Bio 211 > Unit 3: Topic 11 > Flashcards

Unit 3: Topic 11 Flashcards

(62 cards)

Study These Flashcards
1
Q

What is translation?

A

The assembly of amino acids into polypeptides.

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

There are __ common amino acids that can fall into _ categories.

A

20
5

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

Non polar amino acids:

A

Have R groups with CH4 and CH3

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

Uncharged polar amino acids:

A

R groups with O and -OH

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

Charged amino acids:

A

R groups with acids/bases that can ionize.

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

Aromatic amino acids:

A

R groups have alternating single, double bonds.

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

Special function amino acids;

A

Three types:
1) Methionine- first amino acid in the polypeptide sequence
2) Proline- causes a link in the polypeptide.
3) Cysteine- disulfide bonds.

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

Protein structure can be disrupted by ____________ and __________.

A

Denaturation
Mutations

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

tRNAs:

A

Adaptors between codons(mRNA) and amino acids.

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

What is the structure of tRNA?

A

3-D cloverleaf and 3-D-L shape, folded RNA from self complentarity.

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

At what part of the tRNA do amino acids attach?

A

The acceptor stem, contains the sequence 5’CCA-3’ at the 3’ end of the tRNA.

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

What is the anticodon loop?

A

Part of the tRNA where the bottom loop of cloverleaf contains 3 nucleotide sequences that recognize the codon by base pairing with mRNA.

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

What is aminoacyl-tRNA (charging)?

A

Adding the amino acid to the tRNA.

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

What is aminoacyl-tRNA synthase?

A

Enzymes that add the correct amino acid to the acceptor stem of the correct tRNA. each amino acid has its own enzyme(20).

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

What is the correct reaction for charging?

A

amino acid + tRNA + ATP —–> aminoacyl-tRNA

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

The genetic code consists of 61 _____ codons.

A

Sense

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

Codons are written in the ‘-’ direction as they appear in mRNA.

A

5
3

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

Start codon:

A

AUG, methimine/MET

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

Stop codons:

A

UAA, UAG, UGA, not recognized by tRNA so do not code for an amino acid.

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

Genetic code shows __________, an amino acid can be specified by more than one _______.

A

Degeneracy
Codon

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

What are the 3 rules of the genetic code?

A

1) Codons on the mRNA are read from the 5’-3’ direction.
2) Codons do not overlap and the message contains no gaps.
3) Message is translated in a fixed reading frame set by the start codon.

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

What is wobble in the tRNA codon?

A

Some tRNAs have codons that can base pair with more than one codon on the mRNA.

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

How does wobble occurr?

A

When the base at the 5’ end of the anticodon forms H-bonds with more than one type of base located at the 3’ end of a codon.

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

Ribosome(prokaryotes) 70s:

A

Protein synthesis machinery. Composed of 2 subunits, each are a complex of RNA and proteins.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What are the 2 units of ribosomes in prokaryotes?
1. Large Subunit: 50s, made of 5s and 23s rRNA + 34 proteins. Contains peptide transferase centre for formation of peptide binds. 2. Small Subunit: 30s, made up of 16s RNA + 21 proteins and contains decoding centre where charged tRNAs read and decode the codon of mRNA.
26
What is the S/Svedberg unit?
Measure of sedimentation velocity and therefore mass.
27
Each subunit exists ___________ int eh cytoplasm but come together on the ____ _________.
Sperately mRNA molecule
28
What are the unit measurements of eukaryotic ribosomes?
60s(large) and 40s(small)= 80s ribosome
29
What are the 3 tRNA binding sites of ribosomes?
1. A site (aminoacyl) 2. P site (peptidyl) 3. E site (exit)
30
A site:
Bind the tRNA carrying the next amino acid to be added to the growing polypeptide.
31
P site:
Binds to the tRNA attached to the growing polypeptide chain.
32
E site:
Bind to the tRNA that carried the previous amino acid added.
33
What are the 3 stages of translation?
1. Initiation 2. Elongation 3. Termination
34
What is translation elongation?
When the initiator tRNA(met) is brought to the P site of the small ribosomal subunit (requires GTP).
35
What is the first step of initation?
Complex of initiator tRNA(met) and small ribosomal subunit is recruited to the capped 5' end of the mRNA and scans along the mRNA in the 5'-3' direction.
36
What is the second step of initiation?
Complementary base-pairing occurs between anticodon of initiator tRNA(met) and start codon of mRNA.
37
What is the fourth step of initiation?
GTP is hydrolisized to GDP + Pi and translation begins.
37
What is the third step of initiation?
Large ribosomal subunit binds small unit to form the initiation complex, which is now ready to accept the first tRNA at the A site.
38
What is translation elongation?
Growth of the polypeptides.
38
What is the second step of elongation?
Peptide transferase in the large subunit forms a peptide bond between the amino group of the amino acid in the A site and the carboxyl group of the amino acid in the P site.
39
What is the first step of elongation?
Correct aminoacyl tRNA is loaded to the A site by elongation factor-GTP (tRNA anticodon is complementary to the mRNA codon in the A-site).
40
What is the third step of elongation?
Ribosome translocates, in which the tRNA with the polypeptide shifts from A to P site, and the uncharged tRNA shifts from P to E, where it exists.
41
What is the fourth step of elongation?
The next codon of the mRNA is now in the A-site and the next amino-acyl tRNA can be loaded by EF-GTP.
42
What is translation termination?
Releases a completed polypeptide from the ribosome.
43
What is the first step of termination?
3 stop codons (UAA, UAG, UGA) are found at the end of a protein-coding sequence in mRNA. Not recognized by tRNA but by proteins called released factors (RF).
43
What is the second step of termination?
When the ribosome reaches the stop codon, RF binds at the A site and stimulates peptidyl transferase to cleave the polypeptide through addition of H2O from the P site + RNA.
43
What is the third step of termination?
Ribosome subunits seperate and detach from mRNA and the empty tRNA and RF also seperate.
43
What are post-translational regions of proteins?
Modifications of proteins with chemical groups for activity and degredation.
44
What are the 3 types of post-translational regions of protiens?
1) Phosphorylation: Addition of a phosphate group to a protein through a covalent bond. 2) Ubiquitination: Addition of ubiquitin to proteins by covalent bonds. 3) Post-translational cleavage of a protein.
45
What are the steps of phosphorylation?
1. Pyruvate kinase catalyzes the last reaction of glycolysis. 2. Phosphorylation of pyruvate kinase turns the enzyme off. 3. De-phosphorylation of of pyruvate kinase turns the enzyme back on.
46
What is epigenetics?
Post-translational modification of histones that affect transcription, changes in gene transcription occurs without changes in DNA sequence.
47
Modifications to _________ on the _____ tails affect transcription of genes.
Lysines Histone
48
What are the 3 types of modifications to histones?
1. Histone-acetyl-transferase (HAT). 2. Methylation. 3. Chromatin remodelling complex.
49
What is HAT?
Adding an acetly group to histone tails to increase gene transcription by loosening DNA binding.
50
What is methylation?
Addition of CH3 of histone tails that represses the transcription of genes.
51
What is Chromatin remodelling complex?
Displacing nucleosomes from promoter regions (ATP dependent) activating transcription.
52
WhaT ARE THE 4 TYPES OF POST-TRANSLATIONAL/ TRANSLATIONAL REGULATION OF GENE EXPRESSION?
1) Translational regulation. 2) Post-translational regulation. 3) Abundance of proteins. 4) Activity of proteins.
53
Translational regulation:
Control of protein synthesis (rate of translation initiation or formation of initiation complex).
54
Post-translational regulation:
Control of protein abundance/ activity (availability of functional proteins).
55
Abundance of proteins:
Depends on its rate of synthesis and degradation.
56
Activity of proteins:
Depends on post-translational modifications and processing.
57
The expression level of a certain protein is dependent upon its _____ and ________.
Activity Abundance
Bio 211
flashcards
Decks in class (12)
# Cards
Brainscape helps you reach your goals faster, through stronger study habits.
© 2026 Bold Learning Solutions. Terms and Conditions