AQA GCSE Biology B1

Magnification

= size of Image/size of real object

Light Microscope

light passes through one or more lenses to produce an enlarged image of a specimen. Smaller and cheaper but up to x2000

Electron microscope

a microscope that focuses a beam of electrons to magnify objects. Bigger and more expensive but up to x2 000 000

Nucleus

A structure found in animal and plant cells which contains the genetic material

Cytoplasm

A liquid shell which the organelles are suspended and where most of the chemical reactions needed for life take place

Cell membrane

Controls the passage of substances such as glucose and mineral ions into the cell

Mitochondria

Structure in the cytoplasm where aerobic respiration takes place, releasing energy for the cell

Ribosomes

Where protein synthesis takes place, making all the proteins needed in the cell

Chloroplasts

A structure found in plant cells and algae. it is the site of photosynthesis

Chlorophyll

A green substance found in chloroplasts which absorbs light for photosynthesis

Permanent vacuole

Filled with cell sap to help keep the cell turgid (supported)

Cell wall

A structure surrounding plant and algae cells, which give strength and support

Cell membrane

A membrane surrounding a cell, which holds it together and controls what's going in and out

Eukaryotic cells

A complex cell such as a plant or animal cell

Prokaryotic cells

A small, simple cell E.g. Bacterium

Nerve cell

Specialise cell made to carry electrical impulses around the body of an animal.

Muscle cell

A specialised cell that can contract and relax

Sperm cell

They contain the genetic information from the male parent.

Root hair cell

Cell found on the surface of plant roots that has a large surface area to absorb water

Photosynthetic cells

Cells which carry out photosynthesis and have high amounts of chloroplasts

Xylem cells

cells in plants that transport water from roots to leaves (upward direction). They are dead.

Phloem cells

plant cells that move sugars up and down the plant. They are alive and have saved plates instead of cell walls to help dissolve food move freely up and down the tubes.

Diffusion

the process by which molecules move from an area of higher concentration to an area of lower concentration. Doesn't require energy

Osmosis

Diffusion of water through a partially permeable membrane from dilute to concentrated solution. Doesn't require energy.

Turgor

When cells are hard and rigid (due to pressure) which keeps the leaves and stems of the plant Bridget and phone.

Active transport

Energy-requiring process that moves material across a cell membrane against a concentration gradient