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Biology - Unit 1 > LIpids > Flashcards

Flashcards in LIpids Deck (23):
1

What are triglycerides composed of?

Three fatty acids linked to a glycerol molecule

2

What is the structure of glycerol?

Three carbon backbone, each carbon bonded to an OH group. The rest of the bonds are occupied by hydrogen?

3

What group do carboxylic acids have attached?

COOH

4

What is the difference between saturated and unsaturated fats?

Saturated fats contain no double bonds.

5

What bond is formed between the fatty acid and glycerol?

Ester bond

6

What type of reaction is esterification?

Condensation

7

Why are unsaturated fats oils at room temperature?

The double bonds prevent the chains packing closely together.

8

What is the difference between a triglyceride and a phospholipid?

There is a phosphate group in the place of a fatty acid

9

Give an example of a charged group which may be attached to the phosphate

Choline

10

What does the head of a phospholipid consist of?

The phosphate and choline groups

11

Why are the head groups the head groups hydrophilic?

Both of the groups are electrically charged. They are attracted to water

12

Why is the tail of a phospholipid considered hydrophobic?

The fatty acids are uncharged and non-polar, which makes them hydrophobic. They are repelled by water.

13

Why does the membrane form a bilayer?

The hydrophilic heads stay in contact with the cytosol and the hydrophobic tails stay in the middle of the bilayer, away from the water.

14

How do the unsaturated fatty acids keep the membrane fluid.

Prevent phospholipids packing closely together.

15

What structure do steroids have?

They have a four ring structure of 17 carbons.

16

How do steroids vary?

There are different side chains attached to the structure.

17

What role do steroids have?

They play a role in signalling as hormones.

18

How is it that can steroids diffuse across membranes and bind to receptors inside cells.

They are hydrophobic.

19

Can you name two steroids?

Testosterone and cholesterol

20

What is the structure of Cholesterol?

OH group at the bottom left and a C8H17 group on the top right.

21

What is the structure of testosterone?

Double bonded oxygen bottom left and an OH on the top right.

22

What is the role of testosterone?

It plays a large part in male puberty and muscle development.

23

What does cholesterol do?

It fits into the the hydrophobic part of the phospholipid bilayer and reduces phospholipid movement in the membrane. It also prevents solidification of the membrane at low temperatures.