2.2 Lipids Flashcards

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1
Q

What are organic solvents?

A

Solvents containing carbon, such as ethanol

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2
Q

What atoms are lipids made of ?

A

Carbon, hydrogen and oxygen. Like carbohydrates, but they have a higher proportion of hydrogen and lower proportion of oxygen.

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3
Q

What are lipids? Are they soluble or insoluble?

A

A diverse group of compounds that are insoluble in water but soluble in organic solvents

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4
Q

Why are lipids a good energy sources?

A

They contain twice the amount of energy as carbohydrates

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5
Q

Where are lipids stored?

A

Adipose tissue (fat)

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6
Q

What is adipose tissue used for?

A

Layers of fat around organs provide protection, such as around your kidneys. Fat can also provide warmth by reducing heat loss under skin.

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7
Q

When are fatty acids produced?

A

When fats in our food/diet are broken down

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8
Q

What are fatty acids used for?

A

They are essential for many things, for instance they are used in plasma membranes

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9
Q

If a fatty acid is monounsaturated what does it have?

A

It contains one double bond

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10
Q

If a fatty acid is polyunsaturated what does it have?

A

It contains many double bonds

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11
Q

What does it mean if a fatty acid is saturated?

A

It means it contains no double bonds

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12
Q

What molecules do fatty acids contain?

A

Carbon and hydrogen molecules

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13
Q

What type of chains do saturated fatty acids form and what does this mean about their attractions?

A

They form straight chains, consequently molecules can line up closely forming strong attractions between all molecules

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14
Q

Due to strong attractions what do saturated fatty acids have, and why?

A

They have high melting points as a lot of energy is needed to overcome the attractions

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15
Q

What state are saturated fatty acids at, at room temperature?

A

They tend to be solid at room temperature

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16
Q

What are triglycerides and what are they used for?

A

The are a type of lipid used for energy storage, insulation and protection.

17
Q

Where are triglycerides found?

A

In fatty tissues under skin and layers of fat surrounding organs to provide protection

18
Q

What does a triglyceride consist of?

A

A glycerol backbone and 3 fatty acids

19
Q

Are triglycerides soluble or insoluble in water?

A

They are insoluble

20
Q

What reaction occurs to form a triglyceride and what bond is formed?

A
  • a condensation reaction (water is lost)

* an ester bond is formed

21
Q

What is another name for this process?

A

Esterification

22
Q

What does the structure of a phospholipid consist of?

A

A phosphate group, a glycerol head and two fatty acid tails

23
Q

Is a phospholipid hydrophilic or hydrophobic?

A

It is amphipathic, both hydrophilic and hydrophobic

24
Q

What part of a phospholipid is hydrophilic?

A

The phosphate group

25
Q

What does hydrophilic mean?

A

It loves water

26
Q

What part of a phospholipid is hydrophobic?

A

The fatty acids

27
Q

What does hydrophobic mean?

A

It doesn’t like water

28
Q

What does the phospholipid do in water and why?

A

It forms a double bilayer spontaneously in water otherwise the fatty acids would have to be in contact with water

29
Q

What do phospholipids play a key role in?

A

Forming cell membranes as they are able to separate the aqueous environment

30
Q

What are sterols?

A

Lipids that are neither fats nor oils

31
Q

What are sterols otherwise known as?

A

Steroid alcohols

32
Q

Give an example of a sterol:

A

Cholesterol

33
Q

What happens when sterols react with water?

A

They are amphipathic; the hydroxyl group in sterols are polar as it is attracted to water

34
Q

Where is cholesterol made and what role does it play?

A

It is made in the liver and intestines, it plays an important role in the formation of the cell membrane, it becomes positioned between the phospholipids adding stability to the cell

35
Q

What does cholesterol do?

A

It regulates cell membrane fluidity:
• it keeps them fluid at low temperatures (stops them freezing)
• it stops them becoming too fluid at high temperatures

36
Q

What are made using cholesterol?

A

Vitamin D, steroid hormones and bile

37
Q

What are the roles of lipids?

A
  • membrane formation
  • hormone production
  • electrical insulation (fatty sheath)
  • waterproofing (birds feathers)
  • energy storage
  • thermal insulation