Cells Flashcards
What are the main parts of a human/animal cell?
- Nucleus
- Cytoplasm
- Cell Membrane
- Mitochondria
- Ribosomes
What is the nucleus of a cell?
This contains the genetic material that controls the activities of the cell.
What is the cytoplasm of a cell?
This is the surrounding hell like substance where most CHEMICAL REACTIONS take place- it controls ENZYMES that control these chemical reactions.
What are Mitochondria in relation to cells?
These are where most of the reactions for respiration take place.
Respiration releases ENERGY that the cell needs to work.
What are Ribosomes in relation to cells?
Ribosomes are where proteins are made in the cell.
What is yeast?
Yeast is a single cel led organism which has a nucleus, cytoplasm, cell membrane and surrounded by a cell wall.
Does a bacterial cell have a nucleus?
NO.
It has cytoplasm, cell membrane, cell wall but the GENETIC MATERIAL floats in the CYTOPLASM
What is DIFFUSION?
Diffusionism the gradual movement of particles from places where there are lots of them to places where there are fewer of them.
What is the OFFICIAL definition of DIFFUSION?
DIFFUSION is the spreading out of particles from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION.
Does diffusion happen in liquids or gases?
BOTH.
Does the difference in concentration between gases or liquids make a difference to the speed of diffusion.
YES.
The bigger the difference in concentration, the faster the DIFFUSION rate.
Can diffusion happen in relation to cell membranes?
YES.
Cell membranes hold the cell together but they let stuff in and out of the cell.
HOWEVER, only very small molecules can diffuse through cell membranes like OXYGEN, GLUCOSE, AMINO ACIDS and WATER.
Can large molecules diffuse through cell membranes?
NO.
Large molecules like starch and proteins can’t fit through the membrane.
Name 4 specialist cells?
Palisade Leaf Cells
Guard Cells
Red Blood Cells
Sperm and Egg Cells
Why are Palisade cells specialised?
Because they are adapted for photosynthesis
How do palisade cells work?
They are packed with chloroplasts for photosynthesis at the top of the cell.
This means they are nearer the light.
They are also tall with a lot of surface area to absorb CO2.
Why are guard cells specialist?
Because they are kidney shaped which opens and closes the stomata in a leaf.
How do guard cells work?
When a plant has lots of water the guard cells fill with it and go plump and TURGID. This makes the stomata open so gases can be exchanged for photosynthesis.
When the plant is short of water the guard cells lose waters and become FLACCID making the stomata close. This helps stop too much water vapour escaping.
They’re also sensitive to light and close at night to save water without losing out on photosynthesis.
Guard cells therefore adapt their function allowing gas exchange and controlling water loss.
How are red blood cells specialist?
They are adapted to carry oxygen.
How are blood cells specially adapted?
Concave shape gives a big surface for absorbing oxygen.
They are packed with haemoglobin - pigment that absorbs the oxygen.
They have no nucleus to leave even more room for haemoglobin
What are sperm and egg cells specialist for what role?
Reproduction
How are sperm and egg specialist cells?
- The main function of the egg cell carries female DNA and to nourish the developing embryo in the early stages.
- When a sperm fuses with the egg, the egg’s membrane instantly changes its structure to stop any sperm getting in.
- Sperm shaped for swimming - long tail, streamlined egg to help it swim.
- Sperm carries enzymes in their heads to digest through the cell membrane.
What is meant by differentiation?
It is the process where cells become specialised for a particular job
What is a multicellular organism?
It is a human or dog or squirrel - it means where an organism has lots of specialist cells
