Chapters 1-5 Practice Flashcards

Comprehensive vocabulary flashcards covering biomolecules, enzymes, the respiratory system, transport in humans, and homeostasis.

Macromolecule

A giant molecule, such as a polysaccharide, protein, or nucleic acid.

Metabolism

The sum total of all the biochemical reactions in the body.

Monomer

A relatively simple molecule which is used as a basic building block for the synthesis of a polymer.

Polymer

A giant molecule made from many similar repeating subunits joined together in a chain.

Covalent bond

A chemical bond that involves the sharing of electrons to form electron pairs between atoms.

Condensation reaction

A chemical reaction involving the joining together of two molecules by the removal of a water molecule.

Hydrolysis

A chemical reaction in which a chemical bond is broken by the addition of a water molecule.

Monosaccharide

A molecule consisting of a single sugar unit with the general formula $(CH_2O)_n$.

$$\text{alpha-glucose}$$

The form of glucose where the hydroxyl group on carbon atom 1 is below the plane of the ring.

$$\text{beta-glucose}$$

The form of glucose where the hydroxyl group on carbon atom 1 is above the plane of the ring.

Glycosidic bond

A $C-O-C$ link between two sugar molecules formed by a condensation reaction.

Benedict's test

A test for the presence of reducing sugars where a change from blue to a brick-red precipitate indicates sugar presence.

Amylose

A component of starch made of long, unbranching chains of $1,4$ linked $\text{alpha-glucose}$ molecules that coil into helical structures.

Glycogen

A storage polysaccharide in animals made of chains of $1,4$ linked $\text{alpha-glucose}$ with $1,6$ linkages forming branch points.

Cellulose

A mechanically strong polysaccharide made from $\text{beta-glucose}$ subunits used as a strengthening material in plant cell walls.

Triglyceride

A type of lipid formed when three fatty acid molecules combine with glycerol via ester bonds.

Phospholipid

A lipid where one fatty acid is replaced by a polar phosphate group, resulting in a hydrophilic head and hydrophobic tails.

Peptide bond

The covalent $C-N$ link joining neighboring amino acids together in proteins, formed by a condensation reaction.

Primary structure

The specific sequence of amino acids in a polypeptide or protein chain.

Secondary structure

The structure resulting from regular coiling or folding of the amino acid chain, such as an $\text{alpha-helix}$ or $\text{beta-pleated sheet}$.

Tertiary structure

The compact, three-dimensional coiling of a protein chain maintained by hydrogen bonds, ionic bonds, disulfide bonds, and hydrophobic interactions.

Quaternary structure

The three-dimensional arrangement representing the association of two or more polypeptide chains in a single protein molecule, such as haemoglobin.

Nucleotide

A molecule consisting of a nitrogen-containing base, a pentose sugar, and a phosphate group.

Enzyme

A protein produced by a living organism that acts as a biological catalyst by reducing the activation energy of a reaction.

Active site

The specific region of an enzyme molecule to which a substrate binds.

Induced-fit hypothesis

A model of enzyme action where the enzyme or substrate changes shape slightly during binding to ensure a perfect fit.

Activation energy

The energy that must be provided to make a chemical reaction take place.

$$V_{\text{max}}$$

The theoretical maximum rate of an enzyme-controlled reaction, achieved when all active sites are occupied by substrate.

$K_m$ (Michaelis–Menten constant)

The substrate concentration at which an enzyme works at half its maximum rate, used as a measure of enzyme affinity.

Competitive inhibition

When a substance reduces enzyme activity by competing with the substrate for the active site; it can be reversed by increasing substrate concentration.

Immobilised enzymes

Enzymes that have been fixed to a surface or trapped inside beads, such as alginate, to allow for reuse and prevent product contamination.

Alveolus

A small air sac in the lungs composed of squamous epithelium where gas exchange between air and blood occurs.

Goblet cell

A cell found in the epithelium of the gas exchange system that secretes sticky mucus to trap inhaled particles.

Bohr shift

The decrease in the affinity of haemoglobin for oxygen produced by the presence of a high partial pressure of carbon dioxide.

Chloride shift

The movement of chloride ions into red blood cells from plasma to balance the exit of hydrogencarbonate ions.

Emphysema

A chronic respiratory disorder where alveolar walls are destroyed, leading to large air spaces and reduced surface area for gas exchange.

Hypoxia

A condition in which body tissues receive an insufficient supply of oxygen, often occurring at high altitudes.

Systemic circulation

The part of the circulatory system that carries oxygenated blood from the heart to the rest of the body and returns deoxygenated blood to the heart.

Endothelium

The smooth, single layer of squamous epithelial cells that lines the inner surface of blood vessels.

Sinoatrial node (SAN)

A specialised patch of muscle in the right atrium that acts as the heart's pacemaker by initiating the cardiac cycle.

Atrioventricular node (AVN)

A patch of conducting tissue in the septum that delays the excitation wave before passing it to the Purkyne tissue.

Tissue fluid

The fluid formed when blood plasma leaks out of capillaries into the spaces between cells, providing the immediate environment for body cells.

Homeostasis

The maintenance of a relatively constant internal environment for the cells within the body.

Negative feedback

A control mechanism where a change in a physiological factor triggers a response that returns the factor to its set point.

Osmoregulation

The control of the water potential of body fluids, involving the hypothalamus, posterior pituitary gland, and kidneys.

Antidiuretic hormone (ADH)

A hormone that increases the number of aquaporins in the collecting duct's luminal membranes to increase water reabsorption.