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Biology > Inheritance, Variation And Evolution > Flashcards

Inheritance, Variation And Evolution Flashcards

1
Q

Sexual reproduction

A

Involves the fusion of male and female gametes

Mixing of genetic information which leads to variety in the offspring

Sperm and egg cells in animals

Pollen and egg cells in flowering plants

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2
Q

Advantages of sexual reproduction

A

Produces variation in the offspring

If the environment changes variation gives a survival advantage by natural selection

Natural selection can be sped up by humans in selective breeding to increase food production

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3
Q

Asexual reproduction

A

Involves only one parent and no fusion of gametes

No mixing of genetic information leading to genetically identical offspring (clones)

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4
Q

Advantages of asexual reproduction

A

Only one parent needed

Faster than sexual reproduction as do not need to find a mate

Many identical offspring can be produced when conditions are favourable

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5
Q

Reproduction in parasites

A

Malarial parasites reproduce asexually in the human host, but sexually in the mosquito

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6
Q

Reproduction in fungi

A

Many fungi reproduce asexually by spores but also reproduce sexually to give variation

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7
Q

Reproduction in plants

A

Many plants produce seeds sexually, but also reproduce asexually by runners such as strawberry plants, or bulb division such as daffodils

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8
Q

DNA

A

DNA is a polymer made up of two strands forming a double helix

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9
Q

Chromosome

A

The structure made up of DNA that codes for all the characteristics of an organism

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10
Q

Male chromosome

A

XY

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11
Q

Female chromosome

A

XX

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12
Q

Gene

A

A small section of DNA

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13
Q

Genome

A

The entire genetic material of an organism made up of genes

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14
Q

Polymer

A

A long molecule made up of repeating units

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15
Q

DNA bases

A

Adenine (A) - - - - Thymine (T)

Cytosine (C) - - - - Guanine (G)

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16
Q

Triplet code

A

A group of three bases coding for a specific amino acid

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17
Q

Process of protein synthesis

A

The DNA is unzipped and a mRNA (an exact copy of the DNA) binds to each codon (three bases)

This is known as transcription

The mRNA chain moves out of the nucleus into the cytoplasm where it finds a ribosome

tRNA binds to the mRNA and also to amino acids floating in the cytoplasm

Once tRNA joins each mRNA the amino acids join together through bonds created by enzymes

This creates a chain of amino acids known as polypeptides

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18
Q

Mutation

A

A change in the base sequence in a strand of DNA

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19
Q

Three types of mutation

A

Substitution

Addition

Subtraction

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20
Q

Effects of mutations

A

No effect

Alter the proteins appearance

They may change the amino acids coded for and may change the shape of the protein – this could result in it being no longer able to function

They may be advantageous e.g. result in a more efficient enzyme

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21
Q

Allele

A

Different forms of the same gene

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22
Q

Dominant allele

A

Represented by a capital letter

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23
Q

Recessive allele

A

Represented by a lower case letter

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24
Q

Homozygous dominant

A

Both allele’s are dominant

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25
Q

Homozygous recessive

A

Both allele’s are recessive

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26
Q

Heterozygous

A

Two different allele’s

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27
Q

Genotype

A

The genetic make-up of an organism

28
Q

Phenotype

A

An individuals observable traits

29
Q

Polydactyl

A

Inherited condition in which a person has extra fingers or toes

It is caused by a dominant allele

30
Q

Huntington’s disease

A

Inherited disorder that affects the nervous system

It is caused by a dominant allele

31
Q

Cystic fibrosis

A

Inherited condition that causes sticky mucus to build up in your lungs and digestive system

It is caused by a recessive allele

32
Q

Amniocentesis

A

A test to see whether your child could grow up with genetic disorders

Carried out 15-16 weeks before pregnancy

A needle is inserted through the skin

33
Q

Chronic villus sampling

A

A test to see whether your child could grow up with genetic disorders

Carried out 10-12 weeks before pregnancy

A catheter (long tube) is inserted through the the cervix

34
Q

Genetic variation

A

Differences between individuals that are inherited from parents

35
Q

Natural selection

A

When the best adapted organisms are able to survive

‘Survival of the fittest’

36
Q

Selective breeding

A

Involves people taking charge of selection to produce new varieties of species

37
Q

Process of selective breeding

A

Decide which characteristics are most important

Choose parents that show these characteristics

Breed them together

Choose the best offspring from parents to breed the next generation

Repeat the process

38
Q

Advantages of selective breeding

A

Can choose -

Disease resistance in food crops

Animals which produce more meat or milk

Domestic dogs with a gentle nature

Large or unusual flowers

39
Q

Genetic engineering

A

Add, change or remove an organisms gene to alter it’s characteristics

40
Q

Process of making insulin (genetic engineering)

A

A cell which can produce insulin is taken from a healthy human

The insulin gene is cut out of the human DNA using an enzyme

A plasmid is used to transfer the gene

The plasmid is removed from the bacteria and is cut open using an enzyme

The insulin gene is inserted into the plasmid using another enzyme

The plasmid with the insulin gene is taken up by bacteria so it can reproduce quickly

The insulin is then collected and ready for use

41
Q

4.6.2.4 Genetic engineering GM crops

A
42
Q

Cloning

A

When an organism has been produced by asexual reproduction and is genetically identical to its parents

43
Q

Cloning in plants

A

Tissue sample scraped from parent cell

Placed in agar jelly

Grows in a petri dish

Placed in a compost to finish growing

OR

The tip of a plant is cut

You place it in a compost to let it grow

44
Q

Adult cell cloning

A

A cell was taken from the udder of a sheep

An egg was taken from the ovary of a sheep

The nucleus was sucked out of the egg (enucleated)

The udder cell and the enucleated are fused together with electricity

Cell division occurs until an embryo is formed

The embryo is implanted into the female sheep

A calf is now born from the DNA of the male sheep

45
Q

Evolution

A

The gradual change of a species characteristics

46
Q

Charles Darwin’s theory of evolution

A

All species of living things have evolved from simple life forms that first developed

47
Q

Why was Charles Darwin’s theory initially rejected?

A

Not enough fossil evidence

Inheritance and genes where not known at the time

48
Q

Jean-Baptiste Lamarck theory of evolution

A

He proposed that the way an organism behaved affected their features – if they used something a lot over time,
this feature would grow and develop

49
Q

Speciation

A

The formation of new species

50
Q

The process of speciation

A

A population becomes geographically isolated from the original population (rivers)

They are now different environmental conditions in the new population

Mutations can occur causing variation

Natural selection occurs, whereby the best adapted individuals survive and reproduce

The new population eventually changes to the point where it can no longer inbreed with the old population

51
Q

Gregor Mendel’s discovery

A

He found that some traits could be hidden within a generation, leading to the discovery of dominant and recessive alleles

He used different coloured pea plants to do this

52
Q

Fossil

A

The remains of an organisms that lived in the past found preserved in rock

53
Q

Formation of fossils (frozen)

A

The organisms body is frozen to preserve its body

54
Q

Formation of fossils (footprint)

A

A footprint fossil show the characteristics of the animal

55
Q

Formation of fossils (skeletal)

A

The organism dies and gets covered by mud

The organs of the organism decay

The skeletal system of the organism is left

The mud surrounding the organism becomes a rock

The rock mineralises

56
Q

Conditions for decaying

A

No oxygen

Heat

57
Q

Why don’t we have a complete fossil record?

A

Early organisms had soft bodies (no skeletal system)

Fossils may have been destroyed

Fossils have not been found

58
Q

Reasons for extinction

A

The animals could not adapt to their new surroundings or environment

59
Q

MRSA bacteria

A

Resistant to most antibiotics and dangerous once entering the body

60
Q

How to prevent MRSA

A

Wash hands

Only prescribe antibiotics when needed

Patients finish full course

61
Q

Classification

A

Is the organisation of living things into groups, according to their similarities

62
Q

Domains

A

Kingdom
Phylum
Class
Order
Family
Genus
Species

63
Q

Archaea

A

Primitive bacteria usually living in extreme environments

64
Q

Bacteria

A

True bacteria

65
Q

Eukaryota

A

Includes protists, fungi, plants and animals

Biology (10 decks)

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