What does the Cell Theory state?
- All living things are made up of cells.
- Cells are the smallest working units of all living things.
- All cells come from preexisting cells through cell division.
- All cells can carry out all characteristics of living things.
What are Cells?
A cell is the smallest unit that is capable of performing life functions.
What are the characteristics of prokaryotic cells?
- Do not have structures surrounded by membranes.
- Few internal structures.
- One-celled organisms. Bacteria, Virus.
What are the Characteristics of Eukaryotic cells?
- Contain organelles surrounded by membranes.
2. Most living organisms are Eukaryotic.
What does the cell membrane do?
It is the outer membrane of the cell that controls movement in and out of the cell (selectively permeable). It has a double layer.
What does a cell wall do?
It is most commonly found in plant cells and bacteria. It is made of polysaccharides.
It supports and protects cells.
Plant cell is made of cellulose.
What is the function of the nucleus?
It directs the cells’ activities.
It is separated from the cytoplasm by nuclear membrane.
It contains genetic material. It contains chromosomes made of DNA.
The chromosomes contain instructions for traits and characteristics.
What is the Cytoplasm?
It is a gel-like mixture.
Surrounded by cell membrane.
Site of most metabolic reaction.
What is the Endoplasmic Reticulum?
- Moves materials around in cell.
- Smooth type: lacks ribosomes.
- Rough type (pictured): ribosomes embedded in surface.
What are Ribosomes?
- Each cell contains thousands.
- Make proteins
- Found on ribosomes and floating throughout the cell.
What is a Mitochondrion?
- It is a rod shaped organelle that produces energy through chemical reactions - breaking down fats and carbohydrates.
- Controls level of water and other materials in cell.
- Recycles and breaks down proteins, fats and carbohydrates.
What are Golgi Bodies?
- It packages protein.
- It moves materials within the cells.
- Moves materials out of the cell.
What are Vacuoles?
- Membrane - bound sacs for storage, digestion and waste removal.
- Contains water solution
- Help plants maintain shape.
What are Chloroplasts?
They are usually found in plant cells but can be found in bacteria.
Contains green chlorophyll.
Where photosynthesis takes place.
How do cells specialise?
Newly-formed cells in a multi-cellular organism become specialised by turning different genes on and off.
This is known as Differentiation.
What are Erythrocytes?
They carry oxygen from the lungs to respiring tissues. 1. Contain large amounts of Hb 2. Have no nucleus. 3. Are bioconcave 4. Have large surface area 5.
What are Ciliated Cells?
They are epithelial cells which are column shaped and cover many surfaces.
They have tiny projections on their exposed surface called cilia. They move in a synchronised pattern to move mucus, produced by goblet cells along the surface.
eg. Trachea, uterus and bronchi.
What is a spermatozoa?
Spermatozoa are motile reproductive cells, which carries a male’s genetic information.
Their motility comes from their undulipodium whose energy comes the mid-piece Mitochondria.
They have a haploid nucleus with an acrosome with hydrolytic and glycolytic enzymes for dissolving the ovum coat of the egg.
What are Root hair cells?
They are epithelial cells found in the roots of plants.
They have a large surface area due to their hair-like projections which make water and mineral absorption easier.
Their large amount of mitochondria provide large amounts of mitochondria which assist with active transport.
What are Xylem Vessels?
Xylem tissue consist of xylem vessels and parenchyma cells.
They are made of dead, elongated cells and waterproofed with lignin deposits.
They have no end walls so their cells form tubes with wide lumens.
They also support the plant.
What are Phloem Tissue?
Phloem tissue is made up of sieve tubes and companion cells.
Sieve tubes line up and their ends form sieve plates through which substances move.
They companion cells beside the sieve tubes perform the cell’s metabolic functions.
What are Muscle Cells?
They are elongated and elastic cells.
They have many mitochondria.
The strands of protein slide over each other making the muscle cell (fibre) shorter and causing the muscle to contract.
