Cell transport

Question 1

Diffusion:

Answer 1

Random process in which molecules of a substance move from areas with high conc. of that substance to areas with low conc. resulting in an even spread. Requires no energy

Question 2

Simple diffusion

Answer 2

Lipid soluble substances eg Oxygen. Carbondioxide. Nitrogen. Alcohol. Are able to simply diffuse through phospholipid bilayer

Water Soluble: eg water and ions will mostly pass through membrane via channel proteins with hydrophilic pores in membrane

Question 3

Osmosis:

Answer 3

Diffusion of water molecules across a semi-permeable membrane from areas of high water conc. to low

Question 4

Carrier Mediated Transport

Answer 4

Involves use of carrier proteins. Both active and passive
Protein bind to molecules before changing shape to move the substance across the membrane.
Specific to one type of substance
Can become saturated
Regulated by hormones

Question 5

Facilitated Diffusion

Answer 5

Passive use of carrier proteins to move substances (eg glucose, amino acids) from areas with high concentrations of the substance to areas with low conc.

Question 6

Active Carrier Mediated

Answer 6

Active use of carrier proteins. Substances are moved against concentration gradient (low -> to high) eg certain ions, glucose, amino acids

Question 7

Ion Pumps:

Answer 7

Proteins that through an active process move charged molecules against concentration gradient

Question 8

Vesicular Transport

Answer 8

Type of transport where liquids (pinocytosis) or solids (phagocytosis) are brought through the membrane in a vesicle created when the membrane creates a fold around the substance that pinches off and moves through the membrane before releasing its contents.

Endocytosis: solids or liquids are brought into the cell eg micro-organisms and cholesterol, ions.

Exocytosis: substances removed from the cell eg secretions like mucous

Question 9

Carrier protein

Answer 9

Permit passage of specific molecules by facilitated diffusion or active transport

Question 10

Channel protein

Answer 10

Form a hydrophilic pore through hydrophobic interior of the membrane to allow water soluble molecules to pass by facilitated diffusion

Question 11

Receptor Protein

Answer 11

Sensitive to certain molecules outside the cell and when those are present binds with them triggering changes in the cell

Question 12

Glycoproteins:

Answer 12

Proteins with attached carbohydrate. Important in cell signalling. Membrane stability. In cell-cell recognition and acting as receptors for hormones.

Question 13

Cholesterol

Answer 13

Give membrane it’s shape structure and fluidity

Question 14

Passive transport

Answer 14

Movement of substances across a cell membrane without the input of energy