Triple Award Biology

Biology

Cells

Plant and animal cells contain:

- A nucleus, which controls the cells actions and contains cell DNA

- A cell membrane which controls what goes in and out of the cell

- Cytoplasm where all the chemical reactions occur

- Ribosomes where protein synthesis occurs

- Mitachondria where respiration occurs and energy is made

However plant cells have a few extra which you need to know:

- Chloroplasts which absorb sunlight needed for photosynthesis and give the plant its pigment

- Vacuole which contains cell sap a weak sugar solution 

- Cell wall which gives the plant structure and support

(The image does not show ribosomes and mitachondria but ribosomes look like christmas trees and mitachondria look like beans if that helps)

For your exam you need to know everything about the following specialised cells.

The sperm cell is a stermlined shape which aids it to carry out it's function to fertilise the egg cell as this allows it to swim faster. The sperm cell contains 23 single chromosomes in its nucleus, the father's DNA and half the DNA of the child. The sperm cell needs to be able to swim to fertilise the egg cell, which is why it has a tail, but also why it has a small 'box' full of mitochondria which provide the cell energy to carry out its function. In order to fertilise the egg cell, the tip of the sperms head is made from enzymes which allow it to fertilise the egg cell as it allows the sperm to digest the eggs cell membrane.

The egg cell contains large food stores and nutrients for the foetus and a nucleus containing 26 single chromosomes from the mother. It has a cell membrane which the sperm cell digests in order to fertilise the egg

White blood cell can change the shape of its membrane in order to engulf/digest harmful microbes.

Root hair cell has a large finger-like surface area which is good for absorbtion of water. It contains mitachondria for active transport to take place if neccesary. It contains no chloroplasts as it is underground and doesn't need to photosynthesis.

The nerve cell contains a nucleus, a cell membrane, an axon and receptors. The axon is insulated to prevent and 'messages' from escaping.

The red blood cell is a concave shape with no nucleus. It has no nucleus so it is able to carry more oxygen and so more oxygen can be transported to cells. Its shape allows it to easily bend and flow through blood vessels (unlike with sickle cell anemia, see later)

Muscle cells are long, string tissue packed with mitachondria as muscles constantly conrtact and relax and so need energy to carry out this movement, as they need to respire for this energy - which is why they are adapted to this function as they have lots of mitachondria.

Cillia cells line the airways and waft out dust particles etc which you breathe in. Also they produce mucus to trap any harmful…