3B - More Exchange and Transport Systems Flashcards
What type of reaction is used in digestion
Hydrolysis
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) sucrose
b) maltose
c) lactose
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) Glucose
b) Fructose
c) Galactose
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?
Haemoglobin
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?
Oxyhaemoglobin
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.
pO2
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.
pCO2
Partial pressure of CO2
How does increasing pCO2 change affinity for oxygen
Decreases it
Coronary Heart Disease (C.H.D)
A cardiovascular disease which occurs when the coronary arteries have restricted blood flow due to atheromas.
Coronary Arteries
Supply the heart muscle with glucose and oxygen.
