chap 9- genetic changes in a population over time

Question 1

what is a gene

Answer 1

section of DNA that transmits genetic information

Question 2

what is an allele

Answer 2

different forms of a gene

Question 3

what is a genotype

Answer 3

the alleles present in an individual

Question 4

what is a phenotype

Answer 4

observable physical traits

Question 5

what are the types of variation

Answer 5

structural, biochemical, behavioural, developmental, physiological and geographic

Question 6

what are allele frequencies

Answer 6

a measure of how common a particular allele is in the gene pool of a population

Question 7

what are mutations

Answer 7

random/unpredictable changes in DNA. creates new alleles, genes and chromosomes

Question 8

what are spontaneous mutations

Answer 8

copying errors during DNA replication

Question 9

what are mutagens

Answer 9

factors that induce mutation

Question 10

what are somatic mutations

Answer 10

occur in body cells and only affect that individual

Question 11

what are germline mutations

Answer 11

are heritable because they affect gametes and can be passed on to offspring

Question 12

what are point mutations

Answer 12

a mutation that alters, adds or removes a single nucleotide from a sequence of DNA or RNA is called a point mutation. typically affect a single gene

Question 13

what are substitution mutations

Answer 13

a point mutation in which one nucleotide is replaced by another type of nucleotide.
can be silent mutations, missense mutations, or nonsense mutations

Question 14

what are silent mutations

Answer 14

the new codon still codes for the same amino acid

Question 15

what is a missense mutation

Answer 15

the new codon codes for a different amino acid

Question 16

what are nonsense mutations

Answer 16

the new codon is a stop codon and shortens the amino acid chain (which may have severe affects)

Question 17

what is a frameshift mutation

Answer 17

one nucleotide being either added or removed from a nucleotide sequence. alters every codon in that sequence from that point onwards

Question 18

what are block mutations

Answer 18

mutations that affect large sections of a chromosome (multiple genes)

Question 19

when do block mutations occur

Answer 19

in eukaryotic cells during meiosis

Question 20

what are the types of block mutations

Answer 20

duplication, inversion, deletion, insertion, translocation

Question 21

what is a duplication mutation

Answer 21

results in multiple repetitions of a sequence of DNA

Question 22

what is an inversion mutation

Answer 22

mutations involve a broken section of the sequence rotating 180 degrees before reattaching.

Question 23

what is a deletion mutation

Answer 23

involves the loss of large sequences of DNA from the chromosome

Question 24

what is an insertion mutation

Answer 24

involves a sequence breaking off one chromosome and attaching to another

Question 25

what is a translocation mutation

Answer 25

can involve two different chromosomes exchanging segments

Question 26

what is a chromosomal abnormality

Answer 26

when a mutation involves whole chromosomes or the number of chromosomes

Question 27

how is chromosomal abnormality detected

Answer 27

through karyotypes

Question 28

what are the two types of chromosomal abnormality

Answer 28

aneuploidy and polyploidy

Question 29

what is aneuploidy

Answer 29

abnormal number of a particular chromosome, either an extra chromosome or a missing chromosome

Question 30

how can aneuploidy be caused

Answer 30

non-disjunction during meiosis

Question 31

what is polyploidy

Answer 31

cells and organisms that have more than 2 copies of every chromosome

Question 32

what is natural selection

Answer 32

the influence of environmental pressures on allele frequencies of a population. occurs because of genetic variation between individuals.

Question 33

what is gene flow

Answer 33

the movement of alleles into and out of a gene pool

Question 34

how can gene flow occur

Answer 34

when different populations interbreed or individuals migrate between populations

Question 35

what is genetic drift

Answer 35

the change in allele frequencies in a population due to random events

Question 36

how can genetic drift occur

Answer 36

the bottleneck effect and the founder effect

Question 37

what is the bottleneck effect

Answer 37

when an event (often a natural disaster) significantly reduces the size of a population and thus its genetic diversity

Question 38

what is the founder effect

Answer 38

when a small group of individuals breaks away from the main population and colonises a new habitat

Question 39

what is selective breeding

Answer 39

where individuals with desirable traits are deliberately interbred to produce offspring with those desired traits

Question 40

why do people selectively breed plants

Answer 40

to produce higher quality food

Question 41

why do people selectively breed animals

Answer 41

meat, milk quality. wool quantity/quality etc

Question 42

how is selective breeding done

Answer 42

1- determine desired trait 2- interbreed parents who show desired trait 3- select the offspring with the best form of the trait and interbreed these offspring 4- continue this process until the population reliably reproduces the desired trait

Question 43

what are advantages of selective breeding

Answer 43

allows for higher quality products for consumption/use increase yields from plants/animals produce fitter/stronger animals, more viable plants

Question 44

what are disadvantages of selective breeding

Answer 44

can reduce resistance to environmental change can increase genetic abnormalities can lower genetic diversity

Question 45

what is antibiotic resistance

Answer 45

when bacteria become resistant to antibiotic

Question 46

what are antibiotics

Answer 46

chemicals that are toxic to bacteria

Question 47

what is a superbug

Answer 47

when a bacterium becomes resistant to 2 or mor antibiotics

Question 48

why are bacteria ideally suited to develop antibiotic resistance

Answer 48

they are vastly numerous, small in size, have compact genomes, reproduce rapidly

Question 49

how do new genes for antibiotic resistance arise

Answer 49

by a combination of gene duplication and mutation

Question 50

what are some strategies to reduce antibiotic resistance

Answer 50

prohibiting sale of over the counter antibiotics delaying prescription of antibiotics enforcing tighter management/use of antibiotics discovering/developing new antibiotics

Question 51

what is antigen drift

Answer 51

change in the surface of a virus due to gradual accumulation of mutations in the genes that code for virus surface proteins. mutations are small and new antigen is only slightly different

Question 52

what is antigen shift

Answer 52

a sudden change in the antigen of a virus resulting in the combination of genetic material from 2 or more strains/subtypes of the virus. antigens will be substantially different

Question 53

how can antigen shift occur

Answer 53

when different host animals live close together, increasing the chances that the two different subtypes will meet in a common host

Question 54

what is the value of vaccination

Answer 54

prevents outbreaks of new virus strains/subtypes.

Question 55

how many subtypes of influenza can vaccinations normally protect against

Answer 55

can normally protect against 3-4 subtypes of influenza