M1:04 Lipids

Question 1

What percentage of organic matters in cells are lipids?

Answer 1

5%

Question 2

What is a lipid called as a solid and as a liquid?

Answer 2

solid; fatliquid; oil

Question 3

What functions do lipids have within living functions?

Answer 3

-source of energy- energy storage-forms membranes- insulation-protection-hormones

Question 4

How does lipids act as a source of energy?

Answer 4

lipids can be release energy to generate ATP

Question 5

How does lipid act as an energy store?

Answer 5

lipids are stored in adipose cells in ‘fat stores’

Question 6

Give an example of how lipids act as insulation

Answer 6

the blubber in whales is lipid that reduces heat loss; lipids also provide electrical insulation around long nerve cells.

Question 7

Give an example of how lipids act as a form of protection?

Answer 7

the surface (cuticle) of plant leaves is protected against drying out by a layer of lipid.

Question 8

Give an example of a lipid hormone

Answer 8

steriod hormones

Question 9

Where are glycerol and fatty acids found?

Answer 9

in all the fats and oils that perform roles in energy storage and energy supply

Question 10

Which fattys acids cant animals make the fatty acids they need from raw materials?

Answer 10

essential fatty acids which are taken in ‘complete’ as part of a balanced diet

Question 11

Name the main difference between glycerol and fatty acids

Answer 11

glycerol molecules are always the same but fatty acid molecules differ considerably as they have different length hydrocarbon chains

Question 12

Describe a fatty acid molecule

Answer 12

They have an acid group at one end which is always the same as that found on an amino acid.There is a hydrocarbon chain which differs in the amount of carbons (2-20)

Question 13

What is the range of carbons that can be found in a fatty acid tail?

Answer 13

2-20

Question 14

What is the most common number of carbons in a hydrocarbon fatty acid tail

Answer 14

18

Question 15

What is the main cause of an unhealthy diet?

Answer 15

too much unsaturated fat

Question 16

What is often associated with healthier foods in terms of lipids?

Answer 16

unsaturated/ polysaturated

Question 17

What is a lipid?

Answer 17

a diverse group group of chemicals that dissolve in organic substances such as alcohol but not in waterThey include fatty acids, triglycerides and cholesterol

Question 18

Give 3 examples of fatty acids

Answer 18

fatty acids, triglycerides and cholesterol

Question 19

Give an example of a product that lipids do and dont dissolve in

Answer 19

do; alcohol dont; water

Question 20

What does the term ‘saturated fat’ refer to?

Answer 20

whether the hydrocarbon chain is ‘saturated’ with hydrogen or not. (if all possible bonds are connected with hydrogen then it is saturated)

Question 21

What do unsaturated fatty acids have that means fewer hydrogen atoms can be bonded to the molecule?

Answer 21

C=C bonds

Question 22

What does a single C=C double bond in a fatty acid tail form/

Answer 22

a mono-unsaturated fatty acid

Question 23

What is a poly-unsaturated fatty acid?

Answer 23

Two or more C=C double bonds in the fatty acid tail

Question 24

What does the C=C double bond affect in a fatty acid?

Answer 24

the shape of the hydrocarbon chain- as it makes the molecules in a lipid push apart from each other, making it more fluid

Question 25

Which are often oils and which are often fats (saturated/unsaturated)

Answer 25

oil; unsaturatedfat; saturated

Question 26

What is animal fats mainly made up of?

Answer 26

saturated fats

Question 27

Is animal lipid lard and plant lipid olive oil liquid or solid at room temp

Answer 27

animal; solidplant; oil

Question 28

Why do fatty acid tails appear to have kinks?

Answer 28

because of the double bond that forms

Question 29

What does a triglyceride consist of?

Answer 29

one glycerol molecule bonded to 3 fatty acid molecules.

Question 30

How are fatty acid tails joined to the glycerol?

Answer 30

via a condensation reaction between between the acid group of a fatty acid molecule and one of the OH (hydroxyl) groups of the glycerol molecule

Question 31

What is the bond known as between the glycerol and fatty acid tail? and what is the new molecule produced called?

Answer 31

an ester bonda monoglyceride between two, or triglyceride between 3

Question 32

Are triglyceride molecules soluble in water?

Answer 32

no, they are considered to be hydrophobic (as the charges on the molecules are distributed evenly)

Question 33

What is a phospholipid molecule almost identical to/

Answer 33

a triglyceride molecule

Question 34

Describe a phospholipid molecule

Answer 34

It consists of a glycerol molecule bonded by ester bonds (via a condensation reaction) with fatty acid molecules (2 tails)

Question 35

What is the difference between a phospholipid molecule and a triglycerol molecule

Answer 35

phospholipids only have 2 fatty acid tails and the third OH is bonded to a phosphate group

Question 36

Which parts of a phospholipid is hydrophobic and which is hydrophilic?

Answer 36

the phosphate head is hydrophilicfatty acid tail is hydrophobic

Question 37

Why is it helpful that most of a phospholipid molecule doesn't dissolve?

Answer 37

as it helps some of its characteristics, such as forming membranes

Question 38

Can a phospholipid molecule be both saturated or unsaturated?

Answer 38

Yes

Question 39

How do organisms adapt their fatty acid molecules to correspond with their surroundings, using an example

Answer 39

organisms living in a colder environment have an increased number of unsaturated fatty acids to ensure that their membranes remain fluid, despite the cold temperatures

Question 40

What does the respiration of lipids require to begin?

Answer 40

a hydrolysis reaction to occur to break the ester bonds between the phosphate head and the fatty acid tails

Question 41

Describe the respiration of a lipid molecule

Answer 41

- a hydrolysis reaction to occur to break the ester bonds between the phosphate head and the fatty acid tails- Then the glycerol and fatty acid tails are broken down completely into glucose and water which releases energy that is used to generate ATP molecules

Question 42

What is the ratio between the amount of energy given out by respiration of a lipid and a carbohydrate?

Answer 42

2;1

Question 43

Why is triglycerol so good for storing energy?

Answer 43

As lipids are insoluble in water so they can be stored in a compact way and dont affect the water potential of the cells contents.

Question 44

How is cholesterol made up?

Answer 44

4 carbon-based rings

Question 45

Describe a cholesterol molecule

Answer 45

its found in all membranes, and has a small narrow structure which sits between the hydrocarbon tails due to its hydrophobic nature

Question 46

Where are cholesterols found and what is its role their/

Answer 46

found between the fatty acids tails, to regulate the fluidity and strength of the membrane

Question 47

Give 3 examples of steroid hormones that are made of cholesterol.

Answer 47

testosterone oestrogen vitamin D

Question 48

Why are steroid hormones so successful (in terms of their structure and function together)(

Answer 48

As they can pass through phospholipid bilayers to reach their target receptor/site, including the nuclear envelope

Question 49

Why can excess cholesterol be a problem?

Answer 49

as in bile, cholesterol stick together and form lumps called gallstonesin blood, cholesterol can be deposited in the inner linings of blood vessels causing atherosclerosis, which can result in a number of circulatory problems

Question 50

Whats is FHC?

Answer 50

familial hypercholesterolaemia, which is a genetic disorder where cells manufacture and secrete cholesterol even though there is already enough in the blood to provide for the organisms requirements

Question 51

When does FHC occur?

Answer 51

When cells do not obey the signals to stop cholesterol production as they lack a particular cell surface receptor.

Question 52

What affect does FHC have on a person?

Answer 52

Can cause heart attacks and strokes by the age of two years.

Question 53

What is the structure, main role and other features of triglyceride?

Answer 53

st; glycerol plus 3 fatty acids mr; compact energy store, and insoluble in water so doesnt affect the water potentialof; stored as fat, which also has thermal insulation and protective properties

Question 54

What is the structure, main role and other features of a phospholipid molecule

Answer 54

str; glycerol plus 2 fatty acid and a phosphate group mr; forms a molecule that is part hydrophobic and part hydrophillic, making it ideal for the basis of cell surface membranes of; used to form steroid hormones