Lab #6 - Cellular Respiration Flashcards
In which experiment did we do anaerobic respiration?
Glycolysis experiment: yeast fermentation tubes; tubes with bubbles (looked like a bong)
In which experiment did we do aerobic cellular respiration?
Krebs Cycle Experiment: examination of color change in test tubes
Write the reaction for fermentation (anaerobic)
Which substance in the reaction are you actually measuring?
glucose -> 2 pyruvate -> 2 ethanol + 2CO2 + 2NAD
During anaerobic respiration, why was an air bubble seen in tube B, but not in tube A?
no air bubble in tube A because there was no glucose to be broken down (therefore no glycolysis -> no fermentation -> no CO2 production)
tube B had glucose so rxn proceeded
In the fermentation (anaerobic) experiment, name what we added in each test tube
Describe the amount of CO2 in these tubes
Which is the inhibitor?
A (control): yeast + water - no CO2
B: yeast + glucose + water - lots CO2
B: yeast + glucose + NaF - some CO2
How did NaF affect the results of your fermentation experiment? Why?
Only some CO2 was made in test tube #3
NaF is a slow inhibitor of glycolysis (inhibits one of the enzymes), therefore slowing the reaction and produces CO2 at slower rate compared to tube #2
Write the reaction for the conversion of succinate to fumerate. What substance in this reaction are we actually measuring?
SA —————SDH—————> FA
FAD ⤵ FADH2
In the aerobic respiration experiment an indicator was used. Name this indicator and what it indicates.
What happens?
methylene blue (MB)
Indicates presence of: FADH2
If FADH2 is present, it will donate its electrons to MB and the color will change from blue to clear
What happened to methylene blue in test tubes A, B and C during aerobic cellular respiration?
A: blue (control)
B: clear
C: slightly blue
During aerobic respiration, where did the hydrogens come from for converting methylene blue? In which of these tubes did this occur? Why not in the other tubes
Hydrogens came from FADH2
(occured in test tube B and some in C)
Not in A because no glucose present
Describe what was put in each test tube during the krebs cycle (aerobic) experiment
A (control): yeast + water + MB
B: yeast + glucose + SA + MB
C: yeast + glucose + SA + OA + MB
Describe the significance of oxaloacetate (OAA)? Describe the type of inhibition
OA: competitive inhibitor
Competes with SA for active site of SDH
Slowly inhibits all active site of SDH
OAA binds permentaley
This shows the relative color change of methylene blue during aerobic cellular respiration:
A - none
B - significant
C - moderate
Which tube did NOT have an inhibitor?
Which tube did have an inhibitor?
Which tube was the control?
Explain
B (A too technically) - color changed drastically (to clear), meaning rxn proceeded and MB recieved electrons from FADH2
C - color somewhat changes (light blue), meaning there was a slow competitive inhibitor; OAA
A - control because no color change -> no glucose to be broken down
What was the purpose of putting mineral oil in the test tubes during aerobic respiration?
prevent MB from being exposed to oxygen after it accepts the H from the citric acid cycle
