Question 1(Multiple Choice Worth 2 points)

Question

(03.03 MC)

If a tRNA molecule has an anticodon that reads AGGCCG, what was the codon on the mRNA molecule?

TCCGGA
UCCGGC
UCCGGU
CTTAAG
Question 2(Multiple Choice Worth 2 points)
(03.03 MC)

Use the following image to answer the question below.

A double-stranded structure is labeled A and has a sequence of letters ATG ATC TCG TAA on one strand and TAC TAG AGC ATT on the other strand. A single-stranded structure is labeled B and has the sequence AUG AUC UCG UAA on the strand. A structure of three connected circles is labeled C with Met, Ile, Ser, and stop. An arrow is labeled Process 1 and points from the structure labeled A to the structure labeled B. An arrow is labeled Process 2 and points from the structure labeled B to the structure labeled C.
© Evyromerojac 2018
Createive Commons, CC BY-SA 4.0

Select the correctly identified structures and steps in the process of protein synthesis.

The structure labeled A is double-stranded DNA. The structure labeled B is single-stranded mRNA. Process 1 is transcription, because DNA is being used to produce a strand of mRNA.
The structure labeled A is double-stranded mRNA. The structure labeled B is single-stranded DNA. Process 1 is translation, because mRNA is being used to produce a strand of DNA.
The structure labeled A is double-stranded DNA. The structure labeled B is single-stranded mRNA. Process 1 is translation, because DNA is being used to produce a strand of mRNA.
The structure labeled A is double-stranded mRNA. The structure labeled B is single-stranded DNA. Process 1 is transcription, because it shows mRNA being used to produce a strand of DNA.
Question 3(Multiple Choice Worth 2 points)
(03.03 MC)

DNA and RNA are the two nucleic acids that store and transmit genetic information for all living organisms on Earth. Which of the following correctly describes differences between DNA and RNA?

DNA is located in the cytoplasm where RNA is located only in the nucleus. DNA is double-stranded, and RNA is single-stranded.
RNA serves as a template for the synthesis of DNA. DNA contains the nitrogen base uracil, and RNA contains the nitrogen base thymine.
DNA is located in the nucleus where RNA is located only in the cytoplasm. RNA contains deoxyribose sugar, whereas DNA contains ribose sugar.
DNA serves as a template for the synthesis of RNA. DNA contains the nitrogen base thymine, and RNA contains the nitrogen base uracil.
Question 4(Multiple Choice Worth 2 points)
(03.03 MC)

Use the following table to answer the question:

Codons Found in Messenger RNA
Second Base
First Base U C A G Third Base
U Phe
Phe
Leu
Leu Ser
Ser
Ser
Ser Tyr
Tyr
Stop
Stop Cys
Cys
Stop
Trp U
C
A
G
C Leu
Leu
Leu
Leu Pro
Pro
Pro
Pro His
His
Gln
Gln Arg
Arg
Arg
Arg U
C
A
G
A Ile
Ile
Ile
Met(Start) Thr
Thr
Thr
Thr Asn
Asn
Lys
Lys Ser
Ser
Arg
Arg U
C
A
G
G Val
Val
Val
Val Ala
Ala
Ala
Ala Asp
Asp
Glu
Glu Gly
Gly
Gly
Gly U
C
A
G

This table shows the codons found in messenger RNA. Using this information, what sequence of nucleotides in the template strand of DNA could code for the polypeptide sequence Val-His-Thr?
GUA-CAU-ACC
GTA-CAT-ACC
CAT-GTA-TGG
CAU-GUA-UGG
Question 5(Multiple Choice Worth 2 points)
(03.03 MC)

A part of an mRNA molecule with the following sequence is being read by a ribosome: 5'-GGC-UGC-3' (mRNA). The charged transfer RNA molecules shown in the figure below (with their anticodons shown in the 3' to 5' direction) are available. Two of them can correctly match the mRNA so that a dipeptide can form:

tRNA Anticodon Amino Acid
GGC Proline
CGU Alanine
UGC Threonine
CCG Glycine
ACG Cysteine
CGG Alanine

Which of the following dipeptides will be formed?
Proline-Threonine
Glycine-Cysteine
Alanine-Alanine
Cysteine-Alanine
Question 6(Multiple Choice Worth 2 points)
(03.03 MC)

The anticodon of a particular tRNA molecule is

complementary to the corresponding mRNA codon
the part of the molecule that bonds to a specific amino acid
complementary to the corresponding triplet in rRNA
altered, depending on the amino acid that binds to it
Question 7(Multiple Choice Worth 2 points)
(03.03 LC)

A triplet of bases in a template strand of DNA is GAT. What would be the corresponding codon for mRNA?

CTA
CUA
CTU
CUU
Question 8(Multiple Choice Worth 2 points)
(03.03 LC)

Which type of RNA functions to carry copies of the instructions needed to assemble amino acids?

mRNA
rRNA
tRNA
Ribosomes
Question 9 (Essay Worth 4 points)
(03.03 MC)

Use the following table to help you respond to the prompts below.

Codons Found in Messenger RNA
Second Base
First Base U C A G Third Base
U Phe
Phe
Leu
Leu Ser
Ser
Ser
Ser Tyr
Tyr
Stop
Stop Cys
Cys
Stop
Trp U
C
A
G
C Leu
Leu
Leu
Leu Pro
Pro
Pro
Pro His
His
Gln
Gln Arg
Arg
Arg
Arg U
C
A
G
A Ile
Ile
Ile
Met(Start) Thr
Thr
Thr
Thr Asn
Asn
Lys
Lys Ser
Ser
Arg
Arg U
C
A
G
G Val
Val
Val
Val Ala
Ala
Ala
Ala Asp
Asp
Glu
Glu Gly
Gly
Gly
Gly U
C
A
G

Carlos needs help with biology because he is having trouble understanding the process of protein synthesis, and his answer to a question needs to be fixed. In the question, he is given a DNA strand that has the nucleotide sequence GAC CAT GTC. He says that he wrote the mRNA as CTG GTA CAG, but then he's not sure how to use the codon table above to figure out the amino acids.

Part 1: Identify the correct nucleotide sequence and explain why it is different from Carlos's answer.

Part 2: Using the codon table along with the correct nucleotide sequence, teach Carlos how to use the codon chart. Make sure you include each step as well as the final amino acid sequence in your explanation.

Add Audio Add Video
Question 10 (Essay Worth 4 points)
(03.03 HC)

Use the following table to help you respond to the prompts below.

Codons Found in Messenger RNA
Second Base
First Base U C A G Third Base
U Phe
Phe
Leu
Leu Ser
Ser
Ser
Ser Tyr
Tyr
Stop
Stop Cys
Cys
Stop
Trp U
C
A
G
C Leu
Leu
Leu
Leu Pro
Pro
Pro
Pro His
His
Gln
Gln Arg
Arg
Arg
Arg U
C
A
G
A Ile
Ile
Ile
Met(Start) Thr
Thr
Thr
Thr Asn
Asn
Lys
Lys Ser
Ser
Arg
Arg U
C
A
G
G Val
Val
Val
Val Ala
Ala
Ala
Ala Asp
Asp
Glu
Glu Gly
Gly
Gly
Gly U
C
A
G

During DNA replication, a mistake occurs in which a single letter is replaced with a different one. This is called a substitution mutation and can occur in many genetic diseases such as cystic fibrosis. Instead of the nitrogenous bases ATG, the DNA now codes for ATT.

Part 1: Identify the sequence of complementary mRNA nucleotides for the original DNA, ATG, and the mutated DNA, ATT.

Part 2: Use the codon table above to determine if this mutation in the DNA code will cause a change in the amino acid. Explain your reasoning.

Answer 1

Sure! Here are the answers to your questions:

Question 1

Answer: UCCGGC.

• The anticodon AGGCCG suggests that the codon on mRNA would be UCCGGC (complementary to the tRNA).

Question 2

Answer: The structure labeled A is double-stranded DNA. The structure labeled B is single-stranded mRNA. Process 1 is transcription, because DNA is being used to produce a strand of mRNA.

• This correctly identifies the structures involved in the process of protein synthesis.

Question 3

Answer: DNA serves as a template for the synthesis of RNA. DNA contains the nitrogen base thymine, and RNA contains the nitrogen base uracil.

• This statement accurately describes the fundamental differences between DNA and RNA.

Question 4

Answer: GTA-CAT-ACC.

• This is the DNA template strand that would code for the polypeptide sequence Val-His-Thr (Val = GUA, His = CAU, Thr = ACC).

Question 5

Answer: Proline-Threonine.

• The first tRNA with anticodon CCG would pair with the mRNA codon GGC (coding for Proline), and the second tRNA with anticodon ACG would pair with the mRNA codon UGC (coding for Threonine).

Question 6

Answer: complementary to the corresponding mRNA codon.

• The anticodon region of tRNA specifically pairs with the corresponding codon on mRNA during translation.

Question 7

Answer: CUA.

• The triplet GAT in the DNA template strand corresponds to the mRNA codon CUA after transcription.

Question 8

Answer: mRNA.

• Messenger RNA (mRNA) is the type of RNA that carries the genetic instructions needed to assemble amino acids.

Question 9

Part 1

• The correct nucleotide sequence for mRNA transcribed from the DNA strand GAC CAT GTC is CUG GUA CAG. Carlos initially wrote CTG GTA CAG, making a mistake in transcribing the first codon. The second base changed in the first codon, which resulted in a wrong mRNA sequence.

Part 2

• To use the codon table:
  1. Break the correct mRNA sequence (now CUG GUA CAG) into codons: CUG, GUA, CAG.
  2. Look up each codon in the table:
     • CUG = Leu (Leucine)
     • GUA = Val (Valine)
     • CAG = Gln (Glutamine)
• Final amino acid sequence: Leu-Val-Gln.

Question 10

Part 1

• The mRNA sequence for the original DNA codon ATG is UAC, and for the mutated DNA codon ATT, the mRNA sequence is UAA.

Part 2

• Looking at the codon table:
  • UAC (original) codes for Tyr (Tyrosine).
  • UAA (mutated) is a stop codon.
• This indicates that the mutation from ATG to ATT causes an early termination of protein synthesis, thereby changing the amino acid sequence and potentially leading to a nonfunctional protein.

Feel free to ask if you need further explanations on any specific point!