POM MOCK 9 - research, haematology pracs, fluid, cell signaling,

Question 1

Difference between normal range and reference range?

Answer 1

“Normal range” is a range derived from a healthy reference population. Reference ranges take into account age, gender, ethnic origin and physiological status (pregnant or not).

Question 2

What guides data analysis?

Answer 2

The research question the data is trying to answer and the hypotheses to be tested.

Question 3

What contributes to validity of dataset?

Answer 3

A standard operating procedure (SOP) for data collection and analysis
Small proportion of missing data
Explicit inclusion and exclusion criteria
A large and diverse sample

Question 4

When can you exclude outliers?

Answer 4

A case of a mistake in data collection. e.g value inputted is out of range of acceptable values.

Question 5

What are the two gene clusters that code for the haemoglobin molecule?

Answer 5

Alpha and beta cluster.

Question 6

What is the P50 value?

Answer 6

Is the pressure at which hemoglobin is 50% saturated.

Question 7

Explain the shape of Oxygen–haemoglobin dissociation curve?

Answer 7

Sigmoid. Once one haem group binds to oxygen it is easier for other groups to bind to oxygen. This is known as positive cooperative effect.

Question 8

What does 2,3 dpg do to haemoglobin?

Answer 8

Binds to site in deoxyhaemoglobin distant from haem groups and reduces affinity for oxygen.

Question 9

How is 2,3 dpg made?

Answer 9

Conversion of 1,3 bpg made in glycolysis to 2,3 bpg via Rapoport- Luebering shuttle.

Question 10

Why does haemoglobin F have a greater affinity that haemoglobin A?

Answer 10

Single amino acid substitution in gamma chain of haemoglobin F results in reduced affinity for 2,3 bpg and so increased affinity for oxygen.

Question 11

Why is it important that fetal haemoglobin has a greater affinity for oxygen than haemoglobin A?

Answer 11

Allows for O2 to flow from maternal oxyhaemoglobin to fetal deoxyhaemoglobin.

Question 12

What is the bohr effect?

Answer 12

H+ and CO2 production facilitates oxygen release from oxyhaemoglobin. This can be seen in exercise.

Question 13

In relation to the effect on haemoglobin what are H+ ions, CO2 and 2,3dpg?

Answer 13

Allosteric effectors.

Question 14

What are different human haemoglobin type separation based on in electrophoresis?

Answer 14

Charge.

Question 15

What is the beer lambert law used for?

Answer 15

To calculate concentration of substance using absorbance value.

Question 16

What is the path length in beer lambert law?

Answer 16

Length of cuvette.

Question 17

Myoglobin key points?

Answer 17

Has one haem group per molecule and displays a greater affinity for oxygen than haemoglobin. However, the lack of cooperativity means that it is poor at releasing oxygen under the same conditions.

Question 18

What can spectrophotometry be used for in relation to haemoglobin?

Answer 18

Can be used to follow changes in oxygen binding by haemoglobin - absorbance changes when oxygen is bound. Checking the respiratory status of newborn infants.

Question 19

What is methaemoglobin?

Answer 19

Is generated when the Fe2+ion is oxidised to theFe3+

Question 20

In methaemoglobin patients what is the colour of blood?

Answer 20

Bluish/chocolate colour.

Question 21

What does methaemoglobin do to the oxygen dissociation curve? What does this result in?

Answer 21

Shift leftwards, which can result in tissue anoxia, as oxygen is not readily released by MetHb.

Question 22

What causes methaemoglobin to be present in blood?

Answer 22

Lack of methemoglobin reductase or production of a mutant form of haemoglobin known as haemoglobin M, which isresistant to reduction. Exposure to chemicals such as p-chloroaniline, nitrates, and local anaesthetics such as benzocaine.

Question 23

Why does haemoglobin A travel further in electrophoresis that haemoglobin S?

Answer 23

HbA is more negatively charged than HbS.Due to a point mutation occurring in one amino acid of the β-chain. In this mutation, the amino acid glutamate in the normal protein (hydrophilic, negatively charged) is replaced by valine (hydrophobic, uncharged).

Question 24

In someone who is heterozygous for sickle cell disease what would you see on the electrophoresis gel?

Answer 24

Both HbA and HbS bands for that individual.

Question 25

What should graphs always have?

Answer 25

Axis titles, axis units, detailed caption and error bars (if using
averages)

Question 26

What does tonicity take into account?

Answer 26

Osmolarity of impermeable ions.

Question 27

What is the case of osmolarity in a hypertonic solution?

Answer 27

Osmolarity of impermeable solutes outside of the cell is greater than inside the cell, so cell shrinks.

Question 28

What is the case of osmolarity in a hypotonic solution?

Answer 28

Osmolarity of impermeable solutes is greater inside the cell than outside the cell and so cell swells.

Question 29

Osmolarity of impermeable solutes inside a cell is greater than outside. Why does the cell not burst?

Answer 29

Na+K+ATPase pumps high concentration of sodium ions out of cell to balance high concentration of protein inside the cell.

Question 30

What does UW solution contain?

Answer 30

Low Na+ and Cl-. Presence of extracellular impermeable solutes. Presence of macromolecular colloid.

Question 31

What can cause hydrostatic pressure to be much greater than osmotic pressure?

Answer 31

Increased pore size in capillary. Plasma protein leaks out of capillary. Concentration gradient is reduced and so osmotic pressure is reduced. Lots of fluid leaks into interstial space leading to oedema.

Question 32

How does a g protein coupled receptor specifically work?

Answer 32

Ligand binding causes conformational change in 7tm receptor. This allows heterotrimeric g protein to bind to 7tm receptor. GDP is exchanged for GTP and g protein is seperated into alpha and beta sub unit. Each sub unit binds to its target protein.

Question 33

How can g protein be deactivated?

Answer 33

Dephosphorylation of GTP to form GDP. Alpha unit leaves target protein and rejoins with beta unit.

Question 34

What deactivates 7tm receptor?

Answer 34

Unbinding of ligand. Receptor remains active as long as ligand is bound and can activate further heterotrimeric g proteins.

Question 35

How do enzyme linked receptors work specifically?

Answer 35

Ligand binding causes receptors to cluster. This leads to enzyme activity within the cell. Enzymes phosphorylate the receptor. This leads to binding of signalling proteins to cytoplasmic domain of receptor. These signalling proteins lead to a signal cascade within the cell.

Question 36

How do type 1 intracellular receptors work specifically?

Answer 36

Receptor located in cytoplasm. Hormone passes through cell membrane and bind to receptor which leads to heat shock protein dissociation which results in 2 hormone bound receptors join together and form a hormodimer that passes through nucleus and bind to DNA.

Question 37

What is the difference between type 1 and type 2 intracellular receptors.

Answer 37

Type 1 receptors are found in the cytoplasm while type 2 are found in the nucleus.

Question 38

How do type 2 intracellular receptors work?

Answer 38

Binding of hormone to DNA receptor. Transcriptional regulation induced.