GCSE Biology: B1 Cell Structure and Transport (copy)

Cell Membrane

surrounds a cell and controls what can enter or leave the cell

Cell Wall

surrounds and protects a cell; found in plants

Chloroplast

in a plant cell -turns energy from the sun into energy for the plant to use

Cytoplasm

gives the cell shape and holds everything in the cell

Mitochondria

the powerhouse of the cell, where energy is produced

Nucleus

has DNA and controls the cell

Ribosomes

make/synthesises proteins

Organelle

a tiny structure within a cell that performs a specific job

Vacuole

stores nutrients - found in plant cells

DNA

found in the nucleus - the material that carries all the information about how a living thing will look and function

Cells

the basic unit of life

Electron Microscope

- beam electrons
- very clear & high resolution
- black & white
- need dead specimin
- incredibly expensive
- take a whole room

Light Microscope

- beams light
- not that clear / grainer / low resolution
- colour
- specimen can be alive
- quite small
- quite cheap

Magnification

size of image/size of real object

Animal Cells

- cell membrane
- ribosomes
- cytoplasm
- mitochondria
- nucleus

Plant Cells

- cell wall
- chlorophyll/chloroplasts
- large central vacuole
- cell membrane
- ribosomes
- cytoplasm
- mitochondria
- nucleus

Eukaryotic Cells

- animal & plant cells
- has a nucleus
- has cell membrane
- cell wall
- ribosomes
- cytoplasm

Prokaryotic Cells

- bacteria cells
- no nucleus (DNA stored in the Nucleoid)
- pili
- cell membrane
- cell wall
- ribosomes
- cytoplasm

Red Blood Cells

- store & carry oxygen
- no nucleus for more space
- bigger surface area

Muscle Cells

- form muscles
- filaments of proteins for muscle connections
- develop more mitochondria
for more energy

Nerve Cells

- communicate with other cells
- fatty sheath to insulate
- extended

Sperm

- to fertilise
- a tail to swim
- streamline head & enzyme to penetrate eggs

Specialisation in Plants

- stem to support & transport
- leaves for photosynthesis
- roots for anchorage/ absorbing/ storage/ conduction

Diffusion

- movement of molecules from an area of higher concentration to an area of lower concentration
- from random movement
- passive progress
- in liquid & gases

Active transportation

- the movement of molecules from an area of lower concentration to an area of higher concentration
- requires energy ( from respiration)
- needed to make pumps to move particles

Cell Diffusion

- oxygen gas molecules surrounding cells in a high concentration
- CO2 built up inside a cell in high concentration

Osmosis

diffusion of water through a partially permeable membrane from a dilute (high levels of water) solution to a concentrated (low levels of water) solution

Hypotonic

higher concentration of water inside the cell than outside ;
human - too dilute making the cell swell & burst
plant - suitable amount of water - normal & strong & standing up ( turgid)

Isotonic

balanced levels of water in & out of the cell
human - normal working cells
plant - not much water- floppy ( flaccid)

Hypertonic

lower concentration of water in the cell than outside
human- shrivels the cell
plant - not enough water- wilts & kills cell ( plasmolyse)

Osmosis Experiment

- if the mass increases, water entered the potato ( or other)
- if the mass decreases, water left the potato
- water moves via osmosis
- osmosis is diffusion of water through a partially permeable membrane from a dilute (high levels of water) solution to a concentrated (low levels of water) solution
- the change is measured in percentage as the potatoes have different masses at the start of the experiment