Genetics

Question 1

What is a gene?

Answer 1

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

Question 2

What is a genome?

Answer 2

All the genes carried by a cell or organism

Question 3

What is an allele?

Answer 3

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

Question 4

What is the law of uniformity?

Answer 4

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

Question 5

What is the law of segreation?

Answer 5

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

Question 6

What is the law of independent assortment?

Answer 6

Members of different gene pairs will segregate independently from one another

Question 7

What is a genotype?

Answer 7

The genetic makup

Question 8

What is the phenotype?

Answer 8

The appearance of an individual, which allele is physically expressed

Question 9

What is a good way to predict segregation of genes?

Answer 9

Punnet square

Question 10

What does it mean when phenotypes are discrete?

Answer 10

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

Question 11

What does it mean by quantiative phenotypic traits?

Answer 11

Shows a continuous variation over a range of phenotypes

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

Question 12

How to differences in alleles arise?

Answer 12

Mutations in the gene sequence

Question 13

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

Answer 13

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

Question 14

When is a mutation considered an allele?

Answer 14

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

Question 15

Describe a metacentric chromosome:

Answer 15

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

Question 16

Describe a submetacentric chromsome:

Answer 16

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

Question 17

Describe a acrocentric chromosome:

Answer 17

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

Question 18

What is heterochromatin?

Answer 18

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

Question 19

What is euchromatin?

Answer 19

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

Question 20

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

Answer 20

4q26

Question 21

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?

Answer 21

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

Question 22

What is the gene pool?

Answer 22

All of the alleles for every gene in a given population

Question 23

What is a population?

Answer 23

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

Question 24

How do you calculate allele frequency?

Answer 24

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

Question 25

How do you calculate genotype frequency?

Answer 25

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

Question 26

What is the Hardy-Weinberg equation?

Answer 26

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

Question 27

What does HW say about gene frequencies?

Answer 27

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

Question 28

What are the conditions for HW?

Answer 28

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

Question 29

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

Answer 29

Microevolution

Question 30

What are the 2 traits that influence natural selection?

Answer 30

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