Biochemistry and Spectrophotometery

Question 1

What are the “building blocks” for protein macromolecules?

Answer 1

Amino acids

Question 2

What are the “building blocks” for polysaccharides?

Answer 2

20 or more monosacchariddes

Question 3

What are the “building blocks” for nucleic acids?

Answer 3

Nucleotides

Question 4

What are the “building blocks” for lipid aggregates?

Answer 4

Fatty acids

Question 5

What macromolecule/s can be made up of branched chains?

Answer 5

Carbohydrates

Question 6

How many standard amino acids are there?

Answer 6

20

Question 7

What is the general structure of an amino acid

Answer 7

• alpha (α) carbon
• carboxyl group
• amino group
• ‘R’ group

Question 8

How do the standard amino acids differ from one another?

Answer 8

The R group makes each amino acid different

Question 9

Amino acids can be classified according to their R group. Why might it be useful to use this classification?

Answer 9

Each type of R group has similar chemical properties (negatively charged, positive, polar, non-polar etc)

Question 10

What is a peptide bond?

Answer 10

A bond between 2 or more amino acids that form a peptide

Question 11

Explain why amino acids are important.

Answer 11

• Amino acids are a source of energy (10-15% metabolic energy)
• Many inborn errors of metabolism are due to absence
  of enzymes in the metabolism of amino acids
• Amino Acids are precursors to other important
  biomolecules

Question 12

BRIEFLY explain what is meant by each of the terms: Protein Primary Structure, Secondary Structure, Tertiary Structure, Quaternary Structure.

Answer 12

Primary structure: linear sequence of amino acids

Secondary structure: the backbone of the polypeptide chain folds into regular geometric structures (α-helix, β-sheet, turns)

Tertiary structure: final folded form of the protein (the native form)

Quaternary structure: association of two, or more, polypeptide tertiary structures

Question 13

List two examples of terms that describe different secondary structures that can be found in proteins.

Answer 13

α-helix, β-sheet

Question 14

List four of the major roles of Protein.

Answer 14

• transporting molecules
• structural support (e.g. collagen in tendons and ligaments)
• growth (directs growth and development, e.g. growth hormone)
• immune response to foreign matter (antibodies)

Question 15

Lipids may not be considered true macromolecules because of their structure. Briefly explain.

Answer 15

• individual monomers (fatty acids) are not

covalently bound to each other in a macromolecular structure

Question 16

Name three (3) major functions of lipids.

Answer 16

• storage (insulation, fuel)
• structure (membranes)
• specific biological actions (cofactors for enzymes)

Question 17

List some examples of lipid aggregates

Answer 17

Micelles, liposomes, membranes, lipoproteins

Question 18

Give one example of an important Monosaccharide

Answer 18

• D-Glucose (most abundant in nature)
• D-Fructose (common monosaccharide in honey and fruit)
• D-Ribose (component of DNA and RNA)

Question 19

Give one example of an important Disaccharide

Answer 19

• Sucrose (glucose + fructose)
• Lactose ( glucose + galactose)
• Maltose ( glucose + glucose)

Question 20

Can two sugar molecules have different configurations

despite having the same molecular formula?

Answer 20

Yes; most of them have a D configuration and an L configuration

Question 21

Explain the term Diabetes mellitus

Answer 21

State of chronic hyperglycaemia which may
result from genetic or environmental factors
often acting jointly

Question 22

Discuss the statement “The diagnosis and management of Diabetes mellitus is only of concern to a very small portion of the health care industry”

Answer 22

• This statement is false
• The prevalence in Australia is increasing and almost 50% of people with diabetes are undiagnosed which is very concerning to the health care industry
• Side effects of diabetes has very severe effects

Question 23

How is Diabetes mellitus diagnosed

Answer 23

• Glycosuria test is suggestive but not diagnostic

- Blood glucose when fasting and random test can diagnose diabetes mellitus (>7.0 mmol/L fasting = diabetic)

Question 24

Spectrophotometers can be used to measure the absorbance of light of a particular wavelength by a certain material. BRIEFLY explain what is meant by the term absorbance

Answer 24

• The interaction of the light with the matter

Question 25

What is Beer’s Law?

Answer 25

Absorbance is proportional to the concentrations of the reducing species in the material sample

Question 26

What is Lambert’s Law?

Answer 26

Absorbance of a material sample is directly proportional to its path length

Question 27

What is the combined Lambert-Beer Law?

Answer 27

Absorbance is related to both concentration and pathlength

Question 28

Is it more convenient to use Absorbance or Transmittance to determine the concentration of a substance?

Answer 28

Absorbance, there is a directly proportional relationship

between absorbance and concentration

Question 29

Why is the selection of optimal analytical wavelength

important for spectrophotometric measurement?

Answer 29

• To ensure that the spectro can detect the small changes in what is being measured

Question 30

Why is the selection and use of an appropriate Blank

important for spectrophotometric measurement?

Answer 30

• It is like a negative control, and the blank used should not have the same effects as those that are expected to be measured by the spectro

Question 31

List four (4) of the major functions of carbohydrates in a cell.

Answer 31

• Energy source
• Cell recognition
• Cell to cell communication
• Antibiotics