Amino Acids and Their Functions

Questions and Answers

Which classification of amino acids refers to the position of the nitrogen relative to the carbon chain?

β-amino acids (correct)

δ-amino acids

γ-amino acids (correct)

α-amino acids (correct)

Which of the following amino acids is the only achiral one among the standard amino acids?

Isoleucine

Alanine

Glycine (correct)

Valine

What is the primary characteristic of the zwitterionic form of amino acids?

It has both positive and negative charges (correct)

It is neutral and has no charges

It has a negative charge only

It has a positive charge only

Which amino acid is represented by the abbreviation 'Met'?

Methionine Signup and view all the answers

Which statement about the isomerism of amino acids is true?

Most amino acids have the L-configuration at their α carbon Signup and view all the answers

Which amino acid is a precursor for the transmission of nerve impulses?

γ-amino acid Signup and view all the answers

Which amino acid is known as a structural unit present in coenzyme A?

β-amino acid Signup and view all the answers

Which of the following amino acids is commonly classified as a branched-chain amino acid?

Leucine Signup and view all the answers

What does the L and D in Fischer's convention refer to regarding amino acids?

Absolute configuration around the chiral carbon Signup and view all the answers

At a pH of 7.4, which form of amino acids predominates?

Zwitterionic form Signup and view all the answers

What is the net charge of amino acids at pH 7.4?

Neutral due to equal positive and negative charges Signup and view all the answers

Which aspect of amino acids is influenced by the R groups?

Solubility in water Signup and view all the answers

What is the main reason cells synthesize L-isomers of amino acids?

Due to asymmetric active sites of enzymes Signup and view all the answers

What is the general structure of common amino acids?

Carboxyl group and amino group bonded to the same carbon (a-carbon) Signup and view all the answers

What is the role of three-letter abbreviations and one-letter symbols in amino acids?

Indicate the composition and sequence of amino acids in proteins Signup and view all the answers

How do uncommon amino acids differ from common amino acids?

They are less frequent and may have unique structures Signup and view all the answers

What type of carbon is present in amino acids due to its attachment to four different groups?

Alpha carbon Signup and view all the answers

Which of the following functions do amino acids NOT perform?

Storage of genetic information Signup and view all the answers

What is the primary reason most amino acids are found in their L-form in biochemistry?

L-form is associated with life processes Signup and view all the answers

What distinguishes L-amino acids from D-amino acids?

The structural configuration at the alpha carbon Signup and view all the answers

Which of the following amino acids is known to play a role in detoxification?

Glycine Signup and view all the answers

Which functional group is NOT typically found in the structure of amino acids?

Hydroxyl group (-OH) Signup and view all the answers

How many standard amino acids are commonly recognized based on their R groups?

20 Signup and view all the answers

Which of the following is a characteristic of the zwitterionic form of amino acids?

It contains both positive and negative charges Signup and view all the answers

Study Notes

Function of Amino Acids

Amino acids are essential for synthesizing proteins.
Serve as precursors for nitrogen-containing compounds, including nucleic acid bases (purines and pyrimidines), porphyrins (heme, chlorophyll), folic acid, creatine, and glutathione.
Act as chemical messengers and neurotransmitters.
Involved in glucose synthesis and function as buffers.
Participate in detoxification reactions, notably glycine, cysteine, and methionine.

Anatomy of Amino Acids

Consist of an amino group (-NH2) and a carboxyl group (-COOH) attached to the same carbon (alpha-carbon).
The alpha-carbon is a chiral center due to its four different substituents, allowing two unique spatial arrangements of amino acids (L and D isomers).
L-amino acids are predominantly observed in biochemistry, denoting their structural configuration based on L-glyceraldehyde.
Non-ionic forms are negligible in aqueous solutions; zwitterionic forms dominate at physiological pH (7.4).
Charges of the zwitterionic form cancel out, making the net charge dependent on the side chain (R-group).

Classification of Amino Acids

Amino acids are classified based on the carbon atom that bears the nitrogen: α, β, γ, etc.
More than 700 amino acids exist, but 20 are crucial as the building blocks of proteins.
These 20 amino acids are all α-amino acids, thus differing based on their R-groups.

Key Amino Acids

Glycine (Gly or G): Simplest amino acid, achiral.
Alanine (Ala or A).
Valine (Val or V).
Leucine (Leu or L).
Isoleucine (Ile or I).
Methionine (Met or M).
Proline (Pro or P).
Phenylalanine (Phe or F).
Tryptophan (Trp or W).
Asparagine (Asn or N).
Glutamine (Gln or Q).
Serine (Ser or S).
Threonine (Thr or T).

Stereochemistry of Amino Acids

Glycine is achiral; all other protein amino acids possess L-configuration at their α-carbon.

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Description

Explore the essential roles of alpha-amino acids in protein synthesis and their importance as precursors for various nitrogen-containing compounds. This quiz covers neurotransmitter functions and specific derivatives like glutathione and creatine. Test your knowledge on the biochemical significance of amino acids!