Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Fundamentals Of Life Science > The Genetic Code > Flashcards

The Genetic Code Flashcards

1
Q

Define DNA replication

A

DNA is copied to make more DNA

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

Define transcription

A

DNA is used as a template to make RNA

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

Define translation

A

RNA is read and proteins are made

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

Where does transcription occur?

A

In the nucleus

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

Where does translation occur?

A

In the cytoplasm

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

What is the basic structure of an amino acid?

A 
NH3 (amino group)
Central carbon 
R group 
Hydrogen 
COOH (carboxyl group)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What joins two amino acids?

A

A peptide bond

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

Where does the peptide bond form?

A

Between the carboxylic group of one amino acid and the amino group of the next

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

What kind of code is the genetic code?

A

Triplet code

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

What does triplet code mean?

A

Three nucleotides specify one amino acid

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

What is another name for a triplet?

A

A codon

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

What is the start codon in all polypeptides?

A

Methionine

AUG

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

What are the three stop codons?

A

UAA
UAG
UGA

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

What does degenerate mean?

A

Usually there is more than one codon for an amino acid

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

What is an open reading frame?

A

A string of sense codons that start with the codon ATG and end with a stop codon at the 3’ end

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

What determines which reading frame is read?

A

The start codon

Also the largest possible protein is always made

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

How many possible reading frames are there?

A

6

3 in each direction

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

How many subunits make up a ribosome?

A

Two

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

What are the two subunits of a ribosome?

A

The small and large subunit

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

What kind of ribosome is involved in protein synthesis and mRNA?

A

An 80s ribosome

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

Describe the small subunit

A

40s
18s rRNA
30 ribosomal proteins

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

Describe the large subunit

A

60s
28s + 5.8s + 5s rRNA
50 ribosomal proteins
2 binding sites

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

What are the two binding sites present in the large subunit?

A

The P site

The A site

24
Q

What is the A site?

A

The aminoacetyl-tRNA binding site

25
What is the P site?
The peptidyl-tRNA binding site
26
What is the role of tRNA?
tRNA molecules carry the amino acids to the ribosomes to be assembled into polypeptide chains
27
What does mRNA consist of?
Leader Reading frame Trailer
28
What features do all tRNA molecules share?
Similar in size and shape | CCA at the 3' end which amino acids bind to
29
What is the anticodon?
The section of the tRNA molecule which during translation reads the matching codon on mRNA
30
How is an amino acid added to a tRNA molecule?
The enzyme aminoacyl-tRNA synthetase
31
What is the name of the process given to adding amino acids to tRNA
Aminoacylation
32
How many aminoacyl-tRNA synthases are there?
As there are 20 amino acids, there are 20 aminoacyl-tRNA synthases
33
Are aminoacyl-tRNA synthases dependent on the codon?
No | So when an amino acid has multiple codons it will still only have one aminoacyl-tRNA synthase
34
Describe the role of ATP in aminoacylation
ATP binds to the amino acid once it has bound to the enzyme Loses two phosphate groups to become AMP AMP released tRNA binds
35
What is the first step of translation?
A small ribosomal subunit binds to mRNA at start codon region
36
What attracts the large subunit?
Initiation factors This completes the ribosome The start codon occupies the P site
37
What is elongation dependent on?
The appropriate aminoacyl-tRNA binding to the codon in the A site of the ribosome
38
What happens when a stop codon is reached?
Polypeptide synthesis ends Polypeptide released from tRNA tRNA released from the ribosome Ribosomal subunits separate
39
How many ribosomes can be on a piece of mRNA at one time?
Many
40
Name three things that cause DNA mutation?
Substitution Insertion Deletion
41
Name the three kinds of mutation
Silent Missense Nonsense
42
Describe the steps of aminoacylation
Complemintary amino acid binds to a specific AtRNA active site. ATP binds to the amino acid once it has bound to the enzyme after causing a change in shape of the enzyme ATP Llses two phosphate groups to become AMP AMP released exposing a second active site complimentary to the uncharged tRNA tRNA binds to the enzyme Once binding of the amino acid to the acceptor stem of tRNA molecule occurs, it is expelled from the enzyme.
43
What is the structure of tRNA?
Single stranded. Has an acceptor stem of CCA at the 3' for amino acid binding Anticodon loop is variable dependent on the amino acid at the acceptor stem.
44
What are the 3 phases of translation?
Initiation Elongation Termination
45
What happens during the initiation phase of translation?
A small ribosomal subunit binds to mRNA at start codon region allowing a tRNA carrying methionine to bind to the P site. initiation complex of translation forms The A site is free and the next 3 bases of the mRNA are read. A charged tRNA carrying the sepcific amino acid will bind to the A site A peptide bond forms between the adjacent amino acids The tRNA in the P site becomes uncharged and leaves from the ribosome allowing the A site tRNA to move into the P site.
46
What happens during the elongation phase of translation?
Elongation of the polypeptide begins as the appropriate charged tRNA molecule will bind to the A site Peptide bonds form between the amino acids elongating the polypeptide AS the peptide bonds for the P site tRNA moves off and the A site tRNA moves into the P site constantly making the A site free for more tRNAs to bind to. This process repeats until a stop codon is identified.
47
What happens during the termination phase of translation?
No anticodon on tRNA matches a stop codon Nothing occupies the A site Release factor binds to the stop codon Peptidyl transferase is triggered releasing the polypeptide Ribosomal subunits separate
48
What are polysomes?
Where multiple ribosomes bind to the mRNA strand at any one time forming a polysome.
49
What is a silent mutation?
Base substitution which has no effect on the encoded amino acid due to DNA being degenerate
50
What is a missense mutation?
Base substitution encoding for a different amino acid. This has a big influence on the protein folding and therefore its function. This is less effected if the new amino acid is similar biochemically.
51
What is a nonsense mutation?
Base substitution which encodes for a stop codon causing early recruitment of a release factor and therefore forms a shortened non-functional protein.
52
What is an insertion mutation?
Addition of a base in the coding which will cause a frameshift if the insertion is not a multiple of 3 bases added.
53
What is a deletion mutation?
Deletion of a base in the coding which will cause a frameshift if the insertion is not a multiple of 3 bases added.
54
What is extensive missense?
Where a stop codon is deleted via a deletion mutation
55
What is extensive nonsense?
Where a stop codon is added via an insertion mutation.
56
Where must addition and deletion mutations occur?
Within the reading frame of the first methionine.

Fundamentals Of Life Science (26 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions