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Biology 5/6 > Genetics 6.1-6.3 > Flashcards

Genetics 6.1-6.3 Flashcards

1
Q

What is a mutation?

A

A random change to the genetic material.

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2
Q

What is a gene mutation?

A

A random change to base sequence of a gene.

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3
Q

What is a mutagen?

A

A substance or radiation that can cause a mutation.

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4
Q

What is a triplet?

A

A set of the 3 bases in DNA.

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5
Q

What is a point mutation?

A

A substitution of one DNA nucleotide for another, changing the triplet.

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6
Q

What are the 3 types of point mutation?

A

Silent, missense, nonsense

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7
Q

What is a silent point mutation?

A

A change to the DNA base triplet sequence that has no effect on the amino acid sequence in a protein.

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8
Q

What is a missense point mutation?

A

A change to the DNA base triplet sequence that leads to a change in the amino acid sequence in a protein.

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9
Q

What is a nonsense point mutation?

A

A change to the DNA base triplet sequence resulting in a termination triplet that leads to a truncated protein.

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10
Q

What is an indel mutation?

A

Insertion or deletion of one DNA nucleotide causing a frameshift.

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11
Q

What is a frameshift?

A

A change to every DNA base triplet downstream of an indel mutation.

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12
Q

What is the main example of a transcription factor in prokaryotic cells?

A

lac operon

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13
Q

What is the function of the enzyme lactose permease?

A

Allows lactose to enter a bacterial cell.

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14
Q

What is the function of the enzyme beta-galactosidase?

A

Hydrolyses lactose into glucose and galactose.

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15
Q

What are the 4 components of the lac operon?

A

promoter, operator, lacZ structural gene, lacY structural gene

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16
Q

What is a structural gene?

A

A gene that codes for a functional protein.

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17
Q

What is a regulatory gene?

A

A gene that codes for a transcription factor.

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18
Q

What does the gene lacI code for?

A

Repressor protein

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19
Q

What does the gene lacZ code for?

A

Beta-galactosidase

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20
Q

What does the gene lacY code for?

A

Lactose permease

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21
Q

Where does the repressor protein bind in the lac operon?

A

Operator

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22
Q

Where does RNA polymerase bind in the lac operon?

A

Promoter

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23
Q

What is the inducer for the lac operon?

A

Lactose

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24
Q

What is the effect of lactose on the repressor protein?

A

Binds to the repressor protein, altering its shape and preventing it from binding to the operator region of the lac operon.

25
What conditions are necessary for the lac operon to be switched off?
Glucose present, lactose absent
26
What conditions are necessary for the lac operon to be switched on?
Glucose absent, lactose present
27
What is an example of transcriptional gene regulation?
Transcription factors
28
What are transcription factors?
Proteins or non-coding RNA that regulate the transcription of genes.
29
What 2 areas do transcription factors bind to?
Promoters, enhancers
30
What has happened if a transcription factor has repressed a gene?
The TF has attached to the promoter, preventing the attachment of RNA polymerase and expression of the gene.
31
What has happened if a transcription factor has up-regulated a gene?
The TF has attached to the enhancer, aiding the attachment of RNA polymerase to the promoter and expression of the gene.
32
What is an example of post-transcriptional gene regulation?
Maturing of mRNA through removal of introns.
33
What is an intron?
A non-coding region of DNA / RNA.
34
What is an exon?
A coding region of DNA / RNA.
35
What is primary mRNA?
mRNA containing both introns and exons.
36
What is mature mRNA?
mRNA containing only exons (introns have been removed).
37
What is alternative splicing?
The joining of exons in a region of mRNA in different combinations resulting in one gene encoding more than one protein.
38
What is an example of post-translational gene regulation?
Cyclic AMP (secondary messengers)
39
What enzyme catalyses the formation of cyclic AMP from ATP?
Adenyl cyclase
40
What activates a G protein?
A cell signal e.g. hormone.
41
What activates adenyl cyclase?
G protein
42
What activates protein kinase A (PKA)?
Cyclic AMP
43
What is the function of protein kinase A (PKA)?
Activate enzymes / transcription factor proteins by phosphorylation.
44
What is a homeotic gene?
A gene controlling the anatomical development of an animal, plant or fungus.
45
What is a homeobox gene?
A gene controlling the anatomical development of an animal, plant or fungus.
46
What is the homeobox sequence?
A sequence of 180 DNA base pairs found in all homeotic / homeobox genes.
47
What is the homeodomain sequence?
A sequence of 60 amino acids encoded by the homeobox sequence.
48
What is the secondary structure of the homeodomain sequence?
HTH - 2 alpha helices connected by a turn.
49
Where does the homeodomain sequence bind to?
Enhancer
50
What is a Hox gene?
A homeobox / homeotic gene found only in animals.
51
What type of genes are homeotic / homeobox / Hox genes?
Regulatory
52
How many Hox gene clusters are found in humans?
4
53
What is meant by colinearity in embyronic development?
The expression of the Hox genes corresponds to the spatial & temporal development of the body part it encodes.
54
What is apoptosis?
Programmed cell death
55
How is apoptosis different to cell death due to trauma?
Apoptosis does not involve hydrolytic enzymes.
56
What is a bleb?
A protusion from a cell early on in apoptosis.
57
What are 4 cell signals that can induce apoptosis?
Cytokines, hormones, growth factors, nitric oxide
58
What are 4 uses of apoptosis in plant and animal tissue development?
Separation of limbs and digits in embryonic development, removal of anti-self T/B lymphocytes, immune response to viral infection, prevent tumour growth

Biology 5/6 (7 decks)

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