B2 Cell transport systems Flashcards

1
Q

Define diffusion?

A

The movement of a substance from a high concentration to a lower concentration

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2
Q

Give two differences between active transport and facilitated diffusion.

A

Active transport requires energy/ATP whereas facilitated diffusion is passive. Active transport moves substances against the concentration gradient whereas facilitated diffusion moves substances down the concentration gradient.

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3
Q

Give a similarity between active transport and facilitated diffusion.

A

Both use carrier proteins.

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4
Q

Which type of molecule can diffuse across the phospholipid bilayer?

A

Non-polar or lipid soluble molecules.

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5
Q

Through what structure do water soluble molecules cross the membrane?

A

Through channel proteins/aquaporins

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6
Q

Which part of the phospholipid is hydrophobic?

A

Fatty acid tail.

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7
Q

Protein molecules found on the surface of the membrane are called …

A

Extrinsic proteins

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8
Q

Give 2 differences between a triglyceride and a phospholipid.

A

Phospholipids contain a phosphate group whereas triglycerides do not.

Phospholipids have 2 fatty acids whereas triglycerides have 3 fatty acids.

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9
Q

What is the function of the carbohydrates found on the outer surface of the membrane?

A

Antigens

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10
Q

Each carrier protein can transport …. type of molecule.

A

One

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11
Q

Name the two carbohydrate containing chemicals found in cell membranes.

A

Glycoproteins and glycolipid.

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12
Q

What effect does cholesterol have on the fluidity of the membrane?

A

Reduces the fluidity/movement of phospholipids in the membrane.

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13
Q

How can the structure of the membrane be changed to make the diffusion of water soluble molecules more rapid?

A

Increase number of channel proteins Increase surface area.

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14
Q

Give three ways in which the rate of gas exchange can be increased.

A

Increase the surface area.
Increase the concentration gradient.
Decrease the diffusion pathway/distance Increase the temperature

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15
Q

Why is the term fluid mosaic used to describe the model for membrane structure?

A

Fluid - phospholipid move within the membrane.
Mosaic - proteins form blocks on the surface of the membrane.

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16
Q

Define osmosis

A

Net movement of water from a high water potential to a lower water potential through a selectively/partially permeable membrane.

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17
Q

Name a chemical that moves by osmosis into cells.

A

Water

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18
Q

Name 2 molecules that move into cells and are used in respiration.

A

Oxygen and glucose

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19
Q

What happens to ATP during active transport?

A

It is hydrolysed.
A phosphate group is removed. Allowing the release of a small amount of energy.

20
Q

Name the components of a cell surface membrane

A

Phospholipids
Proteins (extrinsic and intrinsic)
Glycoproteins
Glycolipids
Cholesterol

21
Q

What are the functions of the phospholipids in the cell membrane

A

Allow non-polar molecules cross the membrane
Prevent polar molecules crossing the membrane
Makes membrane flexible and self healing

22
Q

What are the functions of proteins in the cell membrane?

A

Provide structural support
Act as channels to transport polar molecules/facilitated diffusion

23
Q

What is the function of cholesterol in the cell surface membrane?

A

Reduces lateral movement of molecules in the membrane
Acts as a buffer against temperature changes
Prevent leakage of water and dissolved ions from the cell

24
Q

What are the functions of glycoproteins in the cell surface membrane?

A

Act as recognition sites for hormones and neurotransmitters
Help cells attach and form tissues

25
Q

What happens to red blood cells if placed in pure water?

A

Swell and burst/undergo lysis

26
Q

What happens to a red blood cell placed in a strong sugar solution?

A

Shrinks

27
Q

Define active transport

A

The movement of molecules or ions against a concentration gradient using ATP and carrier proteins.

28
Q

What is the role of ATP in active transport?

A

Provide the energy needed to transplant a molecule against its concentration gradient.
ATP binds to carrier protein, ATP is hydrolysed causing the protein to change shape, allowing the entry of the molecule/ion

29
Q

Name the molecule shown in the diagram

A

Triglyceride

30
Q

Name the components of this triglyceride

A

Glycerol

3 Fatty acids

31
Q

Name the structure shown on the diagram

A

Phospholipid bilayer

32
Q

Name the molecule shown on the diagram

A

Phospholipid

33
Q

Name the components of a phospholipid

A

Glycerol

2 fatty acids

1 phosphate

34
Q

Describe the structure of this fatty acid

A

Monounsaturated fatty acid

One Carbon carbon double bonds in the hydrocarbon

35
Q

Describe this phospholipid

A

Polyunsaturated

More than one carbon carbon double bond in the hydrocarbon

36
Q

Name the structure shown on the diagram

A

Cell membrane

OR

Plasma membrane

37
Q

Name structure G

A

Channel Protein

38
Q

Name structure F

A

Extrinsic protein

OR

Carrier protein

39
Q

Name structure E

A

Cholesterol

40
Q

Name structure B

A

Glycolipid

41
Q

Name the molecule shown in the diagram

A

Steroid

OR

Oestrogen

42
Q

Name two steroids

A

Oestrogen

AND

Testosterone

43
Q

Give three functions of lipids in humans

A

Energy storage

Heat insulation

Protection of vital organs eg kidney

44
Q

Name two ways in which red blood cells can be classified

A

ABO system

AND

Rhesus system

45
Q

Proteins and lipids in membranes can be glycosylated.
What does this mean?

A

Carbohydrates are added to them.