MoD EXTRA

Question 1

Term used to describe the appearance of macrophages in granulomas?

Answer 1

Epitheloid
(they are activated macrophages resembling epithelial cells. They often appear to merge into eachother and can form aggregates known as giant cells)

Question 2

What is Bradykinin & what is it activated by?

Answer 2

Bradykinin is a vasodilator activated by kallikrein.

It plays a major role in the inflammatory response by inducing vasodilation and increased vascular permeability.

Question 3

An example of a Type III hypersensitivity disease occurring through an intravenous route?

Answer 3

Nephritis.
It is commonly due to autoimmune disorders such as systemic lupus erythematosus (SLE), a Type III hypersensitivity disorder caused by endogenous antigens. (Immune complexes are deposited or formed on the glomerular basement membrane. The resulting inflammation and tissue damage is mediated by neutrophils.)

Question 4

What are toll-like receptors?

Answer 4

Class of cell surface receptors involved in the innate immune system found on macrophages, dendritic cells and neutrophils.

Question 5

What are permanent cells?

Answer 5

Permanent cells are terminally differentiated, have lost all capacity for regeneration, and do not enter the cell cycle. If lost, permanent cells cannot be replaced. (eg= neurons, cardiac myocytes, and cells of the lens were considered permanent cells)

Question 6

What are stable cells?

Answer 6

Rarely divide under normal conditions but retain the ability to divide and regenerate when stimulated.
(eg= The liver and proximal renal tubules)

Question 7

Treatment often used for herpes simplex virus infection?

Answer 7

Acyclovir

Question 8

DNA synthesis inhibitor commonly used to treat urinary tract infections?

Answer 8

Trimethoprim

Question 9

Antimicrobial agent which inhibits the growth of bacteria?

Antimicrobial agent which kills bacteria?

Answer 9

Bacteriostatic

Bactericidal

Question 10

Streptococci are innately resistant to these agents?

Answer 10

Aminoglycosides

Question 11

Type of therapy given on the basis of the most likely pathogen?

Answer 11

Empirical

Question 12

A test to isolate and identify a viable pathogen?

Answer 12

Culture

Question 13

When an antibody detection test changes from negative to positive following infection?

Answer 13

Seroconversion

Question 14

Name of the cascade that plays a role in opsonisation and leads to cell lysis?

Answer 14

Complement

Question 15

Lipid mediators associated with Type I hypersensitivity

Answer 15

Leukotrienes

Question 16

What do people with the APOE e4 allele have an increased risk of?

Answer 16

They inherit an increased risk of developing Alzheimer disease.
(APOE genes provides instructions for making a protein called apolipoprotein E. This protein combines with lipids in the body to form molecules called lipoproteins)

Question 17

How is limb shortening divided into acromelic, mesomelic, and rhizomelic?

Answer 17

Acromelic shortening–> the distal portion of the limb (the hand) which is short.
Mesomelic–> the middle (forearm, ie radius and ulna) Rhhzomelic–> the proximal (humerus) which is short. The term rhizomelia means pertaining to the shoulder joint or upper arm.

Question 18

The noun used to describe reproduction without fertilization?

Answer 18

Parthenogenesis

Question 19

What are imprinted genes and why are they different?

Answer 19

For most genes, we inherit two working copies. But with imprinted genes, we inherit only one working copy. Depending on the gene, either the copy from mum or the copy from dad is epigenetically silenced.

Question 20

What is the alphoid satellite repeat?

Answer 20

A complex family of repetitive DNA sequences found in the centromeric heterochromatin of human chromosomes (basically it is found at the centromere). The alphoid family is composed of tandem arrays of 170 base pair segments.

Question 21

How can Repetitive DNA segments be subdivided?

Answer 21

1) Tandemly arrayed (for example, MICROSATELLITES, MINISATELLITES and telomeres)
2) Interspersed (for example, mobile elements and processed PSEUDOGENES). Interspersed elements can be subdivided on the basis of size, with short interspersed elements (SINEs) being less than 500 bp long.

Question 22

What is a poly-A tail?

Answer 22

It is a long chain of adenine nucleotides that is added to a messenger RNA (mRNA) molecule during RNA processing to increase the stability of the molecule and prevents its degradation.
(Also- the poly-A tail allows the mature messenger RNA molecule to be exported from the nucleus and translated into a protein by ribosomes in the cytoplasm.)

Question 23

Constituents of the fluid exudate associated with acute inflammation?

Answer 23

Fibrin, serum, wbc

Question 24

What are the three types of reaction that make up the acute inflammatory response?

Answer 24

Vascular, exudative and cellular

Question 25

Robertsonian translocations occur between what types of chromosomes?

Answer 25

Acrocentric

Question 26

Metacentric chromosomes?
Submetacentric chromosomes?
Acrocentric chromosomes?
Telocentric chromosomes?

Answer 26

Metacentric- centromere in the center, such that both sections are of equal length.
Submetacentric- centromere slightly offset from the center
Acrocentric- centromere which is severely offset from the center leading to one very long and one very short section
Telocentric- centromere at the very end of the chromosome

Question 27

Type of embolism associated with a ‘mycotic’ aneurysm?

Answer 27

Infective (formation of mushroom shape aneurysm)

Question 28

An ischaemic stroke is often associated with what type of thrombus?

Answer 28

Mural

Question 29

Main agent responsible for cell injury during reperfusion?

Answer 29

ROS.
Initially, ischaemic cellular damage leads to generation of free radical species. Reperfusion then provides abundant molecular oxygen that combines with free radicals to form reactive oxygen species, which will react with virtually any molecule they meet. This can lead to significant membrane damage to cells.