Changing Allele Frequencies (9.1) Flashcards
(149 cards)
1
Q
State what a particular species is defined by
A
Its’ genome
2
Q
State whether or not the genome of individuals within a species varies
A
Yes.
3
Q
State what the uniqueness in the genome for species is determined by
A
Unique allele combinations
4
Q
State what changes in proportion to population changes
A
Percentage of individuals with particular alleles
5
Q
Describe a gene
A
Sequence of DNA nucleotides
6
Q
State what a gene codes for
A
Characteristics within a trait
7
Q
Describe trait
A
A particular characteristic of organism
8
Q
State what slight variations in the code of a gene result in
A
Different forms of a trait
9
Q
State a term used to describe slight variation of a gene that result in different forms of a trait
A
Alleles
10
Q
Describe alleles
A
Different forms of a gene
11
Q
State what the various combinations of an allele in an individual make up
A
Its’ genotype
12
Q
Describe genotype
A
The genetic composition of an individual
13
Q
State what 2 factors determine the phenotype of an individual
A
- Genotype
2. Environmental conditions
14
Q
Describe phenotype
A
Observable characteristics or traits of an organism, determined by genotype and environmental conditions
15
Q
State what individuals within a species share
A
Genome
16
Q
State whether or not individuals within a species are genetically identical
A
No
17
Q
State what provides individuals within a species with genetic uniqueness
A
Different combinations of alleles
18
Q
State a term used to describe traits that are controlled by one gene
A
Monogenic
19
Q
Describe monogenic
A
Traits that are controlled by one gene
20
Q
State the variation of monogenic traits
A
Discrete variation
21
Q
Provide an alternative term for discrete variation
A
Discontinuous
22
Q
State a term used to describe traits that are controlled by multiple interacting genes
A
Polygenic
23
Q
Describe polygenic
A
Traits that are controlled by multiple genes
24
Q
State the variation of polygenic traits
A
Continuous variation
25
State what a gene is referred to as when it has more than one allele
Polymorphic
26
Describe polymorphic
A gene that has more than one allele
27
Provide 1 example of polymorphic genes
Human blood groups
28
State why an individual can have two alleles for a trait
Diploid cells contain two copies of each chromosome
29
Describe homozygotes
Individuals with two copies of the same allele
30
Describe heterozygotes
Individuals with two different alleles
31
Describe gene pool
All alleles possessed by an entire population, which may be passed on to the next generation
32
State what the relative proportion of a particular allele in a population is referred to as
Allele frequency
33
Describe allele frequency
Relative proportion of particular alleles in a population
34
State how the allele frequency of a population is generally represented
- percentage
| - decimal
35
State the equation to find allele frequency
allele frequency=2(no. homozygotes) + no. heterozygotes) /total no. individuals x100
36
State whether or not allele frequencies within a gene pol change over time
Yes.
37
State what all genetic variation between species and between individuals of the same species is a result of
Mutations
38
Describe mutations
Changes in DNA
39
State the 3 possible effects of mutations that cannot be repaired on an organism
1. no effect
2. beneficial effect
3. harmful effect
40
State during what stage mutations often occur randomly
Replication
41
State 3 structures which may be affected by mutations
1. single gene
2. multiple genes
3. whole chromosomes
42
State what mutations occur spontaneously as a result of
Mutagens
43
Describe mutagens
Factors that induce mutations
44
State what factors that induce mutations are referred to as
Mutagens
45
State whether or not mutations can be detected and repaired
Yes
46
State by what medium are mutations detected and repaired
Enzymes
47
Describe the effect of neutral mutations
No effect on organism survival
48
Describe the effect of beneficial mutations
Increase the likelihood of survival
49
Describe the effect of harmful mutations
Decrease the likelihood of survival
50
Describe somatic mutations
Mutations that occur in body cells
51
State whether or not somatic mutations can affect an entire species
No. Somatic mutations only affect the individual.
52
Describe germline mutations
Heritable mutations that affect gametes
53
State whether or not germline mutations can be passed from one individual to another within a species
Yes. These mutations affect gametes and therefore can be passed on to offspring.
54
State whether or not germline mutations may bring a new allele into a gene pool
Yes.
55
State whether or not germline mutations can influence allele frequencies
Yes.
56
State the 2 overall classifications of mutations (location)
1. somatic mutations
| 2. germline mutations
57
State the 2 types of point mutations
1. Substitution mutations
| 2. Frameshift mutations
58
State the 2 major groups of mutations (extensiveness of mutations)
1. Point mutations
| 2. Block mutations
59
State the 3 major classifications of substitution mutations
1. Silent mutations
2. Missense mutations
3. Nonsense mutations
60
Genetic sequences are read in sets of how many nucleotides?
Three nucleotides
61
State what a sequence of three nucleotides on a template DNA strand is referred to as
Triplet
62
State what a sequence of three nucleotides on a mRNA strand is referred to as
Codon
63
State what a triplet sequence codes for
Specific amino acids
64
State how many nucleotides exist
5
65
State how many possible codons exist
64
66
State how many amino acids can be produced
20
67
State whether or not amino acids can be coded for by more than one codon
Yes
68
State what a mutation that alters, adds or removes a single nucleotides from a sequence of DNA or RNA is referred to as
Point mutation
69
State what structure/s are affected by a point mutation
Single gene
70
Describe a substitution mutation
Point mutation - one nucleotide replaced by another
71
Describe a silent mutation
Substitution mutation - new codon still codes for the same amino acid
72
Describe a missense mutation
Substitution mutations - amino acid replacement
73
State whether or not missense mutations still produce a protein
Yes
74
State what the ability of a produced protein affected by a missense mutation to function correctly is dependent upon
Function of replaced amino acid
75
Describe a nonsense mutation
Substitution mutation - STOP codon
76
State the severest situation involving a nonsense mutation is
Mutation occurs early in sequence
77
Describe frameshift mutations
Nucleotides added/removed from sequence
78
State the affect of frameshift mutations
Alter every codon in sequence from impacted point onwards to change polypeptide produced
79
State what frameshift mutations results in a loss of
Functional protein
80
State the 2 types of frameshift mutations
1. Nucleotide insertion
| 2. Nucleotide deletion
81
Describe nucleotide insertion
Addition of nucleotides in sequence to push nucleotides back
82
Describe nucleotide deletion
Removal of nucleotides that is pulled forwards in the sequence
83
Describe block mutations
Mutations that affect large sections of a chromosome
84
State whether or not block mutations typically affect multiple genes
Yes
85
State the 5 main forms of block mutations
1. duplication
2. deletion
3. inversion
4. insertion
5. translocation
86
State when block mutations generally occur
During meiosis in eukaryotic cells
87
State whether or not block mutations can be triggered by mutagens
Yes
88
Describe duplication mutations
Mutations involving replication of sections of chromosomes
89
State what duplication mutations often result in
Increase in gene expression
90
Describe deletion mutations
Removal of section of a chromosome
91
State what deletion mutations lead to
Disrupted or missing genes
92
Describe inversion mutations
Section of sequence break off chromosome, rotate 180 and reattach to the same chromosome
93
State what inversion mutations involve
Two bases or several genes
94
Describe insertion mutations
Mutations that occur when a section of one chromosome breaks off and attaches to a different chrosome
95
State what the effects of insertion mutations are dependent on
The retainment of two copies of every gene
96
Describe translocation mutations
Whole chromosome/section of chromosome attached/exchanged with another chromosome
97
State what translocation mutations typically interrupt
Normal gene regulation
98
State what translocation mutations can result in
Cancer
99
State what always exists between individuals within a population
Variation
100
State what variation between individuals within a population is a result of
Different combinations of alleles
101
State what 4 factors influence the variation between individuals in a population
1. random mating
2. independent assortment
3. recombination during gamete formation
4. mutations
102
State what variation between individuals within a population can lead to
Differences in individuals' phenotypes
103
Describe selection pressures
Conditions or factors that are likely to influence allele frequency in a population
104
State what selection processes along with mutation are combined considered
Driving forces of evolution
105
State the 2 classifications of evolution
1. natural environment pressures
| 2. artificial pressures resulting from selective breeding
106
Describe natural selection
Influence of environmental pressures on allele frequency in a population
107
State what environmental selection pressures affect
Survival and reproduction of an organism
108
State what individuals with the most advantageous phenotypes have
Increased chance of producing fertile offspring
109
State what examples of environmental selection pressures include:
- climatic conditions
- competition for resources
- mate availability
- predator abundance
110
Environmental pressures influence allele frequencies of a gene pool because of a number of factors which include:
1. variation
2. reproduction
3. survival
4. environmental selection pressures
111
Describe adaptive value
A measure of how well suited a particular phenotype is to a particular environmental condition
112
State what high adaptive values provide an individual with
Advantage over individuals with a lower adaptive value
113
State what high and low adaptive value and the relationship to survival is often considered in parallel with
'Survival of the fittest' phenomenon
114
State what having an advantageous trait generally means for the individual
Individual is more likely to survive to reproduce and pass their alleles on to the next generation
115
State what alleles of the advantageous traits tend to do within the gene pool
Increase
116
State what alleles of disadvantageous traits tend to do within the gene pool
Decrease
117
State 3 examples of gene flow
1. interbreeding between different populations
2. seed dispersal in plants
3. migration
118
State when gene pools may change
When new individuals join the population from a different gene pool or when some individuals leave a population
119
Describe gene flow
Movement of alleles between individuals of different populations
120
State what occurs when gene flow exists between two different populations
Gene pools may remain fairly similar
121
State what occurs when gene flow is not possible between two different populations
Gene pools are said to be 'isolated'
122
State what may occur to allele frequencies in a gene pool
Change randomly over time as a result of chance events
123
Describe genetic drift
Random changes of allele frequencies in a gene pool due to chance events
124
State where genetic drifting is more clearly seen
Small population with little or no gene flow
125
State why genetic drifting is emphasised by small population with minimal gene flow
Death of one individual can significantly alter the allele frequencies
126
State what generally occurs as a result of genetic drift in small populations
Loss of genetic diversity over time as alleles are lost from the gene pool
127
State the 2 major types of genetic drift
1. bottleneck effect
| 2. founder effect
128
State what the number of individuals in a population can be drastically and quickly reduced as a result of
Random event
129
Provide an example of a random event that can result in the dramatic and drastic reduction of the number of individuals in a population
Natural disaster
130
Describe the bottleneck effect
Result of removal of a large proportion of a population from their habitat by chance
131
State what the bottleneck effect results in
Reduced possible reproductive pairings
132
State what reduced reproductive pairings results in
High levels of inbreeding
133
State what high levels of inbreeding results in
Reduced variation in the population and increase in numbers of homozygous individulas
134
The smaller the population the _____ the effect of genetic drift
Greater
135
State whether or not alleles can be immediately lost from the gene pool after a natural disaster
Yes
136
State whether or not alleles can be 'bred out' of the gene pool in only a few generations after a natural disaster
Yes
137
State what the lowered variation in a gene pool as a result of the bottleneck effect will make the population more vulnerable to
Environmental change
138
Describe the founder effect
Dispersion of a small portion of a population to a new location which results in a genetic isolation
139
State what the founder effect results in
High levels of inbreeding
140
Describe interbreeding
Mating of two different species
141
Describe inbreeding
Mating of individuals that are genetically related
142
Describe heterozygote advantage
Heterozygous genotype has higher fitness than homozygous dominant/homozygous recessive genotype
143
Describe macromutation
Mutation producing phenotype well outside the range of variation previously existing.
144
State what natural selection acts upon
Organism's phenotype
145
State when genetic drift is most likely to be observed
When the population is small
146
State the two things that can change allele frequencies
1. Genetic mutations
| 2. Environmental pressures
147
Describe adaptive radiation
Organisms diversify rapidly from ancestral species into new forms
148
Describe biodiversity
A measure of variation at the genetic, species, and ecosystem level
149
State between what classification of chromosomes translocation mutations occur
Non-homologous chromosomes
