Biology Video Notes: Water, Carbohydrates, Lipids, Circulation, Blood Transport, CVD, Risk & Exam Techniques

Vocabulary flashcards covering water properties, carbohydrates, lipids, circulation, blood gas transport, CVD, risk factors, and exam technique.

Water polarity

The water molecule has a partial negative charge on the oxygen and partial positive charges on the hydrogens due to unequal sharing of electrons, creating a permanent dipole.

Permanent dipole

A molecule with a constant uneven distribution of charge, giving it a positive and a negative end.

Water as solvent

Water’s polarity allows it to dissolve many substances (e.g., inorganic ions), enabling solutes to move and react.

Carbohydrates

Molecules composed of carbon, hydrogen and oxygen; long chains of sugar units (saccharides).

Monosaccharide

The simple sugar units that join to form larger carbohydrates; soluble in water.

Glucose

A common monosaccharide with six carbon atoms; main substrate for respiration.

Disaccharide

Two monosaccharides joined together by a glycosidic bond in a condensation reaction.

Maltose

A disaccharide formed by condensation of two glucose molecules.

Sucrose

A disaccharide formed by condensation of glucose and fructose.

Lactose

A disaccharide formed by condensation of glucose and galactose.

Glycosidic bond

Bond between two monosaccharides formed in condensation, containing an oxygen atom linking them.

Condensation reaction

Reaction that joins two monosaccharides with release of water to form a glycosidic bond.

Hydrolysis

Bond breaking by adding water, splitting disaccharides or polysaccharides into smaller units.

Polysaccharide

Large carbohydrate polymers made of many monosaccharides; used for energy storage or structure.

Glycogen

Main energy storage molecule in animals; highly branched with 1,4 and 1,6 glycosidic bonds.

Starch

Primary energy store in plants; mixture of amylose (unbranched) and amylopectin (branched).

Amylose

Unbranched glucose polymer with 1,4 glycosidic bonds; coiled and compact.

Amylopectin

Branched glucose polymer with 1,4 and 1,6 glycosidic bonds; many side branches for rapid digestion.

1,4 glycosidic bond

Bond between carbon 1 of one glucose and carbon 4 of the next; forms straight chains.

1,6 glycosidic bond

Bond at branching points in polysaccharides like amylopectin; creates branches.

Lipids

Non-polar biological molecules; insoluble in water but soluble in organic solvents; include fats, oils, phospholipids.

Saturated fats

Lipids with no carbon–carbon double bonds; usually solid at room temperature.

Unsaturated fats

Lipids with one or more C=C bonds; lower melting points; usually from plants.

Triglyceride

Glycerol molecule esterified to three fatty acids; major long-term energy reserve.

Glycerol

Three-carbon backbone of triglycerides.

Fatty acids

Long hydrocarbon chains with a carboxyl group; vary in length and saturation.

Ester bond

Bond formed between glycerol and fatty acids in triglycerides via condensation.

Diffusion

Movement of substances from high to low concentration across a space or membrane.

Mass transport

Systemic movement of substances (via circulatory system) to supply tissues broadly.

Circulatory system

Heart and blood vessels that transport blood and substances around the body.

Arteries

Carry blood away from the heart; thick muscular elastic walls; high pressure; no valves.

Veins

Carry blood to the heart; thin walls, large lumen, low pressure; contain valves.

Capillaries

Very small, numerous vessels with walls one cell thick; site of exchange by diffusion.

Aorta

Main artery carrying oxygenated blood from the left ventricle to the body.

Pulmonary artery

Carries deoxygenated blood from the right ventricle to the lungs.

Pulmonary vein

Carries oxygenated blood from the lungs to the left atrium.

Vena cava

Largest vein returning deoxygenated blood to the heart (superior and inferior).

Double circulatory system

Two circulatory circuits (pulmonary and systemic); blood passes through the heart twice per cycle.

Haemoglobin

Globular protein in red blood cells with four subunits and four heme groups; carries oxygen.

Partial pressure of oxygen

Measure of oxygen concentration; higher pO2 increases Hb affinity and loading of O2.

Bohr effect

Increased CO2 lowers Hb affinity for O2, promoting unloading in tissues.

Atherosclerosis

Hardening of arteries due to buildup of fibrous plaque (atheroma) narrowing vessels.

Atheroma

Fibrous plaque composed of cholesterol, calcium salts and other materials in arteries.

Thrombosis

Formation of a blood clot inside a vessel, potentially blocking blood flow.

Thrombin

Enzyme that converts fibrinogen to fibrin, forming the mesh of a blood clot.

HDL

High-density lipoprotein; helps remove cholesterol to the liver; protective against CVD.

LDL

Low-density lipoprotein; transports cholesterol to arteries; higher levels increase CVD risk.

BMI

Body Mass Index; weight (kg) divided by height (m)^2; used to classify under/normal/overweight/obese.

WHR

Waist-to-hip ratio; indicator of obesity risk; thresholds differ by sex.

Perceived risk

Subjective assessment of risk, which may differ from actual statistical risk.

Correlation vs causation

Correlation: relationship between variables; causation: one variable causes another.

Evaluating studies

Assessing study design, sample size, randomization, controls, bias, and peer review.