Brainscape's Knowledge GenomeTM

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


See full index

Biol 2520 > Chapter 5 > Flashcards

Chapter 5 Flashcards

1
Q

Similarities between DNA and RNA

A

Similarities

  • uses A, C, G
  • has sugar phosphate backbone
  • both have phosphodiester bond
  • A-U and A-T
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Differences between DNA and RNA

A

RNA

  • ribose sugar (5C ) that has an extra O on the second carbon therefore has (OH) on the second carbon
  • uses Uracil not Thymine
  • single stranded
  • complementary nature - can fold into specific 3-D structure

DNA

  • deoxyribose
  • uses Thymine
  • Double stranded
  • anti parallel
  • cant fold into itself
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is transcription

A

It is the process that produces RNA strand that is complementary (opposite) to one of the strand of DNA

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

describe the process of transcription

A
  • RNA polymerase binds to the promoter gene on the template strand (antisense strand)
  • RNA Polymerase unwinds the double helix of just that gene region
  • the RNA strand synthesize in the direction of 5’ ——> 3’ therefore the template strand is being copied in 3’ ——-> 5’ direction
  • the RNA copies the strand using ribose sugar and uracil
  • RNA polymerase stops once it reaches the terminator gene
  • the mRNA strand is formed ( complementary/opposite to template strand)
  • many RNA polymerase can transcribe a gene at the same time.
  • also RNA is transcribe gene by gene, when gene is transcribed it then goes to form the protein instead of transcribing the second gene
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe the three types of RNA and its function

A

1- mRNA : Messenger RNA, an intermediate of gene and a polypeptide
- codes for protein
2- ribosomal RNA
- Forms the core of the ribosome structure
- Catalyze protein synthesis
- MicroRNA
- regulate gene expression
3- TransferRNA
- serves as adaptors between mRNA and amino acids during protein synthesis
- Other noncoding enzymes eg: snRNA , snoRNA, miRNA, incRNA.
- gene regulation, telomere maintenance, RNA splicing

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

What is a gene

A

Segment of DNA thats contains instruction/information ( sequence of nucleotide bases/ nucleotide code) to produce an RNA molecule and protein

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

FLOW OF INFORMATION

Describe briefly, the overview of the flow of information in a cell

A

1- TRANSCRIPTION copies a segment of DNA gene into a pre mRNA
2- the pre- mRNA is PROCESSED into a mature mRNA( only in eukaryotes)
3- the mature mRNA is EXPORTED out of nucleus to the cytoplasm
4- the mRNA is TRANSLATED by ribosomes using tRNA

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

The mRNA is read out in codon by————-

A

Ribosome

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

What is ribosomes made of

A

rRNA and proteins

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

Similarities between mRNA and tRNA and ribosomes sub units

A

Both are made in nucleus and then translocate to the cytoplasm

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

Every gene isn’t transcribed at the same rate - T/F?

A

True

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

The codon/anticodon of mRNA is transcribed to the anticodon/codon of tRNA

A

Codon

Anticodon

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

One anticodon is specific to 1 tRNA T/F

A

True

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

TRANSCRIPTION IN GENERAL

What is a tata box

A

A tata box is a sequence of TATA nucleotides that acts as the promoter gene for RNA polymerase II

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

Where does RNA polymerase bind on a template gene

A

Between the TATA box and + 1

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

Describe the promotor region

A

The promotor region is a specific sequence of nucleotides , usually AT rich
RNA polymerase binds to this region to initiate transcription however the enzyme requires the help of transcription factors to recognize the promotor region

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

Describe the terminator region

A

A specific region on the template strand with GC rich nucleotide. This can cause the RNA POLYMERASE II to stop transcribing

18
Q

Describe in detail the gene transcription initiation by RNA POLYMERASE II

A

1- the TBD region on TFIID ( TATA binding protein) binds to the TATA box
2- this causes a conformal change in DNA ,it bends
3- TFIIA and TFIIB binds to the PROMOTER
4- the TFIIF on RNA POLYMERASE to the promotor
5- the TFIIE and then the TFIIH binds to the promotor completing PIC

19
Q

Function of TFIID, TFIIA , TFIIB

A

TFIID – binds to DNA at the core promoter and bends DNA which is important for recruiting other tfs (eg: TFII A and B)

TFIID TFIIA and TFIIB forms protein - protein interactions to recruit RNA pol II

20
Q

Function of TFIIH

A
  • it pries apart the DNA double helix at +1 exposing the template strand
  • also acts as protein Kinase ( together with other kinase ) to phosphorylate RNA pol II to activate it
21
Q

Overall the function of GTS is (6gtfs + other)

A

6GTs - recruit RNA Pol II and initiate transcription
Other gts - Regulate the rate of transcription , to allow transcription further bcz the 6GTFs only allow minimal trancription

22
Q

What happens After all 6 GTFS bind ( after complete initiation complex forms)

A

TFIIH and other kinase phosphorylates RNA POL II by THIIF also acting as protein kinase to catalyze the phosphorylation
GTFS dissociate

23
Q

Why are additional transcription factors needed

A

Because the 6 GTPS only allow for minimal transcription.

24
Q

If DNA sequence is an enhancer, ———- binds , which ——— the rate of transcription

A

Activator binds

Increses

25
Q

If DNA sequence is a silencer, ———— binds , the rate of transcription ———

A

Repressor

Decreases

26
Q

Sites at which activator or repressor bind is same - T/F

A

False

27
Q

Difference and similarities between eukaryotes and prokaryotes transcription

A

Differences

1 Transcription mechanism
Different factors used in both cells

2 RNA POLYMERASE
Only 1 type in prokaryotes
Three types in eukaryotes

SIMILARITIES
Both have similar promotor and terminator with only slight differences

28
Q

How many upstream and downstream do each GTF occur

A

TFIIB= -35
TBP subunit of TFIID= -30
TFIID = starting site of transcription
TFIID = +35

29
Q

Types of RNApolymerase and gene transcribed

A

RNA POLYMERASE I - Most rRNA genes
RNA POLYMERASE II. - All protein coding genes, miRNA, genes of non coding RNAs
RNA POLYMERASE III - tRNA genes, 5SRNA genes, genes of other small RNAs

30
Q

Precursor of pre- mRNA

A

heterogeneous nuclear RNA - hnRNA

31
Q

Describe hnRNA

A

hnRNA is same as pre mRNA - precursor of mature mRNA
Found in nucleus
Has large molecular weight - exons +introns
Processed to make mRNA ( mature)

32
Q

Where does processing of pre mRNA occur

A

Factories within the nucleus

33
Q

What are the steps in the processing of the RNA

A

7-Methylated guanosine + 5’5 triphosphate bridge - 5’ cap

Polyadenilation - poly A tail

34
Q

5’ CAP - explain the steps

A

1- capping ENZYME recruits a methylated guanosine to the 5’UTR / noncoding end = 7-methylated guanosine ( ribose + sugar - CH3 )
2- a 5’5 triphosphate bridge forms between 5’ of methylated guanosine and 5’ of nucleotide
3- the previously first 1st nucleotide becomes the 2nd after addition of 5’ cap
4- the 2nd nucleotide becomes methylated - 2’ - O - methyl-ribonucleoside ( phosphate + base + ribose - OCH3 )

35
Q

Functions of 5’ cap

A
  • protects RNA from exonuclease
  • helps in transportation from nucleus to cytoplasm
  • plays a role in initiation of translation
36
Q

Describe Polyadenilation

A
  • endonuclease ENZYME binds to the 3’ UTR
  • adds 250 - 500 adenosines forming a tail
  • tail starts 20 bases downstream from the AAUAAA Polyadenilation signal
37
Q

Function of Polyadenilation

A

1 - protects the RNA from exonuclease
2 - Allows mRNA purification by affinity chromatography
By removing mRNAs from rest of the soultion

38
Q

Function of endonuclease

A

Cleaves pre - mRNA downstream from the signal

39
Q

Function of C terminal RNA POL II

A

serves as a scaffold for other factors involved in RNA processing

40
Q

Pre-initiation complex ……….

Complete initiation complex …………

A

Pre-initiation complex = DNA + TFII D

Complete initiation complex = DNA + RNA poly + 6 GTFs

Biol 2520 (16 decks)

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