GCSE Biology: Cell Biology and Microscopy Flashcards

Question 1

Define Cell membrane.

Accepted Answer

A partially permeable barrier around every cell that decides which substances may pass in or out.

Question 2

What is Cytoplasm?

Accepted Answer

The jelly-like fluid filling a cell, where most chemical reactions of the cell take place.

Question 3

What is Nucleus?

Accepted Answer

The organelle holding the cell's DNA as chromosomes, controlling the cell's activities and how it develops.

Question 4

What is Mitochondrion?

Accepted Answer

The organelle where aerobic respiration takes place, transferring energy from glucose for the cell to use.

Question 5

What is Ribosome?

Accepted Answer

A tiny structure in the cytoplasm where amino acids are joined together to build proteins.

Question 6

Define Cell wall.

Accepted Answer

A rigid outer layer made of cellulose in plants, giving the cell strength and stopping it bursting when full of water.

Question 7

What is Chloroplast?

Accepted Answer

A green organelle containing chlorophyll, where a plant absorbs light energy to carry out photosynthesis.

Question 8

Define Permanent vacuole.

Accepted Answer

A large sac of cell sap in a plant cell that pushes outwards to keep the cell firm and hold its shape.

Question 9

Define Prokaryotic cell.

Accepted Answer

A cell with no nucleus, whose genetic material floats free in a single loop, plus small extra rings called plasmids.

Question 10

Define Eukaryotic cell.

Accepted Answer

A cell whose genetic material is enclosed inside a nucleus, and which contains membrane-bound organelles.

Question 11

What is Plasmid?

Accepted Answer

A small circular ring of DNA in a bacterium, separate from its main chromosome and often carrying antibiotic-resistance genes.

Question 12

What is Magnification?

Accepted Answer

How many times larger an image appears than the real object, calculated as image size divided by actual size.

Question 13

What is Resolution?

Accepted Answer

The smallest distance between two points that can still be seen as separate, which sets how much detail an image shows.

Question 14

Define Light microscope.

Accepted Answer

An instrument using light and glass lenses to view specimens, typically up to about 2000 times with limited resolution.

Question 15

Define Electron microscope.

Accepted Answer

An instrument using a beam of electrons instead of light, giving far higher magnification and resolution than a light microscope.

Question 16

What is Differentiation?

Accepted Answer

The process by which a cell gains a specialised structure and function suited to one particular job.

Question 17

Define Stem cell.

Accepted Answer

An undifferentiated cell able to divide repeatedly and develop into one or more different specialised cell types.

Question 18

What is Meristem?

Accepted Answer

A plant tissue at root and shoot tips whose cells keep dividing and can become any plant cell type throughout life.

Question 19

What is Mitosis?

Accepted Answer

A type of division in which one cell copies its chromosomes and splits into a pair carrying exactly the same genes.

Question 20

Define Cell cycle.

Accepted Answer

The repeating sequence in which a cell grows, copies its DNA and organelles, then divides in two.

Question 21

What is Diffusion?

Accepted Answer

The net movement of particles from a higher to a lower concentration, spreading them out without any energy input.

Question 22

What is Osmosis?

Accepted Answer

The movement of water across a partially permeable membrane, from a dilute solution towards a more concentrated one.

Question 23

Define Active transport.

Accepted Answer

Movement of substances against a concentration gradient, from low to high, which requires energy released by respiration.

Question 24

Define Surface area to volume ratio.

Accepted Answer

The surface area of an organism divided by its volume; as something grows larger this ratio falls, slowing exchange.