Genetic Changes in a Population Over Time

Question 1

Gene pool

Answer 1

Refers to the sum of all alleles at the gene loci of a population of a species at a time

Question 2

Allele frequency

Answer 2

the relative proportion of a particular allele in a gene pool

Question 3

Mutation

Answer 3

any change to the DNA of an organism that is UNPREDICTABLE and RANDOM

Question 4

Beneficial, Neutral and Harmful mutations

Answer 4

Neutral - have no effect on survival
Beneficial - increases the likelihood of survival
Harmful - decreases the likelihood of survival

Question 5

Spontaneous mutation v induced mutation

Answer 5

spontaneous: mutation arise during cell division
induced: mutation caused by ionising radiation or chemical mutagen

Question 6

inheritability of mutations

Answer 6

only germline mutations (in reproductive tissue) is inheritable; somatic mutations are not (organs)

Question 7

aneuploidy

Answer 7

the incorrect number of chromosomes (one or multiple extra/less) → result of non-disjunction

Question 8

polyploidy

Answer 8

refers to a condition in which an organism has more than two matched sets of chromosome (ie strawberries)

Question 9

Point mutation

Answer 9

amount of DNA changed is less than a gene (single/multiple bases)\
- substitution
- deletion
- insertion

Question 10

Substitution mutation

Answer 10

whereby a single base or small group of bases are replaced

→ nonsense; mutation causes STOP codon&raquo_space; results in truncated/shortened polypeptide chain
→ missense; conservative&raquo_space; translates diff aa. Protein has same chem. nature and retains functionality
non-conservative&raquo_space; translates diff aa. Changes functional shape of protein due to different chem. nature
→ silent: translates same aa. No functional change to protein

Question 11

frameshift mutation

Answer 11

deletion or additions of a nucleotide that changes the ribosome reading frame from the point of mutation
- every aa from the point of mutation can potentially change
- disruption to the function and shape of the protein

Question 12

Block mutation

Answer 12

changes to segments of the chromosome
- inversion; segment falls out, rotates 180, rejoins
- translocation; segment of chromosome moves to a different (non-homologous) chromosome
- duplication; extra length of chromosome is added
- block deletion; segment is removed altogether from chromosome

Question 13

Gene flow

Answer 13

the movement of alleles in and out of a population by migration&raquo_space; causes a change in allele frequency in the gene pool
- immigration (introduces new alleles into gene pool)
- emigration (removes some alleles from the population)

Question 14

Genetic drift

Answer 14

drastic change in allele frequency due to a random event
- bottleneck effect
- founder effect

Question 15

Bottleneck effect

Answer 15

when majority of the population is eradicated as a result of a catastrophic event
- reduced genetic diversity → loss of alleles (via inbreeding)
- unrepresentative sample of original population’s gene pool

Question 16

Founder’s effect

Answer 16

when a few individuals leave the population to begin a new one in an isolated location
- reduced genetic diversity → loss of alleles (due to only parent alleles being present)
- non-random sample of population
- genetic diversity can increase by accumulating mutations

Question 17

Natural Selection

Answer 17

the process by which new heritable traits evolve and persist in a population

Question 18

Natural Selection Steps

Answer 18

‘Please Veronica, Send Pasta, Girl Friend. Sincerely, Reggie.’

Phenotypic variation; population has different phenotypes → natural selection can occur

Selection pressure; condition or factor that influences which phenotypes are most successful in the population → new selective pressure introduced

Genetic fitness; organisms that are the desired phenotype have greater genetic fitness → more likely to survive and breed

Survival and reproduction; the population becomes adapted to the environment → passed on their alleles to the next generation

Question 19

Selective pressures

Answer 19

PANDA PAW

Predators
Availability of shelter, food
Nutrient supply
Disease
Accumulation of waste

Phenomena (natural disasters)
Abiotic factors (temp, CO2)
Weather conditions (floods, storms)

Question 20

Selective breeding

Answer 20

the process by which humans select the allele frequency of the desired traits in the gene pool
- decreased genetic diversity → detrimental to the species should natural selective pressures change

Question 21

Bacterial resistance

Answer 21

bacteria lack check and repair mechanisms for DNA
- accumulation of mutations at a faster and higher rate

Question 22

Antibiotic resistance mechanisms in bacteria

Answer 22

• modifying the chemical structure of antibiotics
• producing cellular transporters to remove antibiotics
• adjusting bacterial physiology to evade the antibiotic

Question 23

scientific and social strategies against antibiotic resistance

Answer 23

scientific - research different types of antibiotics
social - limit the use of antibiotics → natural remedies to lesson symptoms of infection + gives immune system time to produce immuno. memory against the strain

Question 24

Viral antigenic drift

Answer 24

accumulation of mutations cause change to the antigens on the surface of a virus
- influenza (neuraminidase and hemagglutinin)

Question 25

highly conserved proteins

Answer 25

proteins experience less nucleotide/amino acid mutations
- thus conserving the 3D functional shape and function of the protein