Khorana performed experiments to decipher the codons that code for a particular amino acid. The results of these experiments using synthetic mRNAs and the corresponding polypeptide repeats that were generated are given in the table below. Synthetic mRNAs Polypeptide(s) synthesized CAA n Thr - Thr n and Asn - Asn n and Gln - Gln n UUC n Ser - Ser n and Leu - Leu n and Phe - Phe n UAC n Thr - Thr n and Leu - Leu n and Tyr - Tyr n UUAC n Leu - Leu - Thr - Tyr n Based on the results, the correct combination(s) of codons and amino acids is/are

UUA - Leu ; ACU - Thr ; UAC - Tyr

ACU - Leu ; UUA - Thr ; ACU - Tyr

UAC - Leu ; CUU - Thr ; ACU - Tyr

Due to deletion of certain nucleotides from the terminal end of mRNA now it codes for 99 amino acidsinstead of 100 amino acids How many nucleotides deletion can be responsible for the loss of one amino acid

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

In Escherichia coli, how many codons codes for the standard amino-acids?

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Under which of the following conditions will there be no change in the reading frame of the following mRNA?
5’AACAGCGGUGCUAUU 3’

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

There are

1998

bases in

RNA

that codes

666

amino acids and the base position at

901

is deleted such that the length of the

RNA

becomes

1997

bases. The number of codons altered are

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Find the nucleotide sequence of the

mRNA

which codes for the sequence of amino acids

{}^{'}{Met} - Leu - Val - Arg - {Ala}^{'}

and choose the correct option from below:

HARD

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Khorana performed experiments to decipher the codons that code for a particular amino acid. The results of these experiments using synthetic mRNAs and the corresponding polypeptide repeats that were generated are given in the table below.

Synthetic mRNAs	Polypeptide(s) synthesized
${(CAA)}_{n}$	${(Thr - Thr)}_{n}$ and ${(Asn - Asn)}_{n}$ and ${(Gln - Gln)}_{n}$
${(UUC)}_{n}$	${(Ser - Ser)}_{n}$ and ${(Leu - Leu)}_{n}$ and ${(Phe - Phe)}_{n}$
${(UAC)}_{n}$	${(Thr - Thr)}_{n}$ and ${(Leu - Leu)}_{n}$ and ${(Tyr - Tyr)}_{n}$
${(UUAC)}_{n}$	${(Leu - Leu - Thr - Tyr)}_{n}$

Based on the results, the correct combination(s) of codons and amino acids is/are

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

The codon on $mRNA$ are

$CAU - CCU - AAA - CUG$

Identify the correct sequence of amino acids.

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Which of the following features of genetic code does allow bacteria to produce human insulin by recombinant DNA technology?

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Codon degeneracy means that

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

If molecular weight of a polypeptide is 15.3 kDa, what would be the minimum number of nucleotides in the mRNA that codes for this polypeptide? Assume that molecular weight of each amino acid is 90 Da.

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

In a random DNA sequence, what is the lowest frequency of encountering a stop codon?

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

A mature

mRNA

consists of 900 bases without any stop codon in between. Calculate the number of amino acids coded by the

mRNA

during translation.

HARD

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

If DNA codons are ATG GAA, insertion of thymine after the first codon results in:

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Statement I: The codon 'AUG' codes for methionine and phenylalanine.
Statement II: 'AAA' and 'AAG' both codons code for the amino acid lysine.
In the light of the above statements, choose the correct answer from the options given below.

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

In an In-vitro translation experiment, poly (

UC

) RNA template produced poly (Ser-Leu), while poly (

AG

) RNA template produced poly (Arg-Glu) polypeptide. Which ONE of the following options represents correct interpretations of the codons assignments for Ser, Leu, Arg and Glu?

EASY

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

The codon which codes for methionine and also acts as initiator codon

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Only genetic code with the dual function is _____.

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

Which ONE of the following statements is INCORRECT for translation in cytoplasm?

HARD

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

A new life form discovered on a distant planet has a genetic code consisting of five unique nucleotides and only one stop codon. If each codon has four bases, what is the maximum number of unique amino acids this life form can use?

HARD

Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

If there are 999 bases in an RNA that codes for a protein with 333 amino acids, and the base at position 901 is deleted such that the length of the RNA becomes 998 bases, how many codons will be altered?

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Life Sciences>From Molecules to Organisms: Structures and Processes>Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.>Structure and Function - Systems of specialized cells within organisms help them perform the essential functions of life.All cells contain genetic information in the form of DNA molecules. Genes are regions in the DNA that contain the instructions that code for the formation of proteins, which carry out most of the work of cells.

_____ is a starting codon.

Due to deletion of certain nucleotides from the terminal end of mRNA, now it codes for 99 amino acids instead of 100 amino acids. How many nucleotides deletion can be responsible for the loss of one amino acid ?

Important Questions on Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

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