning of animals
what does DNA do?
DNA controls the joining together of amino acids to make proteins in our cells
how does DNA join together amino acids?
it is because of the sequencing of the base pairs:
- A (adenine) always pairs with T (thymine)
- G (guanine) always pairs with C (cytosine)
what is gene transfer?
this is where a section of DNA (a gene) is transferred from one living things chromosome to another’s. This is called genetic modification or genetic engineering.
what are restriction enzymes used for?
they are used to cut DNA at a specific sites so that a section of DNA can be taken from a cell
what are ligase enzymes used for?
they can be used to join together different sections of DNA at specific sites to create new DNA
what are vectors?
vectors take pieces of DNA and insert them into other cells
how do plasmids act as vectors?
bits of bacterial plasmids can be “cut” with enzymes called restriction endonucleuses. These bits of DNA are called recombinant DNA. New genes can be “glued” into them using ligases. In genetic engineering they are used to transfer genes from one living thing to another.
what is genetic engineering?
the process of removing a gene from one living thing and putting it into another
how do viruses act as vectors?
when a virus or plasmid is inside a host cell it may pick up DNA, it may then carry this into another host cell. The foreign DNA is known as recombinant DNA.
how is GM insulin produced?
- the gene for making insulin is cut from a length of human DNA using restriction enzymes
- it is inserted into a plasmid using ligase enzymes
- the plasmid goes into a bacterial cell
- the transgenic bacterium reproduces, resulting in millions of identical bacteria that produce human insulin
- this mass production is done inside a fermenter
what is a fermenter
a container in which fermentation takes place
what are the advantages of GM crops?
- can be manipulated to get desired characteristics
- can prevent hereditary diseases (less chemicals needed to kill weeds/pests) which is better for the environment
- greater yields
- can be made for specific environments
what are the disadvantages of GM crops?
- irreversible
- natural food chains disrupted
- not scientifically proven that they’re always safe for consumption
- may have unexpected characteristics
how can using GM crops improve food production?
- crops can be genetically modified to increase yield by making them resistant to insects and weed killer
- making them insect resistant means farmer can spend less money on chemicals like pesticides (better for the environment)
- plants may have DNA that give them more nutritional value (eg. golden rice)
how do glasshouses and polythene tunnels increase the yield of certain crops?
- keeps plants enclosed- free from pests or disease
- artificial light, so plants can photosynthesise even when the sun goes down
- glasshouses trap the suns heat the keep plants warm
- increased levels of co2 (using a paraffin heater)
- increased temp, co2 concentration and light
what effect does an increase of carbon dioxide levels in glasshouses have on crop yield?
farmers will burn paraffin to increase co2 levels. When co2 levels increase so does the rate of photosynthesis until a certain point. As rate of photosynthesis increases, there is more energy for growth, increasing crop yield of plants
what effect does increased temperature in glasshouses have on crop yield?
enzymes have an optimum temperature when they are most efficient so trapping heat in a glasshouse increasing temperature will be closer to that optimum temperature increasing enzyme activity. Increased enzyme activity will allow the rate of photosynthesis to increase, so there is more energy for growth and increased yield.
what are fertilisers?
a chemical of natural substance added to soil or land to increase its fertility
what do most fertilisers contain?
nitrates, phosphates and potassium
what is the role of nitrates?
nitrates are needed to make proteins (what plant cells are made of)
what is the role of phosphates?
phosphates are involved in respiration and growth
what is the role of potassium?
potassium must be present for enzymes to work (without it, plants are unable to carry out reactions)
why do farmers use fertiliser?
to replace the nutrients lost by previous yields or increase crop yields
what are the advantages of using pesticides?
- they are very effective in controlling pests
- they produce fast/instant results
what are the disadvantages of using pesticides?
- pesticides can damage the environment and wildlife
- it’s expensive
- pests can become resistant to the pesticide
- it can leach into the soil
- they are dangerous to humans, so the amount used on food has to be below a safe level
what is biological control?
introducing a predator into the environment with crops to kill pests (eg. ladybirds eat aphids)
what are the advantages of biological control?
- it’s less harmful to wildlife
- there’s longer lasting effects
what are the disadvantages of biological control?
- it doesn’t completely remove pests
- it is not as quick as pesticides
- the predator may become a pest itself
how is maintenance of water quality used to farm large numbers of fish?
water is filtered regularly to make sure fish don’t come into contact with anything it would be unsafe to digest. It also minimises the spread of disease and keeps the oxygen levels high enough to maintain the respiration of the fish
what is intraspecific predation?
fish being bred eating each other
how can farmers control intraspecific predation?
- separating fish of different ages
- separating fish of different genders
- feeding fish regularly
- giving fish adequate room
what is interspecific predation?
farmed fish being prayed on by other species
how can farmers control interspecific predation?
- fencing the area the fish are in
- putting nets around the area the fish are in
- keeping the fish inside tanks
how can farmers minimise the spread of disease between fish?
- water changed regularly
- surrounding sterilised often
- keeping small amount of fish together so only few get contaminated if there is an outbreak of disease
- antibiotics can be given to fish to increase their resistance to disease
how can fish farmers remove waste products from the water?
changing the water or changing the nets and location of the fish kept outside
how often should fish farmers feed their fish?
fish need to be fed often in small amounts, this is so they won’t starve but they won’t be able to overeat but also won’t eat each other. It is important to feed with quality nutrients in for growth.
how can fish farmers use selective breeding for fish?
selective breeding can ensure farmers only produce fish with desired characteristics by letting only the fish with the right characteristics breed and pass on the gene
how is yeast used in the production of beer?
- when yeast is added to sugar a process called fermentation takes place
- fermentation is a type of anaerobic respiration where yeast uses the sugars to respire and changes the glucose into ethanol (alcohol) and co2
how is oxygen prevented from entering in the production of alcohol?
froth produced on the surface by carbon dioxide from the reaction traps oxygen so anaerobic respiration can continue
what happens as the alcohol concentration increases?
the yeast cells begin to die and fermentation slows down
what happens after the yeast has produced the beer?
the beer is tapped out and pasteurised to kill any yeast left in the beer
what does biotechnology mean?
the use of microorganisms to produce products that are useful to humans (eg. beer)
what is the word equation for fermentation?
glucose= ethanol (alcohol) + co2
describe an experiment to investigate co2 production by yeast in different conditions
- mix some sugar, yeast and distilled water together, then add the mixture to a test tube
- connect the test tube to another test tube with water, by attaching it with a bung and a tube
- place the test tube containing yeast in a water bath at a certain temperature
- count how many bubbles are produced in a certain amount of time, calculating the rate of carbon dioxide production
- repeat, but change the temperature of the water bath
what is mycoprotein?
protein derived from fungi, especially as produced for human consumption
what are the advantages of mycoprotein?
- it has no animal fat and little fat overall
- it has no cholesterol
- it has a very high protein content
- it has a high amount of dietary fibre
- it has a useful amount of minerals and B vitamins, particularly zinc and vitamin B12
