Transport across membranes

Question 1

What is the difference between passive and active transport?

Answer 1

Active transport requires ATP, whereas passive does not

Question 2

What is the effect of the presence of cholesterol in the cell membrane?

Answer 2

The membrane is more fluid at low temperatures and less fluid at high temperatures (stabilization of fluidity)

Question 3

Phospholipids with unsaturated hydrocarbon tails make the cell membrane more or less fluid?

Answer 3

More fluid

Question 4

What are the two types of movement of phospholipids in a cell membrane?

Answer 4

Lateral (more frequent) and flip-flopping (rare)

Question 5

Fatty acids go into the cell by which means of transport?

Answer 5

Diffusion

Question 6

Amino acids and monosaccharides enter the cell by which means of transport?

Answer 6

Facilitated diffusion

Question 7

Osmosis is the facilitated diffusion of water through ….

Answer 7

Aquaporins

Question 8

How do we call the pressure that must be applied to prevent osmosis?

Answer 8

Osmotic pressure

Question 9

Are animal cells healthiest in an hypotonic, isotonic or hypertonic environment?

Answer 9

Isotonic

Question 10

Are plant cells healthiest in an hypotonic, isotonic or hypertonic environment?

Answer 10

Hypotonic

Question 11

What are the two types of endocytosis?

Answer 11

Pinocytosis and phagocytosis

Question 12

In which type of endocytosis a cell absords a large quantity of fluids?

Answer 12

Pinocytosis

Question 13

In which type of endocytosis a cell absords large particles?

Answer 13

Phagocytosis

Question 14

In active transport, the material moves … the concentration gradient.

Answer 14

Up

Question 15

How do we call an environment in which the solute concentration is greater than in the cell?

Answer 15

Hypertonic

Question 16

How do we call an environment in which the solute concentration is lower than in the cell?

Answer 16

Hypotonic

Question 17

How do we call an environment in which the solute concentration is the same as in the cell?

Answer 17

Isotonic

Question 18

How do we call the transport of large volumes of particles out of the cell? Give an example.

Answer 18

Exocytosis. Milk production

Question 19

How do we call the transport of large volumes of particles in the cell? Give an example.

Answer 19

Endocytosis. An amoeba that engulfs a paramecium (phagocytosis)

Question 20

What is the particularity of a receptor-mediated endocytosis?

Answer 20

It will only take a specific substance.

Question 21

Give an example of a gated channel.

Answer 21

Na+ and K+ channels in nerve cells are pores with gates

Question 22

What is a carrier protein and how does it work?

Answer 22

A carrier protein allows for facilated diffusion to happen. It has a hydrophilic interior and a hydrophobic outside

Question 23

What describes the cell membrane as a two-dimensional liquid in which phospholipid and protein molecules diffuse easily?

Answer 23

The fluid mosaic model of the cell

Question 24

What is a peripheral protein?

Answer 24

A protein associalted with inner/outer layer of the membrane

Question 25

What is an integral protein?

Answer 25

A protein embedded in the membrane

Question 26

What is a lipid raft?

Answer 26

An area where the the membrane is less fluid so that proteins that are associated with this area together in clumps

Question 27

What pushes the plasma membrane against the cell wall of plant, bacteria, and fungi cells as well as those protist cells which have cell walls?

Answer 27

Turgor pressure