Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Cell membranes and transport > Flashcards

Cell membranes and transport Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What makes up the phospholipid bilayer (base of plasma membrane)?

A

Phospholipids, with hydrophilic phosphate heads and hydrophobic fatty acid tails, that are facing each other with the fatty acid tails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

How thick is the plasma membrane?

A

7-8nm thick

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Functions of cell membrane?

A

-Separates cell membrane from outside environment
-Regulates transport of nutrients into and out of cell
-They are receptor sites
-Recognition of pathogens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Functions of internal membranes?

A

-Separation of cell components
-Holding components for metabolic processes in place
-Chemical reactions e.g. ATP synthase in mitochondria

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why is the cell membrane considered a “fluid mosaic” model

A

The components are free to move with respect to each other

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What does a cell membrane look like underneath an electron microscope?

A

Double line

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Draw out a diagram of a plasma/ cell membrane (same thing)

A
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Position in membrane and role for intrinsic proteins?

A

Across the membrane, provide structural support, used for facilitated diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Two types of intrinsic proteins and roles?

A

Carrier proteins- Active transport (ATP required) or diffusion of
large polar molecules by molecule attaching to its a binding site and changing the shape, returning back to og after (similar to enzyme)
Channel proteins- Molecule with pores lined with polar groups that a specific to let one type of molecule through, smaller water-soluble molecules. They open and close

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the role of glycoproteins and glycolipids in the cell membrane?

A

Cell-to-cell communication and recognition, hormone receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is a glycocalyx?

A

Carbohydrate layer around membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the role of cholesterol in membrane?

A

Provides fluidity to membrane by fitting in between the fatty acid tails

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Is the cell membrane permeable or not?

A

It is selectively permeable

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does heat do to membrane and rate of diffusion?

A

More kinetic energy, more fluidity, more permeable for e.g. pigments, more diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does a larger SA and concentration gradient (difference in concentrations) do to rate of diffusion?

A

High rate of diffusion

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Thicker membrane means what to rate of diffusion?

A

Slower rate as greater diffusion distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Rate of diffusion equation

A

SA times difference n concentration divided by length in diffusion path

18
Q

What does the size and lipid solublitiy do to the rate of diffusion

A

Smaller= faster rate
More lipid soluble = faster rate

19
Q

High no. of protein channels does what to rate of diffusion?

A

High rate

20
Q

Definition of diffusion?

A

Movement of molecules from an area of high to low concentration down a concentration gradient

21
Q

Definition of water potential and its symbol?

A

Tendency for water to move out of a solution via osmosis
psi

22
Q

What has the highest water potential?

A

Pure water, which has 0

23
Q

Does -523 kPa solution or -83kPa have a bigger water potential?

A

-83kPa as

24
Q

Definition of osmosis?

A

Form of diffusion in which the water molecules move down the water potential gradient through a selectively permeable membrane

25
Q

Definition of facilitated diffusion

A

Diffusion of molecules or ions across membrane by protein carriers (passive process)

26
Q

How does active transport happen across a membrane?

A

-Molecule binds to specific carrier protein (think enzymes), on the outside of membrane
-ATP transfers phosphate group to carrier protein inside of membrane (energy supplied)
-Carrier changes shape and molecule is carried through
-Molecule and phosphate group released, ADP into ATP
-Protein back to og shape

27
Q

Definition of active transport

A

Movement of molecules from an area of low conc. to high conc. against the conc. gradient

28
Q

If a respiratory inhibitor is present, e.g. cyanide, what would happen to active transport and why?

A

Respiratory inhibitors prevent aerobic respiration and production of ATP, no ATP = no active transport
**this also means that more oxygen in cells = more ATP and more active transport

29
Q

What is cotransport and describe process?

A

Facilitated diffusion which brings two substance across the cell membrane together into a cell
e.g. glucose and sodium ions
-Both bind outside to carrier protein
-Carrier changes shape, glucose and sodium separately diffuse (glucose asses by facilitated diffusion, sodium is carried out of cell by active transport while potassium ions move into the cell)

30
Q

In what type of channel proteins does water move through?

A

Aquaporin (think aqua cause water, pore cause channel proteins have polar pores)

31
Q

If there is a higher concentration of solute (therefore a low concentration of water molecules) on one side of membrane then the other, would water molecules go into or out of the cell?

A

Into the cell as water goes to areas of higher solute concentration through osmosis down a concentration gradient
(think that the water is trying to equalise the concentrations)

32
Q

What is a hypertonic solution?

A

A solution what has a lower water potential compared to the cell cytoplasm. It has more solutes

33
Q

What is a hypotonic solution?

A

A solution what has a higher water potential compared to the cell cytoplasm. It has less solutes

34
Q

What is an isotonic solution

A

A solution what has a equal water potential compared to the cell cytoplasm. It has same concentration of solutes

35
Q

Equation for water potential

A

Pressure potential (always positive) + solute potential (always negative)

36
Q

More solutes = what to water potential?

A

Lower water potential

37
Q

What happens to an animal cell in hypertonic, hypotonic and isotonic solution?

A

Hyper- Animal cell is crenate (water moves out of cell)
Hypo- Cell bursts (lysis)
Iso- Normal as water leaves and enters at same rate

38
Q

What happens to a plant cell in hypertonic, hypotonic and isotonic solution?

A

Hyper- Cell expands and becomes turgid (water goes into cell, pressure is pushed outwards on cell wall)
Hypo- Cell shows incipient plasmolysis (cell membrane moves away from cell wall)
Iso- Cell is plasmolysed and becomes willed

39
Q

What is the pressure potential of cell when its 50% plasmolysis

A

0 (as cell membrane is pulled away from wall), meaning water potential = solute potential

40
Q

What is endocytosis and the two types?

A

Active process (ATP) of bulk movement of substances into cell
Phagocytosis- solids
Pinocytosis- liquids

41
Q

Describe the process of phagocytosis and draw it out

A

-Receptor bind to antigen on bacterium
-Membrane engulfs it and forms a phagosome (a spekil vesicle) and its absorbed by endocytosis
-A lysosome fusses and secrets digestive enzymes into the phagosome forming a phagolysosome
-Bacterium is digested and products are absorbed into cytoplasm

Biology (13 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions