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Biology 6.1.2: Patterns of Inheritance > phenotypic variation > Flashcards

phenotypic variation Flashcards

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1
Q

what is a phenotype?

A

an observable characteristic

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2
Q

what is phenotypic variation?

A

differences between observable characteristics of a group of organisms

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3
Q

what is interspecific variation?

A
  • differences between different species due to different genes
  • code for different proteins so look and function differently
  • not affected by environment
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4
Q

what is a gene?

A

section of DNA that codes for a particular protein

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5
Q

describe continuous variation

A
  • takes any value on a scale
  • caused by mostly genes with many alleles
  • eg height
  • polygenic
  • histogram
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6
Q

describe discontinuous variation

A
  • variation that fits into distinct categories
  • caused by genes with few/no alleles and the environment
  • eg blood group
  • monogenic
  • bar chart
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7
Q

what is a homologous pair?

A

a pair of chromosomes carrying the same genes but different alleles

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8
Q

what is intraspecific variation?

A
  • differences between organisms of the same species
  • same genes, different alleles
  • subtle differences
  • polygenic traits are affected by the environment
  • monogenic less likely
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9
Q

what is an allele?

A

different versions of a gene with a slightly different base sequence
- slightly different proteins are produced

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10
Q

what is genetic variation?

A

variation caused by differences in DNA base sequences
- different hair/eye colour

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11
Q

what is environmental variation?

A

variation caused by the environment in which the organism lives

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12
Q

what is a chromosome?

A

a long section of DNA made up of many genes

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13
Q

what is a gene?

A

a section of DNA that codes for a particular polypeptide

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14
Q

what is the genotype?

A

combination of alleles an organism has

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15
Q

what is the phenotype?

A

observable characteristics resulting from the genotype

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16
Q

describe environmental modification of a genetic trait

A
  • phenotypes of genetic traits are often modified by the environment
  • traits are usually polygenic
  • eg weight
17
Q

what is chlorosis?

A

a condition where a plant doesn’t produce enough chlorophyll so leaves appear yellow

18
Q

what is chlorosis caused by?

A

the environment

19
Q

why does chlorosis occur?

A
  • lack of light
  • magnesium deficiency
  • virus infection
20
Q

what is etiolation?

A

plants grown in the dark will be yellow and grow long and spindly

21
Q

why does etiolation occur?

A

they grow as long as possible to try and reach a light source

22
Q

which phenotypic characteristics are affected by what we eat?

A

height and weight

23
Q

what genetic and environmental factors influence weight?

A
  • exercise
  • presence of disease
24
Q

how does our diet affect our genes?

A
  • obesity genes are triggered
  • eating unhealthily from a young age can trigger the genes and make it harder to lose weight
25
Q

what is epigenetics?

A
  • changes in gene expression that do not involve DNA sequence changes
  • environment and individual lifestyle interact with the genome to influence epigenetic change
26
Q

state the difference between a homozygous and heterozygous genotype (1)

A

homozygous = same alleles of same gene
heterozygous = different alleles of same gene

27
Q

explain the difference between the phenotype and genotype of an oak tree (2)

A

phenotype = physical appearance eg height
genotype = allele that determines the characteristic

28
Q

state and explain the difference between continous and discontinuous variation (6)

A
  • continuous = variation that takes any value on a scale
  • eg height between 1-200cm
  • influenced by environment and genetics
  • discontinuous = variation that fits into distinct categories which you do or do not have
  • eg eye colour blue/green
  • mainly only influenced by genetics
29
Q

what graph would display data that is controlled by one or two genes and is influenced only by genes? (1)

A

bar chart
- only genetic = discontinuous
- few genes = monogenic

30
Q

state 3 phenotypic characteristics that show discontinuous variation (3)

A
  • eye colour
  • hair colour
  • blood group
31
Q

state 3 phenotypic characteristics that show continuous variation (3)

A
  • height
  • weight
  • hand span

Biology 6.1.2: Patterns of Inheritance (10 decks)

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