1: Cell metabolism and integrity Flashcards
Glycolysis
2 stages -
forming high energy compound
splitting a high energy compound
Where does glycolysis occur
Cytoplasm
Glycolysis is
Anaerobic
Converts one molecule of glucose into two pyruvate molecules
Isomerase enzymes are used for
making an isomer
Kinase enzymes are used for
movement of a phosphate group (generally)
First step of glycolysis
Glucose –(hexokinase)–> glucose-6-phosphate
irreversible reaction, commits glucose to glycolysis
uses ATP in order for reaction to start
Fructose bisphosphate splits into
via Aldolase
DHAP (dihydroxyacetone phosphate)
into
G3P (glyceraldehyde-3-phosphate)
via TPI
-2 molecules from now on-
Net result of glycolysis
2 pyruvate molecules
Net gain of 2 ATP
2 NADH
Pentose Phosphate Pathway
When ATP isn’t needed, glucose enters PPP
produces Ribose or NADPH
NADPH produced by the PPP
- electron rich
involved in antioxidant reactions:
RBCs produce Reactive Oxygen Species and glutathione
NADPH is an electron supplier for glutathione
3 fates of pyruvate
Alcoholic fermentation
Lactate production
(Regenerate NAD+ for glycolysis to continue) - Anaerobic processes
Acetyl CoA production (create Acetyl CoA to enter TCA cycle)
-Aerobic process
Pyruvate in alcoholic fermentation
Pyruvate –(pyruvate decarboxylase)–> acetaldehyde –(alcohol dehydrogenase)–> ethanol
occurs in yeast, anaerobic process
NAD+ regenerated for glycolysis
Pyruvate in lactate production
pyruvate–(lactate dehydrogenase)–> lactate
- used in muscles during intense activity
NAD+ regenerated
Pyruvate in Acetyl CoA Production
Pyruvate –(pyruvate dehydrogenase complex)–> acetyl CoA + CO2
- occurs in mitochondria
- acetyl CoA enters TCA cycle
Beri Beri is
Thymine deficiency
(Vit B1)
(thymine needed to form TPP - prosthetic group forming pyruvate dehydrogenase complex)
less TPP=less ATP prod.
Loss of H+, carbanion attacks pyruvate
cannot convert pyruvate into acetyl CoA
so cannot enter TCA cycle
Symptoms of Beri Beri
damage of peripheral nervous system
muscle weakness
Decreased cardiac output
BRAIN particularly vulnerable
TCA cycle occurs in the
mitochondria
Each TCA (Krebs) cycle produces
2x CO2
3x NADH
1x GTP
1x FADH2
Where are TCA cycle enzymes found
Soluble proteins found in mitochondrial matrix space
except for succinate dehydrogenase (inner mitochondrial membrane)
Glucogenic amino acids
amino acids which eventually form glucose
Ketogenic amino acids
amino acids which eventually enter Krebs cycle as Acetyl CoA
How many amino acids are there
20
How many molecules do amino acids give rise to
7
pyruvate
Acetyl CoA
Acetoacetyl CoA
a-ketoglutarate
Succinyl CoA
Fumarate
Oxaloacetate
two groups of amino acids
Glucogenic
Ketogenic