SB4- Natural Selection And Genetic Modification Flashcards

Question

Why are plants and animals often selectively bred

Answer 1

Disease resistance - how well they cope with disease Yield- how much useful product they make Coping with certain environmental conditions Fast growth Flavour

Answer 2

Involves changing the DNA of an organism (it's genome) often by inserting genes from another Creates genetically modified organism (GMO's) Process is much faster than artificial selection but much more expensive

Answer 3

It's a GMO with 2 genes inserted into its genome, one from a daffodil and one from a bacterium They allow rice to produce BETA-CAROTENE in its grains, beta carotene allows humans to make vitamin A - a lack of which can cause blindness

Answer 4

GM goats and sheep to produce proteins in their milk that can treat human diseases GM pigs are being developed with human like organs to use in organ transplants

Answer 5

They make a range of useful substances, including antibiotics and other medicines

Answer 6

The growing of cells or tissues in a liquid containing nutrients or on a solid medium such as nutrient agar This is a useful way to grow many identical cells - this may form a callus (clump of undifferentiated cells) Sometimes the cells are then treated to make them differentiate

Answer 7

It is used to produce new individuals of a plant species that may be difficult to grow from seed - this technique is also used to produce clones of GM plants

Answer 8

In tissue culture everything must be sterile to prevent growth of microorganisms

Answer 9

A Piece of plant is placed in bleach solution to sterilise it Then there are 2 routes The first, then sometimes only a few cells are cut off and placed on sterile nutrient medium to grow into a callus The callus is treated with hormones so the plantlets develop with roots and shoots The plantlets are separated and grown on nutrient medium in sterile conditions When the plants are large enough, they are planted into soil or compost

Answer 10

A piece of plant is placed in bleach solution to sterilise it Sometimes a small piece of plant is cut off and placed on sterile nutrient medium to grow The piece of plant is treated with hormones so it grows roots and shoots When the plants are large enough , they are planted into soil or compost

Answer 11

Used in medicine Used to study viruses Cultures of cancer cells developed to show how they develop and spread - using cell cultures allows scientists to investigate how infected cells respond to new medicines without risking harm to animals or humans Cultures of human cells can be developed into tissues if correctly supported

Answer 12

Selecting certain alleles to breed to make a characteristic

Answer 13

All the organisms are similar so if a change in environment affects one organism - all the others are affected Animal welfare eg chickens produce so much breast they can barely stand up

Answer 14

The GM seeds are expensive Some think that GM crops will reproduce with wild plant varieties and pass on their herbicide and pesticide resistance to wild plants and weeds Others think GM organisms may be bad for health - no evidence to support this

Answer 15

It treats type 1 diabetes Insulin is usually extracted from dead bugs and cows Buy GM bacteria can produce insulin and it's cheaper and suitable for vegans or those who do not eat pork or beef due to religious reasons

Answer 16

The plasmid of a bacteria has genes added, the plasmid of DNA combined in a new and so it's an example of recombinant DNA Scientists use restriction enzymes to cut a useful gene out of an organisms DNA - this cutting leaves sticky ends - they can be joined together using a ligand enzyme Any DNA molecule used to carry new DNA Into another cell is called a vector

Answer 17

A restriction enzyme is used to cut insulin gene from a human chromosome, this makes sticky ends (unpaired bases) The restriction enzyme also cuts plasmids open - creating sticky ends again The sections of DNA containing insulin gene are mixed with cut plasmids so complementary bases on sticky ends pair up An enzyme called ligament is used to joins ends together The plasmids are then inserted back into the bacteria which are then grown in huge tanks and so now the insulin can now be easily extracted

Answer 18

Spraying the crop with insecticides - different ones kill different insects, many only affect the insect once they touch it

Answer 19

A soil bacterium Bacillus thuringiensis was discovered that makes a natural insecticide called the Bt toxin - crystals of it can be sprayed on to cells The genes that control the productions of Bt toxin were introduced into plants so all cells in plants produced it

Answer 20

It only affects insects that chew on the plant tissues - only released when cells are broken while insecticides make kill a range of insect species

Answer 21

Insects that suck the sap from the crop such as aphids don't chew on plant tissue and are not affected and so farmers may still need to spray crops to control other pests Some insects could develop resistance to toxin - But there are many strains (varieties) of B. Thuringiensis bacteria to produce different forms of the toxin

Answer 22

Seeds are more expensive than non GM but farmers usually make more profit by growing GM varieties as long as people are willing to buy it

Answer 23

Using organisms to control pests or weeds

Answer 24

St. John's wort became a weed, it can cause illness in farm animals that eat it, instead of using herbicides Chrysolina beetles that prefer the weed to other plant species, were introduced and within ten years there was less than 1 percent of the original amount of weed left in California

Answer 25

A substance used to increase growth and yield of crop plants

Answer 26

They contain mineral ions such as nitrogen, potassium and phosphorus which allow a crop to grow well

Answer 27

If not all is absorbed by a crop - some can get into a stream, river or lake and can lead to the death of organisms in the water or organisms that drink it