Cell Biology

What is resolution?

The minimum distance between 2 parts at which they can be seen as 2 seperate points in the image

What is a eukaryote?

• Animal and plant cell

• Divides by mitosis

• Membrane bound subcellular structures

What is a prokaryote?

• Bacteria cells

• Small, single loops of DNA called plasmids in cytoplasm

• Divides by binary fission

• No membrane bound subcellular structures

Vacuole

Contains cell sap, stores excess water and provides extra support

Cell membrane

Controls what goes in and out of the cell containing fat and protein molecules

Chloroplasts

Photosynthesis takes place and absorbs light energy, contains chlorophyll to turn green

Ribosomes

Site of protein synthesis

Mitochondria

Site of respiration

Nucleus

Carries DNA and controls activity of the cell

Cell wall

Gives cell strength and shape, contains cellulose

Cytoplasm

Chemical reactions occur, houses organelles

Organelles

Little organs

Magnification with a scale bar
Magnification = actual measurement of scale bar / what measurement it shows

Light microscope

• Beams of light

• Magnification up to 1000-2000

• Alive specimens

• 2D

• Low res of 380nm

• Cheap and easy to use

• Visible colours

Electron microscope

• Beams of electrons

• Magnification up to 2 mil

• Dead specimens

• 2+3D

• High res of 0.001nm

• Expensive and specialised training

• Black and white

Transmission electron microscope

2D high mag

Scanning electron microscope

3D low mag

Magnification =

image size / actual size

Sperm cell

• Swim and fertilise a female egg

• Flegeullum specialised to propel it forwards

• Enough mitochondria so it has enough energy to swim

RBC

• Carry oxygen around the body

• Biconcave shape to increase surface area for oxygen to bind

• Haemoglobin binds to oxygen to store more oxygen

Palisade cell, leaf

• Absorb sunlight for photosynthesis

• Packed with chloroplasts

• Absorbs more light to produce more glucose and oxygen for food and energy.

Root Hair cell

• Absorb water and minerals from the soil

• Long finger like part so cell has larger surface area enabling maximum efficiency for absorption of water

• No chloroplasts as no light underground

Nerve cell

• Carry out messages through electrical signals around the body

• Long tailed axon and insulating sheath so electrical signals are passed efficiently

Ciliated epithelial cells

• Line the trachea where they move mucus and bacteria towards the mouth so it keeps it away from the lungs

• Cilia to waft mucus and bacteria towards the mouth

Egg cell

• Female reproductive cell

• Outer layer allowing only 1 sperm cell in

Why do we need a continuous supply of new cells

for growth, development and repair