Cambridge International AS & A Level BIOLOGY - Mark Scheme

Vocabulary flashcards for review.

Capsid

The protein coat of a virus.

Sinoatrial node (SAN)

Sends out a wave of excitation/impulses/electrical impulses across the atrial wall.

Atrioventricular node (AVN)

Delays impulse, giving time for atria to complete contraction/empty.

Bicuspid valve

A valve (also known as atrioventricular valve) that opens during contraction.

Semilunar valve

A valve that closes when the bicuspid valve opens during contraction.

Mycobacterium tuberculosis

A bacterium that causes tuberculosis.

Artificial active immunity

Deliberate introduction of vaccine/ (foreign) antigens in injection, leading to an immune response and production of antibodies/ memory cells; longer lasting protection that is not immediate.

Natural passive immunity

Non-deliberate transfer of antibodies from mother/in breast milk/across placenta; no immune response, short-lived and gives immediate protection.

Rough Endoplasmic Reticulum (RER)

Site for polypeptide/protein/collagen synthesis.

Trachea

Contains C-shaped/incomplete cartilage rings.

Bronchus

Contains plates/irregular cartilage.

Collagen

A structural/fibrous protein that gives strength/flexibility.

Glycine

Small/smallest amino acid with H as R-group/side chain, found regularly/every third amino acid in collagen.

Hydrostatic pressure

Pressure exerted by a fluid at equilibrium due to the force of gravity.

Glycosidic bond

The bond that joins a carbohydrate (sugar) molecule to another group, which may or may not be another carbohydrate.

Induced fit model

A model that describes when the active site is flexible/moulds around, substrates so that provides a better fit/fully complementary shape.

Lock and key model

A model that describes when the shape of substrates is complementary to the shape of active site; active site does not change shape/is not flexible.

S phase

The synthesis phase is a portion of interphase before mitosis during which DNA is replicated.