outcome 3

Question 1

Explain the following terms, relating to gene mutations.

• Substitutions

Answer 1

The inappropriate replacement of one or more bases, that might or might not result in the production of a new amino acid or protein.

Question 2

Deletions

Answer 2

The removal of one or more bases, which may change the amino acids produced and hence the function of the resulting protein.

Question 3

Insertions

Answer 3

The insertion of a base or bases that can change the amino acids and the protein’s function.

Question 4

Silent Mutation

Answer 4

If a mutation has no impact upon the amino acid/protein generated, it is deemed silent because it has no effect on the organism.

Question 5

Missense Mutations

Answer 5

a type of point mutation that results in a nucleotide that translates for a particular amino acid, causing the translation of a protein with a different amino acid sequence.

Question 6

a DNA alteration that enables a protein’s translation to terminate or finish earlier than intended.

Answer 6

Nonsense Mutations

Question 7

Describe the following chromosome mutations

- Duplication

Answer 7

when a portion of chromosome gets replicated, resulting in two copies of the identical region on the new chromosome

Question 8

Deletion

Answer 8

A chromosomal segment is removed or lost.

Question 9

Inversion

Answer 9

When a chromosomal fragment is rotated around

Question 10

when various chromosomal fragments are transmitted to each other

Answer 10

Translocation

Question 11

Describe the process of natural selection

Answer 11

Organisms possessing a new heritable mutant allele (gene variant) that provides a survival benefit will steadily grow in number over time. Natural selection influences the phenotypic of an organism (observable traits). When a phenotype is well suited to its surroundings, it has a higher survival rate and reproduction.

Question 12

describe Types of Selection plus an example

- Stabilising selection

Answer 12

When a trait stabilises to meet optimum environmental conditions. e.g. Over time, a bird species start to lay on average 4 eggs, instead of the original 2 to 12.

Question 13

Directional selection

Answer 13

A change of trait is favoured due to environmental pressures e.g. The peppered moth changed colour throughout the industrial revolution (and then back again)

Question 14

Disruptive Selection

Answer 14

Opposite extreme traits are favoured. Average/original trait is eliminated.e.g. Birds with average size beaks over time change to birds with short strong seed-eating beaks and long narrow insect-eating beaks. The original form no longer exists.

Question 15

explain sexual selection

Answer 15

Sexual selection is a type of natural selection, sexual selection is involved in the competition for mates. there is male competition, which involves the males of the species competing against each other for a female and the female choice are when a female can choose who to mate with.

Question 16

explain the term ‘gene flow’. and what would occur should gene flow be unable to occur

Answer 16

The transmission of genes among populations is known as gene flow. While populations normally breed amongst themselves, individuals moving from one group to another will introduce additional alleles as well as genetic variants into the population. Restricting gene flow causes speciation or highly fragmented populations, resulting in decreased genetic diversity.

Question 17

explain the term ‘genetic drift’

Answer 17

Genetic drift is an evolutionary mechanism defined by random changes in the frequency of a specific gene (allele) in a species. may lead to the loss of uncommon alleles as well as a population’s gene pool decreasing resulting in low genetic diversity. Genetic drift might result in a new population being genetically unique, which might also aid in the evolution of a new species.

Question 18

Explain what is meant by the bottleneck effect and the founder effect

Answer 18

Bottleneck effect –
A bottleneck effect occurs when the population size decreases dramatically for at least one generation.

Founder effect –
When several organisms relocate to a new area and establish a new colony with little genetic variation, this is known as the founder effect.

Question 19

explain the term ‘environmental limiting factors

Answer 19

A habitat’s carrying capacity is important. This is the maximum population size of that species the surrounding environment can maintain. ‘Population limiting factors’ determine the overall carrying capacity. Food, water, habitat, and mates are all typical limiting elements in ecosystems.

Question 20

Explain the difference between abiotic and biotic factors?

Answer 20

Abiotic factors – All living organisms inside an ecosystem are referred to as biotic factors, such as animals, plants and insects.

biotic factors - while non-living elements such as physical variables (temperature, pH, humidity, salinity, sunshine, etc.) and chemical agents are referred to as abiotic factors