Brainscape's Knowledge GenomeTM

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


See full index

7 Genetics and Early Embryology > Gene Expression > Flashcards

Gene Expression Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

DNA properties

A

antiparallel double-stranded helix
ATGC
less reactive - 2’ deoxyribose

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

RNA properties

A

single-stranded
AUGC
more reactive - 2’ OH in ribose

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

Types of RNA

A
  1. ribosomal (rRNA) 2/3 of ribosomes
  2. transfer (tRNA) molecules that deliver amino acids to ribosomes
  3. messenger (mRNA) nucleotide sequences that direct protein synthesis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How do all cellular RNAs arise?

A

transcription from DNA templates, using DNA-dependent RNA polymerases, which are directed to specific genes (unlike DNAPs)

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

Action of RNA Polymerase

A

couples ribonucleotide triphosphates on DNA template (eg. ATP) which is driven by the release and hydrolysis of PPi

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

Is a primer needed in prokaryotic transcription?

A

no and template is fully conserved

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

How is porkaryotic transcription intiated?

A

promoters - RNAP binds to initiation site through base sequences (promoter), which is recognised by RNAP sigma factor
lies upstream of RNA’s starting nucleotide

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

What causes the DNA strands to separate?

A

RNAP holoenzyme binds in its vicinity

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

What direction is RNA synthesis?

A

5’ to 3’

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

What kind of genome is produced from RNA synthesis in PT?

A

small, single strand genome portions

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

Is PT rapid?

A

yes - RNA synthesis initiated as soon as RNAP clears promoters
and protein synthesis can begin before RNA is completely synthesised (only in Ps)
RNAP is processive and does not dissociate from DNA template

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

How is transcription terminated in prokaryotes?

A

DNA contains specific termination sites:
1. series of 4-10 AT bases
2. A,G,C rich region with palindromic sequence
RNA transcript form self-complementary hairpin, causing RNAP to pause and changes it conformationally

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

How do some prokaryotes terminate transcription without the intrinsic terminator?

A

‘Rho factor’ - helicase that runs along RNA until caused RNAP is found. Pushes it, causing rewinding of dsDNA and release of RNA

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

How does ET differ to PT?

A

similar, but have multiple RNAPs, therefore more complicated control sequences
RNAPs have greater subunit complexity
RNAPs do not have sigma factor
Enhancers

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

What is used to identify promoters in ET?

A

accesory proteins which ID promotors and recruit the RNAPs

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

What are enhancers?

A

certain sequences that encourage transcription

recognised by TFs and can stimulate RNAP II binding and mediate selective gene expression (in Es)

17
Q

What are general transcription factors?

Uses?

A

equivalent of sigma factor

  1. needed for RNAP II transcription
  2. permit basal expression
  3. targeted to TATA box by TBP
  4. switching transcription machinery to elongation mode after RNAP II initiates RNA synthesis
18
Q

What is the preinitiation complex?

A

in basal expression, where TFs combine with an enzyme and DNA

19
Q

How can transcription be inhibited?

A

antibiotics which target RNAP’s essential functions

20
Q

What is RNA capping?

A

RNAp contains CTD, which, when phosphorylated, recruits capping enzyme complex. This modifies the 5’ end to a 7-methylguanosine (joined by 5’-5’-triphosphate bridge)
involves several enzymatic reactions

21
Q

Use of RNA capping

A

provides resistane to degradation and ID of translation start site

22
Q

What is polyadenylation?

A

part of transcription termination, part of the process for producing mRNA for translation
poly(A) added to mRNA
poly (A) tail protects the mRNA from degradation, aids in the export of the mature mRNA to the cytoplasm

23
Q

Splicing

A

introns removed

splicesomes carry out

24
Q

Why are introns removed?

A

source of vulnerability

not required to make polypeptide

25
Q

What are spliceosomes?

A

small ribonucleoproteins (snRNAs + proteins)

26
Q

What is alternative splicing?

A

where primary transcripts are spliced in different ways

leads to proteins with differing destinations in the cell with different catalytic/interactive properties

7 Genetics and Early Embryology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions