Topic 1: Molecules, diet, transport and health - Edexcel A-Level Biology B quiz

An ester bond, as in lipids

A peptide bond, as in proteins

A glycosidic bond

A hydrogen bond, as between bases

Hydrolysis, which breaks the bond

Oxidation

Reduction

Condensation

Three fatty acids by ester bonds

Three amino acids by peptide bonds

Two fatty acids and a phosphate group

Three monosaccharides by glycosidic bonds

It holds a much larger volume of blood than the right ventricle does at once

It must generate higher pressure to pump blood around the whole body

It pumps deoxygenated blood to the lungs, which needs a thicker muscular wall

It contains more one-way valves than the right ventricle to prevent backflow

The atria contract and push the valves shut from above

The semilunar valves pull the AV valves closed as they open

Ventricular pressure rises above atrial pressure

Blood flows back from the arteries and forces the valves shut

Thick elastic walls that stretch and recoil to smooth the blood flow

Valves to prevent the backflow of blood along the vessel as it flows

A narrow lumen lined with smooth muscle to control the rate of flow

A wall one cell thick giving a short diffusion distance

Damage to the endothelium lining the artery

A blood clot forms and blocks a narrowed coronary artery

Cholesterol is removed from the artery wall by HDL particles

The artery wall becomes wider, lowering the blood pressure inside it

LDL, because it carries cholesterol from the liver out to the body cells

HDL, because it carries cholesterol to the liver for removal

LDL, because it removes fatty plaques from the walls of the arteries

HDL, because it increases blood pressure and so widens the arteries

Lower to higher water potential across the partially permeable membrane

High solute to low solute concentration across the cell surface membrane

Higher (less negative) to lower (more negative) water potential

Lower to higher pressure only, with no role for water potential at all

Simple diffusion

Facilitated diffusion

Osmosis

Active transport

Oxygen is small and non-polar, so it crosses the hydrophobic tails

Oxygen is large and polar, so it must use a channel protein to cross

Glucose is non-polar, so it dissolves easily into the hydrophobic core

Glucose dissolves the membrane and passes straight through the gap it makes