What causes genes to mutate?

What causes genes to mutate?

•      Ionising radiation – X Rays, UV light

•      Chemicals –from cigarettes, plastic processing, pollutants,

•      Virus infection – papilloma virus, HBV, etc.

•      Hereditary predisposition – Some families are more susceptible to getting certain cancers. you can’t inherit cancer

Silent: If abase substitution occurs in the third position of the codon there is a good chance that a synonymous codon will be generated. Thus the amino acid sequence encoded by the gene is not changed and the mutation is said to be silent.

Missence: When base substitution results in the generation of a codon that specifies a different amino acid and hence leads to a different polypeptide sequence. Depending on the type of amino acid substitution the missense mutation is either conservative or non-conservative.

Nonsense: When a base substitution results in a stop codon ultimately truncating translation and most likely leading to a non-functional protein.

Aneuploidies- Is the presence of an abnormal number of chromosomes in a cell, for example a human cell having 45 or 47 chromosomes instead of the usual 46. It does not include a difference of one or more complete sets of chromosomes.

Mutated Cancer Genes
Oncogenes	Oncosuppressors
Genes that positively contribute to cancer, they need to be more active. They usually push proliferation, inhibit apoptosis, block differentiation, make stemness.	genes that need to be inactivated to contribute to cancer. They usually inhibit proliferation, induce apoptosis, induce differentiation

!!**REMEMBER TO STAY POSITIVE LIKE A PROTON**!!

RBC Life cycle

Red Blood Cell Life Cycle

1. RBC are produced in the BM from
precursors. This is when Hb is
produced. RBC production is
stimulated by EPO released from
the kidney cells

2. Mature RBC are released in the
circulation where they function
for 120 days

3. Old RBC are recognized and
phagocytized by macrophages in
the spleen (Hemocatheretic
function)

4. The content of the RBC is
recycled: Hb à aa

5. Heme à Protoporphirin + Fe

6. protoporphyrin is recycled or
metabolized by liver (bilirubin)
and excreted in the gut
(stercobilin) or urin (Urobilin)

7. Iron is transported by transferrin
and/or conserved in the protein
ferritin

**!!REMEMBER TO STAY POSITIVE LIKE A PROTON!!**

Acid base disorder

Acid base disorder 

Effects on cell compartmentalisation induced by changes of ionisation state of molecules.

Metabolic acids:

Anaerobic metabolism of glucose to lactate and pyruvate.

Anaerobic metabolism of fatty acids.

Oxidation of suplphur-containing amino acids (Cys and Met) and cationic amino acids (Arg and Lys).

Chemical buffers (intracellular and extracellular)

- Bicarbonate system (seconds).

- Phosphate system.

- Protein buffer system.

Physiological regulation:

- Respiratory control - the brain stem respiratory centres (1-3 minutes). Changes alveolar ventilation.

- Renal mechanisms (hours; up to a whole  day).

Its biological significance lies on the fact that can eliminate buffer hydrogen ions.

Major buffer system of blood plasma (around 70% of buffering capacity).

Not a very efficient system – pKa not within ideal range to buffer pH 7.4

Importance comes from two other features:

High concentrations in the blood.

Open system – excretion of CO2 from the lungs and reabsorption of HCO3- in the kidney.

**!!Remember to stay positive like to proton!!**