Cell Cycle/DNA Flashcards

1
Q

In DNA replication, which enzyme joins fragments of DNA? What are the fragments called?

A

Okazaki fragments

DNA ligase

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2
Q

In which direction does DNA polymerase READ the template strand?

A

3’ to 5’

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3
Q

What happens in termination stage of DNA replication?

A

RNA primers removed and so DNA polymerase dissociates

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4
Q

Why is DNA replication described as semi-conservative?

A

In the 2 daughter copies of the original DNA, 1 strand is original and 1 strand is new

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5
Q

What enzyme lays down which sort of primers in DNA replication?

A

RNA primase

RNA primers

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6
Q

At which stage of the cell cycle do chromosomes replicate?

A

S phase

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7
Q

When writing two strands of DNA nucleotides, conventionally, which strand is on the top?

A

Coding strand (going from 5’–>3’)

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8
Q

In which direction does DNA polymerase synthesise the new strand?

A

5’ to 3’

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9
Q

What promoter sequence is used/recognised in eukaryotes?

A

TATA box (at -30)

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10
Q

What promoter sequence is recognised in prokaryotes?

A

Prob now box (at -10)

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11
Q

What type of ribosomes are present in eukaryotes?

A

80s, has 40s + 60s sub units

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12
Q

What ribosomes are present in prokaryotes? What sub units have they?

A

70s, have 30s + 50s sub units

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13
Q

Which direction does RNA polymerase read the template strand in?

A

3’ to 5’

TF producing new strand in 5’ to 3’

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14
Q

List three types of RNA processing occuring in eukaryotic pre-mRNA.

A

Splicing, 5’ capping, 3’ tailing

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15
Q

What does 5’ capping do?

A

Adds special 5’ cap which protects from degradation

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16
Q

What does 3’ tailing do? Another name?

A

Polyadenylation, adds poly A tail onto 3’ end, protects against degradation.

17
Q

What does splicing do? Why important?

A

Remove selected introns, allows different levels of regulation of gene expression

18
Q

What is the initiation codon for translation? Which amino acid does this code for?

A

AUG, codes for methionine

19
Q

What is the ‘wobble position’? Why is it important?

A

The third position in a codon. Once the first two bases have been paired correctly, whether the third is paired precisely is les important. Allows one tRNA to recognise several codons.

20
Q

Which enzyme makes the peptide bond between AA’s in translation?

A

Peptides transferase

21
Q

What is another name for the template strand? What clue does it give us to its function?

A

Non-coding strand- TF it doesn’t code for mRNA

22
Q

What are the phases of the cell cycle?

A

Interphase, Mitosis

23
Q

What are the 5 stages of mitosis?

A

Prophase, prometaphase, metaphase, anaphase, telophase, cytokinesis

24
Q

What are the stages of interphase?

A

G1, S phase, G2

25
Q

What is G0?

A

At any point cells can leave the cell cycle and enter G0 where they enter an inactive state (cell cycle arrest) Eg nerve cells stay here

26
Q

What occurs in G1 of the cell cycle?

A

Cellular contents, except chromosomes, are replicated ready for S phase (eg organelles etc)

27
Q

What happens in S phase of interphase?

A

DNA replication

28
Q

Why is chromosome number preserved during DNA replication?

A

Because one chromosome is replicated to form a chromosome consisting of two sister chromatids

29
Q

What is termination of DNA replication?

A

When two replication forks meet, DNA ligase joins the DNA fragments together forming two daughter double stranded DNA.

30
Q

Why is DNA replication semi-conservative?

A

Produces two daughter DNA molecules, each with 1 original and 1 new strand of DNA

31
Q

What is the lagging strand?

A

DNA strand being made in the direction away from the advancing replication fork, TF it is discontinuous- forming Okazaki fragments

32
Q

What epigenetic modification activates DNA?

A

DNA demethylation and histone acetylation

33
Q

What epigenetic modification deactivates DNA?

A

DNA methylation and histone deacetylation