Biology 2 Flashcards
What is the purpose of the Nucleus?
It contains genetic material that controls the activities of the cell.
What is Cytoplasm?
Jelly-like substance where most chemical reactions happen which contains enzymes. (These enzymes control the reactions.)
What is the purpose of the Cell Membrane?
Holds the cell together and controls what goes in and out.
What is the purpose of Mitochondria?
Where most of the reactions for respiration happen. Respiration releases energy that the cell needs to work.
What do Ribosomes do?
They make the proteins in the cell.
Generally, do animal cells have cell walls?
No.
What is the cell wall of a plant cell made of and what does it do?
It’s made of cellulose and supports and strengthens the cell.
What does the Permanent vacuole contain?
It contains cell sap which is a weak solution of sugar and salts.
What are Chloroplasts?
They’re where photosynthesis occurs in the cell which make food for the plant.
What do the Chloroplasts contain?
A substance called Chlorophyll which makes the plant green.
What makes Bacteria cells specifically unique?
They don’t have a nucleus.
What parts do Yeast Cells have?
Cell wall, cell membrane, cytoplasm and a nucleus.
What parts do Bacteria have?
Cell wall, cell membrane, cytoplasm and genetic material (which floats in the cytoplasm.)
How are Yeast and Bacteria similar?
They are both single-celled organisms.
What is Diffusion?
It is the spreading out of particles from an area of high concentration to low concentration.
What substances can Diffusion happen?
Liquids and Gases.
What is the link between the concentration of something and the rate of diffusion?
The bigger the difference of concentration, the faster the rate of diffusion.
How can dissolved substances move in and out of cells?
Diffusion.
What molecules can diffuse through cell membranes?
E.g - oxygen, glucose, amino acids and water.
Why can’t big molecules like Starch and Proteins diffuse into cells?
They are too big to fit into the membrane.
What are Palisade Leaf cells adapted for?
Photosynthesis.
How are Palisade cells specialised?
Packed with chloroplasts with lots crammed at the top so they’re near the light. Tall shape means a lot of surface area is exposed for absorbing CO2 from the air in the leaf. Thin shape means you can have lots of them at the top of the leaf.
What are Guard Cells adapted to doing?
Opening and closing pores. The adapted functions allow gas exchange and control water loss in a leaf.
What shape are Guard Cells and why?
Special kidney shape which opens and closes the stomata in a leaf.
What happens to the Guard cells where there is a lot of water?
The guard cells fill with water and go plump which makes the stomata open so gases can be exchanged for photosynthesis.
What happens to the Guard cells where there is not a lot of water?
The Guard cells lose water and become flaccid making the stomata close. This stops too much water vapour escaping from the plant.
What feature makes the opening and closing of the pores work?
They have thin outer walls and thick inner walls.
What happens to the Guard cells at night?
They’re sensitive to light so close at night to save water without losing out on photosynthesis.
What are Red Blood cells adapted to do?
Carry oxygen.
How does their shape help them to carry oxygen effectively?
Concave shape gives a big surface area for absorbing oxygen and helps them pass smoothly through capillaries to reach body cells.
What are Red Blood Cells full of?
Haemoglobin which is the pigment that absorbs oxygen.
Why don’t Red Blood cells have a nucleus?
To leave even more room for the haemoglobin.
What are the Egg and Sperm adapted for?
Reproduction.
What is the main function of the Egg cell?
To carry the female DNA and to nourish the developing embryo in its’ early stages.
In what 2 main ways has the Egg cell specialised?
It has huge food reserves to feed the embryo. Also, when a sperm fuses with the egg, the egg’s membrane instantly changes its structure to stop any more getting in so the offspring end up with the right amount DNA.
What is the main function of the Sperm cell?
To get the male DNA to the female DNA.
How has the Sperm cell specialised?
It has a 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. Sperm also carry enzymes in their heads to digest through the egg cell membrane.
What are Large Multicellular Organisms (e.g. humans) made up of?roup of similar cells that work together to carry out a particular job.
Organ Systems.
What is the process called when cells specialize for a particular job?
Differentiation.
When does Differentiation occur?
During the development of a multicellular organism.
What is a tissue?
A group of specialised cells that have a similar structure and function.
What is an organ?
A group of different tissues that work together to perform a certain function.
What is an Organ System?
A group of organs working together to perform a particular function.