Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Foundation Year MBChB > Cell Cycle, Cellular Ageing and Cell Death, Regulation of Gene Expression > Flashcards

Cell Cycle, Cellular Ageing and Cell Death, Regulation of Gene Expression Flashcards

1
Q

What is a purpose of DNA?

A

Dictates cells’ structure and function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are a major source of mutations?

A

Errors in copying DNA during DNA replication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Why do cells progress through the cell cycle?

A

To undergo mitosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the names of controlled and uncontrolled cell death?

A

Apoptosis: controlled cell death
Necrosis: uncontrolled cell death

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are the definitions of the following terms?
Gene
Allele
Exon
Intron
Genotype
Phenotype
Mutation

A

Gene: functional region of DNA that codes for a sequence of RNA
Allele: individual variant of a gene
Exon: portions of a gene product that are removed via RNA splicing
Intron: portions of a gene product that are retained following RNA splicing
Genotype: the genes (and alleles of them) in a cell/organism
Phenotype: physical features of an organism as of its genotype
Mutation: changes in the genetic sequence (order of base nucleotides)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How can RNA be derived from DNA?

A

Transcription

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the multiple forms of RNA and their function/role?

A

Messenger RNA (mRNA): translated to produce polypeptides
Transfer RNA (tRNA): involved with translation
Ribosomal RNA (rRNA): major part of ribosomes
Short interfering and micro RNA (siRNA and miRNA): inhibit translation of complementary mRNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do miRNA and siRNA inhibit translation?

A

Bind to complementary mRNA and prevent the ribosome from binding and allowing translation to occur
Marks mRNA for degradation, therefore there is no protein synthesised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the function of miRNA and siRNA?

A

To not allow too much mRNA to be present, so as to have no extremes
Reduces likelihood of mutations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is all gene expression due to?

A

Dictating factors such as methylation, acetylation and transcription factors

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is fine tuning?

A

Nuanced activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why may a cell have cell-signalling?

A

To prevent the translation of unnecessary proteins (hence miRNA and siRNA) as cell has multiple things in multiple directions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the meaning of “one gene, one protein”?

A

One gene codes for one protein and determines its function

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Why is there controversy regarding “one gene, one protein”?

A

Not strictly true as multiple proteins may come from one gene as not all triplets read for the gene
Splicing causes certain exons to be lost or kept e.g., antibodies

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a codon?

A

3 base sequences
Read in sets of three

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are mutations?

A

One source of genetic variation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Do mutations require a response to occur?

A

No, they occur randomly

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens in a substitution mutation?

A

One base is replaced with another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the different types of substitution mutations?

A

Silent: new code for same amino acid, so the protein remains the same
Missense: new code changes the amino acid
Nonsense: new code is a STOP codon and stops the protein from being produced

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Are the effects of missense substitution mutations alarming?

A

Effects are dependent on the role of the amino acid
E.g., a linking amino acid will not change as much

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

When will a missense substitution mutation have an alarming effect?

A

If an amino acid responsible for the protein’s structure is changed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is a frameshift mutation?

A

The triplet code is disrupted, so all amino acids after the mutation change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the different types of frameshift mutations?

A

Addition: a new base is added, shifting the rest forward relative to the reading frame
Deletion: a base is removed, pulling the rest back relative to the reading frame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why are frameshift mutations problematic?

A

If a set of 3 nucleotides (new codon) starts a nucleotide after the frameshift mutation, then the amino acids will change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

How can frameshift mutations have little to no effect on a protein?

A

Frameshift mutations may:
Occur at the ends of genes
Occur in introns
Occur outside of genes

26
Q

What two groups can cells be divided into?

A

Somatic and germline

27
Q

Is there a single genome of the whole body?

A

No, each cell has its own DNA

28
Q

Which type of cells are defined as germline cells?

A

Gametes- cells that have genes that can be passed on

29
Q

What are the products of gametes?

A

A person’s “normal” DNA

30
Q

What are germline mutations?

A

Mutations and genetic variation in germline cells- these mutations/genetic variations can be passed through families

31
Q

What happens if there is a mutation in an embryo as of the germline cells that produced it?

A

The resulting embryo will have that germline mutation throughout all its cells

32
Q

What are somatic cells?

A

Any cell in an organism apart from the reproductive (germline) cells

33
Q

What happens if there is a mutation in a somatic cell?

A

Then only the mutated cell will be effected and this mutation won’t be passed on

34
Q

Can somatic mutations be inherited?

A

No

35
Q

What are the effects of embryonic mutations?

A

All the cells (including somatic cells) are effected

36
Q

How can a mutation spread from an affected somatic cell?

A

The mutation will be passed onto the cells it divides into

37
Q

How does cancer develop?

A

From a series of mutations and changes in a stomatic cell

38
Q

How can a germline mutation affect a zygote’s somatic cells?

A

All the cells will have the mutations, as the zygote has the mutation
Zygote continues to divide into foetus

39
Q

What can germline mutations cause?

A

Genetic disorders, as it is the change of DNA over time
Can also predispose affected individuals to other conditions such as cancer

40
Q

What is an example of a germline mutation?

A

Mutation in the BRCA-1 gene or BRCA-2 gene can lead to breast cancer

41
Q

Why do cells divide?

A

Growth: from fertilised egg cell to adult, or for subsequential growth, e.g., muscles
Maintenance: replace dead/injured cells

42
Q

How can cells divide?

A

By mitosis, however gametes are (partially) produced by meiosis

43
Q

Which cells don’t generally divide?

A

Adult cells, like neurones, as they are fully matured

44
Q

Why do some cells divide then stop?

A

They will only divide when triggered, such as when a tissue is damaged or a cell dies

45
Q

What are some examples of cells that continuously proliferate (replicate) and why do they do this?

A

Hair follicles and red blood cells, as to replace things that have broken down

46
Q

Why is proliferation important regarding embryogenesis?

A

Early development is characterised by the embryonic cells’ rapid proliferation
These cells then differentiate
When the cells differentiate, the rate of proliferation usually decreases

47
Q

What other process is proliferation important in?

A

Maintenance of adult tissue homeostasis:
Matured cells lose the ability to proliferate, however there are some cells that proliferate but only when triggered e.g., replacing damaged cells

48
Q

What affects proliferation?

A

Environmental conditions: pH, nutrients, temperature and oxygen
Interactions with other cells and signaling molecules
Intracellular signaling

49
Q

What is true about all body cells?

A

They can broadly be divided into germline and somatic cells

50
Q

Why does a germline cell require both mitosis and meiosis?

A

Meiosis ensures that the DNA is halved
Mitosis is to produce the cells that precede the germline production
E.g., spermatogonia need to undergo mitosis to enable spermatozoa to keep being produced

51
Q

Why can somatic cells not be passed onto the offspring?

A

They don’t produce gametes

52
Q

What is the cell cycle?

A

When a cell divides via a series of stages

53
Q

What are the stages of the cell cycle?

A

G1
S phase
G2
M phase
(G0- resting phase)

54
Q

What are the sub-stages of the M phase?

A

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

55
Q

What is are the purposes of the G1 and G2 phases?

A

They are gap/growth phases and also incorporate checkpoints to see if the cell is capable of being replicated

56
Q

What roles do the G1 and G2 phases have?

A

G1: Preparation for DNA synthesis (S phase), replication
G2: Preparation for cell division (M phase), doubles in size

57
Q

What would happen if damage to the DNA is detected in the dividing cells?

A

The cell will not progress through the cell cycle until the DNA damage has been fixed
If the damage cannot be fixed, then the cell will undergo apoptosis

58
Q

What occurs during S phase?

A

DNA replication:
DNA helicase separates DNA strands by breaking hydrogen bonds between them
DNA polymerase catalyses the addition polymerisation of the DNA nucleotides

59
Q

How do the new nucleotides form the new DNA strands?

A

New nucleotides are added to the 3’ (“3 prime”) end of the new strand. New nucleotides are attached via their 5’ (“5 prime”) end
Leading strand is made continuously, following helicase
Lagging strand is made in fragments in the opposite direction to helicase action, then combined by DNA ligase

60
Q
A

Foundation Year MBChB (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions