IB Ecology

Amino acids

The monomers of proteins, containing an amine group (-NH₂), carboxyl group (-COOH), and an R-group.

N-C-C

The backbone structure of an amino acid, referring to the Nitrogen (N) from the amine group, Carbon (C) from the central alpha carbon, and Carbon (C) from the carboxyl group.

Peptide bond

A covalent bond formed between the carboxyl group of one amino acid and the amine group of another, linking amino acids in a polypeptide chain.

Carboxyl group (-COOH)

The acidic functional group of an amino acid, involved in forming peptide bonds.

Amine group (-NH₂)

The basic functional group in amino acids, crucial for peptide bond formation.

Polypeptide

A chain of amino acids joined by peptide bonds, which can fold into functional proteins.

Protein

A functional molecule made of one or more polypeptides that performs various cellular functions.

Essential amino acids

Nine amino acids that must be obtained from the diet, as the body cannot synthesize them (e.g., lysine, tryptophan).

Non-essential amino acids

Amino acids that the body can synthesize and do not need to be consumed in the diet.

Conditional amino acids

Amino acids that are normally non-essential but may become essential during illness or stress (e.g., arginine).

20 total

There are 20 amino acids used in protein synthesis across all living organisms.

Vegan diet

Plant-based diets must ensure all essential amino acids are obtained through protein complementation (e.g., combining rice and beans).

Alpha helix

A spiral-shaped secondary structure stabilized by hydrogen bonds (e.g., found in keratin).

Pleated sheets

A folded, sheet-like secondary structure, also stabilized by hydrogen bonds (e.g., found in silk fibroin).

Insulin

A hormonal protein that regulates blood glucose levels by stimulating cellular glucose uptake.

Amylase

A digestive enzyme that breaks down starch into maltose.

Histones

DNA-associated proteins that help in chromatin packaging and gene regulation.

Denaturing

The loss of a protein’s structure and function due to disruption of hydrogen bonds, ionic interactions, and disulfide bridges.

Temperature

High temperatures can cause denaturation by breaking hydrogen bonds, leading to loss of function (e.g., in enzymes).

pH

Extreme pH changes alter the charge of amino acids, disrupting ionic bonds and potentially causing denaturation.

Primary structure of proteins

Amino acids & peptide bonds form the primary structure of proteins, which then fold into secondary, tertiary, and quaternary structures.

Essential vs. non-essential amino acids

Relate to human nutrition & metabolism.

Protein function

Ties into enzymes, gene expression, and homeostasis (e.g., insulin, amylase, histones).

Denaturation by temperature & pH

Is crucial for understanding enzyme activity in metabolism and digestion.