Glycolysis Flashcards
___ is the first of three linked metabolic pathways
glycolysis
Glycolysis generates ___ ___ in the form of high energy bonds of ATP molecules
cellular energy
Glycolysis generates cellular energy in the form of high energy bonds of ___ ____
ATP molecules
Glycolysis involves the breakdown of _____ and other simple sugars, to produce ___
glucose (6-carbon molecule)
pyruvate (3-carbon molecule)
What does the glycolysis pathway provide for the TCA cycle?
precursor molecules
What is the TCA acid?
the second of the three linked pathways
Does glycolysis generate ATP?
Yes
When does glycolysis generate ATP?
When oxygen is limited
How many phases of glycolysis are there?
2 (5 reactions in each)
Phase 1: a series of 5 enzyme catalyzed reactions transforms each glucose molecule into ___ molecules of ___
2, glyceraldehyde-3-phosphate
Phase 2: 5 enzyme catalyzed reactions transforms 2 molecules of glyceraldehyde-3-phosphate into __ molecules of __
2, pyruvate
Phase 1 consumes __ molecules of ATP
2
Phase 2 generates __ molecules of ATP
4
What is the net gain of ATP between phase 1 & 2
2 (-2+4)
Is phase 1 or phase 2 more active?
Phase 1
Phase 1 of glycolysis:
Glucose to glyceraldehyde-3-phosphate
What is the second of the three linked pathways?
TCA cycle
How many enzyme catalyzed reactions are in the phases of glycolysis?
10 enzyme catalyzed reactions
Conversion of glucose into two molecules of glyceraldehude-3-phosphate
Phase 1 of glycolysis
Conversion of glyceraldehyde-3-phosphate into pyruvate
Phase 2 of glycolysis
What phase of glycolysis generates 4 ATP?
Phase 2
ATP to ADP generation occurs in what phase of glycolysis?
Phase 1
Phase __ is like an investment
1
NAD to NADH in glycolysis are essential in activating the __ pathway
3rd
NADH play an important role in __ ___
energy generation
What are the three possible metabolic pathways that use the pyruvate molecules generated in glycolysis?
- Animals and plants in aerobic conditions
- Anaerobic glycolysis in contracting muscle
- Alcoholic fermentation in yeast
ATP synthesis in phase 2 occurs in what way?
ADP to ATP by addition of phosphate group
What are the two anaerobic conditions of the possible metabolic pathways?
Anaerobic glycolysis in contracting muscle &
Alcoholic fermentation in yeast
ATP is used up in phase 1 in what way?
ATP energy is being used and converted to ADP
NAD+ is converted to ___ in phase 2
NADH
How many NADH are made per glucose?
2
Why is NADH produced in phase 2?
to stimulate the electron transport chain
What is created with pyruvate when oxygen is present (aerobic conditions)
energy
in aerobic conditions, the ____ from pyruvate can be directly linked to the TCA cycle via a _____ bond
carbons, covalent
when oxygen is limited, the pyruvate from glycolysis produces ___ ____
lactic acid
the production of lactic acid from pyruvate is commonly found in ____ _____
muscle cells
when there is no oxygen, the pyruvate produces _____
ethanol
the production of ethanol from pyruvate is common in ___
yeast
when ethanol is produced from pyruvate, what else is produced?
carbon dioxide
(1) ____ adds a phosphate group to glucose to form glucose-6-phosphate
hexokinase
(2) ______ converts glucose-6-phosphate into fructose-6-phosphate
phosphoglucose isomerase
why is glucose converted to fructose in step 2?
build up to the proper substrate that can bind to the active site of the enzyme that will split glucose into 2
(3) ____ adds a second phosphate group to fructose-6-phosphate making it fructose,1,6-biphosphate
phosphofructokinase
(4) ______ is the correct enzyme for the substrate of splitting the glucose molecule, and converts fructose-1,6-biphosphate into glyceraldehyde-3-phosphate and dihydroxyacetone phosphate (2 3 carbon fragments)
aldolase
of the 2 3 carbon fragments produced at the end of phase 1, which is the desired one?
glyceraldehyde-3-phosphate
(5) what enzyme is used to convert dihydroxyacetone phosphate into the desired form, glyceraldehyde-3-phosphate?
triose phosphate isomerase
Is glucose the only monosaccharide that can enter the glycolysis pathway?
No!
What other monosaccharides can enter the glycolysis pathway?
Galactose, fructose, and mannose
___ is a monosaccharide that is similar to glucose and is a component of the carbohydrate chains of many glycoproteins
Mannose
Mannose is converted into what intermediates to enter the glycolysis cycle?
Fructose-6-Phosphate (F6P)
Fructose is converted into what intermediates to enter the glycolysis cycle?
DHAP, G3P
Galactose is converted into what intermediates to enter the glycolysis cycle?
Glucose-6-Phospahte (G6P)
Phosphorylation of glucose is the __ reaction of glycolysis
first
How is glucose kept in the cell?
Glucose is kept in the cell by phosphorylation to G6P, which cannot easily cross the plasma membrane.
The phosphorylation of glucose to produce glucose-6-phosphate creates a ___ molecule that cannot easily cross the plasma membrane and stays inside the cell
charged
what ensures that the glucose remains inside the cell and does not go back to the extracellular fluid in phase 1?
by the phosphorylation of glucose to glucose-6-phosphate in step 1
glucose-6-phosphate is a ___ charged molecule to make it hard to get through the lipid bilayer and glucose transporter to leave the cytoplasm and go back to the extracellular fluid
negatively
(6) ____ adds a phosphate to glyceraldehyde-3-phosphate to produce 2 1,3-biphosphoglycerate
glyceraldehyde-3-phosphate dehydrogenase
(7) ____ removes the previously added phosphate group from 2 1,3-biphosphoglycerate to produce 2 3-phosphoglycerate and adds the phosphate to ADP to create ATP
phosphoglycerate kinase
the removal of the phosphate group in step 7 converts the ______ into a ______ group
aldehyde, carboxyl group
(8) ____ moves the phosphate group form carbon 3 to carbon 2, therofore converting 2 3-phosphoglycerate into 2 2-phosphoglycerate
phosphoglycerate mutase
(9) ______ removes a phosphate group from 2 2-phosphoglycerate to crease 2 phosphoenolpyruvate
enolase
(10) _____ adds a phosphate group to ADP to form ATP and therofore converts 2 phosphoenolpyruvate into 2 pyruvate molecules
pyruvate kinase
pyruvate is a combination of an ____ group and a ____ group
acetyl, carboxyl
In animal and plant cells in aerobic conditions, ___ is metabolized by the TCA cycle and the electron transport/oxidative phosphorylation pathway to generate ___
pyruvate, ATP
what is the purpose of yeast cells making ethanol?
they gain NAD+ when acetaldehyde is converted to ethanol
what enzyme converts acetaldehyde to ethanol in yeast?
alcohol dehydrogenase
yeast cells need a balance of ___ and ____ and this is achieved by the conversion of acetaldehyde to ethanol
NAD+ and NADH
what enzyme converts pyruvate to lactate?
lactate dehydrogenase
in oxygen-depleted muscles, _____ is generated by the reaction of converting pyruvate to lactic acid
NAD+
In skeletal muscles under strenuous exercise, the anaerobic conditions result in the buildup of __ __ which is associated with cramps and muscle fatigue
lactic acid
When exercise ceases and oxygen becomes available, lactic acid can be directly converted back to ____. Which is used to fuel the TCA cycle
pyruvate
Where is the excess lactic acid transported if anaerobic conditions continue? What is it resynthesizes into?
Transported into the blood and liver
Resynthesized into glucose
In microbes, lactic acid fermentation produces sour __, ___, and ____
milk, yogurt, and sauerkraut
