Chapter 6

Question 1

Genetics

Answer 1

the science that describes the inheritance of traits from one generation to another

Question 2

Gene

Answer 2

a length of DNA coding for a particular gene product, is the fundamental unit of inheritance

Question 3

Alleles

Answer 3

different versions of a gene

Question 4

Genotype

Answer 4

is the DNA sequence of the alleles a person carries

Question 5

Heterozygote

Answer 5

a person carrying two different alleles at a given locus

Question 6

Homozygote

Answer 6

individual carrying two identical alleles

Question 7

Phenotype

Answer 7

is the physical expression of the genotype

Question 8

Incomplete dominance

Answer 8

phenotype of a Heterozygote is a blended mix of both alleles

Question 9

Codominance

Answer 9

two alleles are both expressed but not blended

Question 10

Meiosis

Answer 10

reduces the number of copies of each chromosome from two to one

Question 11

Difference between mitosis and meiosis

Answer 11

replication of the genome is followed by one round of cell division in mitosis and two rounds of cell division in meiosis, meiosis I and meiosis II

In meiosis, recombination occurs between homologous chromosomes

Question 12

Bivalent or tetrad

Answer 12

Homologous chromosomes that align themselves very precisely with each other in synapsis, with the two copies of each gene on two different chromosomes

Question 13

Nondisjunction

Answer 13

failure of chromosomes to separate correctly during meiosis

Question 14

Gametes resulting in nondisjunction

Answer 14

will have two copies of a given chromosome

Question 15

Law of segregation

Answer 15

states that the two alleles of an individual are separated and passed on to the next generation singly

Question 16

Law on independent assortment

Answer 16

states that the alleles of one gene will separate into gametes independently of alleles for another gene

Question 17

Pure-breeding strain

Answer 17

A group of identical individuals that always produce offspring of the same phenotype when intercrossed

Question 18

Rule of multiplication

Answer 18

the probability of both of the two independent events happening can be found by multiplying the odds of either event alone

A*B = AB

Question 19

Rule of addition

Answer 19

calculate the chances of either of two events happening. (A+B) - (AB) = A or B

Question 20

Linkage

Answer 20

failure of genes to display independent assortment

when genes are located close to each other on the same chromosome, they will display linkage and may not assort independently

Question 21

Recombination

Answer 21

produces new combinations of alleles not found in the parent and also allows genes located on the same chromosome to assort independently

Question 22

Frequency of recombination between two genes on a chromosome is proportional

Answer 22

to the physical distance between the genes along the linear length of the DNA molecule

The farther two genes are away from each other, the greater the odds that recombination will occur between them

Question 23

RF= Recombination frequency

Answer 23

(number of recombinants)/(total number of offspring)

Question 24

Autosomal dominant

Answer 24

in which case a single copy of the allele will confer the trait or disease phenotype

Does not skip generations male and females affected equally, affected parent passes trait to either all or half of the offspring

Question 25

Autosomal recessive

Answer 25

in which case two copies of the allele are require for the affected phenotype

can skip a generation, number of affected males is usually equal to the number of affected females

Question 26

Y-linked

Answer 26

Affects males only; females never have the trait, affected father has all affected sons, unaffected father cannot have an affected son

Question 27

X-Linke recessive

Answer 27

Can skip generations, tend to affect males more than females, unaffected females can have affected sons, affected female has all affected sons, but can have both affected and unaffected daughters

Question 28

Pedigree

Answer 28

researchers can determine the pattern of inheritance of a gene, whether it is linked to other genes and whether an individual is likely to pass on a trait to their offspring

Question 29

Population Genetics

Answer 29

describes the inheritance of traits in populations over time

Question 30

Population

Answer 30

consists of members of a species that mate and reproduce with each other

Question 31

Gene pool

Answer 31

sum total of all genetic information in a population

Question 32

Hardy-Weinberg Law

Answer 32

States that the frequencies of alleles in the gene pool of a population will not change over time, provided that

There is no mutation, migration, natural selection, random mailing, and the population its sufficiently large to prevent random drift in allele frequencies

Question 33

alelle frequency equation

Answer 33

p+q=1

Question 34

genotype frequency equation

Answer 34

p^+pq+q^=1

Question 35

Hardy-Weinberg Equillibrium

Answer 35

After one generation allele frequencies no longer change