Enzymes, Chromatography & Specimens

Question 1

What is meant by the term “metabolism”?

Answer 1

A sequence of enzyme catalysed

chemical reactions in the cell - both anabolic and catabolic reactions

Question 2

Anabolic and catabolic pathways are different. Briefly
explain two of the differences between an anabolic
pathway and a catabolic pathway.

Answer 2

Anabolic: Concerned with the processes
involved in the assembly of complex
organic molecules, requires energy and has divergent pathway

Catabolic: Processes related to degradation of
complex substances, with resulting
generation of energy, conserves energy and has a convergent pathway

Question 3

What is an enzyme?

Answer 3

Catalysts that regulate the chemistry of cells and organisms

Question 4

What is an enzyme active site?

Answer 4

Part of enzyme involved in the catalytic reaction

Question 5

When referring to an enzymatic reaction, what is meant

by the term “substrate”?

Answer 5

The reactant in an enzyme-catalysed reaction (Substance acted upon by the enzyme)

Question 6

When referring to an enzymatic reaction, what is meant by the term “product”?

Answer 6

What is produced after the enzyme and substrate have bonded togther

Question 7

List and briefly explain four (4) variables that can effect

enzyme activity.

Answer 7

Temperature: Each enzyme has an optimum temperature, and can only work within a certain range of temperatures

pH: Each enzyme has an optimum pH, and can only work within a certain range of pH levels

Substrate concentration: The more substrates that bind with available enzymes, the faster the reaction

Enzyme concentration; The greater the number of enzymes that are able to bind with a substrate, the faster the reaction

Question 8

A laboratory assay uses an enzymatic reaction as part of the assay procedure. Explain why the incorrect
incubation time for the laboratory assay may effect the
results of the assay

Answer 8

This could affect the temperature that the enzyme is working in, and the enzyme may not be able to work effectively

Question 9

List 4 different types of biological specimens that may be used in a Biomedical Science or Pathology laboratory.

Answer 9

• Blood
• Urine
• Faeces
• Solid tissue

Question 10

Name the cellular components of blood.

Answer 10

RBC, WBC, platelets

Question 11

Name 3 components of blood required for clotting.

Answer 11

• Ca2+
• Platelets
• Clotting proteins e.g. fibrinogen

Question 12

Is there a difference between serum and plasma? Explain your answer.

Answer 12

Plasma: liquid portion of blood
Serum: liquid portion of blood without clotting components

Question 13

What is an anticoagulant?

Answer 13

A substance that allows the plasma portion of blood to be separated from the rest

Question 14

List one anticoagulant and explain its mode of action.

Answer 14

Heparin:

- inhibits clotting proteins (eg thrombin)

Question 15

Why are different anticoagulants used when collecting

blood?

Answer 15

Different coagulants have different purposes and modes of action, e.g. sodium fluoride preserves glucose in blood and oxalate joins calcium ions together

Question 16

Why is correct identification of a patient sample important?

Answer 16

So that the patient waiting for results does not get an incorrect diagnosis, treatment or intervention

Question 17

List 2 reasons that a patient sample may be unsuitable for a laboratory assay, necessitating the recollection of a sample.

Answer 17

• If the patient is identified incorrectly

- If the sample is damaged while being transported

Question 18

Haemophilia is a disease studied in a Coagulation

laboratory. What is Haemophilia?

Answer 18

A blood disorder where blood is not able to clot properly

Question 19

Why might a protein need to be separated

from a mixture of other proteins?

Answer 19

There may only be one protein that is of interest to be analysed

Question 20

What types of molecules can be separated

from a mixture using Chromatography?

Answer 20

DNA, RNA, other organic molecules

Question 21

List three Chromatography principles that

can be used to separate a molecule of interest from a mixture.

Answer 21

Ion Exchange:
- Solid stationary phase and liquid mobile phase
Size Exclusion:
- Liquid stationary phase and liquid mobile phase
Affinity:
- Stationary ligand and liquid mobile phase

Question 22

For each of the principles that you listed in
answer to the question above, what property
of the molecule of interest is being utilised
(eg size, charge, etc)

Answer 22

Ion exchange: charge

Size exclusion: size

Question 23

What factors may affect the reliability of a

laboratory test result?

Answer 23

Accuracy and precision

Question 24

Explain the term Accuracy when referring to

laboratory results. Use a hypothetical example in your explanation.

Answer 24

Closeness of measured value to true value

Question 25

Explain the term Precision when referring to | laboratory results. Use a hypothetical example in your explanation.

Answer 25

How close together a set of measurements (of the same parameter) are to each other