2a.1 - Cells Flashcards
What does the standard adult body cell contain?
- Nucleus
- Mitochondria
- Ribosomes
- Cytoplasm
- Cell membrane
Why do cells need a nucleus?
Contains genetic material which control the activities of the cell
Why do cells need cytoplasm?
Where most of the chemical reactions happen because it contains enzymes
Why do cells need a cell membrane?
Holds the cell together and controls what goes in and out
Why do cells need mitochondria?
Where most of the reactions for respiration take place. Respiration releases energy
Why do cells need ribosomes?
Where proteins are made
What features do plant cells have that animal cells don’t?
- Cell wall
- Vacuole
- Chloroplasts
Why do plant cells need a cell wall?
Made of cellulose and it supports and strengthens the cell
What is a vacuole?
Contains cell sap which is a weak solution of salts and sugar
Why do plant cells need chloroplasts?
Contains a green substance called chlorophyll and is where photosynthesis happens which provides the cells with food
What does a yeast cell contain?
- Cell membrane
- Cytoplasm
- Cell wall
- Nucleus
What does a bacteria cell contain?
- Cell membrane
- Cell wall
- Cytoplasm
- Loose genetic material
What is the definition of diffusion?
The spreading out of particles from an area of high concentration to an area of low concentration
What can diffuse into and out of a cell membrane?
Oxygen, glucose, amino acids and water
How are palisade cells adapted for photosynthesis?
- Lots of chloroplasts crammed near the top of the cells
- Tall so lots of surface area for absorbing CO2
- Thin so lots of palisade cells can fit at the top of the leaf
What are guard cells adapted to do?
Open and close pores
What do guard cells do when the plant has too much water?
- Guard cells become turgid. This makes the stomata open do gases can be exchanged for photosynthesis
What do guard cells so when they don’t have enough water?
Guard cells lose water and become flaccid making the stomata close. This helps stop water vapour escaping
How are guard cells adapted to open and close pores? (2)
- They are thin and have thick inner walls which makes the opening and closing work
- Sensitive to light and close at night to save water without losing out on photosyntheses
How are red blood cells adapted to carry oxygen?
- Concave - big surface are for absorption
- Packed with haemoglobin - the pigment that absorbs oxygen
- No nucleus - more haemoglobin
How are egg cells specialised for reproduction?
- Contain huge food reserves for the embryo
- When sperm fuses with the egg the cell membrane instantly changes to stop any more sperm
How are sperm cells specialised for reproduction?
- Long tail and streamlined head to help it swim
- Lots of mitochondria to provide energy
- Carry enzymes to break up cell membrane
What is differentiation?
The process where by which cells become specialised for a particular job
What is a tissue?
A group of similar cells
What do glands do? (e.g. the pancreas and salivary glands)
Produce digestive juices
What does the stomach and the small intestine do?
Digest food
What does the liver do?
Produces bile
What does the large intestine do?
Absorb water from undigested food
