B2 – Biology

Cells, Cell Structure and specialised functions of cells

Mr. P. Collins

B2.1 – Biology – Cells

All living things are made up of cells. The structures of different types of cells are related to their functions.

AIM:

to relate the structure of different types of cells to their function in a tissue or an organ.

B2.1 – Biology Most human cells like most other animal cells have the

following parts: a nucleus which controls the activities of the cell cytoplasm in which most of the chemical reactions take

place a cell membrane which controls the passage of

substances in and out of the cell mitochondria, which is where most energy is released in

respiration ribosomes, which is where protein synthesis occurs.

B2.1 – Biology

Animal Cell!

B2.1 – Biology

Plant cells have a cell membrane, a nucleus and cytoplasm as do animal cells. They also have a cell wall which strengthens the cell.

Plant cells also often have: chloroplasts which absorb light energy to make food a permanent vacuole filled with cell sap.

B2.1 – Biology

Plant Cell!

B2.1 – Biology

The chemical reactions inside cells are controlled by enzymes

Cells may be specialised to carry out a particular function. Types of Specialised Cell:

Sperm cell Egg Cell Palisade Cell Root Hair Cell Cilia Cell

B2.1 – Biology Specialised Cells: 1) The sperm cell - designed to fertilise eggs

A sperm cell is very small and has a little tail which provides movement so it can swim and find an egg to fertiliseIts head contains enzymes (in the vacuole) which allow it to digest its way through an egg membrane so the two nuclei can joinIt contains half the number of chromosomes in the nucleus - these carry genetic information from the father, which will be passed on to the offspring

2) The ovum (egg) cell - designed to be fertilisedAn ovum is large and bulky because no active movement is needed - it just sits and waits for the sperm to find itIt contains yolk (in the cytoplasm) which provides a large food store needed for the developing young organism once it's fertilisedIt contains half the number of chromosomes, which carry genetic information from the mother - this will be passed on to the offspring

3) The palisade cell - designed for photosynthesisA palisade cell is tall with a large surface areaIt's found on the top side of a leaf - ideal for good absorption of carbon dioxide and light - both are needed for photosynthesisThey're packed with chloroplasts, which contain the green pigment chlorophyll, which is needed for photosynthesis

4) The cilia cell - designed to stop lung damageCilia cells line all the air passages in your lungsThey have tiny hairs, which filter the air as it blows throughThe hairs sweep mucus (snot) with trapped dust and bacteria up to the back of the throat where it is swallowed

5) The root hair cell - designed for absorbingThe long hair cell increases the surface area of the root, which helps absorption of water and mineralsIt has a really thin cell wall, which makes it easier for minerals to pass across into the root itself

B2.1 – Biology

Cilia Cell

Palisade Cell

Root Hair Cell

B2.1 - Biology

B2.1 – Biology

B2.1 – Biology

B2 – Biology