Cells Flashcards
(37 cards)
What do all animal cells have?
Nucleus Cytoplasm Cell Membrane Mitochondria Ribosomes
What do all plant cells have that animal cells do not?
Cell wall
Vacuole
Chloroplasts
What does a bacterial cell have?
Cell membrane Cytoplasm Cell wall Genetic material Plasmid
How are palisade cells adapted for photosynthesis?
- packed with chloroplasts, more of them at the top so they are nearer the light
- tall shape, so more surface area down the side for absorbing Co2
- thin shape so you can pack loads of them at the top of the leaf
How are guard cells specialised?
- special kidney shape which opens and closes the stomata
- when the plant has lots of water the guard cells turn plump and turgid, so the stomata opens
- when the plant is short of water, the guard cells lose their water and become flaccid. So the stomata close
- they have thin outer walls and thickened inner walls
- sensitive to light and close at night to save water
- generally on lower side of leaf as it is shaded and cooler, so less water lost
How are red blood cells adapted to carry oxygen?
- concave shape for greater surface area. Also helps to pass smoothly inside capillaries
- packed with haemoglobin
- have no nucleus, more space for haemoglobin
How are egg cells specialised for reproduction?
- the egg cell contains huge food reserves to feed the embryo
- when the sperm fuses with the egg, the egg’s membrane instantly changes its structure to stop any more sperm getting in
How are sperm cells adapted for reproduction?
- long tail and streamlined head to help it swim to the egg
- there are a lot of mitochondria in the cell to provide the energy needed
- enzymes in their heads to digest through the egg cell membrane
How does a cell become specialised?
Differentiation
What is a tissue?
A group of similar cells that work together to carry out a particular function
Give three examples of tissue of humans ?
Muscular tissue
Epithelial tissue
Glandular tissue
What is an organ?
A group of different tissues that work together to perform a certain function
What are the tissues in the stomach and what do they do?
- Muscular tissue - allows food to move through the digestive system
- Glandular tissue - makes digestive juices to digest food
- Epithelial tissue - covers the outside and inside of the stomach
What is an organ system?
A group of organs working together to perform a particular function. E.g Digestive system
Give examples of tissues in plants
- Epidermal tissues- covers the whole plant
- Palisade mesophyll tissue- where most photosynthesis happens
- Spongy mesophyll tissue - contains big air spaces to allow gases o diffuse in and out of cells
What is diffusion?
The spreading out of particles from an area of high concentration to an area of low concentration
What is the link between concentration difference and diffusion rate?
The bigger the difference in concentration, the faster the diffusion rate
What kind of molecules can diffuse through cell membranes?
Very small molecules - oxygen, glucose water. Big molecules like starch and water can’t fit through
What is osmosis?
The movement of water molecules across a partially permeable membrane from a region of high water concentration to a region of low water concentration.
What is a partially permeable membrane?
A membrane with very small holes in it
What is a hypertonic solution?
A more concentrated solution
What is an isotonic solution?
A solution with the same concentration?
What does it mean if a plant is turgid?
It’s cells draw in water by osmosis and become swollen
What is turgor pressure?
When the contents of the cell push against the inelastic cell wall. It helps to support the plant.
