Topic 3B: More Exchange Systems Flashcards
Why is digestion important
Larger biological molecules in food are too big to cross the cell membranes meaning this can’t be absorbed from the gut into the blood r
What digestive enzyme breaks down starch
Amylase
What 2 polysaccharides is starch made out of
Amylose and amylopectin
How does amylase work
By catalysis hydrolysis reactions that break the glycosidic bonds in starch to produce maltose
Where is amylase produced
Salivatory glands
What are membrane-bound disaccharides
Enzymes that are attached to the cell membrane of epithelial cells lining through ileum
Helping to break down disaccharides into monosaccharides
What are lipase enzymes
Catalyse the breakdown of lipids into monoglycerides
How do lipase enzymes work
Involves hydrolysis of ester bonds in lipids
What do bile salts do and where are they produced
Produced by liver and emulsify lipids
What do micelles do
Help products of digestion to be absorbed
How are micelles formed
Monoglycerides and fatty acids stick with the bile salts to form micelles
What does exopeptidases do
Acts to hydrolyse peptide bonds at the ends of a protein molecule
What does endopeptidases do
Acts to hydrolyse peptide bonds within a protein
What does dipeptidases do
They are exopeptidases that work specifically on dipeptides
Act to separate the amino acids that make up a dipeptide by hydrolysing the peptide bond
Where are dipeptidases found
Cell-surface membrane of epithelial cells in the small intestines
What’s the role of haemoglobin
To carry oxygen around the body
What’s the structure of haemoglobin
Large protein with a quaternary structure, made up of 4 peptide chains each chain had a haem group
It can carry 4 oxygen molecules at one time
What does a haem group do
Contains iron giving Hb its red colour
What’s the name of the structure when HB and oxygen bind?
Oxyhaemoglobin
What’s the process called when oxygen joins to Hb
Association or loading
What’s the process called when oxygen leaves oxyhaemoglobin
Disassociation or unloading
What is meant by affinity for oxygen
Tendency a molecule has to bind to with oxygen
What affects affinity
Partial pressure of oxygen
What’s partial pressure of oxygen a measure of
Oxygen concentration
When does oxygen load/unload
Loads when there’s a high pO2
Unloads when there’s a low pO2
What happens when cells respire
They use up oxygen lowering Po2
What does an oxygen dissociation curve show
How saturated the haemoglobin is with oxygen at any given pO2
What is Hb like in an organism with low oxygen environments
Hb has a higher affinity for oxygen than human Hb
As there isn’t must oxygen available
Hb has to be good at loading any available o2
What is Hb like in an organism with high activity levels
Hb has a lower affinity for oxygen than human as they need Hb to easily unload oxygen so it’s available to use
How does size affect the type of Hb
Small mammals tend to have high SA:V ratio than larger mammals
So they lose heat easily and quickly so have a high metabolic rate to help keep warm
So have a increased oxygen demand meaning they have Hb with lower affinity than humans as they need Hb to easily unload o2
What is cardiovascular disease
General term used to describe diseases associated with the heart and blood vessels
What is coronary heart disease
A type of cardiovascular disease, which occurs when coronary arteries have a lot of atheromas in them which restricts blood flow to the heart muscles
It can lead to myocardial infarction
Name 4 risk factors associated with cardiovascular disease
High blood pressure
High blood cholesterol
Poor diet
Smoking
Why do large mammals need specialised mass transport
Due to larger mammals smaller sa:v ratio they need to carry raw materials from specialized exchange organs to their body cells
What is the circulatory system made up of
Heart and blood vessels
What does the heart do
Pumps blood through blood vessels to reach different parts of the body