Transport across cell membrane

Question 1

What are the two types of processes for transport?

Answer 1

Passive processes: doesn’t need energy and it flows with the concentration gradient.
Active processes: needs energy - can be because it flows against the concentration gradient (but not necessarily)

Question 2

Diffusion

Answer 2

• passive movement of liquid or gas molecules from a place of higher concentration to lower concentration
• this is technically called net diffusion
• if the concentration gradient increases, then rate of diffusion increases

Question 3

Osmosis

Answer 3

• the passive diffusion of water across a semi-permeable membrane from an area of higher water concentration to lower water concentration

Question 4

What is osmotic pressure

Answer 4

• a measure of the tendency of a solution to take in water by osmosis
• higher concentration of solute = higher osmotic pressure

Question 5

Facilitated diffusion

Answer 5

• passive movement of substances from an area of higher concentration to lower concentration using carrier proteins

Question 6

Active transport

Answer 6

• active form of transport as it requires ATP because substances are being transported across the membrane against the concentration gradient

Question 7

Vesicular transport

Answer 7

• active form of transport
• movement of substances across the membrane in membranous bags called vesicles
• it’s active because energy is needed to form the vesicles (nothing to do with the concentration gradient)

Question 8

Endocytosis

Answer 8

• taking liquids/solids INTO the cell through vesicular transport
• the cell membrane folds around the particle until it’s enclosed
• 2 types:
• pinocytosis: transport of liquids
• phagocytosis: transport of solids

Question 9

Exocytosis

Answer 9

• when contents of a vesicle (inside the cell) are released outside
• the vesicle migrates to the cell membrane and fuses
• the contents are pushed out without breaking the membrane