Chapter 22, Problem 55P

For each codon, give its anticodon and the amino acid for which it codes.
a. CUG
b. UUU
c. AAG
d. GCA

Interpretation Introduction

(a)

Interpretation:

Anticodon and amino acid for codon CUG should be identified.

Concept Introduction:

DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis. Anticodon is the triplet that is represented in tRNA molecules corresponding to a complementary codon in mRNA.

Answer to Problem 55P

Anticodon − GAC

Amino acid − Leucine (Leu)

Explanation of Solution

Codons are written from 5 prime-end (5) to 3 prime-end (3) of mRNA. There is a unique triplet representation for a particular amino acid. The below-mentioned table represents the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

First Base (5' end)	Second Base								Third Base (3' end)
	U		C		A		G
U	UUU	Phe	UCU	Ser	UAU	Tyr	UGU	Cys	U
	UUC	Phe	UCC	Ser	UAC	Tyr	UGC	Cys	C
	UUA	Leu	UCA	Ser	UAA	Stop	UGA	Stop	A
	UUG	Leu	UCG	Ser	UAG	Stop	UGG	Trp	G
C	CUU	Leu	CCU	Pro	CAU	His	CGU	Arg	U
	CUC	Leu	CCC	Pro	CAC	His	CGC	Arg	C
	CUA	Leu	CCA	Pro	CAA	Gln	CGA	Arg	A
	CUG	Leu	CCG	Pro	CAG	Gln	CGG	Arg	G
A	AUU	Ile	ACU	Thr	AAU	Asn	AGU	Ser	U
	AUC	Ile	ACC	Thr	AAC	Asn	AGC	Ser	C
	AUA	Ile	ACA	Thr	AAA	Lys	AGA	Arg	A
	AUG	Met	ACG	Thr	AAG	Lys	AGG	Arg	G
G	GUU	Val	GCU	Ala	GAU	Asp	GGU	Gly	U
	GUC	Val	GCC	Ala	GAC	Asp	GGC	Gly	C
	GUA	Val	GCA	Ala	GAA	Glu	GGA	Gly	A
	GUG	Val	GCG	Ala	GAG	Glu	GGG	Gly	G

According to the above table; one amino acid has several triplets, but triplet code is unique for an amino acid.CUG codon is responsible for GAC anticodon and this happens because of the complementary base pairing. In DNA; Adenine (A) pairs with Thymine (T). Cytosine (C) pairs with Guanine (G). In RNA; Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G). According to the above table, leucine is the responsible amino acid for the CUG code.

Interpretation Introduction

(b)

Interpretation:

Anticodon and amino acid for codon UUU should be identified.

Concept Introduction:

DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis. Anticodon is the triplet that is represented in tRNA molecules corresponding to a complementary codon in mRNA.

Answer to Problem 55P

Anticodon − AAA

Amino acid − Phenylalanin (Phe)

Explanation of Solution

Codons are written from 5 prime ends (5) to 3 prime ends (3) of mRNA. There is a unique triplet representation for a particular amino acid. The below-mentioned table represents the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

First Base (5' end)	Second Base								Third Base (3' end)
	U		C		A		G
U	UUU	Phe	UCU	Ser	UAU	Tyr	UGU	Cys	U
	UUC	Phe	UCC	Ser	UAC	Tyr	UGC	Cys	C
	UUA	Leu	UCA	Ser	UAA	Stop	UGA	Stop	A
	UUG	Leu	UCG	Ser	UAG	Stop	UGG	Trp	G
C	CUU	Leu	CCU	Pro	CAU	His	CGU	Arg	U
	CUC	Leu	CCC	Pro	CAC	His	CGC	Arg	C
	CUA	Leu	CCA	Pro	CAA	Gln	CGA	Arg	A
	CUG	Leu	CCG	Pro	CAG	Gln	CGG	Arg	G
A	AUU	Ile	ACU	Thr	AAU	Asn	AGU	Ser	U
	AUC	Ile	ACC	Thr	AAC	Asn	AGC	Ser	C
	AUA	Ile	ACA	Thr	AAA	Lys	AGA	Arg	A
	AUG	Met	ACG	Thr	AAG	Lys	AGG	Arg	G
G	GUU	Val	GCU	Ala	GAU	Asp	GGU	Gly	U
	GUC	Val	GCC	Ala	GAC	Asp	GGC	Gly	C
	GUA	Val	GCA	Ala	GAA	Glu	GGA	Gly	A
	GUG	Val	GCG	Ala	GAG	Glu	GGG	Gly	G

According to the above table; one amino acid has several triplets, but triplet code is unique for an amino acid. UUU codon is responsible for AAA anticodon and this happens because of the complementary base pairing. In DNA; Adenine (A) pairs with Thymine (T). Cytosine (C) pairs with Guanine (G). In RNA; Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G). According to the above table, phenylalanine is the responsible amino acid for the UUU code.

Interpretation Introduction

(c)

Interpretation:

Anticodon and amino acid for codon AAG should be identified.

Concept Introduction:

DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis. Anticodon is the triplet that is represented in tRNA molecules corresponding to a complementary codon in mRNA.

Answer to Problem 55P

Anticodon − UUC

Amino acid − Lysine (Lys)

Explanation of Solution

Codons are written from 5 prime ends (5) to 3 prime ends (3) of mRNA. There is a unique triplet representation for a particular amino acid. The below-mentioned table represents the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

First Base (5' end)	Second Base								Third Base (3' end)
	U		C		A		G
U	UUU	Phe	UCU	Ser	UAU	Tyr	UGU	Cys	U
	UUC	Phe	UCC	Ser	UAC	Tyr	UGC	Cys	C
	UUA	Leu	UCA	Ser	UAA	Stop	UGA	Stop	A
	UUG	Leu	UCG	Ser	UAG	Stop	UGG	Trp	G
C	CUU	Leu	CCU	Pro	CAU	His	CGU	Arg	U
	CUC	Leu	CCC	Pro	CAC	His	CGC	Arg	C
	CUA	Leu	CCA	Pro	CAA	Gln	CGA	Arg	A
	CUG	Leu	CCG	Pro	CAG	Gln	CGG	Arg	G
A	AUU	Ile	ACU	Thr	AAU	Asn	AGU	Ser	U
	AUC	Ile	ACC	Thr	AAC	Asn	AGC	Ser	C
	AUA	Ile	ACA	Thr	AAA	Lys	AGA	Arg	A
	AUG	Met	ACG	Thr	AAG	Lys	AGG	Arg	G
G	GUU	Val	GCU	Ala	GAU	Asp	GGU	Gly	U
	GUC	Val	GCC	Ala	GAC	Asp	GGC	Gly	C
	GUA	Val	GCA	Ala	GAA	Glu	GGA	Gly	A
	GUG	Val	GCG	Ala	GAG	Glu	GGG	Gly	G

According to the above table; one amino acid has several triplets, but triplet code is unique for an amino acid. AAG codon is responsible for UUC anticodon and this happens because of the complementary base pairing. In DNA; Adenine (A) pairs with Thymine (T). Cytosine (C) pairs with Guanine (G). In RNA; Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G). According to the above table, lysine is the responsible amino acid for the AAG code.

Interpretation Introduction

(d)

Interpretation:

Anticodon and amino acid for codon GCA should be identified.

Concept Introduction:

DNA and RNA transform genetic information of the living cells through triplet code, which is a sequence of three nucleotides on DNA or RNA molecules codes for a specific amino acid in protein synthesis. Anticodon is the triplet which is represented in tRNA molecules corresponding to a complementary codon in mRNA.

Answer to Problem 55P

Anticodon − CGU

Amino acid − Alanine (Ala)

Explanation of Solution

Codons are written from 5 prime ends (5) to 3 prime ends (3) of mRNA. There is a unique triplet representation for a particular amino acid. The below-mentioned table represents the relationship between nucleotides and amino acids.

The Genetic Code- Triplets in Messenger RNA

First Base (5' end)	Second Base								Third Base (3' end)
	U		C		A		G
U	UUU	Phe	UCU	Ser	UAU	Tyr	UGU	Cys	U
	UUC	Phe	UCC	Ser	UAC	Tyr	UGC	Cys	C
	UUA	Leu	UCA	Ser	UAA	Stop	UGA	Stop	A
	UUG	Leu	UCG	Ser	UAG	Stop	UGG	Trp	G
C	CUU	Leu	CCU	Pro	CAU	His	CGU	Arg	U
	CUC	Leu	CCC	Pro	CAC	His	CGC	Arg	C
	CUA	Leu	CCA	Pro	CAA	Gln	CGA	Arg	A
	CUG	Leu	CCG	Pro	CAG	Gln	CGG	Arg	G
A	AUU	Ile	ACU	Thr	AAU	Asn	AGU	Ser	U
	AUC	Ile	ACC	Thr	AAC	Asn	AGC	Ser	C
	AUA	Ile	ACA	Thr	AAA	Lys	AGA	Arg	A
	AUG	Met	ACG	Thr	AAG	Lys	AGG	Arg	G
G	GUU	Val	GCU	Ala	GAU	Asp	GGU	Gly	U
	GUC	Val	GCC	Ala	GAC	Asp	GGC	Gly	C
	GUA	Val	GCA	Ala	GAA	Glu	GGA	Gly	A
	GUG	Val	GCG	Ala	GAG	Glu	GGG	Gly	G

According to the above table; one amino acid has several triplets, but triplet code is unique for an amino acid. GCA codon is responsible for CGU anticodon and this happens because of the complementary base pairing. In DNA; Adenine (A) pairs with Thymine (T). Cytosine (C) pairs with Guanine (G). In RNA; Adenine (A) pairs with Uracil (U). Cytosine (C) pairs with Guanine (G). According to the above table, alanine is the responsible amino acid for the GCA code.