Answer:
C. Threonine
Definitions
⇒ Codon is a triplet of adjacent nucleotides in the messenger RNA chain that codes for a specific amino acid in the synthesis of a protein molecule.
⇒ Adenine is a purine base, C5H5N5, one of the fundamental components of nucleic acids, as DNA, in which it forms a base pair with thymine, and RNA, in which it pairs with uracil. Symbol: A.
⇒ Cytosine is a pyrimidine base, C5H5N3O, that is one of the fundamental components of DNA and RNA, in which it forms a base pair with guanine. Symbol: C.
⇒ Amino acids are any class of organic compounds that contains at least one amino group, -NH2, and one carboxyl group, -COOH: the alpha-amino acids, RCH (NH2) COOH, are the building blocks from which proteins are constructed.
⇒ Isoleucine is a fundamental branched chain aliphatic amino acid found in various proteins.
⇒ Proline is a alcohol-soluble amino acid, C4H9NhCOOH, occurring in high concentration in collagen.
⇒ Threonine is an essential amino acid, CH3CHOHCH(NH2)COOH, obtained by the hydrolysis of proteins.
⇒ Valine is an essential amino acid, (CH3)2CHCH(NH2)COOH, white, crystalline, and water-soluble, present in most plant and animal proteins, required for growth.
To determine which amino acid is coded by the base pair sequence ACA, we need to use a codon table.
Here is a standard codon table:
First Base Second Base Third Base Amino Acid
U U U Phenylalanine (Phe)
U U C Phenylalanine (Phe)
U U A Leucine (Leu)
U U G Leucine (Leu)
U C U Serine (Ser)
U C C Serine (Ser)
U C A Serine (Ser)
U C G Serine (Ser)
U A U Tyrosine (Tyr)
U A C Tyrosine (Tyr)
U A A Stop
U A G Stop
U G U Cysteine (Cys)
U G C Cysteine (Cys)
U G A Stop
U G G Tryptophan (Trp)
C U U Leucine (Leu)
C U C Leucine (Leu)
C U A Leucine (Leu)
C U G Leucine (Leu)
C C U Proline (Pro)
C C C Proline (Pro)
C C A Proline (Pro)
C C G Proline (Pro)
C A U Histidine (His)
C A C Histidine (His)
C A A Glutamine (Gln)
C A G Glutamine (Gln)
C G U Arginine (Arg)
C G C Arginine (Arg)
C G A Arginine (Arg)
C G G Arginine (Arg)
A U U Isoleucine (Ile)
A U C Isoleucine (Ile)
A U A Isoleucine (Ile)
A U G Methionine (Met) or Start
A C U Threonine (Thr)
A C C Threonine (Thr)
A C A Threonine (Thr)
A C G Threonine (Thr)
A A U Asparagine (Asn)
A A C Asparagine (Asn)
A A A Lysine (Lys)
A A G Lysine (Lys)
A G U Serine (Ser)
A G C Serine (Ser)
A G A Arginine (Arg)
A G G Arginine (Arg)
G U U Valine (Val)
G U C Valine (Val)
G U A Valine (Val)
G U G Valine (Val)
G C U Alanine (Ala)
G C C Alanine (Ala)
G C A Alanine (Ala)
G C G Alanine (Ala)
*It goes on.
To answer your question, the base pair sequence ACA codes for the amino acid threonine