2: Cell membranes Flashcards Preview

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Flashcards in 2: Cell membranes Deck (30)
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1
Q

The cell membrane is ___ permeable.

A

selectively

2
Q

Functional differences between cell types are due to variations in the composition of the ___ ___.

A

cell membranes

3
Q

What are the two main components of cell membranes?

A

Lipids

Proteins

4
Q

Phospholipid heads are (hydrophilic / hydrophobic).

A

Heads are hydrophilic

5
Q

Phospholipid tails are (hydrophilic / hydrophobic).

A

hydrophobic

6
Q

Due to the hydrophilic/phobic nature of the phospholipid heads and tails respectively, the lipids arrange themselves into a ___.

A

bilayer

7
Q

The cell membrane consists of embedded ___ and a phospholipid ___.

A

proteins , bilayer

8
Q

Is the phospholipid bilayer fluid or rigid?

A

Fluid

9
Q

All phospholipids are constantly ___.

A

moving

10
Q

What molecule helps to stabilise the fluid phospholipid bilayer?

A

Cholesterol

11
Q

What kind of molecule can pass through the phospholipid bilayer?

A

Small, uncharged polar molecules

12
Q

Water soluble substances (can / cannot) pass through the phospholipid bilayer.

A

cannot

13
Q

Name some substances which can pass through the phospholipid bilayer.

A

O2

H2O

CO2

14
Q

What are the two classes of membrane protein?

A

Integral

Peripheral

15
Q

What is another name for integral protein?

A

Transmembrane protein

16
Q

What is peripheral protein?

A

Protein which is not embedded in the membrane - adheres to cytoplasm instead

17
Q

What is integral protein?

A

Protein which spans the membrane one or more times

18
Q

Give some examples of types of integral protein.

A

Ligand-binding receptors

Adhesion molecules

Pores and channels

Carriers

Pumps

Enzymes

19
Q

Which cellular process do docking-marker acceptors help with?

A

Exocytosis of vesicles

20
Q

Apart from lipids and protein, what other molecule can be found on cell membranes in small amounts?

A

Carbohydrate

21
Q

When carbohydrate is bound to a) protein and b) lipid, what are those molecules called?

A

a) glycoproteins

b) glycolipids

22
Q

What layer is formed by glycoproteins and glycolipids on the surface of the cell membrane?

A

Glycocalyx

23
Q

What do membrane carbohydrates serve as on the cell membrane?

A

Self-identity markers

24
Q

What kind of molecule makes up self-identity markers on the cell membrane?

A

Carbohydrate

25
Q

Self-identity markers have an important role in cell-to-cell ___ and cell ___.

A

interactions , growth

26
Q

What are tight junctions?

A

Structures which join the lateral ends of epithelial cells together

27
Q

What are desmosomes?

A

Structures which anchor cells which stretch (e.g cardiac muscle, skin)

28
Q

What are gap junctions?

A

Communication junctions which allow the passage of ions between cells

29
Q

a) Structures which anchor stretchy cells
b) Structures which join the lateral ends of epithelial cells
c) Communication structures which allow for the passage of ions between cells

Match these definitions to tight junctions, desmosomes and gap junctions.

A

a) Desmosomes
b) Tight junctions
c) Gap junctions

30
Q

Overall, what are the three main molecules involved in the structure and function of the cell membrane?

A

Phospholipids (forming a bilayer)

Proteins

Carbohydrates