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biology > inquiry question 1 module 6 > Flashcards

inquiry question 1 module 6 Flashcards

How does mutation introduce new alleles into a population?

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AP® Biology flashcards Biology 101 flashcards
1
Q

main process that contributes to variation

A

meiosis

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2
Q

crossing over

A

swapping of genetic material in homologous chromosomes during prophase I and reshuffles/recombines alleles

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3
Q

meiosis

A

produces gamete that are genetically different from each other
and the main source of variation within a population
- crossing over
- random segregation
- independent assortment

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4
Q

random segregation

A

homologous chromosomes are distributed in daughter cells randomly in anaphase I

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5
Q

independent assortment

A

Homologous chromosome pairs align randomly where genes are inherited independently of each other during metaphase I

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6
Q

define a mutation and types

A

A permanent change in the DNA sequence that occurs that are the source of new alleles within a gene pool spontaneously or as a result of mutagens
- point
- chromosomal

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7
Q

define a mutagen and the types and how they are obtained

A

natural or synthetic substance that can alter the structure or sequence of DNA and that can dramatically increase the rate of mutation that can occur at the gene or chromosome level

  • neutral
  • beneficial
  • harmful

spontaneous or induced

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8
Q

beneficial mutagens

A

increase the likelihood of survival and results in allele that allows adaptability to the environment and successful reproduction

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9
Q

neutral mutagens

A

no effect on the survival (most are neutral as they are in the non-coding region)

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10
Q

harmful mutagen

A

decrease the likelihood of survival - results in allele that reduces adaptability to environment or increases susceptibility to disease or disability

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11
Q

what process leads to the creation of mutations

A

mutagenesis which can occur in both somatic and gametic cells but they cant be passed down to offspring from somatic cells as they are bodily cells
- spontaneous
- induced

physical chemical biological

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12
Q

spontaneous mutations

A

randomly occurs during DNA replication where DNA polymerase can make mistakes while copying the bae sequence which can result in mutations if ot detected and repaired

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13
Q

induced mutations

A

exposure to caused by mutagens eg. UV radiation, tobacco smoke, HPV etc.

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14
Q

chemical mutagens

A
  • intercalating agents
  • base analogues:
  • DNA reactive chemicals

eg. tobacco smoke which contain mutagenic compounds that can be carcinogenic, outdoor air pollution, asbestos ( fibres are inhaled and the body is unable to remove)

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15
Q

intercalating agents

A

chemical mutagen
chemicals that insert themselves into bonds between base pairs preventing hydrogen bonds from forming and bends the DNA double helix out of shape causing to errors in DNA replication

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16
Q

base analogues

A

chemical mutagen
inhibits DNA from functioning –> chemicals that are structurally similar to the nitrogenous bases in DNA that they are incorporated into DNA sequence during replication instead of the normal base

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17
Q

DNA reactive chemicals

A

chemical mutagen
chemicals that react directly with the nitrogenous bases of DNA → modify the DNA structure causing a mutation

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18
Q

ultraviolet light

A

physical mutagen and a form of ionising radiation
- form of radiation not visible to the eyes and has shown to increase skin cancer rates

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18
Q

physical mutagens

A
  • ionising radiation (eg. gamma radiation, ultraviolet light, x-rays)
  • non-ionising radiation (not associated with damage to DNA eg. microwaves, visible light)
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18
Q

gamma radiation

A

physical mutagen and ionising radiation that is a result of radioactive decay interrupt the cellular process and ionise molecules by penetrating cells and breaking or changing chemical bonds that give the double helix its structure
- hiroshima atomic bombs which causes a tenfold increase in cancer deaths and provides evidence for its mutagenic nature

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18
Q

biological mutagens

A

Living molecules that can cause mutations and canvas by interfering with the functions
of oncogenes and tumour-suppressor genes
eg. viruses, transposable elements

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19
Q

transposable elements

A

biological mutagen
- short DNA sequences that move around the genomethat cause
errors in normal DNA replication
Interference with gene function
Insertion into the middle of a functional gene
eg.. corn kernel which uses it to manipulate its qualities

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20
Q

viruses

A

biological mutagen
- Insert DNA into host cell → host undergoes transcription and translation of viral genes → produces viral DNA and viral proteins
-If infected cell does not die → permanent mutation in host genome

eg. HPV

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21
Q

point mutations

A

A mutation that alters, adds or removes only one nucleotide from a sequence of DNA or RNA and often only effects a single gene
- base substitutions
- frameshift mutations

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22
Q

nonsense mutation

A

base substitution in point mutations
- codon is changed to a stop codon signalling chain termination
- Stops the translation process as it truncates the polypeptide

  • Results in incomplete, usually non-functional protein products
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22
Q

base substitutions

A

silent mutation: codon is changed which codes for the same amino acid
nonsense mutation: codon is changed to a stop codon signalling chain termination
missense mutation: a codon is substituted with another codon which encodes for a different amino acid

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23
Q

silent mutation

A

base substitution in point mutations
- codon is changed which codes for the same amino acid
- AGG → CGG (both encode for arginine)

24
Q

missense mutation

A

base substitution in point mutations
- a codon is substituted with another codon which encodes for a different amino acid
- Codes for an altered polypeptide sequence → still produces a protein but its function depends on the importance of the amino acid replaced

conservative: specify codons that are chemically similar to the original → Protein function is not altered

non-conservative: codones are dissimilar to the original → often produces non-functional proteins

eg. sickle cell anaemia –> chain in amino acids Aggregates the red blood cells created a distorted, sickle shaped cells that are inefficient in oxygen transport

24
Q

frameshift mutations

A

involve one or two nucleotides being either added or removed from a nucleotide sequence, altering every codon in that sequence from that point onwards
- If it occurs in coding regions → non-functioning proteins are produced as the polypeptide is completely different

  • insertions
  • deletions
24
Q

insertions

A

frameshift mutation –> point mutation
- one or more extra nucleotides are added into a DNA sequence
AAG CTT CCT (original)

AAG CTA TCC T (addition of A)

25
Q

deletions chr

A

chromosomal mutation
- section of a chromosome breaks off and a segment is permanently deleted
- Results in the loss of genetic information which can have serious effects on the growth and development

eg. cri-du chat syndrome

25
Q

inversion

A

chromosomal mutation
-ccurs when a segment of a chromosome breaks off and is inverted before being reinserted back into its original location
- genetic information remains the same

25
Q

deletion

A

frameshift mutation –> point mutation
- one or more nucleotides are deleted from the DNA sequence

AAG CTT CCT (original)
AAG CTC CT.. (deletion of T)

26
Q

chromosomal mutations

A

Changes in DNA that occur because of the alterations in structure or number of chromosomes
- usually during meiosis

  1. duplication
  2. inversion
  3. deletion
  4. insertion
  5. translation
27
Q

chromosome

A

macrostructure made up of DNA wrapped around histone proteins and is visible during nuclear division

28
Q

translocation

A

chromosomal mutation
- whole chromosome or a segment of a chromosome becomes attached or exchanged with another non-homologous chromosome

balanced: no loss or gain of genetic material
unbalanced: total amount of genetic material is lost
eg. down syndrome

28
Q

insertions chr

A

chromosomal mutations
- section of one chromosome breaks off and is inserted into a different chromosome

29
Q

duplication

A

chromosomal mutation
- occurs when the same segment of a chromosome is copied, repeated or occurs twice
- Increases gene expression that can be harmful or beneficial depending on the gene involved

30
Q

aneuploidy

A

presence of an abnormal number of particular chromosome
- down syndrome

30
Q

point mutation strength

A

Nonsense > non-conservative mutation > missense conservative > silent mutation

31
Q

somatic mutations

A

4Changes to DNA to specific body cells
- cant be passed down to offspring
- localised effect on individuals

  • found everywhere
  • mitosis
  • diploid
  • 6 chromosomes
31
Q

nondisjunction and what does it result in

A

two homologous chromosomes don’t separate properly during first division of meiosis
- Results in gametes with incorrect number of chromosomes →
- If gametes are involved in fertilisation → offspring with incorrect chromosomes will be formed → birth defects / genetic disorders

  • aneuploidy
  • polyploidy
32
Q

what are chromosomal abnormalities

A

total number of chromosomes changes
- Detected with a karyotype
- Change in chromosome number can occur due to nondisjunction of chromosomes in cell division in Anaphase I

33
Q

germline mutations

A

Changes to the DNA of cells that produces eggs and sperm
- meiosis
- found in gametes
- haploid
- 23 chromosomes

33
Q

polyploidy

A

change to the total number of chromosomes → presence of more than two sets of chromosomes
- If this gamete is fertilised → the zygote will have more than the usual two sets of chromosomes

Triploid (3n) → haploid gamete fuses with diploid gamete → low fertility

Tetraploid (4n) → two diploid gametes fuse

34
Q

how do mutations effect the gene pool of species

A

They provide genetic variation for the population → if it results in a favourable trait it can increase the survival and effect evolution

35
Q

cancer

A

Group of diseases characterised by abnormal, uncontrolled cell division that can result in the formation of a tumour (Undifferentiated group of cells that do follow normal cell division which inhibit the normal functioning of the body)

36
Q

genes that regulate cell growth and division

A

mutations of these= cancer

proto-oncogenes (gas pedal)
- code for proteins that stimulate mitosis
- mutation = uncontrolled cell division

tumour suppressor genes (brake pedal)
- codes for proteins that inhibit cell division to help stop mitosis
- mutation = division out of control

36
Q

non-coding DNA double check this stuff

A

98% of dna sequence
is the sequence of DNA which DO NOT encode for proteins

  • control the action of regulatory proteins
  • Introns (within genes) –> spliced out during
  • intergenic non-coding DNA (between genes)
37
Q

coding DNA (check how much we need to know)

A

sequence of DNA that encodes for proteins
Number of difference in DNA caused by mutations is used to determine how closely related two species are

38
Q

mutations and variation

A

higher level of variation and increases diversity in the gene pool
- favourable = increase chance of survival and likely to be passed on
- unfavourable = likely to be fatal to individual and disappear from population

39
Q

regulatory proteins

A

proteins that control the rate of transcription
- activator proteins: bind to enhancer regions that increase transcription to reduce mutation
- repressor proteins: bind to silencer regions that decrease transcription and contribute to increased rate of mutations

40
Q

epigenetics

A

Study of factors that influence gene expression
- genes can be turned on/off –> chemical tags or activator and repressor genes
- regulatory proteins - proteins that control the rate of transcription

41
Q

enzymes

A

catalyses reactions within a cell
- catabolism= breaks molecules apart
-anabolism = joins molecules together

Enzyme 1 converts glutamate to ornithine
Enzyme 2 converts ornithine to citrulline
Enzyme 3 converts citrulline to arginine

42
Q

enzyme effect on gene mutations

A
  • if gene for enzyme is mutated the enzyme may not be fully functional
  • and effects the biosynthetic pathway
43
Q

biosynthetic pathway

A

a chain of reactions associated with the formation of complex compounds from simple substances by a living organism
- Check if an enzyme is working in a cell by looking at which product is missing and which substrate has accumulated

44
Q

gene pool

A

total number of alleles for all genes found within a population of species
Constantly changing
large=ensure genetic variation and diversity to survive sudden selection pressure in the environments

small = higher chance of extinction and less biodiversity

45
Q

microevolution

A

small changes that occur in gene pool from generation to generation

46
Q

mechanisms for gene pool change

A
  • Mutation and natural selection
  • Gene flow
  • Genetic drift
47
Q

evolution

A

gradual change and development of a living species

47
Q

mutations and natural selection

A

darwins theory of evolution by natural selection
- Process by which mutations are advantageous to survival are passed onto future generations

  • in order for this to occur there needs to be variation within individuals in a population which is caused by mutations and meiosis

favourable = increases chances of survival and can be passed on
unfavourable = likely to be fatal and disappear from population

48
Q

gene flow

A

refers to the movement of alleles between different populations through interbreeding
- genetic differences between two populations is minimised
- breeding between two populations to make the populations more similar to each other = increase in genetic diversity within a population an positive effect son isolated populations

49
Q

how does gene flow occur

A
  • migration between populations
  • horizontal gene transfer in bacteria –> Transfer of DNA from a donor to a recipient by asexual means in prokaryote (antibiotic resistance)
50
Q

how is gene flow limited

A
  • mobility of organisms –> lower in species that have low dispersal or mobility and fragmented habitats due to bigger distances between populations and smaller sizes
  • small isolated populations = increase in interbreeding –> amish population, black footed rock wallaby
51
Q

genetic drift and two situations

A

change in allele frequencies in a population due to random fluctuation in the allele frequencies of a particular gene
- does not result in formation of new alleles
- no influenced by environment or selection pressures
- greater effect on smaller populations

two situations:
- genetic bottle neck: occurs when there is a sudden decrease in population size due to environmental factors

  • founder effect: New population is established by a small number of individuals being separated from a larger population it results in a small gene pool size in the founder population
51
Q

founder effect

A
  • type of bottleneck effect
  • New population is established by a small number of individuals being separated from a larger population it results in a small gene pool size in the founder population
  • population expands = diversity of alleles do not increase
  • new colony becomes isolated –> lower genetic diversity

eg. amish
- culturally isolated, reduced genetic diversity –> maple syrup urine disease

51
Q

genetic bottleneck

A

Type of genetic drift that occurs when there is a sudden decrease in population size due to environmental factors
- disease, natural disasters –> Devil facial tumour disease in tasmanian devils
- cheetahs = small number survived due to mass extinction , diversity low as few families survived + interbreeding

biology (11 decks)

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