Chapter 6.5 (Exam 1) Vesicular Transport

Question 1

Which molecules require membrane vesicles to be taken in or secreted?

Answer 1

Macromolecules (proteins, polysaccharides, nucleic acids) are too large to cross the membrane

Question 2

What is endocytosis?

Answer 2

Brings molecules and cells into a eukaryotic cell

The cell membrane folds inward around the material, forming a vesicle

Question 3

What are the three types of endocytosis?

Answer 3

Phagocytosis

Pinocytosis

Receptor-mediated endocytosis

Question 4

Describe phagocytosis.

Answer 4

Molecules or entire cells are engulfed

Some protists feed in this way

Some white blood cells engulf foreign substances in this way

A food vacuole or phagosome forms, which fuses with a lysosome where the contents are digested

Question 5

Describe pinocytosis.

Answer 5

A vesicle forms to bring small dissolved substances or fluids into a cell

Vesicles are much smaller than in phagocytosis

Pinocytosis is constant in endothelial (capillary) cells

Question 6

Describe receptor-mediated endocytosis.

Answer 6

Highly specific

Macromolecules to be moved bind to receptor proteins

Sites coated with proteins like clathrin for structural support

Question 7

What are receptor proteins?

Answer 7

integral membrane proteins located at specific sites on the cell membrane

Question 8

What is exocytosis?

Answer 8

materials packaged in vesicles (e.g., digestive enzymes and neurotransmitters) are secreted from a cell when the vesicle fuses with the membrane

Question 9

What are the two ways exocytosis can release materials in a vesicle out of the cell?

Answer 9

The vesicle can fuse with the cell membrane

The vesicle forms a pore upon touching the cell membrane releasing the vesicle’s contents; no membrane fusion