Inherited change Flashcards

1
Q

What does codominant mean?

A

Alleles which are both expressed in the phenotype (if they occur together)

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2
Q

What is the genotype?

A

The combination of alleles expressed by an organism

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3
Q

What is a phenotype?

A

The observable characteristics of an organism due to their genotype and environment

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4
Q

What is an example of co-dominance?

A

Flower colour in snap dragons, the can be red (CrCr), white (CwCw) or pink (CrCw)

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5
Q

What allele exist for blood groups and how do they interact?

A

Ia, Ib and Io for blood group A, B and O, A and B exist in co-dominance, causing AB blood group, O is reccesive to both

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6
Q

What combination of alleles is used in the test cross?

A

Homozygous dominant + homozygous recessive produces all dominant alleles, heterozygous and homozygous recessive produces half and half

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7
Q

What is the difference between blood group?

A

A or B antigen is displayed on the membrane of red blood cells, the O group displays neither

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8
Q

Which sex chromosome carries more alleles?

A

The Y chromosome is shorter than the X chromosome, so it carries fewer alleles

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9
Q

How is colour vision affected by gender?

A

The allele for colour vision is only on the X chromosome, colour blindness is recessive therefore boys, who only have one X chromosome are more likely to have the colour blindess

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10
Q

What are some other inheritance sex linked?

A

Haemophilia

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11
Q

What is a Barr Body?

A

Supercoiled inactivated X chromosome, which occurs early in females embryonic development

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12
Q

What are dihybrid crosses?

A

Consideration of two characteristics at the same time

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13
Q

If the genotype is RrYy, what are the gametes produced?

A

RY, Ry, rY, ry

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14
Q

What is an autosome?

A

A non-sex chromosome

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15
Q

What is autosomal linkage?

A

When two genes are located on sex chromosomes, so are inherited today

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16
Q

How does distance relate to chances of autosomal links crossing over?

A

The further away they are the more likely crossing-over will occur

17
Q

If a population has 5,000 people, how many alleles of each gene are there?

A

10,000

18
Q

What 5 things are assumed in the Hardy-Weinberg equation?

A

No mutations, population is isolated, no selection, large population and mating is random

19
Q

What is the Hardy-Weinberg equation?

A

p^2 +2pq+ q^2, where p represents the dominant allele and q represents the recessive allele

20
Q

What are the types of variation?

A

Intraspecific (differences that exist between same species) and interspecific (differences that exist between different species)

21
Q

What causes variation?

A

Genetic causes- random mutation, meiosis and random fertilisation
Environmental causes
Combinations

22
Q

What types of adaptations are there?

A

Behavioural, physiological and anatomical

23
Q

What is selection pressure?

A

An environmental factor that confers a greater chance of survival to reproductive age on some members of the population

24
Q

What are the three types of selection?

A

Directional- for or against an extreme phenotype
Stabilising- selects against both extreme phenotypes
Disruptive- selects against the most common/average phenotype

25
Q

What is genetic drift?

A

The change in frequency of an existing gene variant in the population due to random chance

26
Q

What is speciation and what are the types?

A

The formation of a new and distinct species in the course of evolution
Allopatric and sympatric speciation

27
Q

What is allopatric speciation?

A

Involves the geographical isolation of individuals

28
Q

What are the possible types of barriers in allopatric speciation?

A

Mountain ranges, the sea(for terrestrial species) or bodies fo freshwater, the land(for aquatic species), glacial masses and valleys

29
Q

What is sympatric speciation?

A

When there is no geographical isolation of the population, it involves reproductive isolation within a randomly mating population, this leads to a rapid genetic change which alters morphology, behaviour and habitat preferences

30
Q

What is polyploidy?

A

Cell division error that leads to the chromosomes doubling, this is an example of sympatric speciation

31
Q

What’s genetic bottlenecks?

A

When the population is reduced, with the genetic diversity, so when the population rises again, inbreeding is likely, this means the population will not be able to adapt as readily