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OCR A-LEVEL Biology > Module 2 Section 2 - Lipids > Flashcards

Module 2 Section 2 - Lipids Flashcards

1
Q

What are the three types of lipids we need to know

A

Triglycerides
Phospholipids
Cholesterol

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2
Q

What are triglycerides

A

Macromolecules

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3
Q

What is a macromolecule

A

Complex molecules with a relatively large molecular mass

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4
Q

What do all lipids contain

A

Carbon
Hydrogen
Oxygen

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5
Q

What is the structure of triglycerides

A

1 molecule of glycerol with 3 fatty acids attached to it

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6
Q

What are the structure of the fatty acids molecules

A

-Made of hydrocarbons
-long tails
-hydrophobic

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7
Q

What bonds do triglycerides contain

A

Ester bonds

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8
Q

Triglycerides are synthesised by the formation of ….

A

An ester bond between each fatty acid and the glycerol molecule

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9
Q

How did each ester bond formed

A

Condensation reaction

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10
Q

What happens in a condensation reaction

A

A water molecule is released

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11
Q

What is the process in which triglycerides are synthesised called

A

Esterification

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12
Q

How are ester bonds broken

A

Hydrolysis reaction (water molecule is used up)

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13
Q

What are the 2 types of fatty acids

A

Saturated
Unsaturated

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14
Q

What is the difference between saturated and unsaturated fatty acids

A

Their hydrocarbon tails

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15
Q

Saturated fatty acids don’t have any ….

A

Double bonds between carbon atoms - fatty acids is saturated with hydrogen

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16
Q

Unsaturated fatty acids have at least …

A

One double bond between carbon atoms which cause the chain to kink

17
Q

What are triglycerides mainly used for in animals and plants

A

energy storage molecules

18
Q

What do some bacteria use triglycerides as

A

To store energy and carbon

19
Q

Why are bacteria good for storage

A

Long hydrocarbon tails that contain lots of chemical energy
They are insoluble so water doesn’t enter the cells by osmosis

20
Q

What do the long tails of triglycerides allow

A

It allows lipids to contain about twice as much energy per gram as carbohydrates

21
Q

How does triglycerides repel/deter water from entering cells

A

They act as insoluble droplets in cells because fatty acid tails are hydrophobic - the tails face inward, shielding themselves from water with their glycerol heads

22
Q

Where are phospholipids found

A

Cell membranes of all eukaryotes and prokaryotes

23
Q

Phospholipids make up what in cell membranes

A

Phospholipid Bilayer

24
Q

Cell membranes control what enters and exits a cell how does a phospholipid do this

A

The head is phospholipids are hydrophilic and their tails are hydrophobic - they form a double layer with their heads facing out toward the water on either side

25
Q

How does the phospholipid bilayer allow the membrane to act as a barrier

A

The centre of the bilayer is hydrophobic meaning water-soluble substances can’t easily pass through

26
Q

What is the structure of cholesterol

A

It has a hydrocarbon ring attached to a hydrocarbon tail

27
Q

What is attached to the ring structure

A

A polar Hydroxyl group

28
Q

What does cholesterol do to eukaryotic cells

A

They help strengthen the cell membrane by interacting with the phospholipid bilyaer

29
Q

Phospholipids are also….

A

Macromolecules

30
Q

What is the structure of a phospholipid

A

1 molecule of Glycerol
2 Fatty acids attached to the glycerol
1 phosphate group attached to the glycerol

31
Q

The phosphate group is….

A

Hydrophilic

32
Q

The fatty acid tails are….

A

Hydrophobic

33
Q

What is said about cholesterols size and shape

A

Small size and flat shape

34
Q

What is the significance of the size and shape of cholesterol

A

The size and shape allows cholesterol to fit in between the phospholipid molecules in the membrane

35
Q

How does cholesterol help to make membranes less fluid and more rigid

A

They bind hydrophobic tails of the phospholipids, causing them to pack more closely.

OCR A-LEVEL Biology (48 decks)

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