Topic 3 B Flashcards
(38 cards)
What is digestion?
When large biological molecules are broken down into smaller molecules which can be absorbed
What two enzymes digest carbohydrates?
Amylase and Membrane-bound disaccharidases
Where are amylase enzymes found and how do they work?
Produced by the salivary glands and the pancreas. The work by catalysing hydrolysis reactions to break glycosidic bonds in starch
Where are membrane-bound disaccharidases found and how do they work?
attached to the cell membrane of epithelial cells in the ileum. They breakdown disaccahrides into monosaccharides, hydrolysing a glycosidic bond
What is used to digest lipids?
Lipase enzymes and bile salts
How does lipase work and where is it made?
Made in pancreas and secreted into small intestine. Hydrolyse ester bonds, breaking down lipids into monoglycerides
Where are bile salts produced and how do they work?
Made in the liver and emulsify lipids. Muliple lipids droplets have a larger surface area allowing it to be easier for lipas to work. once the lipid is broken down, monoglycerides and fatty acids stick to bile salts to form micelles. They are then carried to the epithelium and break down to release the monoglycerides and fatty acids which allow them. to be absorbed
What enzymes are used to digest proteins?
Endo/exopeptidases and dipeptidases
How do endopeptidases work?
Hydrolyse peptide bonds within the protein chain
How do exopeptidases work?
Hydrolyse peptide bonds at the end of a protein chain.
How do disaccharides work?
Exopeptidases that work on dipeptides, hydrolysing the peptide bond between two amino acids
What is haemoglobin?
Protein with 4 chains, each has a haem group containing an iron ion. Can carry 4 oxygen molecules, which creates oxyhaemoglobin
What does affinity mean?
Tendency a molecule has to bind to oxygen. affected by partial pressure
What happens when there is a high and low partial pressure?
Oxygen loads onto haemoglobin during a high partial pressure due to a high affinity, and unloads when there is a low partial pressure
Which way does a dissociation curve shift at a low/high pCO2?
Low- left
High- right (gives oxygen more readily)
Bohr affect
What happens to organisms at low oxygen environments?
Have a higher affinity for oxygen as there isn’t much available, curve to left
What happens to organisms with high activity levels?
Lower affinity for oxygen, need it easy to unload to use, curve to right
What happens to organisms with a small size?
Lose heat quickly, high metabolic rate, higher oxygen demand, lower affinity, curve to right
How is tissue fluid made?
From small molecules that leave the blood plasma. At the arteriole end there is a high hydrostatic pressure inside the capillaries. The pressure forces fluid out of the capillary into the space surrounding cells, forming tissue fluid. The pressure now decreases so its lower at the arteriole end then the venule end. Water potential is lower at venule end then in the tissue fluid so some water is reabsorbed into the capillary by osmosis. Excess fluid is drained out via the lymphatic system.
How does the cardiac cycle happen?
Ventricle contract and atria relax, decreasing volume and increasing pressure which pushes the blood into the ventricle. Volume increases in ventricle. ventricle contract and atria relax, decreasing volume and increasing pressure. Pressure higher than atria so AV valves shut to prevent back flow. Blood is then forced out of the aorta and pulmonary artery. They both relax and the SL valves close due to higher pressure in pulmonary artery and aorta to prevent back flow. Atria start to fill again until pressure is higher than ventricles, AV valves open blood flows into ventricles
how do you find cardiac output?
Stroke volume times heart rate
What is stroke volume?
Vol of blood pumped during each heartbeat
What is heart rate?
No of beats per minute
What is atheroma?
Damage caused to the endothelium, white blood cells and lipids clump together under the lining. Eventually grow and harden to form plaque which blocks the lumen, preventing blood flow
