Acid base regulation Flashcards
why is pH important
- if we don’t have the correct pH in the correct body parts this can cause the protein to denature and loose there biological activity
- this is especially important for enzymes
why is pH important for enzymes
- as you deviate form the pH the efficiency of the enzyme decreases this is because there is not a precision in forming the correct active site
name the pH for
- pepsin
- amylase
- trypsin
- pepsin - 0-6
- amylase - 4-10
- trypsin - 5-12
different parts of the cells have ….
different pH for example
- In the mitochondria pH 8
- Nucleus 7.2
- Lysosomes 4.7
what is an acid
• An acid is any substance which can DONATE an H+ ion
what is a base
A base is any substance which can ACCEPT an H+ ion
write the dissociation equation of an acid
• When an acid (generically written as HA) is added to
water, it dissociates reversibly according to the reaction:
HA <=> H+ + A-
what happens when an acid dissociates
When an acid dissociates, it yields a free H+ and its conjugate base (A- is a base because it can combine with a H+ to form HA)
what is pH determined by
The numerical value of pH is determined by the molar concentration of hydronium (OH-) / hydrogen ions (H+)
what does the pH also control
- it also controls the speed of our body biochemical reactions - does this by controlling the speed of enzyme activity as well as the speed of electrical reactions in our body
what is acidosis
acidosis (acidemia specifically in the blood)
what is alkalosis
alkalosis (alkalaemia- specifically in the blood)
what is the bodies normal pH range
- 7.34 (venous) to 7.45 (arterial)
what happens if the bodies pH range is outside the normal range
still compatible with life but leads to disturbance of body functions, as it disrupts many enzyme systems and the electron transport chain in mitochondria
what pH canc sue death
- Below 6.8 and above 8.0 = DEATH
what happens when carbon dioxide enters the blood stream
- it is converted to carbonic acid by carbonic anhydrase
- this lowers the pH
what are the ways in which acid is produced
- either intake it in the diet
- or they form via cellular metabolism
How does acid intake happen
the normal human diet is almost neutral containing only small amounts of acids. (diets with large amounts of proteins produce more acids than bases)
How does acid formation happen
Most hydrogen ions originate from cellular metabolsim, which produces large amounts of carbonic, sulphuric, phosphoric & other acids
What are the ways in which protons are continually produced
1- Acids produced during the breakdown of foods (esp. proteins)
2- CO2 metabolically produced and form carbonic acid with H2O
3- Acids resulting from other metabolic activity e.g. lactic acid in exercise
how do we produce hydrogen ions
- Aerobic respiration of glucose which causes carbonic acid formation - most important produces about 15mol/d
- Anaerobic respiration of glucose which forms lactic acid - produces about 1.5mol/d
- Oxidation of sulphur containing amino acids and this forms sulfuric acid
- Incomplete oxidation of fatty acids – this form acidic ketone bodies
- Hydrolysis of phosphoproteins and nucleic acid – this forms phosphoric acid
how many mol/d of protons does acid in diet and acids produced by metabolism produce
• Acid in diet (eg, phosphoric, sulphuric) and acids produced by metabolism (eg, lactic and ketoacids) – about 60 mmol/d
name the ways in which there can be pathological formation of acid (hydrogen ions)
- methanol poisoning can lead to formic acid production
- ethylene glycerol poisoning can lead to glycolic acid, glyoxylic acid, oxalic acid
- uncontrolled diabetes, starvation can lead to acetate and betahydroxyburlate production
- hypotension and hypoxia leads to impaired o2 delivery which leads to anaerobic metabolic and lactic acid
- liver disease leads to impaired lactate clearance and lactic acid production
- drug and toxins inhibits oxidative phopsophoylated learning to anaerobic metabolism and lactic acid production
- CO poisoning leads to impaired o2 delivery which leads to inhibition of oxidative phosphorylation and anaerobic metabolism producing lactic acid
name the three ways in which you can limit changes in Ph
1, Chemical buffer systems in the ECF and ICF
2, the respiratory centre in the brain stem
3, renal mechanisms
describe the three ways in which you can limit changes in pH
1- Chemical buffer systems in blood and ICF:
- Immediate action - but these will not get rid of the hydrogen ions, they simply buffer it - look up the chemical buffers
2- The respiratory center in the brain stem:
- acts within 1-3 minutes - this acts quite rapidly, this allows you to regulate the respiration so you can get rid of carbon dioxide
3- Renal mechanisms:
- Requires hours to days to affect pH changes - Longest one to take effect, useful as it is the best way to get rid of acid
what is a buffer
Buffer = solution that can resist pH change upon the addition of an acide or a base. Able to neutralize small amounts of added acid or base, thus maintaining the pH of the solution relatively stable.
