Edexcel GCSE Biology Topic 1 Key concepts in biology overview quiz quiz

A cell surface membrane controlling what enters and leaves

Jelly-like cytoplasm where reactions occur

A nucleus enclosed in a membrane

Ribosomes for making proteins

Nucleus, ribosomes and mitochondria for respiration

Cell membrane, jelly-like cytoplasm and a nucleus

Plasmids, flagella and a loop of free DNA in cytoplasm

Cellulose cell wall, chloroplasts, permanent vacuole

40 $\mu m$

4 $\mu m$

400 $\mu m$

0.04 $\mu m$

It is cheaper, smaller and easier to carry around

It has much higher magnification and resolution

It can view living cells while they are still alive

It uses ordinary visible light to form the image

It can speed up any chemical reaction taking place in the cell

It is broken down and used up during the reaction it controls

Its active site has a shape that fits only one substrate

It works equally well at every pH value

It simply keeps on working faster and faster without limit

It turns itself into the substrate molecule

It is killed off because the enzyme is alive

Its active site changes shape and it is denatured

Benedict's solution heated, turns brick-red

Iodine solution added cold, turns a deep blue-black

Biuret solution added, turns from blue to bright purple

Sudan III stain added, turns a vivid grass green

The mass of the food sample that was burned

The mass of water

The volume of the surrounding air in the boiling tube

The energy released per gram of the food

The movement of any dissolved particle down a concentration gradient through any membrane present

The movement of dissolved substances against a concentration gradient using energy from respiration in the cell

The diffusion of water across a partially permeable membrane from a dilute to a more concentrated solution

The active uptake of dissolved mineral ions by the root hair cells of a plant

Because it moves substances down the concentration gradient passively

Because active transport only ever happens inside plant cells

Because water molecules cannot move at all without added energy

Because it moves substances against the concentration gradient

-10%

-4%

+10%

-0.4%

A smaller surface area of the membrane

A steeper concentration gradient

A much lower surrounding temperature

A longer distance for particles to diffuse