Unit 2 - Lipids Flashcards Preview

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Flashcards in Unit 2 - Lipids Deck (33)
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1
Q

What are the 3 types of lipids?

A
  • Triglycerides
  • Phospholipids
  • Sterols
2
Q

What are the 5 functions of triglycerides?

A
  • Major source of energy
  • Source of metabolic water
  • Makes up adipose tissue
  • provides thermal insulation under skin of animals
  • Provides protection around internal organs
3
Q

How do triglycerides compare to carbohydrates in terms of energy?

A

-Per g triglycerides release more energy

4
Q

Being a source of metabolic water makes them useful for organisms in what kind of environment?

A

Desert

5
Q

Give an example of an animal that uses triglycerides as thermal insulation

A

Killer whale in the form of blubber

6
Q

When are triglycerides stored as adipose tissue?

A

When energy input is greater than energy output

7
Q

Why is cholesterol transported as a lipoprotein?

A

They allow lipids and cholesterol to dissolve in the blood

8
Q

What are the functions of sterols (2 functions)?

A

-Cholesterol used in cell membranes to give stability and regulate fluidity -Used to make steroid hormones

9
Q

Give 2 examples of steroid hormones

A

Testosterone and oestrogen

10
Q

Where is cholesterol manufactured?

A

The liver and intestines

11
Q

What is the function of HDL?

A

-used to make cell membranes and organelle membranes -decreases membrane fluidity

12
Q

Which is ‘good’ cholesterol; HDL or LDL?

A

HDL

13
Q

What does too much LDL lead to?

A

-atherosclerosis (deposits in artery walls) -gall stones

14
Q

How are triglycerides formed?

A

A condensation reaction between a glycerol molecule and 3 fatty acids

15
Q

What kind of bonds are formed when a triglyceride is formed?

A

Ester bonds

16
Q

Which part of a glycerol molecule takes part in the condensation reaction to form a triglyceride?

A

The hydroxyl groups

17
Q

What is the structure of a glycerol molecule?

A
18
Q

How many molecules of water are formed from the condensation reaction to form a triglyceride?

A

3

19
Q

What does a hydrolysis reaction of a triglyceride produce?

A

A glycerol molecule and 3 fatty acids

20
Q

i) How are phospholipids formed? ii) What kind of bonds are formed?

A

i) A condensation reaction between a glycerol molecule, 2 fatty acids, and a phosphate group ii) Ester bonds

21
Q

What property does the head of a phospholipid have?

A

It is hydrophillic and polar

22
Q

What property does the tail for a phosphlipid have?

A

It is hydrophobic and non-polar

23
Q

Explain the differences between phospholipids and triglycerides

A

-Triglycerides contain 3 fatty acids but phospholipids only contain two and a phosphate group - Triglycerides contain 3 ester bonds but phospholipids only contain 2 - Phospholipids have a hydrophilic head

24
Q

Draw a simplified version of a phospholipid

A
25
Q

Draw a phospholipid bilayer

A
26
Q

Explain why membranes exist as bilayers

A

-Both the inside and outside of cells are aqueous -therefore a single layer would repel on one side -Bilayers mean that hydrophilic heads can face into the tissue fluid and cytoplasm -with the hydrophobic tails facing away from the aqueous environments

27
Q

How does cholesterol sit in phospholipid bilayers?

A

With the hydroxyl group in contact with the Phosphate head

28
Q

What are sterols made up of?

A

Large alcohol molecules

29
Q

As cholesterol increases membrane fluidity ____

A

Decreases

30
Q

A decrease in cholesterol ____ fluidity

A

Increases

31
Q

How can you test for the presence of lipids?

A

Add ethanol first and then the resulting mixture add to water and shake

32
Q

State two roles of cholesterol in living organisms

A

1) Increases stability of phospholipds in cell membrane 2) Waterproofing to skin

33
Q

Name two molecules that combine with cholesterol to form LDLs

A

1) Saturated fatty acids 2) Triglycerides/lipids