Flashcards in 3B - More Exchange and Transport Systems Deck (48):
What type of reaction is used in digestion
Describe the digestion of carbohydrates
Amylase produced in the salivary glands breaks down starch in the mouth into maltose
Amylase produced in the pancreas is also released into the ileum.
Maltase, a membrane bound disaccharide breaks maltose down into glucose.
Glucose is absorbed through co-transport
Describe the digestion of lipids
The pancreas produces lipases which catalyse the break down of lipids into monoglycerides by hydrolysing the ester bonds.
Bile salts made in the liver emulsify the lipids to increase surface area.
The monoglycerides and fatty acids stick to the bile salts forming micelles.
For each of the following disaccharide name it disaccharidase and the monosaccharaides it is composed of:
a) lactase => glucose + fructose
b) maltase => glucose + glucose
c) lactase => glucose + galactose
Describe the digestion of polypeptides
Peptides are broken down by peptidases which hydrolyse their peptide bonds between the amino acids.
What are the differences between endo and exo peptideases?
Endo: - hydrolyse bonds with in a polypeptide to form two shorter polypeptides
Exo: - hydrolyse the peptide bond at the end of a chain to make a polypeptide and an amino acid
What is a dipeptidase?
Exopeptidases that work specifically on dipeptides to break them into two amino acids
How are the following monosaccharaides absorbed?
a) Active transport with sodium ions via a co-transporter
b) Facilitated diffusion using a transporter protein
c) Active transport with sodium ions via a co-transporter
How are monoglycerides and fatty acids absorbed?
They diffuse across the epithelial membrane as they are lipid soluble.
Where is haemoglobin found in humans?
Red blood cells
What is Hb?
Describe the structure of haemoglobin.
A large protein with a quaternary structure which is composed of 4 polypeptide chains. Each chain has a haem group containing iron. Each molecule of Hb can carry 4 O2 molecules.
What do oxygen and haemoglobin form?
What is association?
When an oxygen molecule joins to a haemoglobin.
What is dissociation?
When an oxygen molecule leaves a haemoglobin
What is affinity for oxygen.
The tendency haemoglobin has to bind with oxygen.
Partial pressure of oxygen - a measure of oxygen concentration
As partial pressure increases haemoglobins affinity for oxygen....
Increases. This means in areas with high oxygen concentrations oxygen will bind to haemoglobin.
What does a dissociation curve show?
How saturated haemoglobin is with oxygen at a given partial pressure.
How does the saturation of haemoglobin affects its affinity?
The first O2 molecule is hard to bind to the haemoglobin as the binding site is hard to reach. Once this oxygen has bound to the haemoglobin it changes the shape of the molecule so the 2nd and 3rd O2 molecules are easier to bind.
Partial pressure of CO2
How does increasing pCO2 change affinity for oxygen
Coronary Heart Disease (C.H.D)
A cardiovascular disease which occurs when the coronary arteries have restricted blood flow due to atheromas.
Supply the heart muscle with glucose and oxygen.
Fatty deposits that form in the wall of an artery
White blood cells what have taken up L.D.L's
Deposits of cholesterol, fibres and dead muscle cells within the artery wall.
A blood clot
Lining of the blood vessel
A reduction in blood flow that has deprived an area of oxygen and glucose.
A blood filled swelling formed at a weakened point in an artery wall
Loss of blood
Heart attack - a reduced blood flow supplying the heart muscle
Reduces the O2 carried by red blood cells
Makes red blood cells sticky
high density lipoproteins - removes cholesterol from the tissue
low density lipoproteins - transports cholesterol to tissues.
How do valves in the heart work
Higher pressure behind the valve forces it open. This increases the pressure in front of the valve which closes the valve.
What do valves do?
Prevent backflow of blood
What are semi-lunar valves
Valves that link the ventricles to the pulmonary artery and aorta
What are atrioventricular valves
Valves that link the ventricles and atria
What is the vena cava
A vein which bring deoxygenated blood from the body into the right atrium
What is the pulmonary artery
An artery which takes deoxygenated blood from the heart and to the lungs
What blood vessel takes oxygenated blood from the heart to the body
What blood vessel take s oxygenated blood from the lungs to the heart
Compare and explain the thickness of the walls of the atria and the ventricles.
The ventricles have thicker walls than the atria so then they are able to push the blood out of the heart where as the atria only have to push blood into the ventricles