Membrane Fluidity

Question 1

Describe the fluid properties of the cell membrane and vesicles

Answer 1

Fluidity refers to viscous flow of phospholipids

in the cell membrane/ organelles of the endo-membrane system (EX: Vesicles)

Question 2

Fluidity in the cell membrane/vesicles are affected by: -

Answer 2

• temperature
• fatty acid length
• fatty acid saturation
• presence of cholesterol

Question 3

Explain vesicle formation via endocytosis

Answer 3

In endocytosis, the cell actively transports molecules into the cell

by engulfing them into vesicles

formed through cell membrane capture and fusion

Question 4

Outline 2 examples of materials brought into the cell via endocytosis

Answer 4

• White blood cells can engulf bacteria when fighting infection
• single celled organisms (EX: amoeba) can engulf bacteria as a food source

Question 5

Explain release of materials from cells via exocytosis

Answer 5

A secretory vesicle moves towards the cell membrane,

fuses with the membrane,

and releases the contents into extracellular space

Question 6

Outline 2 examples of materials released from a cell via exocytosis

Answer 6

• secretion of neurotransmitter at synaptic terminus

- secretion of digestive juices from exocrine glands