Additional Biology AQA - Cells

Animal cells have:

Nucleus - to control the the cell's activities.

Cytoplasm - where many chemical reactions happen.

Cell membrane - conntrols movement of materials.

Mitchondria - where energy is released during aerobic respiration.

Ribosomes - where proteins are made.

Plant cells have:

Nucleus - to control the the cell's activities.

Cytoplasm - where many chemical reactions happen.

Cell membrane - conntrols movement of materials.

Mitchondria - where energy is released during aerobic respiration.

Ribosomes - where proteins are made.

Cell wall - for support.

Chloroplasts - contain chlorophyll for photosynthesis.

Permanent vacuole - contains cell sap.

As an organism develops some oftheir cells become specialised to carry out particular jobs.

Differentiation is the name given to this change.

Differentiation happens earlier in animals than it does plants.

Some examples of a specialsed cell is:

Root hair cell - Has a large permanent vacuole and a root hair.

Sperm cell - Has a nucleus full of memory of different genes etc., middle section full of mitochondria and a lond tail to move fast.

Exam tip - It's not only important to know the different specialised cells but also need to know their structure and what makes them different.

Molecules move randomly because of the energy they have.

Diffusion is the random movement of particles from a high to a low concentration .

The greater the concentration the faster the rate of reaction.

An example of this is the diffusion of oxygen from the blood stream into the cells of the body because of respiration.

Osmosis is a special case of diffusion

Osmosis is the diffusion of water across asemi permable brain form a high concentration to a low concentration.