Biomolecules

Question 1

What are the X4 main groups of biomolecules?

Answer 1

1) amino acids
2) sugars
3) nucleotides
4) fatty acids

Question 2

What blood test looks at glycosylated haemoglobin?

Answer 2

HBA1c

Question 3

What is the Fischer projection?

How would you determine a D or L sugar from this projection?

Answer 3

It draws sugars in a linear form, with the most oxidised carbon at the top.

For D sugars, the OH group on lowest chiral centre carbon will be on the right hand side of the chain.

L sugars have the OH group on the left.

Question 4

What type (D or L) of sugars and amino acids do humans use?

Answer 4

D-sugars

L-amino acids

Question 5

What percentage of hexoses are in linear form at any one time?

Answer 5

<1%

Question 6

What are the X2 forms of glucose that exist?

How are they different?

Answer 6

1) Alpha
= has the H on carbon 1 above

2) Beta
= has the H on carbon 1 below

Question 7

What percentage of glucose is in the alpha or beta form at any one time?

Answer 7

They interconvert all the time between alpha to open chain to beta and back again…

Question 8

What are the X3 monosaccharide sugars?

Answer 8

1) glucose
2) lactose
3) fructose

Question 9

What are the X3 disaccharide sugars and which monosaccharides bind to form these?

Answer 9

1) maltose = alpha glucose + alpha glucose
2) galactose = glucose + lactose
3) sucrose = glucose + fructose

Question 10

What bond links glucose in glycogen?

Answer 10

Alpha 1-4 glycosidic bonds with alpha 1-6 glyocosidic bond branches

Question 11

Which enzyme is located at the brush boarder of the small intestine for glycogen breakdown when it has been broken down into a disaccharide?

Answer 11

Maltase

Question 12

Explain lactose intolerance?

Answer 12

A lack of the lactose enzyme in the small intestine.

This means galactose travels through the small intestine without being broken down and can be digested by bacteria in the large intestine which produces CO2, hydrogen and methane.

Question 13

What are the X3 components of a mononucleotide?

Answer 13

1 = pentose sugar
2 = nitrogenous base
3 = phosphate group

Question 14

What are the X2 classes of bases?

Which bases belong to each of these?

Answer 14

Purines
= adenine
= guanine

Pyramidines
= cytosine
= thymine

Question 15

What are the X2 types of pentose sugar and which is used in:

• DNA
• RNA

Answer 15

DNA = deoxyribose

RNA = ribose

Question 16

What bond links nucleotides to form polynucleotides?

Answer 16

Phosphodiester bonds between the phosphate of one nucleotide and the pentose sugar of another

Question 17

What is the orientation and structure of the X2 strands of DNA?

Answer 17

They run anti parallel in a double helix

Question 18

Which bases undergo complementary base pairing?

How many bonds does each pair make?

Answer 18

A — T = X2 bonds

G — C = x3 bonds

Question 19

What does the 3 or 5 prime end of a DNA strand actually refer to?

Answer 19

It refers to the number of the carbon in the sugar molecule at that end of the strand.

Question 20

What are the x3 types of RNA?

What is the function of each?

Answer 20

1) mRNA
= a copy of a gene which enables the genes code to be copied to the ribosome for translation

2) rRNA
= structural component for ribosomes

3) tRNA
= transports amino acids for protein synthesis

Question 21

What is gene expression?

Answer 21

The process by which information from a gene is used to synthesis a gene product

Question 22

What are the X2 stages of gene expression?

Answer 22

1) transcription
= forming mRNA

2) translation
= synthesis of a protein based on the mRNA

Question 23

What is the structure of a TAG?

What bonds are formed in the synthesis of a TAG?

Answer 23

X1 glycerol molecule

X3 fatty acid chains

Ester bonds

Question 24

What is the structure of a phospholipid?

Answer 24

X1 glycerol molecule

X2 fatty acids chains

X1 phosphate group

Question 25

What is the name of the property of phospholipids whereby they are polarised and have a both hydrophobic and hydrophilic parts?

Answer 25

Ampipathic