Biological Molecules

Question 1

Are all molecules carbon based?

Answer 1

Biological molecules are carbon based except for some inorganic molecules

Question 2

What roles do small molecules often play ?

Answer 2

As building blocks for macromolecules and as some other specific function in their own right

Question 3

What is the Composition of a cell?

Answer 3

Water 70%
Inorganic ions 1%
Small organic molecules 3%
Macromolecules 26%

Question 4

What is the general formula for sugars ?

Answer 4

(CH2O)n

Question 5

What are some functions of carbohydrates?

Answer 5

Energy storage , fuel, metabolite and structural element

Question 6

What are the two types of monosaccharides?

Answer 6

Ketone based or aldehyde based

Question 7

What does it mean for a carbon atom to have a chiral centre?

Answer 7

The molecules can make mirror images of each other,can never superimpose so therefore are enantiomers

Question 8

State the location of the ketone/aldehyde group in the D configuration of glucose

Answer 8

The aldehyde/ketone group will be most distant from the asymmetric c-atom

Question 9

Condensation reaction

Answer 9

One molecule of H2O is released for every bond formed in a reaction

Question 10

Why can we not break down cellulose?

Answer 10

Cellulose contains 1-4 beta glycosidic bonds which we cannot break down

Question 11

How does glycogens structure help its function?

Answer 11

Glycogen is branched and therefore able to form 1-6 bonds aswell as 1-4 ,enabling more molecules of sugar to be packed together in one space.

Question 12

What is an oligosaccharide ?give an example

Answer 12

Polysaccharide with different types of monosaccharides

Eg: blood group

Question 13

What triggers the breakdown of glycogen and what does it break down into?

Answer 13

Tyrosine triggers the breakdown into adrenaline

Question 14

How is histidine converted into histamine ?

Answer 14

Histidine is converted into histamine through the loss of CO2 in a vasodilator

Question 15

What makes up a nucleotide ?

Answer 15

Sugar,phosphate and base

Question 16

Why is sugar-phosphate binding important ?

Answer 16

Creates chains which are needed when DNA forms a double helix .
In a DNA helix,chains are going anti-parallel from 5’ end to the 3’ end

Question 17

Why is Adenosine 3’,5’-cyclic monophosphate(cAMP) important?

Answer 17

It is essential for blood pressure regulation

Question 18

What is Adenosine 5’ -monophosphate(AMP) involved in?

Answer 18

RNA synthesis

Question 19

What produces more ATP ,fats or glucose?

Answer 19

Fats produce significantly more ATP than glucose on its own

Question 20

Where do you find saturated fats(unhealthy) ?

Answer 20

Found predominantly in animal fats that we consume within our diets

Question 21

Why are saturated fats considered healthy fats?

Answer 21

A reactive metabolite would react with the fatty acid , breaking the double bond . Providing an energy source from that , metabolite and can then be reabsorbed by the fatty acid instead of going elsewhere

Question 22

Describe a triglyceride

Answer 22

One glycerol reacting with 3 fatty acids joined by an ester bond .releasing one molecule of water per bond

Question 23

Describe a phospholipid

Answer 23

One glycerol , two fatty acid chains and one phosphate group and one head group

Question 24

Give some functions of lipids

Answer 24

Phospholipid bilayer
Liposome
Micelle(fats transported throughout the body )
Bilayer sheet

Question 25

What is cholesterol?what enables it to intercalated into the membrane?

Answer 25

A steroid

Different components of its structure

Question 26

What parts of cholesterol do the phospholipids react with?

Answer 26

Oh group reacts with polar head and steroid scaffold reacts with fatty acids

Question 27

Why is cholesterols role in the membrane so important ?

Answer 27

Cholesterol decreases fluidity and increases flexibility of the membrane .
It reduces permeability for soluble molecules and helps stabilise the membrane with transmembrane proteins which help increase rigidity

Question 28

Diabetes (insulin dependant)

Answer 28

Absence of a protein hormone (insulin)leads to failure to regulate blood glucose

Question 29

Sickle cell disease

Answer 29

One amino acid change (glutamic acid to a valine) in a gloving chain causes haemoglobin to aggregate into polymers -changes red blood cell nick cave disc to moon shape

Question 30

Cystic fibrosis

Answer 30

Absence of a membrane protein that transports chloride leads to altered properties of secretions