Name a difference between an animal and a plant cell:
Plant cell has: chloroplasts/vacuole/cell wall
Name two specialised cells and two of their adaptions
Sperm cell - Acrosome contains enzymes so the tail can move faster
Root hair cell - Increases surface area so that there’s more space for plants to absorb nutrients
Cilia cell - Has tiny hairs to move dust and mucus from the lungs
What is a tissue?
A group of similar cells that perform a specialised function
What is an organ?
A part of the body with a specialised function.
What is the organ system?
A group of organs that work together to perform a function.
Define ‘diffusion’
The random NET movement of particles from a high to low concentration.
How is diffusion increased?
Stirring
Heat
Surface Area
How is diffusion slowed down?
- Lower temperature
- More area to diffuse
- Smaller concentration gradient
How does diffusion of O2 occur in breathing?
In the alveoli.
O2 has low concentration in the blood and high concentration in the airspace.
It diffuses from high to low (into the blood)
Define ‘organelle’
The structures within a cell
What is the endocrine system for?
The production of hormones.
Where conditions allow for faster diffusion?
- Large surface area
- Large blood supply
- Thin cell
- Small distance = faster diffustion
How does diffusion occur in nerve cells?
- (electrical) impulse is converted into a chemical signal (at the synapse)
- Neurotransmitter released from one neurone into a synapse
- they diffuse across the gap, towards the next neurone’s receptors
- moving from a high concentration to low concentration
- binding converts the chemical signal to an (electrical) impulse
How does diffusion occur in digestion?
- breaks down large food molecules into smaller SOLUBLE molecules (e.g. glucose, amino acids, and fatty acids easily absorbed)
- diffuse across intestine wall into bloodstream
- Small intestines have villi
- Villi: increase SA (surface area) of small intestines = more substances absorbed through diffusion
- Villi have lots of capillary= good blood supply. molecules go straight to bloodstream (when diffused)
What are the adaptations of a root hair cell?
- Increases surface area of root
- No chloroplasts
What are the adaptations of a palisade cell?
- Packed with chloroplasts for photosynthesis
- At the top of the leaf
What are the adaptations of a sperm cell?
- Vacuole has enzymes to break the surface of the egg cell
- Nucleus has half of the father’s chromosomes
- Has a filament (tail) for movement
- Contains a large number of mitochondria for energy release
What happens when a plant doesn’t get enough water?
Because the vacuole shrinks, the plant shrivels and wilts. The cell wall separates from the cell membrane. This is called PLASMOLYSIS
Name a similarity between an animal cell and a plant cell.
-both have a cell membrane/cytoplasm/ribsomes/mitchondria/nucleus
Give two differences between an animal cell and the cell of a bacterium.
- Bacterium has a flagellum to help it move
- Animal cells have a nucleus
Why do sperms need many mitochondria?
Sperm cells need a lot of energy to swim
What is the main job of a leaf mesophyll cell?
Allows photosynthesis to take place
Explain one way in which the structure of the leaf mesophyll cell helps is to carry out its job
It has a large surface area so it can more sunlight. Photosynthesis can happen faster
What is the function of the nucleus?
nucleus - controls activity of the cell. contains DNA
