Biochemistry Flashcards
Acetone
Dihydroxy Acetone
Glyceraldehyde
Glycerate
Glyceric Acid
Glycerol
Hydroxy Acetone
Fill in the blank:
- Glucose
- Glucose-6-phosphate
- hexokinase/glucokinase (liver)
- ATP -> ADP
Fill in the Blank:
- Glucose-6-phosphate
- Fructose-6-phosphate
- Phosphogluco-isomerase
Fill in the blank:
- Fructose-6-phosphate
- Fructose 1,6-bisphosphate
- Phosphofrucktokinase-1
- ATP -> ADP
Fill in the Blank:
- Fructose 1,6-bisphosphate
- Glyceraldehyde-3-phosphate
- Dihydroxyacetone phosphate
- aldolase
Fill in the blank:
- Dihydroxyacetone phosphate
- Glyceraldehyde-3-phosphate
- triose phosphate isomerase
Fill in the Blank:
- Glyceraldehyde-3-phosphate
- 1,3-Bisphosphoglycerate
- Glyceraldehyde-3-phosphate dehydrogenase
- NAD -> NADH, +Pi
Fill in the Blank:
- 1,3-bisphosphoglycerate
- 3-Phosphoglycerate
- Phosphoglycerate kinase
- ADP –> ATP
Fill in the Blank:
- 3-Phosphoglycerate
- 2-phosphoglycerate
- Phosphoglycero-mutase
Fill in the Blank:
- 2-phosphoglycerate
- Phosphoenolpyruvate
- Enolase
- H2O
Fill in the Blank:
- Phosphoenolpyruvate
- Pyruvate
- Pyruvate kinase
- ADP –> ATP
What are some causes of lactic acidosis?
- Circulatory insufficiency
- anemia
- mitochondrial enzyme defects
- Poisons (CN, CO)
- cancer
- ethanol intoxication
- hepatic failure
Which glycolysis steps are irreversible?
Glucose –> Glucose -6-Phosphate
(Enzyme: hexokinase, glucokinase)
Fructose-6-phosphate –> Fructose-1,6-BP
(Enzyme: PFK-1)
Phosphoenol Pyruvate –> Pyruvate
(Enzyme: Pyruvate Kinase)
What important molecules of metabolism CAN cross the inner mitochondrial membrane?
Malate
Aspartate
glutamate
alpha-ketoglutarate
pyruvate
Why is the malate-aspartate shuttle important?
(where is it used?)
It is a shuttle system for electrons involving NAD+/NADH since NADH cannot cross the IMM
- used mainly in liver, kidney, and heart
Draw the Malate-aspartate shuttle
What is the product of anearobic glycolysis?
Lactate
What cells use lactate, what cells produce it?
Produce:
RBC
Working Muscle (esp. fast twitch)
Use:
Liver (precursor for gluconeogenesis)
Resting Muscle (as fuel)
Heart (as fuel)
How is lactate produced?
Through anaerobic glycolysis:
Pyruvate + NADH –> Lactate + NAD+
(Enzyme: Lactate dehydrogenase)
What is the ATP production for aerobic and anaerobic metabolism?
- *Aerobic**: 30-32 ATP
- *Anaerobic:** 2 ATP/glucose
What are the advantages and disadvantages to aerobic glycolysis?
More Efficient: Aerobic produces 15x more ATP than anaerobic
Less Powerful: aerobic is 30x slower than anaerobic
Anaerobic can result in lactic acidosis
What is the anaerobic threshold?
Biochemical definition: aerobic system of working muscle is “maxed out”
Physiolgoical definition: level of exercise at which lactate begins to rise in the blood
What tissues are dependent on anaerobic glycolysis?
- RBC (no mitochondria)
- WBC
- Lens of the eye
- Kidney medulla
- exercising muscle
How is lactate utilized in the body?
Through the Cori Cycle:
Resting muscle and heart use lactate as a fuel
Liver can convert lactate to glucose via gluconeogenesis
How does glucokinase and hexokinase regulate glycolysis?
Hexokinase has a high affinity for hexoses and is able to remove glucose from the blood even at low blood-glucose levels
- inhibited by G6P
Glucokinase has a lower affinity for glucose and does not allow the “altruistic” liver to use glucose at low blood-glucose levels
- no product inhibition
How is glycolysis regulated by phosphofructokinase?
PFK-1 is allosterically activated by:
F-2,6-BP (liver)
AMP (muscle)
PFK-1 is allosterically inhibited by:
ATP (all tissues)
Citrate (all tissues)
H+ (all tissues)
Explain the Pyruvate Dehydrogenase Complex
- Enyzme that converts Pyruvate to Acetyl CoA
- Contains Three different enzymes:
E1 = pyruvate dehydrogenase (contains Thiamine pyrophosphate)
E2 = transacetylase (contains lipoic acid)
E3 = dihydrolipoyl dehydrogenase (contains FAD)
What makes production of Acetyl CoA from the PDH complex so irreversible?
Carbon dioxide is a product
- since CO2 is promptly removed from the system through respiration, there is never enough built up to push the reaction to the left
What regulates the PDH complex?
It is inactivated by phosphorylation (kinase)
The kinase is activated by a build-up of products:
Acetyl CoA and NADH
and Inactivated by a need for ATP:
ADP and Pyruvate
Activated by dephosphorylation (phosphatase)
The phosphatase is activated by Ca2+
- this makes sense b/c Ca is released while muslces are working and need more ATP
What is Leigh Syndrome?
Neurodegenerative disorder (subacute necrotizing encephalomyelopathy) caused by lactate build-up
- Both acute and chronic killing of cells in the brain and spinal cord
- pediatric onset 1-5yrs present with:
Weakness
Hypotonia (low muslce tone)
ataxia (lack of muscle control)
spasticity
dyspnea (respiratory distresss)
opthalmoglia (paralysis of ocular muscles) - ultimately lethal
- Patients with E1 disorders can be treated with thiamine
Draw the Citric Acid Cycle and label the Irreversible reactions
What are the steps regulated in the TCA cycle?
1. Acetyl CoA –> Citrate
(Enzyme: Citrate Synthase)
Citrate negatively inhibits rxn
2. Isocitrate –> Alpha-ketoglutarate
(Enzyme: Isocitrate Dehydrogenase)
Inhibited by: NADH
Activated by: ADP and Ca+
3. Alpha-KG –> Succinyl CoA
(Enzyme: Alpha-KG dehydrogenase)
Inhibited by NADH and Ca+
4. Malate –> Oxaloacetate
(Enzyme: Malate Dehydrogenase)
Inhibited by NADH
What are the complexes of oxidative phosphorylation?
Complex I: NADH Dehydrogenase
Complex II: Succinate Dehydrogenase
Complex III: Cytochrome bc1
(Cytochrome c reductaes)
Complex IV: Cytochrome oxidase
(Cytochrome aa3)
Complex V: ATP Synthase
(F1F0ATPase)
(NADH:Q reductase)
name two saturated fatty acids
Palmatate C16:0
Stearate C18:0
Name Two unsaturated fatty acids
Oleate C18:1
Linolate 18:2
What does CPT I do?
Makes FA-CoA into FA-Carnatine so it can get into the mitochondrial matrix
What does CPT II do?
Makes FA-carnitine back into FA-CoA so it can undergo ß-oxidation.
How does FA-Carnatine get into the mitochondrial matrix?
Carnatine-acetylcarnatine translocase
What is generated from one ß-oxidation cycle?
1 NADH
1 FADH2
1 Acetyl CoA
+
Initial FA chain - 2 C’s
