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What does the term Carbohydrate mean?
polyhydroxy aldehydes and ketones
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Monosaccharide name for an aldehyde
Aldose
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Monosaccharide term for Ketones
Ketose
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3 carbons in a monosaccaride
triose
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4 carbons in a monosaccharide
tetrose
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5 carbons in a monosaccharide
pentose
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6 carbons in a monosaccharide
hexose
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Dihydroxyacetone
only ketotriose
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Glyceraldehyde
only Aldotiose
*has a chiral carbon
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In a Fischer projection where is the most oxidized carbon?
The top
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Groups that aren't part of the main chain are pointed which way?
They project horizontally towards the viewer
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If the sterocenter at the bottom of the chain has an OH to the right, is the sugar D or L
D
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If the sterocenter at the bottom the chain has an OH to the left is the sugar D or L?
L
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Are the most common sugars in D or L form?
D
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Enantiomers
There is a change at every chiral carbon
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Epimers (special Diasteriomers)
If theres a change at 1 chiral carbom
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Diasteriomers
There is a change at more then 1 chiral carbon
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The most simple sugars of four or more carbons exist in what form?
cyclic (hemiacetal/hemiketal) form
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What group in the sugar reacts with the carbonyl carbon?
A hydroxy group
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For D sugars if the OH on the anomeric carbon is "up" then the carbon is what?
Beta carbon
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For D sugars if the OH on the anomeric carbon is "down" then the carbon is what?
Alpha carbon
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a 6-membered ring is called?
Pyranose
(most stable)
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A 5-membered ring is called?
Furanose
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To form a cyclic sugar the attack of an alcohol on the carbonyl carbon forms what?
Glucose
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What is formed at the anomeric carbon during the formation of cyclic sugars?
Hemiacetal
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In the formation of the hemiacetal, an alpha anomeric carbon has the OH pointing?
Down
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In the formation of the hemiacetal, a beta anomeric carbon has the OH pointing?
Up
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What is a reducing sugar?
a free aldehyde that can be oxidized
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In what function are reducing sugars important?
They are important in the metabolism of polysaccarides
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The OH groups of sugars can reach with a phosphorylating agent to give what?
Phosphate ester
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Phosphoesters are common in what kind of pathways?
In metabolic pathways
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GlcNAc
N-Acetylglucosamine
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What can the anomeric carbon react with?
an OH group or an alchohol
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when the anomeric carbon reacts with an alchohol on another sugar what does it yeild?
a glucosidic bond
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Animals lack what when it comes to cellulose?
The enzymes necessary to hydrolyze cellulose
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what are starches
starches are storage forms of glucose found in plants
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how do animals store glucose?
as glycogen
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Where is the division between the 2 stages of glycolysis?
Right after the second ATP is invested
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What is a kinase?
It does phosphorylation with ATP, either using it or producing it.
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Step 1 of Glycolysis
- 1. Hydroxy group attacks the phosphoanhydride on ATP
- 2. Gives Glucose a charge
- 3. Makes the Oxygen on C6 of Glucose more reactive
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Why is glucose given a charge in step 1 of glycolysis
to keep it in the cell.
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What type of intermediate does step 2 of glycolysis go through?
It goes through an enodiol intermediate to isomerize from an aldehyde to a ketone
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Why isn't C1 available for phosphorylation on glucose in glycolysis?
It is anomeric, but C1 on Fru can be phosphorylated
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Step 1 of Glycolysis
Glucose -> Glucose-6-Phosphate
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Step 2 of Glycolysis
Glucose-6-Phosphate -> Fructose-6-Phosphate
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Step 3 of Glycolysis
Fructose-6-Phosphate -> Fructose-1.6-biPhosphate
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Step 4 of Glycolysis
Fructose-1,6-biPhosphate -> Trioses
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Step 5 of Glycolysis
Isomerization of DHAP
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What does bis-phosphate mean?
2 separate phosphates
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Allosteric regulation is based on what?
Cell condition
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the reverse reaction of step 4 of glycolysis is what?
an aldol condensation reaction
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Having 2 phosphose on a 6-carbon sugar allows what?
Cleavage into 2 phosphorylated trioses
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DHAP and Glyc-3-P are in equilibrium that favors which one?
DHAP
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Even though DHAP is favored over Glyc-3-P, it is rapidly converted. Why?
Le'Chatlier's Principle
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The loop in Triose Phosphate Isomerase serves as what?
A lid to prevent biologically useless but energtically favorable side reaction.
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overall glycolysis yields what?
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Step 6 of Glycolysis
Glyceraldehyde-3-Phosphate -> 1,3- Bis phosphoglycerate
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What does step 6 of Glycolysis produce?
A high energy mixed anhydride bond
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In step 6 of glycolysis what preserves energy from the first step to couple it to the second step?
The thiosester intermediated with the enzyme's cys residue
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Step 7 of Glycolysis
1,3-Bisphosphoglycerate -> 3-phosphoglycerate
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What does step 7 of glycolysis produce?
the first production of ATP from the high energy mixed anhydride.
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Step 8 of Glycolysis
3-Phosphoglycerate -> 2-Phosphoglycerate
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What do the first 2 steps of step 8 make?
a phosphoend pyruvate
( a molecule with high phosphoryl transfer potential)
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What is the function of Mutas phosphoglycerate?
It catalyzes step 8 of glycolysis
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Step 9 of Glycolysis
3-Phosphoglycerate -> Phosphoenolpyruvate
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Step 9 of glycolysis is catalyzed by what?
By enolase
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What does the phosphate group to in step 9?
It hold the PEP in the enol form, rather then the keto form
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Step 10 of Glycolysis
Phosphoenolpyruvate-> Pyruvate
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What catalyzes step 10 of glycolysis?
Pyruvate kinase
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Is step 10 energetically favorable or unfavorable?
It is favorable, pyruvate is very stable compared to the enol from. and PEP has a very high transfer potential
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What does step 10 produce?
the second ATP
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Glycolysis Produces ATP, but uses what?
NAD+
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In Aerobic conditions what happens to NADH
it is reoxidized in electron transport
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In anaerobic conditions what needs to happen to NAD+?
It needs to be regenerated in order to continue producing ATP through glycolysis
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Lactose=?
Galactose + Glucose
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Sucrose= ?
Glucose - Fructose
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Gluconeogenesis
Synthesis of glucose from pyruvate instead of carbs
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Does gluconeogenesis use the same enzymes as glycolysis?
no, they each use different enzymes gluconeogenesis uses phosphatase, which removes a phosphate group.
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In the reaction of Pyruvate to PEP what enzyme cofactor is used?
Biotin, to carry CO2
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In the reaction of Pyruvate to PEP is ATP consumed or produced?
It consumes 2 ATP
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What is the biotin cofactor bound to?
To a Lys residue
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What carries the biotin cofactor?
Pyruvate carboxylase
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In the reaction of fructose-1,6-bisphosphate to fructose-6-phosphate how is the phosphorus released?
It is released as PO43- instead of ATP
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What happens to the glucose produced by glucose-6-phosphate?
it is released into the blood
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how is the glucose from glucose-6-phosphate stored?
as glycogen
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Why is Glycogen metabolism regulated?
So that sufficient glucose is available for the body's energy needs
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what controls glycogenesis and glycogenolysis?
insulin, glucagon, and epinephrine
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what does insulin do to glycogenesis?
it speeds it up
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what does glucagon do to glycogenolysis?
it speeds it up
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what is the function of glycogen phosphorylase during glycogenolysis?
it removes glucose unites from non-reducing end of glycogen until 4 are left approaching a branch point.
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