Biochemistry Module 4: Chemistry of Proteins

Study Notes

Proteins are the most abundant organic molecules in cells, comprising over 50% of dry weight.
Each species has a unique set of proteins due to chemical distinctions.
Proteins perform diverse functions: biological catalysts, structural elements, antibodies, hormones, and fluid balance maintenance.
They play roles in blood clotting and transport oxygen and lipids.
Can also be toxins or poisons (e.g., venoms, bacterial toxins).
A single cell may contain thousands of proteins, each with unique functions.
Proteins are composed of one or more polypeptide chains made from amino acids.

Amino acids are the monomers that combine to form proteins, organized in linear chains called polypeptides.
There are 20 common amino acids, each containing at least one carboxyl (-COOH) and one amino (-NH2) group.
The basic structure includes a central carbon (alpha carbon) bonded to amino and carboxyl groups, a hydrogen atom, and an R group that varies between amino acids.
The R group defines the specific amino acid identity (e.g., glycine = hydrogen, alanine = methyl -CH3).
At physiological pH (7.27 - 7.47), the amino group is protonated (+ charge), while the carboxyl group is deprotonated (- charge).

Humans can synthesize 11 out of 20 amino acids; 9 must be obtained through diet, termed essential amino acids.
Essential amino acids include: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Different animal species have varying abilities to synthesize amino acids (e.g., humans can synthesize arginine; dogs and cats cannot).
Cats cannot synthesize taurine, which makes certain dog foods unsuitable for them.
Dietary requirements for amino acids change based on species.

Understand amino acid general structure.
Classify 20 amino acids based on structure and polarity.
Illustrate the amphoteric nature of amino acids (acting as both acids and bases).
Describe the polymerization process of amino acids into proteins.
Classify proteins based on their structural organization.
Discuss the four levels of protein organization: primary, secondary, tertiary, and quaternary.

Proteins are the most abundant organic molecules in cells, comprising over 50% of dry weight.
Each species has a unique set of proteins due to chemical distinctions.
Proteins perform diverse functions: biological catalysts, structural elements, antibodies, hormones, and fluid balance maintenance.
They play roles in blood clotting and transport oxygen and lipids.
Can also be toxins or poisons (e.g., venoms, bacterial toxins).
A single cell may contain thousands of proteins, each with unique functions.
Proteins are composed of one or more polypeptide chains made from amino acids.

Amino acids are the monomers that combine to form proteins, organized in linear chains called polypeptides.
There are 20 common amino acids, each containing at least one carboxyl (-COOH) and one amino (-NH2) group.
The basic structure includes a central carbon (alpha carbon) bonded to amino and carboxyl groups, a hydrogen atom, and an R group that varies between amino acids.
The R group defines the specific amino acid identity (e.g., glycine = hydrogen, alanine = methyl -CH3).
At physiological pH (7.27 - 7.47), the amino group is protonated (+ charge), while the carboxyl group is deprotonated (- charge).

Humans can synthesize 11 out of 20 amino acids; 9 must be obtained through diet, termed essential amino acids.
Essential amino acids include: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.
Different animal species have varying abilities to synthesize amino acids (e.g., humans can synthesize arginine; dogs and cats cannot).
Cats cannot synthesize taurine, which makes certain dog foods unsuitable for them.
Dietary requirements for amino acids change based on species.

Understand amino acid general structure.
Classify 20 amino acids based on structure and polarity.
Illustrate the amphoteric nature of amino acids (acting as both acids and bases).
Describe the polymerization process of amino acids into proteins.
Classify proteins based on their structural organization.
Discuss the four levels of protein organization: primary, secondary, tertiary, and quaternary.