PM1A DEFINITIONS

Question 1

Immune system

Answer 1

includes all cells, tissues, molecules and barriers that mediate resistance to infections.

Question 2

Immunity

Answer 2

The body’s ability to fight off harmful microorganisms (pathogens) that invade it.
e.g. bacteria, fungi and viruses.

Question 3

Immune response

Answer 3

Is the collective and coordinated response to the introduction of foreign substances in an individual mediated by the cells and molecules of the immune system.

Question 4

Phagocytosis

Answer 4

ingestion and digestion of pathogens

Question 5

antigen

Answer 5

Is a foreign substance/toxin that stimulates an immune response leading to production of antibodies.

Question 6

Give a definition of a skeletal motor unit at the NMJ

Answer 6

A motor unit is defined as a single motor neuron and all the muscle fibers that it activates.

Question 7

Gene therapy

Answer 7

technique for correcting defective genes that are responsible for disease development.
A carrier molecule called a vector must be used to deliver the therapeutic gene to the patient’s target cells (for in vivo therapy).
The most common vector is a virus that has been genetically altered to carry normal human DNA.

Question 8

Genetics

Answer 8

the study of heredity and the variation of inherited characteristics/ the genetic properties of features of an organism, characteristics etc

Question 9

Vaccination

Answer 9

the process of induction of immunity to a pathogen by injecting a weakened, modified or related form of a pathogen which is inactivated.

Question 10

cytokines in immune system

Answer 10

Are regulatory proteins secreted by WBC’s (macrophages and dendritic cells) bind bind to receptors on target cells and trigger signal transduction pathways and alter gene expression patterns, can be pro or anti inflammatory.

Pro- stimulate the immune system
Anti- suppress the immune system

TNF-alpha is the most important mediator of inflammation.

Question 11

Proprioception
and describe the 2 way process

Answer 11

is defined as ‘the perception of self’, where your body is in relation to the surroundings.
2 way process where
1. proprioceptors signal to the spinal cord (affarent)
2. motor neurons signal to skeletal muscle (efferent)

Question 12

surfactant
respiratory system topic

Answer 12

is a mixture of amphipatic complex, phospholipids, proteins and neutral lipid produced by type II pneumocytes

Question 13

Cardiac output and give equation

Answer 13

Volume of blood pumped out of one ventricle in one minute
Cardiac output = heart rate x stroke volume

Question 14

Define perfusion pressure and vascular resistance. For EACH, describe what happens to blood flow when they are increased

Answer 14

Perfusion pressure is the difference in pressure between arteries and veins

Increase perfusion pressure – blood flow increases

The blood vessels themselves offer resistance to flow this is the vascular resistance

Increase vascular resistance blood flow decreases

Question 15

negative feedback and example

Answer 15

effector system opposes the initiating stimuli
e.g. increase in BP causes a compensatory decrease in BP

Question 16

positive feedback and example

Answer 16

effector system amplifies or reinforces the initiating stimuli
e.g. formation of a blood clot leads to further blood clotting.

Question 17

codon
Anticodon

Answer 17

Codon- found in mRNA, is a sequence of 3 nucleotides in a DNA/RNA molecule used to code for amino acids.

Anticodon- found in tRNA, also a sequence of 3 nucleotides that binds to corresponding mRNA sequence.

Question 18

Genetic code

Answer 18

is the nucleotide base sequence on DNA and subsequently on mRNA by transcription which will be translated into a sequence of amino acids of the protein to be synthesis

Question 19

3 features of genetic code

Answer 19

universal- the same code is used in all living organisms, prokaryotes and eukaryotes

specific- a SPECIFIC codon ALWAYS codes for the same amino acid.

Degenerate- more than codon can code for the same amino acid.

Question 20

telomeres

Answer 20

protective caps at the end of linear chromosomes, they contain a unique repetitive sequence called telomere tandem repeats.

Question 21

homologous chromosomes

Answer 21

A pair of chromosomes that are the same size, shape and carry the same genes, one is inherited from each parent.
They are numbered according to size.

Question 22

replication origins

Answer 22

are nucleotide sequences where replication starts

Question 23

TATA box

Answer 23

DNA sequence that indicates where a genetic sequence can be decoded. is an example of a promoter.

Question 24

Transcription factors

def of general TF’s

the largest TF?

Answer 24

are proteins that regulate the transcription of genes.
They bind to regulatory DNA sequences are they recognise target sequences in DNA.
Two types are general and promoter:

general TF’s are active in most cell types and ALWAYS affect gene transcription positively.
General TF’s are the most basic proteins needed to activate gene expression.

TNF II D is the largest TF

Question 25

gene regulation topic

gene regulation at chromatin level:
define chromatin remodelling

Answer 25

sliding the nucleosomes along the DNA to expose the promoter region, chromatin must be open for gene expression to take place.

Question 26

promoter

Answer 26

region of DNA where RNA polymerase ( and transcription factors) binds to initiate transcription.
Defines the direction of transcription as well as which DNA strand will be transcribed.

Question 27

mutation

Answer 27

permanent change in the genetic material of an organism, mutations can be neutral
( neither positive or negative consequences).
neither beneficial nor detrimental to the ability of the organism to survive and reproduce.

Question 27

mutation

Answer 27

permanent change in

Question 27

mutation

Answer 27

Permanent change in the genetic material of an organism
mutations can be neutral (neither positive or negative consequences)
neither beneficial nor detrimental to the ability of the organism to survive and reproduce.

Question 28

Nervous system

All or nothing or principle

Answer 28

If threshold is exceeded, action potentials have a similar magnitude and duration

Question 29

Nervous system

Absolute refractory period ( ARP)

Answer 29

In the period that Na+ channels are open or inactivated, an action potential cannot be generated, neurones CANNOT fire

Question 30

respiratory system:

compliance and elastance

Answer 30

compliance- the measure of the distensibility of a system, specifies the ease at which matter can be stretched or distorted.

elastance- measure of ability of system to oppose stretch or distortion and to return to the original form (recoiling)

Question 31

lung compliance

lung elastance

Answer 31

lung compliance- the volume change that could be achieved in the lungs per unit pressure change .
Describes the ability of the lungs to expand under pressure.

lung elastance- the pressure change required to elicit a unit volume change.
Is a measure of the resistance of a system to expand.

Question 32

respiratory system:

loading and unloading

Answer 32

loading- binding of O2 to Hb, takes place in the lungs where high partial pressure of O2, Hb has a high affinity for O2, therefore loads oxygen. =Positive cooperativity.

unloading-Hb unbinds from O2, takes place in tissues, where low PO2, Hb has a low affinity for oxygen therefore O2 is unlaoded.

Question 33

Bohr effect

how is it advantageous?

Answer 33

Increase in Co2 conc, causes the o2-Hb dissociation curve to shift to the right, as affinity decreases, leading to dissociation of O2.

When RO respiration high, high conc of co2 is released which lowers the blood pH as carbonic acid and lactic is produced.

Advantageous: as it provides more o2 for tissues for aerobic respiration, increasing metabolic activity in cells when exercising.

Question 34

humoral response

Answer 34

removes extracellular microbes and their toxins, mediated by antibodies

Question 35

cellular response

Answer 35

removes intracellular microbes that survive within phagocytes or other infected cells, involves T cells.

Question 36

Nervous system:

Relative refractory period

Answer 36

In the period that K+ channel are open (activated), membrane is hyperpolarised and makes therefore makes it more difficult to fire action potential = a stronger stimuli is required to generate an AP.