BioChem Block 4 Flashcards
ATP can be used do work such as what 4 things?
Contract muscles
Synthesize large molecules
Nerve impulses
Move substances across cell mem.
Define metabolism
All chemical reactions that provide energy and substances required for continued cell growth
What are the two metabolism reactions?
Catabolic- breaking down
Anabolic- build
What are the 3 stages of digestion?
1- digestion/hydrolysis
2- degradation/small oxidation
3- release of energy to synthesize ATP
What events occur in stage 1 of Digestion?
Polysaccharieds->mono
Fats->glycerol and FAs
Proteins-> aa
How does catabolism begin?
Digestion
As long as cell shave oxygen, ? and ? can be reoxidized via ?
NADH
FADH2
ETC
What are the 3 parts of ATP?
Adenine
Ribose sugar
3 phosphate groups
Hydrolysis of ATP can provide _ k/cal/kj
7.3 kcal
31kJ
Hydrolysis of ATP is an ___ reaction on an energy curve
Exothermic
What is the first step in breaking down glucose?
What does this require?
Adding phosphate
Requires 3.3kcal/14kj
ATP= ? + ? + ?
ADP + Pi + 7.3
G6P= ? + ? + ?
Glucose + Pi + 3.3
Overall ATP + glucose= ?
ADP + G6P + 4.0
Define Oxidation
Gain of O
Loss of H/e-/energy
Define Reduction
Gain of H/e-/energy
Loss of O
What does NAD stand for?
Nicotinamide adenine dinucleotide
What are the 3 parts of NAD?
Nicotinamide group
Ribose sugar
ADP
Oxidized form of NAD undergoes reduction when?
C atom in Nicotinamide reacts w/ 2 H, leaving one H
What kind of reactions is NAD required for?
Dehydrogenation that produce C=O
Give an example of a reaction that NAD would be a part of?
Oxidation of alcohols to aldehydes/ketones
Oxidation of ethanol to ethanal in liver w/ reduction of NAD to NADH + H
What does NADP stand for?
Nicotinamide adenine dinucleotide phosphate
What kind of reactions is NADP used for?
Anabolic reactions, lipid/nucleic acid synthesis
NADP and NAD are similar except
2’ OH group replaced w/ phosphate group
What is the reduced form of NADP?
NADPH
What does FAD stand for?
Flavin adenine dinucleotide
What are the 2 parts of FAD?
ADP
Riboflavin
What are the 2 parts of riboflavin?
(Vit B2)
Ribitol- sugar alcohol
Flavin
What happens when FAD is reduced?
2 N atoms from flavin react w/ 2 H atoms
Fad-> FADH2
What kind of reactions is FAD used for?
Dehydrogenation
C-C -> C=C
What is an example of a reaction that would require FAD?
In CAC, conversion of succinates C-C -> C=C in fumarate w/ FAD->FADH2
What are the 3 parts of Coenzyme A?
Pantothenic Acid (B5)
Phosphorylated ADP
Aminoethanethiol
What is the function of CoA?
Prepare acyl groups for reactions w/ enzymes
Where/what is the reactive feature of CoA?
Thiol group -SH
What form ACoA?
Acetyl group + CoA
To digest carbs, enzymes in salivary glands hydrolyze what bonds?
a-glycosidic in amylose and amylopectin
Produces: maltose, glucose, dextrins
Define dextrins
Small polysaccharides 6-8 glucose in length
What happens to carbohydrate digestion in the stomach?
Stops due to pH
Glucose + glucose
Glucose + galactose
Glucose + fructose
Maltose
Lactose
Sucrose
Enzymes in pancreas continue carb digestion how?
Hydrolyze dextrins-> maltose and glucose
Enzymes produces in intestinal mucus lining can hydrolyze which disaccharides?
Maltose
Lactose
Sucrose
What 2 sugars does the liver use to make glucose?
Hexoses fructose and galactose
Glucose is primary energy source for ? 3 things
Muscle contractions
RBCs
Brain
Where is glycogen stored?
Liver
Skeletal muscle
Glucose is degraded through what pathway?
Glycolysis- anaerobic path
Where does glycolysis occur?
Cytosol
First 5 steps of glycolysis are called?
Last 5 steps are called?
Energy investment
Energy generating
What are the 10 reactions of glycolysis
Phosphorylation Isomerization Phosphorylation Cleavage Isomerization Oxidation/Phosphorylation Phosphate transfer Isomerization Dehydration Phosphate transfer
Overall, what is the net gain from glycolysis?
2 ATP
2 NADH when glucose is converted to two pyruvate
How/where does galactose enter glycolysis?
Galactose->ATP->G1P->G6P at Reaction 2
How does fructose from muscles enter glycolysis?
How does fructose from the liver enter glycolysis?
F6P-> Reaction 3
Fructose->F1P-> Glyceraldehyde 3 Phosphate, Reaction 6
Where/how is glycolysis regulated?
1- Hexokinase, inhib by high G6P
3- PFK-1, inhib by high ATP, stim by high AM/DP
10- pyruvate kinase, inhib by high ATP or ACoA
What is it called when the first enzyme of a pathway is inhibited?
Feedback control, type of enzymatic regulation
What/where are the allosteric enzymes of glycolysis?
3- PFK 1
10- pyruvate kinase
What is the purpose of the PPP?
Alternative route to oxidize glucose for anabolic purposes
What does the PPP produce?
NADPH
5C pentoses
NADP is used for biosynthesis of ? 3 things where?
Nucleic acids
Cholesterol
FAs
In liver and adipose cells
How is PPP started?
G6P converted to ribulose-5-phosphate
Reqs two NADP
What is the second step of the PPP?
R5P isomerized by PPP isomerase to ribose-5-phosphate
What is the final step of the PPP?
Three R5P to two hexose molecules and one triose to participate in glycolysis
Under aerobic conditions, oxygen will convert pyruvate into ?
What about under anaerobic conditions?
ACoA, CO2
Lactate
What do yeast cells reduce pyruvate into?
Ethanol
CO2
How many ATP are generated in glycolysis when glucose is converted into two pyruvate?
2 ATP
Where does pyruvate move to during aerobic conditions?
Move from cytosol into mitochondria
Aerobic conditions produce what products from pyruvate?
CO2
NAD reduced
Acetyl CoA
What happens to pyruvate during anaerobic conditions?
Remains in cytosol, reduced to lactate
NAD oxidized G3P to produce ATP
After exercise and O2 debt is repaid, what happens to lactate?
Transported to liver, converted to pyruvate
Bacteria converting pyruvate to lactate is seen in what examples?
Pickling
What type of conditions do yeast convert sugars to ethanol?
Fermentation, anaerobic conditions
3 steps of fermentation
Pyruvate formed from glycolysis
CO2 removed
NAD regenerated from ethanal reducing to ethanol
Glycogen is a polymer of glucose with what types of bonds?
a1-4 in chain
a1-6 on branches
When glycogen stores are full, what happens to any remaining glucose?
Converted to triacylglycerols and stored as fat
Define glycogenesis
Converting glucose to glycogen
What product of glycolysis can also be stored as glycogen?
G6P
What are the 3 Reactions of Glycogenesis?
Isomerization
Activation
Synthesis
What happens in Reaction 1 of Glycogenesis?
G6P->G1p by phosphoglucomutase
What happens in Reaction 2 of Glycogenesis?
UDP added to glucose by pyrophosphorylase
What happens in Reaction 3 of Glycogenesis?
UDP-glucose broken by Glycogen Synthase
Glucose added to glycogen chain
Define Glycogenolysis
Glycogen conversion to glucose
What are the 4 Reactions of Glycogenolysis?
Phosphorylation
Hydrolysis
Isomerization
Dephosphorylation
What does insulin do to regulate glycogen metabolism?
Inc glycogen synthesis
Inc oxidation reactions (glycolysis)
What does glucagon do to regulate glycogen metabolism?
Increases glycogenolysis
Inhibits synthesis of glycogen
What converts glycogen phosphorylase from inactive to active?
Epinephrine
G1P and G6P can both be seen as intermediates of what 2 processes?
Glycogenesis
Glycogenolysis
UDP-glucose is only involved with which process?
Glycogenesis
With plentiful O2, pyruvate from glycolysis is converted to _____ , catalyzed by _____
ACoA
Pyruvate Dehydrogenase
CAC connects what two things?
ACoA from stage 2 to ETC in stage 3
CAC uses ___ to produce CO2 and reduce ___ and ___
ACoA
FADH2
NAD
Each turn of the CAC includes ___ oxidation reactions
4
In 4 oxidation reactions from one turn of CAC, what is produced?
3 NADH
1 FADH2
1 ATP
What 3 things inhibit CAC?
What stims CAC?
ATP, NADH, Citrate
ADP
What 3 CAC enzymes respond to both allosteric regulation and feedback inhibition?
Citrate Synthase #1- +ADP, -ATP, NADH, citrate
Isocitrate Dehydrogenase#3- -ATP, NADH, +ADP
a-Ketoglutarate dehydrogenase #4- - NADH, succinyl CoA, + ADP
PTs w/ diseases of their CAC will show what S/Sx?
Neurological problems
Excrete high amounts of CAC compounds in urine
For each molecule of glucose that completes glycolysis, the oxidation of two pyruvate and CAC, what is created?
4 ATP
10 NADH
2 FADH2
Glycolysis = _ATP _ NADH
2 Pyruvate Oxid= _ATP _NADH
CAC w/ 2 ACoA= _ATP _NADH
2 2
0 2
2 6 2 FADH2
Each step of the ETC is an individual ?
Oxidation-reduction reaction
Define Oxidative Phosphorylation
Energy from ETC used to synthesize ADP + Pi-> ATP
ETC and oxidative phosphorylation will continue as long as __ is present
O
Which protein complexes extend through inner mitochondrial membrane?
1 3 4
One end- matrix
Other end- intermembrane space
What are the two e- carriers of the ETC?
CoQ
Cytochrome C
Define Chemiosmotic Model
Links energy from ETC to H ion gradient to drive ATP synthesis
Moving H from matrix to intermembrane space lowers the pH in the ____ and creates a ______
intermembrane
H gradient
electrochemical gradient
NADH enters ETC @ complex _
FADH2 enters ETC @ complex _
What does this cause?
1
2- doesn’t connect outside of the matrix, FADH2 generates less energy
Total ATP for complete oxidation of glucose under aerobic conditions can be calculated by combining what numbers?
Glycolysis- 7
Oxidation of pyruvate- 5
CAC- 20
ETC
Where does the malate-aspartate shuttle operate?
Heart
Liver
2 ACoA= __ CO2 + _ATP from two turns of CAC
4 CO2
20 ATP
Grand summary of TOTAL ATP produced from oxidation of one glucose?
32
What are the two main components of a cell membrane?
Glycerophospholipids
Sphingolipids
What are the 2 parts of a phospholipid?
Non-polar/hydrocarbon tail w/ 2 long chain FA
Polar region of phosphate and ionized amino alcohol
Why don’t phospholipids fit closely together in the bilayer?
Most are unsat FA, kinks in C chains @ cis-double bonds
Define Fluid Mosaic Model
Lipid bilayer is not rigid, but dynamic and fluid like
Where do peripheral proteins show up in the bilayer?
Just one surface
Where do integral show up in the bilayer?
Extend through whole bilayer
Carbohydrates that emerge from cell membrane perform what 2 functions?
Cell recognition
Cell communication- hormones/neurotransmitters
Cholesterols majority presence but large and rigid nature causes what to a cell membrane?
Reduces flexibility
Adds strength to membrane
Prevents crystalization
________ membranes separate aqueous solutions
Nonpolar