IMMS

Question 1

Describe water distribution in the body.

Answer 1

ECF= 14L

• Interstitial fluid = 11L
• Plasma = 3L

ICF= 28L

Question 2

What are the predominant electrolytes in the ICF and ECF respectively?

Answer 2

ICF:
K+

ECF:
Na+, Cl-, HCO3-

Question 3

Define osmosis and osmotic pressure.

Answer 3

Osmosis-
movement of H20 across a partially permeable membrane from an area of high>low water potential

Osmotic pressure-
pressure that must be applied to a solution to prevent inward osmosis through a partially permeable membrane

Question 4

Outline and contrast osmolality and osmolarity.

Answer 4

• measure of solute conc.

- no. of osmoles per L (osmolarity) or kg (osmolality)

Question 5

Define oncotic pressure.

Answer 5

a form of osmotic pressure exerted by proteins, notably albumin, that tends to pull fluid into its solution

Question 6

Describe a chromosome and their arrangement.

Answer 6

DNA double helix, coils around nucleosome which then supercoils again into chromosomes
23 pairs of chromosomes
10^7 base pairs & hundreds of genes per chromosome
long arm= q, short arm= p

Question 7

Describe the first 2 stages of mitosis.

Answer 7

Prophase- chromatin condenses>chromo, centrosomes create microtubules (tubulin) and move to opposite poles
Pro-metaphase- nuclear membrane breaks down & chromatids attach to microtubules
Metaphase- chromo line up along equator

Question 8

Describe the last 2 stages of mitosis.

Answer 8

Anaphase- microtubules shrink & pull chromatids apart and are pulled to opposite poles
Telophase- nuclear membrane reform, chromosomes unfold back into chromatin & cytokinesis begins

Question 9

What is a chromatid?

Answer 9

1 half of a pair of chromosomes

Question 10

How is genetic diversity made using meiosis?

Answer 10

Independent assortment

chiasmata chromatids

Question 11

What is an eicosanoid?

Answer 11

20C acids with C=C at 3,4,5

Involved in fever and cause the mobilisation of proteins to cause immune response

Question 12

Describe a steroid.

Answer 12

Steroid nucleus= 3 benzene rings & 1 pentene ring

Question 13

What is a supersecondary structure and give examples?

Answer 13

Combination of secondary structures
Examples:
Helix-turn-helix
Beta-alpha-beta unit
Leucine zipper
Zinc finger

Question 14

Describe DNA replication.

Answer 14

DNA helicase opens strands- SSb protein keeps it open
Topoisomerase unwinds
DNA polymerase reads 3’>5’ and prints 5’>3’
Get Okazaki fragments on lagging strand- joined together by ligase

Question 15

What are the differences between heterochromatin vs. euchromatin?

Answer 15

Heterochromatin is compact after being methylated & few acetyl
Euchromatin is spread out after being acetylated & few methyl