Biological membranes - Bulk Transport

Question 1

Define bulk transport

Answer 1

Large molecules that are too large to move through carrier or channel proteins, enter or leave cells within vesicles. An active process.

Question 2

Is bulk transport an active or passive process

Answer 2

Active

Question 3

What is phagocytosis compared to pinocytosis

Answer 3

Phagocytosis- solid material
Pinocytosis- liquid material

Question 4

What is endocytosis

Answer 4

The bulk transport of material into cells

Question 5

Describe the process of endocytosis

Answer 5

• the substance is outside the cell. It may bind to a receptor site
• the cell surface membrane folds around the substance to engulf it
• the membrane pinches off to form a vesicle
• the vesicle can be moved into the cytoplasm along the cytoskeleton. This requires ATP

Question 6

what is exocytosis

Answer 6

the bulk transport of material out of cells

Question 7

describe the process of exocytosis

Answer 7

• vesicles formed by the Golgi apparatus
• the vesicle is moved towards the cell surface membrane by cytoskeleton. this requires ATP
• the vesicle fuses with the cell surface membrane
• the vesicle membrane becomes part of the cell surface membrane
• the contents of the vesicle are released outside the cell

Question 8

what are the four examples of bulk transport and are they endo/exo

Answer 8

hormones - exocytosis
plant cells - exocytosis
phagocytes - endocytosis
nerves - exocytosis

Question 9

explain the hormones example of exocytosis

Answer 9

pancreatic cells make insulin. it is processed and packaged into vesicles in the golgi apparatus. these vesicles fuse with the outer membrane to release insulin into the blood

Question 10

explain the plant cells example of exocytosis

Answer 10

materials required to build the cell wall are carried outside in vesicles

Question 11

explain the phagocytes example of endocytosis

Answer 11

phagocytes engulf invading microorganisms forming a vesicle around them. this vesicle then fuses with lysosomes. lysosomes contain hydrolytic enzymes that can break down and digest the microorganisms

Question 12

explain the nerves example of exocytosis

Answer 12

at the gaps between neurones (synapses), neurotransmitters are secreted into the synaptic cleft