CCEA A-Level Biology Cells, Viruses and Reproduction overview quiz quiz

A cell membrane surrounding the whole cell

Ribosomes for the synthesis of proteins

Cytoplasm filling the interior of the cell

A nucleus and membrane-bound organelles

Peptidoglycan

Cellulose, as in plant cells

Chitin, as found in fungi

A double layer of lipid

It is a completely solid sheet with proteins fixed rigidly in position

It is made only of protein with no phospholipid component at all

Phospholipids can move and proteins are scattered through the bilayer

It is permanently fixed in place and cannot change its shape at all

Active transport

Endocytosis

Facilitated diffusion of solutes

Osmosis

Active transport

Diffusion

Facilitated diffusion

Osmosis

They are far too small to be seen using even the most powerful optical light microscope

They have no cytoplasm, organelles or metabolism and cannot reproduce without a host

They contain no genetic material of any kind, neither DNA nor RNA molecules

They are made only of a simple outer coat of lipid and nothing else inside

DNA polymerase, the replication enzyme

Ligase, which joins fragments together

Reverse transcriptase

Helicase, which unwinds the double helix

Two diploid cells

Two haploid cells

Four diploid cells

Four haploid cells

Crossing over and independent assortment

Semi-conservative replication of the DNA molecule

Active transport of ions across the cell membrane

The action of the sodium-potassium pump in the membrane

A thick, dry surface that gases must cross by slow diffusion over a long distance

A large surface area that is thin and moist with a steep diffusion gradient

A small surface area relative to the volume of the organism it serves

No blood supply at all, so that no concentration gradient is ever maintained

Dissolved in plasma

Bound to haemoglobin only

As hydrogencarbonate ions

As solid crystals

It reduces oxygen release by shifting the dissociation curve to the left instead

It stops haemoglobin from binding any oxygen at all when blood passes the lungs

It has no effect whatsoever on the amount of oxygen released at the tissues

It increases oxygen release by shifting the dissociation curve to the right