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Biology Module 6 > Section 1 > Flashcards

Section 1 Flashcards

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1
Q

Mutations

A

A change in the genetic code (DNA structure) altering the sequence of nucleotides

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2
Q

When can mutations occur

A

They can occur spontaneously (because of mistakes in meiosis and mitosis)

Can happen naturally overtime

Or induced from environmental agents - mutagens

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3
Q

Mutagen

A

An environmental agent that has the potential to cause mutation

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4
Q

Mutagenesis

A

The process of mutations occurring that changes normal base pairs to altered pairs

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5
Q

Name a physical mutagen

A

Electromagnetic radiation sources

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6
Q

What are the main sources of radiation

A

The higher ends of spectrums; UV rays, X rays and Gamma rays

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7
Q

Why are X rays and gamma rays so dangerous

A

They have ionising radiation which causes damage to DNA and produces free radicals- reactive molecules

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8
Q

What is ionising radiation

A

The ability to strip electrons from atoms (ionisation)

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9
Q

How is UV radiation different from X rays and gamma rays

A

It is non-ionising

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10
Q

How does Uv radiation effect DNA

A

It penetrates through the skin and has enough energy to hit DNA

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11
Q

What does UV radiation cause

A

It causes a thymine dimmer

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12
Q

Thymine dimer

A

When 2 thymine nucleotides next to each other bond together to cause a bulge in DNA (a bump)

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13
Q

Why is thymine dimer a problem to DNA

A

When copying DNA or making an amino acid (via polypeptide synthesis) it can form a cyclobutane ring and distort DNA

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14
Q

How do chemicals cause mutation

A

Tricks DNA into thinking they’re part of the sequence = changing nucleotides = directly getting in between nucleotide pairs (desperate bitch)

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15
Q

Chemical mutagens cause

A

Misreading and changes in polypeptide synthesis

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16
Q

How do chemical mutagens get into the body

A

They are often ingested like alcohol/ cigarettes

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17
Q

Naturally occurring mutagens

A

They are mutagenic agents that exist within the natural environment

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18
Q

What are examples of naturally occurring mutagens and biological naturally occurring mutagens

A

Metals; mercury and cadmium - occur naturally in environment

Viruses, bacteria, fungi and their products are biological mutagenic agents

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19
Q

Name a common naturally occurring mutagen that alters DNA and how it works

A

Microbes (Specifically viruses)
Viruses will insert their own DNA(rude) into a cell then when the cell reproduces, the cell replicates and alters the function of the cell

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20
Q

Point mutation

A

Only one base is changed

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21
Q

How are bases impacted by point mutations

A

They can either be substituted, deleted or added

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22
Q

Out of all the different types of mutation which one has the least impact

A

Point mutation

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23
Q

Silent mutation

A

Produces an amino acid of the same type of the original - no change in the proteins

Note: multiple codons can code for the same amino acid

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24
Q

Nonsense mutation

A

Adds a stop codon in the sequence- changing the amino acid and stopping everything

Often produces a protein that isn’t able to properly function

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25
Q

Missense mutation

A

Changes original amino acid to something different

[effect on protein depends on how many amino acids are changed and if they can still bond the same way to form protein’s 3D structure]

26
Q

Frameshift mutation

A

This impacts all amino acids added to a polypeptide chain

27
Q

How do frameshift mutation impact sequence

A

The reading frame is shifted and results in completely different amino acid sequence

28
Q

Why are frameshift mutations more likely to produce proteins that cannot function properly

A

They affect large sequences of base pairs - affecting large numbers of amino acids

29
Q

Chromosomal mutations

A

Made on large scales - changes to multiple genes occurring on one chromosome

30
Q

Somatic mutation

A

Occur in somatic cells (THE BODDYYYYY) and will affect that cell and others that are produce via mitosis
NOTE: WILL NOT BE PASSED TO OFFSPRING (SOO DRAMATIC IT WONT BE GIVEN TO YOU)

31
Q

Germ-line mutation

A

Occurs during meiosis
(Like when the sperm is penetrating to the egg - the mutation happens there and then the mutation spreads to the whole body)
NOTE: WILL BE PASSED ONTO OFFSPRING (GERMS SPREAD EW)

32
Q

What is an example of point mutation

A

Sickle cell anemia

33
Q

Sickle cell anaemia

A
  • it is a condition that involves 2 alleles; the normal allele and the mutant sickle allele

-normal allele DNA codes for protein - GLU
-mutated sickle DNA codes protein- VAL because it has base adenine instead of thymine

-normal allele produces normal haemoglobin proteins = normal red blood cells

-people - homozygous- with mutant allele = abnormal haemoglobin - sickle shaped red blood cells = poor oxygen transport

But
-people - heterozygous- produce both normal and abnormal haemoglobin - because they produce this mutant allele, they are less likely to catch malaria since infectious parasite dies inside sickle cells

34
Q

What are the two parts that makes up DNA

A

Coding (exons) and non-coding (introns)

35
Q

Is exons or introns used to produce proteins

A

Exons

36
Q

Is DNA exons or introns

A

Exons - they are expressed

37
Q

Frameshift mutations

A

They affect all amino acids added to polypeptide chains
(They shift all the base pairs)

38
Q

What are the 4 types of chromosomal mutation

A

Deletion - section is removed
Duplication - section of chromosome is copied
Inversion - section is moved to another section in the same chromosome
Translocation- section is swapped to another section of another chromosome (crossing over but gone wrong type thing)

39
Q

Chromosomal mutation

A

Changes to multiple genes on one chromosome

40
Q

What is an example of chromosomal mutation

A

Aneuploidy - entire chromosomes being added or removed

41
Q

How does chromosomal mutation affect large sequence of base pairs

A

They often have many proteins that aren’t affected, not produced or produced in wrong amounts

42
Q

What are the 4 types mutation can be

A

Silent - cause no change in organism
Beneficial - giving organism advantage, improving chances of survival
Neutral - causing change with neither advantage or disadvantage
Deletion (very harmful) - disadvantage organism, lowering chances of survival

43
Q

Outline how entirely new alleles can be introduced into a gene pool

A
  • mutation must occur that produces a new trait
  • mutation must occur in germ-line cells so it can passed to next generation to be part of the gene pool
  • mutations will mainly happen in meiosis during cell replication
44
Q

What is an example of mutations as a source of variation

A

Blue eyes is a mutation bringing variation into humans

  • mutation impacts a cell called OCA2 lowering melanin production = blue eyes that was not seen before
45
Q

What are coding DNA

A

DNA sequences that are used directly to make proteins and RNA

46
Q

Gene pool

A

The combination of all genes including alleles present in a reproducing population

47
Q

Gene flow

A

Changes in allele frequency due to new individuals entering a population or from individuals exiting a population

48
Q

Genetic drift

A

Change in allele frequency due to chance - random events -

Since one or more alleles are lost in a population due to random events, the allele frequency of gene pool will decrease

49
Q

What causes somatic mutation

A

Environmental factors

50
Q

What causes germ-line mutation

A

DNA replication errors

51
Q

Outline how fertilisation relates to the causes of genetic variation

A
  • increases genetic variation
    -combines maternal (mum) and paternal (dad) genetic material in zygote
  • as a result of independent assortment + random segregation in meiosis
  • new gene combinations form in that person and contributes to population
52
Q

Outline how meiosis relates the causes of genetic variation

A
  • meiosis has a very significant role in making genetic variation
  • meiosis introduces new alleles through crossing over and random segregation
    (Exchanging genes between homologous chromosomes)
    (Two chromosomes separated randomly to reproductive cells’ gametes)

-replication errors in meiosis can also lead to point mutation = errors in crossing over = chromosomal mutation

53
Q

How does mutation relate to genetic variation

A
  • mutations can increase number of alleles for a trait
  • can occur during DNA replication = replication errors
  • can occur during disjunction of chromosomes (separating) = chromosomal mutation
54
Q

Natural selection

A

Process individuals possessing traits that give them advantage for survival in their environment

55
Q

Sexual selection

A

Process where some traits become more common in population because of mating partners being selected based on having certain traits

56
Q

If the rate of mutation of DNA in germ line cells increase

A

The frequency of new alleles being passed onto offspring’s increases

Increase in gene pool
=
Decrease in mutation

57
Q

Bottleneck effect

A

A type of genetic drift
When chance event causes drastic decrease in population size
Lowering allele frequency
Lowering genetic variation
Decreasing gene pool

58
Q

Founder effect

A

A type of genetic drift
New population is stared by small numbers of individuals = founder
New population has different allele frequency from old population

Founders might not carry all genetic variation from old population so it will - lower genetic variation in gene pool

59
Q

Conservation genetics

A

Use of data on the DNA and genes of a population

60
Q

How does conservation genetics help

A

They help guide management decisions that aim to preserve the population

61
Q

What does conservation genetic projects usually aim towards

A

Endangered species and development of suitable preservation plans

62
Q

Genetic diversity

A

Assists in the long term survival of a population

Biology Module 6 (4 decks)

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