Lecture 4

Question 0

Type and percentage of atomic constituents of the human body (4) C.H.O.N

Answer 0

Oxygen = 65.0%

Carbon = 18.5%

Hydrogen = 9.5%

Nitrogen = 3.2%

Question 1

Composition of typical prokaryotic cell (4)

Answer 1

Water = 70%

Nucleic acid = 7%

Lipids = 2%

Inorganic ions = 1%

(Protein = 15%

Carbohydrates = 3%

Other small molecules = 1%)

Question 2

Molecular building blocks and their respective higher order structures (Macromolecules, Supramolecular assemblies & Organelles) (NB: With the exception of lipids)

Answer 2

1) Building blocks

• amino acids
• nucleobases
• simple carbohydrates
• lipids (non-polymeric biomolecule)
  2) Macromolecules
• proteins
• DNA & RNA (nucleic acid)
• complex carbohydrates (polysaccharides)
  3) Supramolecular assemblies
• membrane
• ribosomes
• chromatin
  4) Organelles
• nucleus
• mitochondria
• Golgi apparatus
• endoplasmic reticulum (SER & RER)

//lipids do not form higher order structures or polymeric molecules as they are very different in structure and therefore are not made by the same building blocks//

Question 3

Identify this structure:

Answer 3

Glucose

Question 4

Identify this structure:

Answer 4

Galactose (left side OH on top)

Question 5

Identify the disaccharide:

Answer 5

Glucose + Fructose = Sucrose

Question 6

Identify the disaccharide:

Answer 6

Galactose + Glucose = Lactose

Question 7

Identify the disaccharide

Answer 7

Glucose + Glucose = Maltose

Question 8

Identify the following Polysaccharides

Answer 8

1. Starch - Plant carbohydrate
   (glucose monomers linked
   with α1,4 glycosidic bonds)
2. Glycogen - Animal carbohydrate
   (glucose monomers linked
   with α1,4 glycosidic bonds)
3. Cellulose (Fiber) - Plant carbohydrate
   (glucose monomers linked
   with β1,4 glycosidic bonds)

Question 9

These are all structures of which monomer

Answer 9

Glucose

Question 10

Glucose isomers

Answer 10

(Alpha = OH is below)

(Beta = OH is above)

Question 11

Linking of isomers

Answer 11

• Alpha only joins with Alpha
• Beta only joins with Beta
• They do NOT interjoin with each other (i.e. Alpha+Beta)
• 1-4 linkage = joining the 1st carbon with the 4th carbon.

The image (left) shows starch, and (right) cellulose

Question 12

What are glucose monomers linked by (what bond)

Answer 12

Glycocidic bond

Question 13

Roles of Carbohydrate

Answer 13

1. Cell Recognition
2. Energy provider & storage (Glycogen & Starch)
3. Strcuture (cellulose and microtubules)

Question 14

Roles of Lipids

Answer 14

1. Regulatory (Cholesterol -> Testostrone and Estriol)
2. Structural (Cholestero/Phospholipids)
3. Energy - (Triglyceride ‘fat’ ; Free fat acid)

Question 15

Roles of Proteins (9)

Answer 15

1. Enzymes - (Amylase, RNA polymerase)
2. Structural Collagen - a protein in skin and bones
3. Regulatory Insulin - a peptide hormone
4. Contractile Actin, myosin - muscle proteins
5. Transport Haemoglobin - carries oxygen around body
6. Storage Egg white (albumin), seed proteins
7. Protective Antibodies (e.g. IgG) - immune proteins
8. Catalytic Amylase, RNA polymerase - enzymes
9. Toxic Botulinum toxin, diphtheria toxin

Question 16

Roles of nucleic acid (2)

Answer 16

1. DNA (deoxyribose)
2. RNA (Ribose)

*Nucleic acids are* polymers* of nucleotides