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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
Missense mutation
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
Frameshift mutation
This impacts all amino acids added to a polypeptide chain
27
How do frameshift mutation impact sequence
The reading frame is shifted and results in completely different amino acid sequence
28
Why are frameshift mutations more likely to produce proteins that cannot function properly
They affect large sequences of base pairs - affecting large numbers of amino acids
29
Chromosomal mutations
Made on large scales - changes to multiple genes occurring on one chromosome
30
Somatic mutation
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
Germ-line mutation
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
What is an example of point mutation
Sickle cell anemia
33
Sickle cell anaemia
- 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
What are the two parts that makes up DNA
Coding (exons) and non-coding (introns)
35
Is exons or introns used to produce proteins
Exons
36
Is DNA exons or introns
Exons - they are expressed
37
Frameshift mutations
They affect all amino acids added to polypeptide chains (They shift all the base pairs)
38
What are the 4 types of chromosomal mutation
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
Chromosomal mutation
Changes to multiple genes on one chromosome
40
What is an example of chromosomal mutation
Aneuploidy - entire chromosomes being added or removed
41
How does chromosomal mutation affect large sequence of base pairs
They often have many proteins that aren’t affected, not produced or produced in wrong amounts
42
What are the 4 types mutation can be
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
Outline how entirely new alleles can be introduced into a gene pool
- 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
What is an example of mutations as a source of variation
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
What are coding DNA
DNA sequences that are used directly to make proteins and RNA
46
Gene pool
The combination of all genes including alleles present in a reproducing population
47
Gene flow
Changes in allele frequency due to new individuals entering a population or from individuals exiting a population
48
Genetic drift
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
What causes somatic mutation
Environmental factors
50
What causes germ-line mutation
DNA replication errors
51
Outline how fertilisation relates to the causes of genetic variation
- 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
Outline how meiosis relates the causes of genetic variation
- 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
How does mutation relate to genetic variation
- 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
Natural selection
Process individuals possessing traits that give them advantage for survival in their environment
55
Sexual selection
Process where some traits become more common in population because of mating partners being selected based on having certain traits
56
If the rate of mutation of DNA in germ line cells increase
The frequency of new alleles being passed onto offspring’s increases = Increase in gene pool = Decrease in mutation
57
Bottleneck effect
A type of genetic drift When chance event causes drastic decrease in population size Lowering allele frequency Lowering genetic variation Decreasing gene pool
58
Founder effect
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
Conservation genetics
Use of data on the DNA and genes of a population
60
How does conservation genetics help
They help guide management decisions that aim to preserve the population
61
What does conservation genetic projects usually aim towards
Endangered species and development of suitable preservation plans
62
Genetic diversity
Assists in the long term survival of a population

Biology Module 6 (4 decks)

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