Cell Biology - Cell structure Flashcards
What type of cells are eukaryotic?
Plants, animals, protists and fungi.
How big are eukaryotic cells?
10-100 micrometres.
What are the properties of eukaryotic cells?
- Unicellular = single-celled.
- Have DNA that forms chromosomes in a nucleus.
What type of cell is prokaryotic?
Bacteria.
How big are prokaryotic cells?
0.1-5 micrometres.
What are the properties of prokaryotic cells?
-Small rings of DNA called plasmids.
-Unicellular = single celled.
-Single DNA loop in cytoplasm (where DNA is stored).
-No mitochondria or chloroplasts.
No nucleus.
What sub-cellular structures do prokaryotic cells have?
- Cell wall.
- Cytoplasm.
- Cell membrane.
- Flagellum.
- Bacterial DNA loop.
- Plasmid DNA rings.
What do all plant and animal cells have?
- Cell membrane.
- Nucleus.
- Mitochondria.
- Ribosomes.
- Cytoplasm.
What sub-cellular structures do all plant cells have that animal cells don’t?
- Permanent vacuole.
- Chloroplasts.
- Cell wall.
What is the function of the cell membrane?
Controls what substances move in and out of the cell.
What is the function of the nucleus?
Contains the cells DNA.
What is the function of ribosomes?
Site of protein synthesis.
What is the function of mitochondria?
Where energy is released through aerobic respiration.
What is the function of cytoplasm?
Jelly like substance where chemical reactions take place.
What is the function of the permanent vacuole?
Stores water and contains cell sap.
What is the function of chloroplasts?
Contains chlorophyll for photosynthesis.
What is the function of the cell wall?
Made of cellulose, which strengthens the cell.
When do animal cells differentiate?
Early on in their development.
When do plant cells differentiate?
All throughout its lifetime.
What are the 3 steps of taking plant cuttings for plant cells to differentiate?
-Cut small section off a plant stem.
Plant the cut section.
-Some cells differentiate and create a new root tissue.
Why do animal’s cells divide?
- Replace cells.
- Repair tissues.
What is the function of the specialised sperm cell?
Fertilise an egg.
How are sperm cells adapted?
- Tail to swim to egg.
- Acrosome at tip of head (contains enzyme to penetrate egg).
- Half DNA of organisms genetic material.
- Mitochondria for energy to swim to egg.
What is the function of the specialised red blood cell?
To transport oxygen around the body.
How are red blood cells adapted?
- No nucleus- more room for oxygen.
- Contains haemoglobin that binds to oxygen molecules.
What is cell differentiation?
When a cell gains new sub-cellular structures in order to perform a specific function. The cell them becomes specialised.
What is the function of the specialised muscle cell?
To contract and relax to allow movement.
How are muscle cells adapted?
- Contains protein fibres that can contract to allow movement.
- Contains mitochondria to release energy.
What is the function of the specialised nerve cell?
To carry electrical impulses around the body.
How are nerve cells adapted?
- Have a long axon to increase the distance electrical signals can travel.
- Have dendrites (branched endings) to make connections with other neurones.
- Myelin sheath insulates the axon and stops electrical nerve signals leaking out the cell, increasing the transmission speed of the electrical impulses.
What are gaps between neurones called?
Synapses.
What is the function of the specialised root hair cell?
To absorb mineral ions and water from the soil.
How are root hair cells specialised?
- Long projections that increase the surface area that the plant can use to absorb more water and minerals.
- Mitochondria to release energy for the active transport of mineral ions.
What is the function of the specialised palisade cell?
To enable photosynthesis in the leaf.
How are palisade cells adapted?
- Lots of chloroplasts containing chlorophyll to absorb light energy.
- Located at top of surface of leaf to absorb the most light energy.
What is the equation to find magnification?
Magnification= image size / actual size
What does magnification tell us?
How many times larger an image seen through a microscope is compared to the real object.
Define resolution
The ability to distinguish between two or more objects that are close together.
What do light cells allow us to do?
Distinguish between types of cells.
What do electron microscopes allow us to see?
Sub-cellular structures - ribosomes, mitochondria etc.
What are advantages of light microscopes?
- Cheap.
- Living samples can be seen.
What are the disadvantages of light microscopes?
- Low magnification.
- Low resolution.
How do light microscopes work?
Uses light to form images.
What are the advantages of electron microscopes?
- High magnification.
- High resolution.
What are the disadvantages of electron microscopes?
- Samples cannot be living.
- Expensive.
How do electron microscopes work?
Uses a beam of electrons to form images.
What are the steps of completing a light microscope experiment?
1 Put a thin sample of tissue onto a microscope slide.
2 Add a few drops of suitable dye/stain.
3 Place a coverslip on top of the tissue and place the slide onto the microscope stage.
4 Use the objective lens with the lowest magnification and focus on the sample.
5 Increase the magnification and refocus to see different features of the cell.
