Part 1: Biochemistry (Pathways & Cycles) Flashcards
Glycolysis occurs in
The Cytosol (Cytoplasm)
Aerobic Glycolysis = ___________ -> ______________
Glucose -> 2 pyruvate (pyruvic acid)
Anaerobic Glycolysis = ____________ -> _____________
Glucose -> 2 lactate (lactic acid)
Glycolysis is stimulated by what hormone?
Insulin
Glycolysis is inhibited by what hormone?
Glucagon
What are the regulatory enzymes involved in glycolysis?
1) Hexokinase
2) Phosphofructokinase (PFK)
3) Pyruvate Kinase
Match the step with the regulatory enzyme in glycolysis:
Hexokinase
Phosphofructokinase
Pyruvate
Step 1: Hexokinase
Step 3: Phosphofructokinase
Step 9: Pyruvate
What is the rate limiting enzyme of glycolysis?
Phosphofructokinase (PFK)
What reaction of glycolysis has a net gain of ATP?
Step 9 (where pyruvate kinase acts)
What is the net gain of ATP and NADH in aerobic glycolysis?
2 ATP
2 NADH
Aerobic glycolysis continues in the…
Kreb Cycle
Anaerobic glycolysis continues in the…
Cori Cycle
What is the net gain of ATP in anaerobic glycolysis?
2 ATP
The Cori cycle occurs under ______________ conditions and involves the ________ and the _________.
Anaerobic; Muscle & liver
What is the net gain at the end of the Cori cycle?
2 Pyruvate
2 NADH
2 ATP
The Pyruvate Dehydrogenase Complex occurs in
The mitochondrial matrix
The Pyruvate Dehydrogenase Complex converts…
Pyruvate into acetyl-CoA
What type of reaction is the Pyruvate Dehydrogenase Complex?
Oxidative decarboxylation (NADH is produced and CO2 is lost)
The Pyruvate Dehydrogenase Complex is stimulated by what hormone?
Insulin
The Pyruvate Dehydrogenase Complex is inhibited by what hormone?
Glucagon
What coenzymes are involved in the Pyruvate Dehydrogenase Complex? (5)
1) NAD+ (B3)
2) FAD+ (B2)
3) Thiamine Pyrophosphate (B1)
4) Lipoic Acid
5) CoA (B5)
AKA’s for the Kreb’s Cycle:
Citric Acid cycle & Tricarboxylic acid cycle (TCA)
The Krebs Cycle occurs in
The mitochondrial matrix
What are the regulatory enzymes involved in the Krebs Cycle? (3)
1) Citrate synthase
2) isocitrate dehydrogenase
3) alpha-keto glutamate dehydrogenase
How many steps are there in the Krebs Cycle?
8 (not including production of cis aconitate)
For every 1 round of the Krebs Cycle, how many ATP are produced?
12
Order of products during the Krebs Cycle. (10)
Oxaloacetate
Citrate
Cis Asconitrate
Isocitrate
Oxalosuccinate
Alpha Ketoglutarate
Succinyl-CoA
Succinate
Fumarate
L-Malate
For every 1 NADH, ____ ATP are produced in the Krebs Cycle via the _______________
3; electron transport chain
For every 1 FADH2, ____ ATP are produced in the Krebs Cycle via the ___________________.
2; electron transport chain
For every 1 GTP, ____ ATP are produced in the Krebs Cycle.
1
The synthesis of ATP in the Electron transport chain is referred to as
Oxidative phosphorylation
Electron transport chain occurs in…
The INNERmitochondrial membrane
Each NADH in the Electron transport chain produces how many ATP?
3
Each FADH in the Electron transport chain produces how many ATP?
2
What molecules most readily accepts electrons?
Oxygen
What hypothesis couples the Electron transport chain with ATP synthesis?
Chemiosmotic Hypothesis (Mitchell hypothesis)
Coenzyme Q10 is similar in structure to
Vitamin K
Coenzyme Q10 is naturally produced in the
Liver
What does Coenzyme Q10 do in the Electron transport chain?
1) delivers Oxygen to the ETC
2) activates complex I,II & III in the ETC
What are the inhibitors of the Electron transport chain? (5)
1) Cyanide
2) Amitol
3) Rotinone
4) Carbon Monoxide
5) Excessive Energy
Gluconeogenesis occurs in
Primarily cytosol, but conversion of pyruvate -> oxaloacetate -> malate occurs in the mitochndria
What does Malate do during Gluconeogenesis?
Crosses the mitochondrial membrane to the cytosol where it is converted back into oxaloacetate
What are the 3 primary precursors for gluconeogenesis?
1) Glycerol
2) Lactate
3) Amino acids
When is glycerol generated?
During breakdown of triglycerides in adipose tissue
Where is Lactate derived from?
Muscle during anaerobic exercise
What are the enzymes of Gluconeogenesis? (4)
1) Pyruvate carboxylase
2) PEP carboxykinase
3) Fructose-1,6-biphosphatase
4) Glucose-6-phosphatase
The Gluconeogenesis reaction involving Pyruvate carboxylase is a ____________ reaction with ______ as the coenzyme.
Carboxylation; biotin
The reaction produced by pyruvate carboxylase in Gluconeogenesis occurs in
Mitochondria
Both ___________________ and _________________ are needed to bypass pyruvate kinase in glycolysis.
Pyruvate carboxylase & PEP carboxykinase
What enzyme in Gluconeogenesis bypasses PFK in glycolysis?
Fructose-1,6-biphosphatase
Glucose-6-phosphatase is present in the
LIVER not the muscle
What enzyme allows the liver to generate free glucose from glycogen breakdown in Gluconeogenesis?
Glucose-6-phosphatase
What enzyme in Gluconeogenesis bypasses glucokinase in glycolysis?
Glucose-6-phosphatase
Glycogen is stored in the cytoplasm of the…
Liver and muscle
What is the enzyme during Glycogen Synthesis?
Glycogen synthase
Glycogen Synthesis is inhibited by what hormone?
Glucagon
Glycogen Synthesis is stimulated by what hormone?
Insulin
What is the Major Intermediate of Glycogen Synthesis?
UDP-Glucose
What is the enzyme for Glycogen Degradation?
Glycogen phosphorylase
Glycogen Degradation is stimulated by what hormones?
Glucagon & Epinephrine
Glycogen Degradation is inhibited by what hormones?
Insulin
AKA’s for the Pentose Phosphate Pathway
1) HMP Shunt
2) phosphogluconate pathway
Pentose Phosphate Pathway occurs in
The cytosol
What is the enzyme used in the Pentose Phosphate Pathway?
Glucose-6-phosphate dehydrogenase
What are the function of the Pentose Phosphate Pathway? (2)
1) production of NADPH for fatty acid and steroid hormone synthesis
2) production of ribose-5-phosphate for nucleotide (DNA/RNA) synthesis
What is the net gain/loss of ATP in the Pentose Phosphate Pathway?
None
Where does Fatty Acid Synthesis occur?
Cytosol
What enzyme is involved in Fatty Acid Synthesis?
Acetyl CoA carboxylase
Fatty Acid Synthesis is a ___________ process.
Reductive
Acetyl CoA is transported from the mitochondria to the cytosol as __________ in Fatty Acid Synthesis?
Citrate
What are the coenzymes used in Fatty Acid Synthesis?
NADPH
Fatty Acid Synthesis is AKA:
Lipogenesis
Fatty Acid Degradation is AKA:
1) Beta-Oxidation
2) Lipolysis
Fatty Acid Degradation occurs in…
The mitochondria
What is the enzyme involved in Fatty Acid Degradation?
Hormone-sensitive lipase
What is the function of Hormone-sensitive lipase in Fatty Acid Degradation?
Cleaves fatty acids off triacylglycerides that are stored in adipose tissue
Fatty Acid Degradation is stimulated by what hormone?
Epinephrine
Fatty Acid Degradation is inhibited by what hormone?
Insulin
In Fatty Acid Degradation, what transports fatty acids from the cytosol to the mitochondria?
Carnitine
What is the precursor to Carnitine in Fatty Acid Degradation?
Lysine
Fatty Acid Synthesis is inhibited by what hormone?
Glucagon
Fatty acid synthesis is stimulated by what hormone?
Insulin
The Urea Cycle occurs in…
Both Cytosol & Mitochondria
Urea contains ___________ and a single __________.
2 nitrogen atoms and 1 carbon
Both of the nitrogen atoms of Urea come from…
Glutamate
What is the rate limiting enzyme of the Urea Cycle?
Carbomoyl Phosphate Synthase
What reaction does the enzyme Carbamoyl phosphate synthase catalyze in the Urea Cycle?
(CO2 + NH3 + 2ATP -> carbamoyl phosphate)
Where is the rate limiting enzyme of the Urea Cycle located?
In the mitochondria
What are the intermediates of the Urea Cycle? (3)
1) Arginine
2) Citrulline
3) Ornithine
Fatty Acid Metabolism occurs in a ______ ____ _______.
Well Fed State
