Genetics Flashcards

1
Q

What is a gene?

A

A part of the DNA molecule of a chromosome that directs the synthesis of a specific polypeptide chain

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2
Q

What is a genome?

A

All the genes carried by a cell or organism

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3
Q

What is an allele?

A

A characteristic controlled by a pair of factors, on inherited from each parents

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4
Q

What is the law of uniformity?

A

When 2 homozygotes with different alleles are crossed, the Fl generation will all be identical heterozygotes

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5
Q

What is the law of segreation?

A

Each individual posses 2 genes for each specific characteristic, only one will be passed on at any give time

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6
Q

What is the law of independent assortment?

A

Members of different gene pairs will segregate independently from one another

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7
Q

What is a genotype?

A

The genetic makup

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8
Q

What is the phenotype?

A

The appearance of an individual, which allele is physically expressed

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9
Q

What is a good way to predict segregation of genes?

A

Punnet square

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10
Q

What does it mean when phenotypes are discrete?

A

The phenotypes are clearly defined, like flies where only have red or white eyes, never pink

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11
Q

What does it mean by quantiative phenotypic traits?

A

Shows a continuous variation over a range of phenotypes

Polygenic expression is possible - where 2 or more genes contribute to outcome

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12
Q

How to differences in alleles arise?

A

Mutations in the gene sequence

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13
Q

What are mutations in alleles called and what does it denote?

A

Single nucleotide polymorphism (SNPs) and constitutes one base pair change

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14
Q

When is a mutation considered an allele?

A

When 1% or more of the population has it, otherwise is known as a rare variant

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15
Q

Describe a metacentric chromosome:

A

Equally long “short” and “long” arms because the centromere is in the center

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16
Q

Describe a submetacentric chromsome:

A

Shorter appearing “short” arms because the centromere is close to the short end, providing unequal chromatids

17
Q

Describe a acrocentric chromosome:

A

Has almost no “short” arms, which are replaced by satellites because the centromere is all the way at one end

18
Q

What is heterochromatin?

A

The “dark bands” on a chromosome indicating tightly packed chromatin (DNA)

19
Q

What is euchromatin?

A

The “light bands” on a chromosome indicating light packed chromatin (DNA)

20
Q

How would you name an area on a chromosome which is chromosome 4, long arm, region 2, band 6?

A

4q26

21
Q

How would you name a reciprocal translation in a male between the long arm of chromosome 6 region 4 band 1 with the short arm of chromosome 3 region 8 band 3?

A

46, XY, t(6;3)(q41;p83)

22
Q

What is the gene pool?

A

All of the alleles for every gene in a given population

23
Q

What is a population?

A

Groups of individuals of the same species that occupy the same enviornment and can inbreed with one another

24
Q

How do you calculate allele frequency?

A

of copies of a specific allele in a population
divided by
total # of all alleles for the gene in population

25
Q

How do you calculate genotype frequency?

A

of individuals within a particular genotype in a population
divided by
total number of individuals in a population

26
Q

What is the Hardy-Weinberg equation?

A

p^2 + 2pq + q^2 = 1

27
Q

What does HW say about gene frequencies?

A

All subsequent generations will have the same proportion of genotypes and allele frequencies

28
Q

What are the conditions for HW?

A
  1. No new mutations
  2. No natural selection
  3. Population is large enough that allele frequency doesn’t change due to sampling error
  4. No migration
  5. Random mating
29
Q

What is it called when genetic variation occurs in a population?

A

Microevolution

30
Q

What are the 2 traits that influence natural selection?

A

Characteristics that make organism better adapt to their environment and more likely to survive to reproduce
Traits directly associated with reproduction will produce more viable offspring