Changes In Genetic Makeup Of A Population

Question 1

What is a dominant gene?

Answer 1

A gene where only 1 copy of the allele is required for the trait to be expressed

Question 2

What is a recessive gene?

Answer 2

A gene where 2 copies of the allele are required for the trait to be expressed

Question 3

Heterozygote gene

Answer 3

Ww, i.e. 2 different alleles

Question 4

Homozygote gene

Answer 4

WW, i.e. 2 copies of the same allele

Question 5

What determines if 2 organisms are part of the same species?

Answer 5

If they can sexually reproduce to create viable and fertile offspring

Question 6

Define a population

Answer 6

A group of the same species living in a specific population

Question 7

Define a Gene pool

Answer 7

All the different genetic material found within a population

Question 8

Define allele frequency

Answer 8

The proportion of an allele in a population

Question 9

Define Allele

Answer 9

An alternative form of a gene

Question 10

What is the difference between a genotype and a phenotype?

Answer 10

Genotype is the genetic makeup of an organism for a specific trait, whereas phenotype is how that genotype interacts with the organism’s environment resulting in various characteristics

Question 11

How is allele frequency calculated?

Answer 11

(Total number of alleles for a specific gene)/(total number of alleles for that gene in a population)

Question 12

How are new alleles formed?

Answer 12

Through genetic mutations

Question 13

Why is genetic variation in a species important?

Answer 13

It increases that species chance of survival, as diversity increases the chance not all the of the population will be killed by new selection pressures

Question 14

What are genetic mutations?

Answer 14

Random unpredictable change that occurs to genetic material

Question 15

Why are mutations important?

Answer 15

They provide a new source of alleles

Question 16

Are mutations good or bad?

Answer 16

They can be good as they may provide a new source of alleles, but may also have negative effects like cancer.

Question 17

What is the difference between a spontaneous and an induced mutation?

Answer 17

Spontaneous mutations occur randomly due to errors in DNA replication whereas induced mutations are brought on by environmental factors

Question 18

What is the difference between a somatic and germline mutation?

Answer 18

Germline mutations occur in organisms reproductive tissue and can be passed down to the organisms offspring, whereas somatic mutations occur in a tissue other than reproductive tissue and cannot be inherited.

Question 19

What type of mutation can be inherited and why?

Answer 19

Germline mutations as they occur in reproductive tissue and can be passed onto offspring during fertilization

Question 20

What is the difference between a polyploidy and aneuploidy chromosomal abnormality?

Answer 20

Aneuploidy is the change in number of chromosomes by a factor of 1 and only affects 1 set, whereas polyploidy is the change in number of chromosomes in every set

Question 21

What is the difference between block mutations and point mutations?

Answer 21

Block mutations are changes that occur to whole sections of chromosomes, whereas point mutations are changes to only 1 single base pair in the DNA sequence

Question 22

What is a block inversion mutation?

Answer 22

When a section of a chromosome is flipped upside down/inverted

Question 23

What is a block deletion mutation?

Answer 23

Where a section of a chromosome is deleted

Question 24

What is a block duplication mutation?

Answer 24

Where a section of a chromosome is duplicated so that there are 2
identical sections joined together

Question 25

What is a block insertion mutation?

Answer 25

when a section of DNA from one chromosome is inserted in the middle of another

Question 26

What is a block translocation mutation?

Answer 26

when a section of DNA from one chromosome switches with a section of DNA from another chromosome

Question 27

What is the difference between a substitution and frame shift mutation?

Answer 27

A substitution mutation is where a single base is substituted for another, whereas a frame shift mutation is where a single base is either added or deleted

Question 28

What kind of mutation is a silent mutation?

Answer 28

A point substitution mutation

Question 29

What is a silent mutation?

Answer 29

When a base is substituted in place of another, but the gene will still code for the same amino acid sequence as the original base

Question 30

What is a Missense mutation?

Answer 30

A base is substituted for another, which results in a change in the amino acid sequence

Question 31

What is a nonsense mutation?

Answer 31

1 base is substituted for another, whereby the mutated triplet in the DNA now codes for a stop codon, resulting in a shorter amino acid chain.

Question 32

What kind of mutation will result in a shortened amino acid chain?

Answer 32

A nonsense mutation

Question 33

What effect do frame shift mutations have on the amino acid the gene codes for?

Answer 33

All the triplet codons after the mutation will be altered until the end of the chain, resulting in a drastically different protein.

Question 34

How many amino acids do substitution mutations affect?

Answer 34

1

Question 35

What is the first step in natural selection?

Answer 35

A variation existing in a trait within a population

Question 36

What is the second step in natural selection?

Answer 36

A selection pressure act on the population and members with a selective advantage are more likely to survive

Question 37

What is the third step in natural selection?

Answer 37

The members with a selective advantage are more likely to survive and reproduce with the frequency of the allele that correlates to the trait increasing over time

Question 38

Why is variation important in a population?

Answer 38

It increases the chance the species will survive in the presence of a selection pressure, as some members may be able to survive due to their different traits

Question 39

What is gene flow?

Answer 39

The movement of alleles between populations of the same species

Question 40

What is immigration?

Answer 40

when individuals enter a population

Question 41

What is emigration?

Answer 41

When individuals leave a population

Question 42

Define genetic drift

Answer 42

When a populations allele frequency is changed due to a random event

Question 43

What is the founder effect?

Answer 43

When a small group of organisms leaves the population to form a new one that isn't genetically representative of the original

Question 44

What is the bottleneck effect?

Answer 44

When there is a sudden change in allele frequency due to the reduction in a population as a result of a random event.

Question 45

What occurs during allopatric speciation?

Answer 45

When part 2 groups from the same population become isolated from each other with no gene flow, and face different selection pressures resulting in the development of new traits

Question 46

What are the 3 steps in allopatric speciation?

Answer 46

isolation -> divergence ->reproductive isolation

Question 47

How is selective breeding different from natural selection?

Answer 47

Humans act as the selection pressure

Question 48

What are the steps in selective breeding?

Answer 48

Genetic variation exists in a population resulting in different traits. Humans select members that have desirable traits and breed them together to produce offspring with that desirable trait. The gene pool is then reduced but a higher proportion of the population will have the desirable trait.

Question 49

What are some reproductive isolating mechanisms?

Answer 49

• Temporal – species don’t have a chance to interact with each other because they may breed in different seasons or be nocturnal • Behavioral – Species may have different mating calls or rituals • Structural – species may have different genitalia that is not compatible with each other • The chromosomes from the different species may be too different so that they would be unable to pair up during meiosis, making the offspring sterile (hybrid sterility)

Question 50

What size population are affected by genetic drift?

Answer 50

Small populations