Chapter 12- Genetics

Question 1

Each human inherits how many alleles of each gene

Answer 1

Two (one from mom, one from dad)

Question 2

What is the difference between homozygous, heterozygous and hemizygous

Answer 2

Homozygous- two of the same alleles
Heterozygous- two different alleles
Hemizygous- only one allele present for a given gene

Question 3

Complete dominance

Answer 3

When only one dominant and one recessive gene exist for a given gene. Dominant masks recessive.

Question 4

Codominance

Answer 4

When two dominant alleles exist for one allele

Both alleles express traits simultaneously

Question 5

Incomplete dominance

Answer 5

When a heterozygous pair shows blend of the two characteristics (red and white= pink)

Question 6

Penetrance

Answer 6

Number of individuals in a population who carry the allele AND actually express the phenotype.

Question 7

Expressivity

Answer 7

Varying phenotype for given genotype

Constant same phenotype
Variable differing phenotypes despite same genotype

Question 8

Silent Mutation

Answer 8

When a change in nucleotide has no effect on the final proteins synthesized from the gene

Question 9

Missense

Answer 9

When they change a nucleotide results in substituting one amino acid for another in the final protein

Question 10

Nonsense Mutation

Answer 10

When they change the nucleotide results in substituting one amino acid for a stop codon

Question 11

What are the three types of single chromosome mutations?

Answer 11

Deletion, duplication, inversion

Question 12

What are two types of multiple chromosomal mutations

Answer 12

Insertion, translocation

Question 13

What is leakage?

Answer 13

Flow of genes BETWEEN species

mule/ beefalo

Question 14

What is genetic drift?

Example?

Answer 14

Changes in the composition of the gene pool due to chance.

Founder effect

Question 15

Founder effect

Answer 15

Extreme case of genetic drift.

Small population of species finds itself in reproductive isolation from other populations as a result of natural barriers for catastrophic events.

Question 16

Bottleneck

Answer 16

Cause for drastically and suddenly reducing the size of the population available for breeding

Question 17

Inbreeding

Answer 17

Meeting between two genetically related individuals

Leads to a decrease in genetic diversity

Question 18

Inbreeding depression

Answer 18

The negative results of inbreeding that causes reduced fitness of a population because of the loss of genetic variation

Question 19

Outbreeding/Outcrossing

Answer 19

Introduction of unrelated individuals into a breeding group

Increases the fitness of the population.

Question 20

What are the two types of mutations?

Answer 20

Nucleotide mutations and chromosomal mutations

Question 21

What are the 5 types of chromosomal mutations?

Answer 21

Deletion, Duplication, Inversion, Insertion, Translocation

Question 22

Deletion mutation

Answer 22

Deletion of a large segment of DNA

Question 23

Duplication mutation

Answer 23

Segment of DNA is copied multiple times

Question 24

Inversion mutation

Answer 24

Segment of DNA is reversed

Question 25

Insertion

Answer 25

Segment of DNA is moved from one chromosome to another

Question 26

Translocation mutation

Answer 26

When a segment of DNA is swapped with a segment of DNA from another chromosome

Question 27

Recombination Frequency

Answer 27

Likelihood of two alleles being separated by crossing over

Question 28

What is the Hardy Weinberg Principle

Answer 28

As long as population meets certain criteria, allele frequency will remain constant.

Question 29

What are the two Hardy Weinberg equations? What are the differences?

Answer 29

p+q=1 (frequency of dominant/recessive alleles) | p^2+2pq+q^2=1 (frequency of genotypes/phenotypes)

Question 30

Result of a heterozygous mono hybrid cross?

Answer 30

1: 2:1 (homo dominant, heterozygous, homo recessive) 3: 1 phenotypical

Question 31

Result of a homo dom vs homo recessive mono hybrid cross

Answer 31

100% heterozygotes

Question 32

Test Cross (back cross)

Answer 32

Used to determine the unknown genotype of a parent

Question 33

Test cross results

Answer 33

?? X rr = all heterozygous unknown likely homozygous dominant ?? X rr = 50/50 unknown likely heterozygous

Question 34

Dihybrid cross for heterozygous traits

Answer 34

9:3:3:1 | Homo dom, hetero one, hetero other, homo rec

Question 35

Result of sex link trait where mother is a carrier and father is unaffected vs mother carrier and father is affected?

Answer 35

A. 25% affected male (1/2 female carrier) | B. 50% affected male and female (1/2 female, 1/2 male)

Question 36

Natural selection

Answer 36

Chance variations exist between individuals and advantageous variations Increases an individuals fitness for survival/adaptation

Question 37

Inclusive fitness

Answer 37

theory in evolutionary biology in which an organism's genetic success is believed to be derived from cooperation and altruistic behaviour.

Question 38

Punctuated equilibrium

Answer 38

Considers evolution to be a very slow process with intermittent rapid bursts of evolutionary activity

Question 39

What are the different types types of selection that lead to changes in phenotype?

Answer 39

Stabilizing selection, directional selection, disruptive selection

Question 40

Stabilizing selection

Answer 40

Avoids extremes, keeps phenotypes in narrow range (weight in babies when born)

Question 41

Directional selection

Answer 41

Moves the average phenotype towards one extreme Antibiotic resistance in bacteria

Question 42

Disruptive selection

Answer 42

Two different phenotypes at the extremes which can lead to speciation Bird beak

Question 43

Speciation

Answer 43

Formation of new species through evolution

Question 44

Differential reproduction

Answer 44

When a mutation or recombination results in a change that is favorable to the organisms reproductive success Change is more likely to pass on tot the next generation

Question 45

Divergent evolution

Answer 45

When two species sharing a COMMON ancestor become more DIFFERENT

Question 46

Parallel evolution

Answer 46

When two species sharing a COMMON ancestor evolve in similar ways

Question 47

Convergent evolution

Answer 47

When two species NOT SHARING COMMON ancestor become more SIMILAR due to analogous selection pressures

Question 48

Molecular clock model

Answer 48

Degree if difference between two species related to the amount of time since the two species broke off from a common ancestor