KS3 Genetics and Inheritance Flashcards

Not sure if complete (probs good for revision anyways)

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1
Q

What are chromosomes?

A

Thread-like structures composed of proteins and a single molecule of deoxyribonucleic acid (DNA).

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2
Q

Where are chromosomes located (eukaryotes and prokaryotes)?

A
  • Eukaryotes: inside the nucleus.
  • Prokaryotes: inside the nucleoid.
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3
Q

What is DNA?

A

A polymer that contains biological instructions (genes) - makes each species unique.

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4
Q

What is a gene?

A

A segment of DNA which encodes for a particular type of protein.

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5
Q

What are alleles?

A

Different forms of a particular gene.

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6
Q

What are dominant alleles?

A

Alleles whose characteristics are always expressed.

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7
Q

What are recessive alleles?

A

Alleles whose characteristics are only expressed when inherited from both parents.

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8
Q

What is a genotype?

A

The genetic makeup of an individual.

(It is also known as the collection of alleles that an individual has).

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9
Q

Do we have different or similar genotypes? Why?

A

Everyone has different genotypes because everyone has different alleles and different genetic codes.

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10
Q

What is a phenotype?

A

The physical appearance of the characteristics.

(It is also known as the characteristics an organism has as a result of their genotype).

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11
Q

Do we have different or similar phenotypes?

A

It depends:

  • Having the same physical characteristics = same phenotypes.
  • Having different physical characteristics = different phenotypes.

e.g. A blue eyed person and a brown eyed person have different phenotypes.

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12
Q

What is a homozygote?

A

An individual who has identical alleles for a particular gene; a homozygous individual.

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13
Q

What is a heterozygote?

A

An individual who has different alleles for a particular gene; a heterozygous individual.

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14
Q

What is genetic variation?

A

The difference in DNA sequences between individuals within a population.

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15
Q

How many chromosomes are in skin cells?

A

46

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16
Q

How many chromosomes are in gametes? Why?

A

23; When the sperm cell fuses with the ova, the chromosomes from both gametes add up to equal 46, allowing a new cell (zygote) to be formed (aka, you).

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17
Q

What is monohybrid inheritance?

A

The inheritance of a characteristic that is controlled by a single gene or a pair of allele.

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18
Q

What is fertilisation?

A

The fusion of a male and female gamete.

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19
Q

What is a gamete?

A

The reproductive cell of an organism.

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20
Q

What is a zygote?

A

The fertilised egg.

21
Q

What is natural selection?

A

A process where organisms that are better adapted to an environment are more likely / will survive and reproduce.

22
Q

What does natural selection cause in species?

A

A wide range of variations to be seen due to differences in genes.

23
Q

What is variation?

A

The differences (in characteristics) that exists between individuals of the same species.

24
Q

What factors can cause variation? (3)

A
  • Genetics.
  • Environment.
  • Both together (genetics & environment).
25
Q

What are the types of variations / data?

A
  • Continuous.
  • Discontinuous.
26
Q

What is continuous data? (3)

A

Data that can be measured - has infinite number of possible values (can be broken down into smaller values).

27
Q

What is discontinuous data? (4)

A

Data that can be counted - has finite number of possible values (cannot be broken down into smaller values; can be assigned a fixed numerical value).

28
Q

What are examples of continuous data?

A

Data that can be measured, for example:

  • Height
  • Weight
  • Temperature
  • Time (hours → minutes → seconds → milliseconds etc..)
29
Q

What are examples of discontinuous data?

A

Data that can be counted, for example:

  • The number of…
  • The result of rolling a die etc.
30
Q

What questions can be asked to see whether data is continuous of discontinuous? (3)

A
  • Can these values be counted?
  • Can these values be measured?
  • Can these values be broken down into smaller parts and still make sense?
31
Q

What is competition?

A

Refers to when organisms have to compete for limited resources in order to survive - the best adapted are more likely to win and survive.

32
Q

What do plants compete for? (4)

A
  • Water
  • Light
  • Space
  • Minerals (from the soil)
33
Q

What do animals compete for? (4)

A
  • Food and water
  • Shelter
  • Space / territory
  • Mates
34
Q

What is adaptation?

A

The process in which an organism’s features or characteristics improves its chances of surviving and/or reproducing.

35
Q

What causes adaptation?

A
  • Mutation
  • Natural selection
36
Q

What is mutation?

A

The sudden genetic change which could be accidental or random.

37
Q

What are structural adaptations? Give an example.

A

The physical features of an organism that helps it survive in a particular environment.

For example: polar bears have black skin to absorb heat more efficiently.

38
Q

What are behavioural adaptations? Give an example

A

Changes in the way an organism behaves or acts in order to better suit an environment (e.g. the way it feeds, breeds, moves etc.).

e.g. Some birds migrate to warmer regions during winter for food.

39
Q

What is extinction?

A

When there are no remaining individuals of a species alive.

40
Q

What does it mean when a species is extinct in the wild?

A

When the only known living individual of species are in captivity (e.g. zoos).

41
Q

How is continuous data represented?

A

As a line graph or histogram with a bell shaped curve (🔔).

42
Q

How is discontinuous data represented?

A

As a bar chart with random pattern.

43
Q

What is evolution?

A

The process where inherited characteristics in a population change over time due to natural selection.

44
Q

What does the theory of evolution state?

[include person]

A
All species on earth today have evolved from simple life forms from over 3 billion years ago. 
– Charles Darwin.
45
Q

Why do identical twins have identical characteristics?

A

Identical twins develop from a single fertilise egg so they have the same genome.

46
Q

Why do children have characteristics of both parents?

A

Children inherit the genes from both parents which carry inherited traits.

47
Q

How is genetic information passed on from parent to child?

A

The 23 chromosomes from each parent are in the male and female gamete which fuse to create a zygote.

48
Q

What are examples of genetic variation? (7)

A
  • Natural eye / hair colour.
  • Blood group - AB, A, B or O.
  • Maximum potential height.
  • Earlobe attachement.
  • Freckles.
  • Dimples.
49
Q

What are examples of environmental variation? (6)

A
  • Hair length / colour (length you choose to have / hair dye).
  • Scars (personal experience).
  • Muscle strength (dependent on amount of exercise).
  • Piercings / tattoos (your choice).