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Biology > Topic 3- Transport in membranes > Flashcards

Topic 3- Transport in membranes Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

What are cell membranes composed of?

A

Phospholipid bilayer, proteins, glycoprotein, glycolipids

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2
Q

What is the fluid mosaic model?

A

Fluid refers to the components as constantly moving

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3
Q

What substances would not be able to pass through the cell surface membrane?

A

Polar, charged, large molecules, water soluble

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4
Q

What substances would be able to pass through the cell surface membrane?

A

Non-polar, uncharged, small molecules, lipid soluble

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5
Q

Describe the phospholipid bilayer.

A

The hydrophobic tails face each other
The hydrophilic heads turn towards the water

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6
Q

Why do proteins allow the transport of some substances?
What substances would be able to move?

A

Proteins have hydrophilic channels in the middle
Glucose, polar, small

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7
Q

What are the functions of intrinsic proteins?

A

Transport- channel/carrier proteins

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8
Q

What are the functions of extrinsic proteins?

A

Enzymes
Receptors
Antigens

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9
Q

What are glycoproteins?

A

Carbohydrate chains attached to proteins

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10
Q

What is the function of glycoproteins?

A

Receptors for hormones
Antigens

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11
Q

What are glycolipids?

A

Carbohydrate covalently bonded to a lipid

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12
Q

What is the function of glycolipids?

A

Act as recognition sites
Help maintain the stability of membrane

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13
Q

What is the function of cholesterol?

A

Restricts movement of components in the cell membrane
Help keeps cell membrane strong and rigid by making it less flexible
Prevents loss of water and dissolved ions

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14
Q

Define simple diffusion

A

Movement of particles down a concentration gradient

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15
Q

What 6 factors affect the rate of diffusion?

A

Temperature
Surface Area
Concentration gradient
Size of diffusing molecule
Thickness of exchange surface
Water solubility

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16
Q

What is Fick’s Law?

A

surface area x difference in concentration gradient/ thickness of exchange surface

17
Q

How can the diffusion rate be increased?

A

Increase the surface area
Increase the concentration gradient
Short diffusion pathway

18
Q

Define facilitated diffusion

A

Passive process
Uses carrier proteins/channels
Transport charged/polar molecules
Down a con gradient
Limited to number of carrier proteins (saturated)

19
Q

Define osmosis

A

Movement of water molecules from a high water potential to a low water potential across a partially permeable membrane

20
Q

Define active transport

A

Movement of substances against a concentration gradient
Requires ATP
Requires carrier protein

21
Q

What is the unit of pure water?

A

0kPa

22
Q

What is endocytosis?

A

Movement of large amounts of material into the cell
Transported via vesicles (made from plasma membrane)

23
Q

What is exocytosis?

A

Movement of large amounts of material out of the cell
Transported via vesicles (made from plasma membrane)

24
Q

What are the two groups of lipids?

A

Triglycerides and phospholipids

25
Q

How are triglycerides formed?

A

Condensation reaction between one molecule of glycerol and three molecules of fatty acids
Bonds between the -OH group of glycerol and the -COOH group of the fatty acid are called ester bonds.
3 molecules of water are also released

26
Q

Why are lipids insoluble in water?

A

The hydrocarbon chains of fatty acids are hydrophobic so repel water molecules.

27
Q

What is the structure of glycerol?

A

Contains 3 hydroxyl -OH groups

28
Q

What is the structure of a fatty acid?

A

They are made up of a carboxylic acid group (-COOH) and a hydrocarbon chain of varying lengths.

29
Q

What are the two kinds of fatty acids?

A

Saturated- single bonds between carbon atoms
Unsaturated- double bonds between carbon atoms

30
Q

What are the lipids found in cell membranes called?

A

Phospholipids

31
Q

What is the structure of a phospholipid?

A

One glycerol molecule bonded to two fatty acids and a phosphate group held together by ester bonds

32
Q

What are the properties of triglycerides?

A

Insoluble
Storage molecule
Source of energy

33
Q

Explain the properties of triglycerides.

A

Insoluble- fatty acid tails are hydrophobic = prevents osmotic lysis
Storage molecule- due to the large ratio of energy storing carbon-hydrogen bonds compared to carbon atoms

34
Q

What are the properties of phospholipids?

A

Bilayer of cell membrane- hydrophilic (glycerol and phosphate group) head and hydrophobic (fatty acid) tail

35
Q

What is the emulsion test for lipids?

A

Dissolve in alcohol
Pour into water
+ result = milky emulsion should appear

Biology (16 decks)

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