Cell biology Flashcards
Where is the genetic material in a prokaryotic cell?
In a bacterial DNA loop and there may be one or more plasmid rings.
What organelles are in plants and animals?
Nucleus, Cytoplasm, Cell membrane, Mitochondria, Ribosomes
What do plants and bacteria share?
Cytoplasm, Cell membrane, Cell wall
What do Sperm cells do?
Function is to fertilise an egg.
They are streamlined to allow for swimming without using as much energy as it needs
Where is the genetic material in a eukaryotic cell?
The DNA is in chromosomes enclosed in a nucleus.
Why do scientists use prefixes?
To make very small numbers more manageable
Define ‘diffusion’?
The spreading of the particles from a region where they are of a higher concentration to an area of lower concentration.
State three places where diffusion occurs in the body.
Small intestines, lungs, kidneys
Which has the largest surface area to volume ratio an elephant or a meerkat?
The meerkat.
What three factors affect rate of diffusion?
Concentration gradient, temperature, surface area.
What is surface area to volume ratio?
The size of a surface compared to its volume.
Which has the largest surface area to volume ratio an elephant or a meerkat?
The meerkat.
What do nerve cells do?
Function is to carry electrical signals.
They have lots of branches so that they can connect to other nerve cells as well
Name organisms that are adapted to diffusion?
The small intestine, the lungs, gills in fish, roo0ts and leaves.
How are the small intestines adapted for diffusion?
Have villi to increase surface area, good blood supply, thin membranes.
What is a partially permeable membrane?
A membrane that lets some but not all substances through.
How are gills in fish adapted for diffusion?
Have gill filaments and lamella to increase surface area, good blood supply, thin membranes.
How are roots adapted for diffusion?
Have gill filaments and lamella to increase surface area, good blood supply, thin membranes.
Define osmosis
Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.
What is a partially permeable membrane?
A membrane that lets some but not all substances through.
Why does active transport need to occur in the gut?
Because the glucose in the blood is at a higher concentration than in the gut.
What happens to an animal cell in a hypertonic solution?
It will lose water by osmosis and shrivel
What happens to an animal cell in a hypotonic solution?
It will absorb water by osmosis and get bigger/burst.
Define active transport.
Active transport moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient) using energy from respiration.
