Plasma membrane and organelles - 4

Question 1

Name four eukaryotic cells

Answer 1

Animal, Plantae, fungi and protozoa

Question 2

What does the plasma membrane do

Answer 2

It is a semi permeable membrane which means that it allows certain molecules in and keeps others out.

Question 3

Why is the plasma membrane important

Answer 3

It creates specific environments for specific processes
Keeps incompatible processes apart
Allows a concentration gradient to occur (which is used in passive transport and osmosis)

Question 4

What is passive transport

Answer 4

Transport of molecules across plasma membrane, from high concentration to low concentration, that does not require energy.

Question 5

What are the two types of passive transport

Answer 5

Facilitated - Uses protein channels or carriers that open and close in response to signals (allows hydrophilic molecules to pass)
Osmosis (aquaporins) - Allows water to cross to create osmoregulation.

Question 6

What is active transport

Answer 6

Transport of molecules against concentration gradient (low concentration to high concentration) that requires energy in the form of ATP. Requires transport proteins and allows internal gradients to differ from surroundings.

Question 7

What is the final type of transport

Answer 7

Co-transport - Requires ATP and a protein pump. The molecule required can only cross with another. Once inside the one not needed is pumped back out so the process can continue.

Question 8

What are the four uses of membrane proteins

Answer 8

Signal transduction - Getting internal messages into the cell through receptors.
Cell recognition - Proteins with added sugar help to detect harmful things like bacteria.
Intercellular joining - creates long lasting connections between cells.
Stability - Helps to keep cell in place by linking the cytoskeleton and extra cellular matrix to cell and each other.