Biology 2a Flashcards
What is cytoplasm?
Gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions. (Plant and animal)
What does the nucleus do?
It contains genetic material that controls the activities of the cell (plant and animal)
What does the cell membrane do?
It holds the cell together and control what goes in and out. (Plant and animal)
What is the mitochondria?
Where most of the reactions for respiration takes place, energy is released that the cells need to work. (Plant and animal)
What are ribosomes?
These ads where proteins are made in a cell. (Plant and animal)
What are rigid cell walls for?
They are made of cellulose and support the cell/strengthens it. Only in plant cells.
What is a permanent vacuole?
It contains cell sap which is a weak solution of sugar and salts. Only in plant cells.
What are chloroplasts?
These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll.
Is yeast a single or multi celled organism?
Yeast is a single-celled microorganism.
What organelles does a yeast cell contain?
A yeast cell contains a nucleus, cytoplasm and cell membrane, surrounded by a cell wall.
Are bacteria single or multi celled organisms?
Bacteria cells are single-celled microorganisms.
What organelles do bacteria cells contain?
Bacterial cells contain cytoplasm and a cell membrane, surrounded by a cell wall. The genetic material floats in the cytoplasm because they don’t have a nucleus.
What is the definition of diffusion?
Diffusion is the spreading out of particles from an area of high concentration to an area of low concentration.
Where does diffusion occur and why?
Diffusion happens in liquids and gasses as the particles are free to move about randomly.
If the difference in concentration is bigger, will diffusion happen at a faster or slower rate?
The bigger the difference in concentration, the faster the diffusion rate.
What organelle does diffusion take place in?
The cell membrane, dissolved substances move in and out of cells via diffusion. But only very small molecules can diffuse through the cell membrane. Eg starch and proteins can’t be diffused through the cell.
What are palisade leaf cells adapted for?
Palisade leaf cells are adapted for photosynthesis.
Where and why are there many chloroplasts in a palisade leaf cell?
Palisade leaf cells contain many chloroplasts for photosynthesis, most of them are stored on top of the leaf do they’re nearer to the light.
Why are palisade leaf cells tall?
They have a tall shape so their surface area is larger down the side of the leaf so more co2 is absorbed from the air.
What are guard cells adapted to do?
Guard cells are adapted to open and close pores.
What are the pores in a leaf called?
The stomata.
How is the guard cell specialised?
It is a special kidney shape which opens and closes the stomata in a leaf.
What happens when the plant has a lot of water, in terms of the guard cell?
The guard cell fills with water and becomes fatter, opening the stomata so gases can be exchanged for photosynthesis.
What happens when the plant is short of water, in terms of the guard cell?
The guard cells lose water and becomes flat and limp, closing the stomata. This stops too much water vapour escaping.
In a guard cell, are the inner walls or outer walls thinner?
Thin outer walls and thickened inner walls, to make the opening and closing work.
Why is it good that guard cells are sensitive to light?
Because this means they close at nigh to save water without losing out on photosynthesis.
What are red blood cells adapted to do?
Red blood cells are adapted to carry oxygen.
Why do red blood cells have a concave shape?
It gives the a big surface area for absorbing oxygen. It also helps them pass smoothly though the capillaries to reach body cells.