GCSE Biology Unit 2

• Animal and plant cells have structures that enable them to do their jobs
• Plant cells have some structures that animal cells do not
• Enzymes control the chemical reactions inside cells

Animal and Plant cells have these structures in common:

• A nucleus to control the cell's activities
• cytoplasm where many chemical reactions take place
• a cell membrane that controls the movement of materials
• mitochondria where energy is released during aerobic respiration
• ribosomes where proteins are made (synthesised)

Plant cells also have:

• a rigid cell wall for support
• chloroplasts that contain chlorophyll for photosynthesis
• a permanent vacuole containing cell sap

NOT ALL PLANT CELLS HAVE CHLOROPLASTS

• As organisms develop, some of their cells become specialised to carry out their particular jobs. This is called 'differentiation'
• Differentiation happens much earlier in the development of animals than it does in plants

Root Hair Cells:

• Found at tips of growing roots
• Increased surface area for more water movement
• Large permanent vacuole which affects water movement
• Positioned next to xylem tissue

Sperm Cells:

• Contain genetic information from the male parent
• long tail with muscle-like protein to swim
• Middle section contains mitochondria for energy
• Acrosome (tip) contains enzymes to break down the egg
• A large nucleus contains the genetic information

Fat Cell:

• Excess fat store
• Very little normal cytoplasm, leaving more room for fat
• Very few mitochondria as they don't need much energy
• Can expand up to 1000 times its original size

Cone cell (eye):

• In the retina and help us see in colour
• Chemical called visual pigment in outer layer which changes chemically in coloured light
• Mitochondria in middle section to produce energy to continually chemically change the visual pigment
• A connection to the optic nerve (synapse) which is how the impulse triggered by the visual pigment is carried to the brain