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videos used - eukaryotes and prokaryotes, sizes of cells,
What are eukaryotic cells?
Cells that contain their genetic material (DNA) enclosed in a nucleus.
What are prokaryotic cells?
Cells where the genetic material (DNA) is not enclosed in a nucleus.
Where is the DNA in a bacteria cell?
Plasmids and loops of DNA (nucleoids).
What organelles do bacteria cells have?
Cells wall, cell membrane, cytoplasm, plasmids, nucleoids
How many centimetres in a metre?
How many millimetres in a metre?
How many micrometers in a metre?
1 million.
How big is a typical human cell?
10-20 micrometers
How many nanometres in a metre?
1 billion.
How big is a molecule of haemoglobin?
5 nanometres.
How many times is 2 orders of magnitude?
x100
What is order of magnitude?
An order of magnitude is 10x greater than the one before.
What happens in the cytoplasm?
Most chemical reactions.
What does a cell membrane do?
Controls what molecules can enter and leave the cell.
What takes place in the mitochondria?
Aerobic respiration.
What would you use to see ribosomes?
An electron microscope.
What happens in the ribosomes?
Protein synthesis.
How are the shapes of plant cells different to animal cells?
Plant cells have a regular shape but animal cells can easily change their shape.
What do chloroplasts contain?
Chlorophyll.
Where is the site of photosynthesis?
Chloroplast.
What are plant cell walls made of?
Cellulose.
What does the cell wall in a plant cell do?
Strengthens the cell.
What is a plant cell filled with?
Cell sap.
What does a plants permanent vacuole do?
Hold the shape of the cell.
What are specialised cells?
Cells which have certain adaptations which allow them to carry out a specific function.
What is differentiation?
When cells become specialised.
What is the job of a sperm cell?
To join with/ fertilise an egg.
How much genetic information is there in a sperm cell?
Half of a normal adult cell.
Why do sperm cells have a tail?
To let them swim to the egg and make them more streamlined.
Why are sperm cells full of mitochondria?
To provide the energy needed to swim to the egg.
Why do sperm cells contain enzymes?
Allows them to digest their way through the outer layer of the egg.
What is in the head of a sperm cell?
Enzymes and nucleus.
Where are the mitochondria in a sperm cell?
The middle part.
What is the role of a nerve cell?
To send electrical impulses around the body.
What does the axon in a nerve cell do?
Carries electrical impulses from one part of the body to another.
What does myelin do in a nerve cell?
Insulates the axon and speeds up the transmission of nerve impulses.
Where is the myelin located in a nerve cell?
Around the axon.
What are synapses?
Junctions which allow the impulses to pass from one nerve cell to another.
Where are synapses on a nerve cell?
At the end of the axon.
What do dendrites do for a nerve cell?
Increase surface are of the cell so other nerve cell can connect more easily.
What is the key thing muscle cells can do?
Contract.
How do muscles cells contract?
They contain protein fibres which can change their length.
Why are root hair cells covered in hair?
To increase the surface area of the cell, letting it absorb water and dissolved minerals more effectively.
What is the sticky out bit of a root hair gel called?
The root hair.
Why do root hair cells not contain chloroplast?
They cannot photosynthesise as they are underground.
Where are xylem cells found?
The stems of plants.
What do xylem cells do?
Carry water and dissolved minerals up the plant.
How are xylem cells adapted to their function?
They have thick walls containing lignin which supports the plant and they have no end walls between cells, forming a tube that lets water and dissolved minerals flow easily. They also have no internal structures.
Why do xylem cells die?
The cell walls being sealed with lignin.
What do phloem cells do?
Carry dissolved sugars up and down the plant.
What are phloem made of?
Phloem vessel cells and phloem companion cells.
What do end walls in phloem have?
Pores cakes cell plates.
How are the two phloem cells connected?
Pores.
What is the use for the second cell in phloem?
Provide energy for the vessel cell as the vessel cell has no mitochondria.
What are the downsides to light microscopes?
They have a limited magnification and resolution.
How are electron microscopes better?
Higher magnification and resolution.
What is the equation for magnification?
Image size / real object size.
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