Digestion And Intro To Metabolism Flashcards
For digestion in the mouth, what happens?
What are the enzyme in the saliva that do this
The food gets homogenized to an aqueous slurry
This happens because of amylase and lipase
For digestion in the stoumach, what happens?
What are the enzyme in the stomach that do this
Uses low ph to denature the protiens
These denatured protiens work better as substrates for pepsin which is protease that breaks down the protiens.
For digestion in the pancrease, what happens?
What are the enzyme that do this
NaHCO3 is released to neutralize the food
Digestive enzymes are also released that digest protiens, lipids, and carbohydrates
For digestion in the gall bladder , what happens?
The gall bladder releases bile salt to digest lipids
What is a protease in the digestion of proteins
It cleaves protiens
What is a zymogen in the digestion of protiens
The inactive form of a protease
so that the protease doesn’t cleave protiens it not supposed to (including itself)
How are zymogens used
They’re first stored in granules near the cell membrane
They get released then activated by cleavage
What is a zymogen that can self activate and doesn’t need to be cleaved to be activated
Pepsinogen that turns into the protease pepsin
What is the process of the digestion of protiens
Theses protiens are first cut into amino acids and oligopeptides through use of proteases in the lumen of the intestine
These proteases then get dissolved in the lumen
Peptidases that cleave oligopeptides are attached to the outside surface of the intestinal cells. The olgopeptides get cleaved into di and tri peptides
The di and tripeptides and amino acids are sent into the intestinal cell then out into the bloodstream via transporters in the cell membrane
What are the enzymes used in the digestion of carbohydrates
Alpha amylase
Maltase
Sucrase/lactase
What does alpha amylase do
It cleaves alpha 1-4 glycosidic bind of carbs
Cant cleave alpha 1,6 bonds or any closer
What does Maltase, alpha glucosidase, and alpha dextrinase do
Maltase, alpha glucosidase, and alpha dextrinase complete the hydrolysis of starch
What do Sucrase and lactase do
Where are they
Their on the surface of intestinal cells and also cleave carbohydrates
How is the digestion of lipids done
Triacylglycerols are mostly the lipids getting digested (three fatty acids and a glycerol back bone)
These form an emulsion in the stomach, but amphipathic bile salts enhance break down of these emulsions
Lipases cleave two of the fatty acids off of the lipids and leave one (to make a mono acyl glycerol)
What happens after the lipase cleaves off the fatty acids and forms the mono acyl glycerol
The fatty acids and monoacylglycerol turn into micelles get sent through a fatty acid binding protien on the surface of the intestinal cell membrane
Then inside the cell there is a fatty acid transport protien that send the fatty acids and monoacylglycerol micelles to the smooth ER
In the smooth ER there are chylomicrons that transport the triacylglycerols, protiens, phospholipids, cholesterol and fat soluble vitamins to the lymph system
What is the size of the chylomicron
2000A in diameter
What is stage 1 2 3 in metabolism
- Digestion
- Breakdown to small units
- Energy production
Large molecules are prepared for use in metabolism
What is metabolism
A series of linked chiral reactions that transform one molecule to another that’s required by the organism, give energy as well
Involves catabolism and anabolism
What is catabolism
Breakdown of fuel molecules to useful energy, H2O and co2
What is anabolism
The building up of simple molecules and energy to complex molecules
The degradation (catabolism) and biosynthstic (anabolism) pathways are generally _______
Separate, which allows for control
What is metabolomics
A tool to understand changes in metabolites
What does adp to atp signify
Oxidation of fuel molecules or photosynthesis
What does atp to adp signify
Motion, active transport, biosynthesis, or signal amplification
Why is atp energy rich
It has phosphoanhydride bonds (the bonds between each of the three alpha beta gamma phosphate groups)
What are the factors of why atp hydrolyzes to adp or amp
The electrostatic repulsion of the 4 negative charges in the 3 phosphates
There is better resonance stabilization for ADP, Pi
Theres less solvation for atp, making it easier to lose a phosphate group
The entropy of atp is lower than adp.
What is the free energy for atp to adp
what about atp to amp
What about under cellular conditions
What does the exact value depend on
-30.5kj/mol
-45.6kJ/mol
-50
The ionic strength of the solution and to concentrations of mg2+ and other ions
Explain how atp can be coupled to other reactions to make them more favourable and happen faster
A to B had free energy of +16, not favourable
If the hydrolysis of atp is paired to the reaction of A to B, the to free energy for the reaction becomes -13.8, more favourable
For keq, atp hydrolysis couple with the reaction of a to B makes more products at equilibrium (higher keq)
If not couple the keq<1 and the reactants are favours (reaction to B less favourable
Slides 15 and 16
Explain
Is atp used as long term storage
No it’s an immeasurable donor of free energy but isn’t use for long term energy storage
What does catabolism to to atp and how
In catabolism ATP is made from ADP and Pi
The energy to make the atp comes from the oxidation of fuel molecules
What is oxidation and how is it related to free energy
It’s the loss of electrons of one thing to give to another molecule , For aerobic organisms these electrons are gained by oxygen
The most reduced molecule (most hydrogens, ex. Methane) has the most energy that can be released by being oxidized (most negative delta G)
The most reduced molecule (most hydrogens, ex. Methane) has the most energy that can be released by being oxidized (most negative delta G)
Why is this
As the compund gets oxidized one carbon atom at a time, that energy from its oxidation is used
to make a compund with a high phosphoryl transfer potential (giving up phosphate)
Or to make an ion gradient
The end point is usually atp
What are activated carriers
Atp is an activated carrier of a phosphoryl group
Others can be activated carriers of electrons or two carbon fragments
What are the types of activated carriers
Carriers of Electrons in fuel oxidation
Carriers of electrons in biosynthesis
Carriers of two carbon fragments
What are examples of Carriers of Electrons in fuel oxidation
NADH FADH2
What are examples of Carriers of Electrons in biosynthesis
The reduced form of NADP+ (NADPH)
What are examples of Carriers of two carbon fragments
Acetyl coa
How is metabolism regulated
Through the control of
Amount of enzymes (how fast they’re made and degraded)
Catalytic activities of those enzymes (feedback inhibition where the product inhibits the enzyme, reversible covalent modification)
The accessibly of their substrates (compartmentalizations in eukaryotes, flux of substrates between these compartments)
What is the energy charge of the cell
The metabolic reactions of the cell are controlled by the energy status of the cell
When the energy charge is 1 all atp is being use and none is being made
When the energy charge is 0 all atp is being made and none is being used
What is the energy charge of most cells
Between 0.8 and 0.95
Equations for energy change and phosphorylation potential
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