Biological Molecules Practice Flashcards

Definition-based vocabulary flashcards covering the classification and properties of biological molecules, including water, carbohydrates, proteins, lipids, and nucleic acids.

Biological molecules

Chemical compounds found in living organisms that are essential for structure, energy, regulation, and heredity.

Inorganic molecules

A classification of biological molecules that includes water and mineral salts.

Organic molecules

A classification of biological molecules that includes carbohydrates, proteins, lipids, and nucleic acids.

Polarity (Water)

A property where oxygen attracts electrons more strongly than hydrogen, allowing for hydrogen bonding.

Hydrolysis

The process of using water to break large molecules into smaller ones by adding $H$ and $OH$ across a bond.

Specific heat

The property that allows water to absorb and release a lot of heat with little temperature change, helping maintain body temperature.

Cohesion

The tendency of water molecules to stick to each other due to hydrogen bonding, aiding in capillary action and surface tension.

Ionization (Water)

The process where a small number of water molecules ionize into $H^+$ and $OH^-$ ions to help maintain pH balance.

Carbohydrates

Organic compounds made mainly of carbon, hydrogen, and oxygen, often in a ratio of $1:2:1$.

Monosaccharides

The simplest carbohydrates, such as glucose, which cannot be hydrolyzed into smaller sugars.

Glucose

The main respiratory substrate in cells and a major source of energy.

Sucrose

A disaccharide also known as cane sugar, made of glucose and fructose.

Lactose

A disaccharide also known as milk sugar, made of glucose and galactose.

Starch

The storage carbohydrate found in plants.

Glycogen

The storage carbohydrate in animals, stored mainly in the liver and muscles.

Cellulose

A structural carbohydrate in plant cell walls that provides rigidity and is not digested by humans.

Proteins

Large nitrogen-containing biological molecules made of amino acids joined by peptide bonds.

Amino Acid Structure

Consists of a central carbon atom attached to an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom, and a variable $R$ group.

Primary structure

The specific sequence of amino acids in a polypeptide chain.

Secondary structure

The folding of a polypeptide into an alpha helix or beta pleated sheet due to hydrogen bonding.

Tertiary structure

The overall $3D$ shape of a single polypeptide chain.

Quaternary structure

The arrangement of two or more polypeptide chains in one protein.

Triglycerides

Fats and oils made of glycerol and $3$ fatty acids joined by ester bonds.

Phospholipids

Amphipathic molecules containing glycerol, two fatty acids, and a phosphate-containing head that form cell membranes.

Acylglycerols

Lipids formed by an ester linkage between fatty acids and glycerol, including mono-, di-, and triglycerides.

RNA (Ribonucleic Acid)

A usually single-stranded molecule containing ribose sugar, phosphate, and nitrogenous bases (adenine, uracil, cytosine, guanine).

mRNA (messenger RNA)

An RNA type that carries genetic information from DNA to ribosomes.

tRNA (transfer RNA)

An RNA type that brings specific amino acids to ribosomes.

rRNA (ribosomal RNA)

An RNA type that forms part of ribosomes and assists in protein synthesis.

Conjugated molecules

Functional compounds formed when a simple molecule combines with another chemical group.

Glycolipids

Lipids linked with carbohydrates, found in cell membranes to help in cell recognition.

Glycoproteins

Proteins linked with carbohydrates that are important in membranes, receptors, and immune recognition.

DNA (Deoxyribonucleic acid)

The genetic material in most organisms, composed of two polynucleotide strands in a double helix.

Watson and Crick Model

The model describing DNA as two antiparallel strands (running $5'$ to $3'$ and $3'$ to $5'$) held by complementary base pairing.

Complementary base pairing

The rule that Adenine pairs with thymine (via $2$ hydrogen bonds) and Guanine pairs with cytosine (via $3$ hydrogen bonds).

Gene

A sequence of nucleotides in DNA that codes for the formation of a polypeptide or a functional RNA molecule.