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Science > Natural Selection and Genetic Modification > Flashcards

Natural Selection and Genetic Modification Flashcards

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Biology 101 flashcards
1
Q

What is evolution?

A

A gradual change in the characteristics of a species over time

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2
Q

How old are homo habilis fossils?

A

2.4-1.4 million years old

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3
Q

Describe homo habilis

A

Short with long arms but walked upright

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4
Q

Describe homo erectus

A

Tall (1.79m) and strongly built

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5
Q

Who was Ardi?

A

Most complete set of 4.4 million year old fossilised bones from a female of an extinct human-like species

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6
Q

Describe Ardi

A

About 1.2m tall and 50kg

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7
Q

Who was Lucy?

A
  • Lived 3.2 million years ago and was 1.07m tall
  • Could probably walk upright, though her toe bones were arranged in the same way as those of modern humans but much more curved
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8
Q

What is the order of the homo species?

A

Homo habilis, homo erectus and homo sapiens

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9
Q

What is genetic variation?

A

The characteristics of individuals vary due to differences in genes

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10
Q

What is natural selection?

A

Individuals that have characteristics that allow them to survive better than others in a certain area

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11
Q

What is a common ancestor?

A

Animals that evolved from the same animal

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12
Q

Why is it bad for people to stop taking an antibiotic to treat an infection early because they feel better?

A

Because it leaves resistant bacteria still alive which reproduce and spread, causing infections that cannot be treated with the antibiotic because all the bacteria are now resistant

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13
Q

What is classification?

A

Dividing organisms into groups based on what they looked like

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14
Q

What are the main groups of classification?

A

Kingdoms - animals, plants, fungi, protists and prokaryotes

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15
Q

What are the main characteristics of animals?

A
  • Multicellular with cells arranged as tissues and organs
  • Cells have nuclei
  • No cell walls
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16
Q

What are the main characteristics of plants?

A
  • Multicellular with cells arranged as tissues and organs
  • Have chloroplasts for photosynthesis
  • Cells have nuclei
  • Cellulose cell walls
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17
Q

What are the main characteristics of fungi?

A
  • Multicellular apart from yeasts
  • Live in or on the dead matter on which they feed
  • Cells have nuclei
  • Cells walls contain chitin (not cellulose)
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18
Q

What are the main characteristics of protists?

A
  • Mostly unicellular
  • Cells have nuclei
  • Some have cell walls made of different substances but not chitin
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19
Q

What are the main characteristics of prokaryotes?

A
  • Multicellular
  • Cells do not have nuclei
  • Flexible cell walls
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20
Q

What do all organisms besides prokaryotes have?

A

Unused sections of DNA in their genes - most of a gene is used to make a protein, but these ‘unused’ sections do not help with this

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21
Q

What are the 3 domains that all organisms are divided into?

A
  • Archaea = cells with no nucleus, genes contain unused sections of DNA
  • Bacteria = cells with no nucleus and no unused sections in genes
  • Eukarya = cells with a nucleus, unused sections in genes
22
Q

What is artificial selection?

A

When humans choose certain organisms because they have useful characteristics

23
Q

What is selective breeding?

A
  • When humans breed plants and animals for particular genetic characteristics
  • Repeating this over and over again, humans end up with organisms with the desirable characteristics
  • Still done today to produce new breeds of animal species and new varieties of plant species
24
Q

Name some reasons why plants and animals are often selectively bred

A
  • Disease resistance
  • Yield
  • Coping with certain environmental conditions
  • Fast growth
  • Flavour
25
Q

What is genetic engineering?

A

Involves changing the DNA of one organism (genome), often inserting genes from another

26
Q

What does GMO stand for?

A

Genetically modified organisms

27
Q

What is wrong with genetic engineering?

A

Although it is much faster than artificial selection, it is much more expensive

28
Q

What is tissue culture?

A

The growing of cells or tissues in a liquid containing nutrients or on solid medium (like nutrient agar)

29
Q

How can it be easier for a person’s body to not reject a new organ?

A

By using stem cells from their bone marrow so the immune system would not attack the new organ

30
Q

What may tissue culture form?

A

A callus (clump of undifferentiated cells) that can be treated to make them differentiate (become specialised)

31
Q

Give examples as to what tissue culture is used to produce

A
  • New plants of very rare species which are at risk of extinction
  • New individuals of plant species that are difficult to grow from seed (like orchids)
  • Produce clones of GM plants
32
Q

Describe the process of tissue culture

A
  • Plant is placed in bleach solution to sterilise it
  • 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 plants large enough, planted into soil or compost
33
Q

Why is tissue culture useful in medicine?

A
  • Study viruses which cannot replicate outside of cells
  • Study how cancers develop and spread
  • Investigate how infected cells respond to new medicines without risk to animals/humans
34
Q

Why are alleles a selective breeding risk?

A

In selective breeding, only certain alleles are selected so others become rare or disappear, so these alleles that might be useful in the future are no longer available

35
Q

Why is farming in huge numbers a selective breeding risk?

A

All the organisms are very similar and so if condition changes affects one organism, all the others are affected

36
Q

Why is animal welfare a selective breeding risk?

A

The animals are often exposed to adaptations that cause them pain and suffering (e.g. chickens who produce so much breast meat they can hardly stand up)

37
Q

What are herbicides?

A

Weed killers - kill the weeds but not the crop

38
Q

What useful products do GM bacteria produce?

A

Insulin (treats type 1 diabetes)

39
Q

What does a bacterium have as DNA?

A

One large loop of DNA and plasmids

40
Q

What needs to be done to genetically engineer bacteria?

A

Additional genes added to a plasmid (example of recombinant DNA)

41
Q

What are restriction enzymes used for?

A

To cut a useful gene out of an organism’s DNA, leaving strands of DNA with sticky ends

42
Q

What happens when 2 sticky ends match?

A

They can be joined together using ligase enzyme

43
Q

What is a vector?

A

Any DNA molecule used to carry new DNA into another cell

44
Q

What is yield?

A

The amount of useful crop

45
Q

How can insect pests be controlled?

A

By spraying the crop with chemical insecticides

46
Q

Name an advantage of GM Bt toxin

A

It only affects insects that chew the plant tissues, as the toxin is released when the cells are broken

47
Q

Name a disadvantage of insecticide

A

The sprays may kill a wide range of insect species

48
Q

Name a problem with growing crop plants that make their own insecticide

A

The insects can develop resistance to the toxin, meaning it no longer harms them

49
Q

What is biological control?

A

Using organisms to control pests

50
Q

What are mineral salts?

A

Naturally occurring compounds found in rocks and salts

51
Q

What mineral ions do fertilisers contain?

A

Nitrogen, potassium and phosphorus

52
Q

What happens if not all the fertiliser is absorbed by a crop?

A

Some may get into nearby streams, livers and lakes, which could cause pollution and lead to the death of organisms in the water; this could also cause health problems for humans and animals if they drink the water

Science (23 decks)

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