Brainscape's Knowledge GenomeTM

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


See full index

Bio 202 Test 3 > DNA to Protein > Flashcards

DNA to Protein Flashcards

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

Where are EUKARYOTIC mRNAs processed?

A

the nucleus

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

Are introns or exons the noncoding part of pre-mRNAs? How are these removed?

A

Introns are the noncoding sequence

RNA splicing is how these are removed

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

Where does RNA processing occur?

A

inside the nucleus, when mature they are exported from the nucleus

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

What are the segments of DNA that are coded into RNA called?

A

genes

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

Can different genes be expressed at different rates?

A

YES

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

What are the base pairs in RNA vs DNA?

A

DNA - AT CG

RNA - AU CG

RNA uses uracil while DNA uses thymine

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

What type of bond is formed in both DNA and RNA to hold nucleotides together in a strand?

A

Phosphodiester bond

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

When base pairs form, what type of bondage is used?

A

Hydrogen bonding

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

Do all RNA molecules have the same basic 3D structure?

A

NO, different nucleotides will pair with one another on different stretches of the molecule forming unique structures.

There are conventional base pairs (UA and CG) which forms the double helix, as well as nonconventional base pairs (CU and AG) that occur to allow more unique 3D structure.

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

When RNA is transcribed, is it the coding DNA strand or the template DNA strand that the new RNA is identical to?

A

It is complementary to the template strand and identical to the coding strand.

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

What direction is RNA formed in?

A

5’ to 3’

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

What is the primary enzyme involved in transcribing DNA into RNA?

A

RNA polymerase?

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

How does RNA polymerase get to the template strand of DNA to read it?

A

by unwinding the DNA in front of it as it moves along stepwise on the strand, adding single ribonucleotides to the RNA chain as it goes. It also displaces the RNA chain behind it to allow the DNA to wind again.

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

How long is the DNA/RNA window that forms with RNA polymerase and the template DNA strand?

A

Approximately nine nucleotides in length.

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

Is the resulting RNA from the template DNA single stranded or double stranded?

A

single stranded

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

What are 5 types of RNAs and their basic functions?

A

mRNAs - code for proteins

rRNAs - form ribosome core structure and catalyze protein synthesis

miRNAs - regulate gene expression

tRNAs - serve as adapters between amino acids during protein synthesis

other noncoding RNAs - used in RNA splicing, gene regulation, telomere maintenance, etc…

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

How does RNA polymerase know when to start or stop transcrition? GIVE PROKARYOTE EXAMPLE

A

RNA polymerase has a sigma factor that recognizes the promoter of a gene. The sigma factor is released when transcription is started until it reaches the terminator sequences on the gene. it then releases from DNA template and RNA transcript and reassociates with sigma factor. Then the process repeats itself.

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

In prokaryotes, describe the terminator and promoter? where are they located, do they get transcribed?

A

Promoter: commonly located -10 and -35 from where transcription is actually started and are usually very similar sequences, not transcribed.

Terminator: These are towards the end of the template, but are transcribed by the RNA polymerase.

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

Which way does the RNA polymerase travel down the DNA template? Think about the direction of the synthesis of the ANTIPARALLEL RNA transcript.

A

3’ to 5’

This allows for the RNA transcript to be constructed in the 5’ to 3’ direction.

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

How is the template strand vs the coding strand distinguished?

A

Based on the polarity of the promoter

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

Describe the genes transcribed by the 3 RNA polymerases of the eukaryote.

A

RNA polymerase I - mose rRNA genes

RNA polymerase II - all protein-coding genes, miRNA genes, and genes for other noncoding RNAs (such as the spliceosome)

RNA polymerase III - tRNA genes, 5S rRNA gene, genes for many other small RNAs.

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

What is required for RNA polymerase to function in eukaryotes?

A

GENERAL TRANSCRIPTION FACTORS

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

What do most eukaryotic promoters contain in their sequence?

A

a TATA box

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

Describe the TATA box and how it contributes to the start of transcription using transcription factors.

A

The TATA box is recognized by a subunit of the general transcription factor TFIID, called the TATA-binding protein (TBP).

The binding of TFIID enables the adjacent binding of TFIIB.

The rest of the general transcription factors, as well as the RNA polymerase itself, then assemble at the promoter.

TFIIH pries apart the double helix at the transcription start point, using the energy of ATP hydrolysis, which exposes the template strand of the gene.

TFIIH also phosphorylates RNA polymerase II, releasing the polymerase from most of the general transcription factors, so it can begin transcription.

The site of phosphorylation is a long polypeptide “tail” that extends from the polymerase. Once the polymerase moves away from the promoter, most of the general transcription factors are released from the DNA; the exception is TFIID, which remains bound through multiple rounds of transcription initiation.

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

What does TBP (TATA binding protein) do to the DNA when it binds to the TATA box?

A

It bends the DNA double helix.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Do the promoters of EUKARYOTE DNA contain sequences that promote the binding of transcription factors? can some of them be upstream OR downstream?

A

YES YES YES

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Where does translation occur in eukaryotes?

A

mRNAs are transported out of the nucleus via nuclear pores to the CYTOSOL, where translation occurs.

28
Q

Where are ribosome components produced?

A

In the nucleolus

29
Q

RNA polymerase II has a tail that is phosphorylated to begin transcription, then it can be phosphorylated even further. What is the purpose of this?

A

This allows for the binding RNA-processing proteins here that will cap, polyadenylate, or splice the new RNA that is being synthesized

30
Q

What is at the 5’ end and at the 3’ end of mRNA?

A

5’ cap and 5’ untranslated region (UTR)

3’ poly-A-tail and 3’ untranslated region

31
Q

Do JUST EUKARYOTES have introns and exons?

A

YES, bacterial genes have uninterrupted coding sequences.

32
Q

How are introns removed?

A

RNA splicing

33
Q

Does only a portion of an intron need to have a specific nucleotide sequence in order to be removed? What recognizes these specific sequences?

A

YES, the rest can be occupied by any nucleotide

snRNPs (small nuclear ribonucleoproteins) recognize these and direct the cleavage at the intron-exon border and catalyze the linkage of the exon sequences.

34
Q

How does the branch point (adenine) begin the first step in the RNA splicing process?

A

the branch point attacks the intron/exon splice site cutting the backbone, the newly released 5’ site links to the OH group of the adenine and forms a lariat

35
Q

What happens in the second step of RNA splicing?

A

The free 3’OH end of exon reacts with start of next exon sequence and joins them together and the lariat structure is released at the same time and is degraded in the nucleus.

36
Q

there are 5 snRNPs and many other (200) proteins involved in splicing, but what are the three nmost important snRNPs that are covered in this class?

A

U1, U2, and U6

37
Q

Describe the first step of RNA splicing.

A

U1 recognizes the 5’ splice site and U2 recognizes the branch-point site via complementary base pairing.

38
Q

Describe the second step of RNA splicing.

A

U6 rechecks the 5’ splice site by displacing U1 and base-pairing to the intron sequence itself, THIS IMPROVES ACCURACY BY DOUBLE CHING PROPER SPLICING ZONE.

39
Q

Describe the last steps of RNA splicing.

A

U2 and U6 undergo conformational changes triggered by ATP HYDROLYSIS to drive formation of spliceosome active site and splicing occurs.

the spliceosome deposits RNA binding proteins knwon as the exon junction complex to mark splice site as completed.

40
Q

While intron and exon order can’t be rearranged, what can be done via RNA splicing to make alternatively-spliced RNAs.

A

Exons can either be included or excluded in the splicing process to produce many different combinations of exons.

41
Q

What is the concept of RNA “factories” within the cell?

A

When lit up with fluoroscopy, it can be seen that RNA synthesis and processing and DNA replication occur in their own compartments throughout the nucleus of mammalian nucleus.

THERE ARE SOME SITES THAT HAVE BOTH TRANSCRIPTION AND REPLICATION AND ARE THEREFORE YELLOW.

42
Q

How are mature mRNAs exported from the nucleus to the cytosol?

A

They are marked by RNA binding proteins at their 5’ cap and 3’ poly-A-tail along with successful splices being marked by exon junction complexes.

These all help deem the mRNA “export ready”.

Then a nuclear transport receptor associates with the mRNA and guides it through the nuclear pore.

43
Q

What happens to the mRNA once it reaches the cytosol?

A

the mRNA sheds some of its RNA binding proteins and binds new ones that act along with the poly-A-tail as initiation factors for protein synthesis

44
Q

LOOK AT SLIDE 85 FOR OVERVIEW

A

DO IT

45
Q

How is an mRNA sequence decoded?

A

In sets of 3 nucleotides

46
Q

What is the function of tRNA molecules?

A

to match amino acids to codons in mRNA.

47
Q

What do some antibiotics inhibit?

A

prokaryotic protein synthesis.

48
Q

What is special about the codon AUG?

A

This is the only codon for methionine, and is also the initiation codon to start the protein-coding process.

49
Q

What are the three codons that do not code for an amino acid and are the STOP CODONS?

A

UAA
UAG
UGA

50
Q

How many reading frames are there for an mRNA molecule, of those three how many are the actual reading frame?

A

Three

only one is the true frame.

51
Q

What is the simple way that scientists learned what codon codes for what? Does this experiment have its limitations? How?

A

by filling a test tube with synthetic poly-u mRNA, placing ribosomes, tRNAs, enzymes, and other small molecules. when the proper radioactive amino acid is added a radioactive polypeptide will form in this case it would be phenylalanine.

It does have its limitations, for instance, when doing poly-UG two amino acids are on the polypeptide chain and it is impossible to distinguish which of the two (UGU, GUG) codons code for VAL or CYS. THERE IS AMBIGUITY.

52
Q

What does the anticodon of the tRNA bind to?

A

the complementary codon on the mRNA.

53
Q

What is the function of aminoacyl-tRNA synthetase, describe what it attaches to and how it attaches things.

A

This is an enzyme that binds to the tRNA molecule. making contact at multiple locations including the anticodon loop and the amino-acid-accepting arm.

then ATP is hydrolyzed to AMP to provide the energy to attach the amino acid to the tRNA.

54
Q

What is the process called when the aminoacyl-tRNA synthetase couples a particular amino acid to its corresponding tRNA?

A

CHARGING

55
Q

After being charged what happens with the tRNA?

A

The anticodon of the tRNA forms base pairs with the codon in mRNA.

56
Q

What would happen if either the charging step or the binding of the charged tRNA to its codon had an error?

A

The wrong amino acid would be incorporated into a polypeptide chain.

57
Q

What decodes the messages from the mRNA?

A

The ribosomes.

58
Q

Where do you find ribosomes?

A

On the ER or in the cytoplasm.

59
Q

What do eukaryotic ribosomes consist of?

A

its a large complex made of four rRNAs and more than 80 small proteins.

Formed from one large and one small subunit.

60
Q

When do the two subunits of the ribosome come together?

A

When the small subunit has bound an mRNA.

61
Q

What accounts for most of the mass and shape of the ribosome?

A

the RNAs that help make them up.

62
Q

What binding sites are located on a ribosome?

A

Three tRNA binding sites and one mRNA binding site.

63
Q

What is the order that tRNA travels along the binding sites of the ribosome? What is the name for each site?

A 
A (aminoacyl) 
then
P (peptidyl)
then
E (exit)
64
Q

Describe step 1 of translation.

A

In step 1, a charged tRNA carrying the next amino acid to be added to the polypeptide chain binds to the vacant A site on the ribosome by forming base pairs with the mRNA codon that is exposed there.

Only a matching tRNA molecule can base-pair with this codon, which determines the specific amino acid added.

The A and P sites are close enough together that their two tRNA molecules are forced to form base pairs with codons that are contiguous, with no stray bases in-between.

This positioning of the tRNAs ensures that the correct reading frame will be preserved throughout the synthesis of the protein.

65
Q

Describe Step 2 of translation.

A

In step 2, the carboxyl end of the polypeptide chain (amino acid 3 in step 1) is uncoupled from the tRNA at the P site and joined by a peptide bond to the free amino group of the amino acid linked to the tRNA at the A site.

This reaction is carried out by a catalytic site in the large subunit.

66
Q

Describe step 3 of translation.

A

In step 3, a shift of the large subunit relative to the small subunit moves the two bound tRNAs into the E and P sites of the large subunit.

67
Q

Describe step 4 of translation.

A

In step 4, the small subunit moves exactly three nucleotides along the mRNA molecule, bringing it back to its original position relative to the large subunit. This movement ejects the spent tRNA and resets the ribosome with an empty A site so that the next charged tRNA molecule can bind

Bio 202 Test 3 (1 decks)

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