Cycle 5 BMP Workshop Flashcards
How is respiration measured?
Using O2 Electrode Chamber
Using chlamydomonas:
State the process of preparing O2 Electrode Chamber
- Break the chlamy cells
- Purify the intact mitochondria
- Wash mitochondria
- Incubate isolated mitochondria with buffer (NADH + ADP + P)
What is measured in the O2 electrode chamber?
Speed of O2 consumption
This directly correlates to speed of respiration
List:
Ingredients of the Electron Transport Chain
- Mitochondria: Starts consumption if both mitochondria and NADH are present
- NADH: Starts consumption if both mitochondria and NADH are present
- ADP + P: Speeds up O2 consumption, only if NADH and mitochondria are present
- Uncoupler: Speeds up O2 consumption, only if NADH and mitochondria are present
Rank:
NADH, ADP+P, Uncouplers
Based on O2 consumption
- Uncoupler (Highest rate of O2 consumption)
- ADP+P
- NADH
Explain:
How ADP+P causes higher O2 consumption
- Causes proton entry through ATP synthase
- Makes easier for electron transport chain to pump H+
- Consumes O2 faster
Explain:
How Uncouplers causes the highest rate of O2 consumption
- Dissipates the proton gradient
- Speeds up electron transport chain
- Highest rate of O2 consumption
State the O2 consumption in the event of:
NADH, no mitochondria
No O2 consumption
State the O2 consumption in the event of:
NADH and Mitochondria
Low rate of O2 consumption
State the O2 consumption in the event of:
NADH, ADP+P, and mitochondria
High rate of O2 consumption
State the O2 consumption in the event of:
ADP+P and mitochondria, no NADH
No O2 consumption
State the O2 consumption in the event of:
Uncoupler, ADP+P, mitochondria; no NADH
No O2 consumption (no electrons for the electron transport chain)
What is the G3P from the Calvin Cycle sourced for?
- Energy through respiration
- Biosynthetic reactions
Define:
Cell growth
One cell divides into two cells
How is G3P used in cell growth?
Used as a source of carbon for the backbones of molecules needed for cell growth (e.g. nucleic acids, amino acids, fatty acids etc.)
What is the use of G3P in cell growth known as?
Autotrophic Cell Growth (as G3P originates from photosynthesis, an autotrophic process)
What is used in heterotrophic cell growth in chlamy?
Acetate, as it has acetate transporters
What kind of metabolism does chlamy have? Explain
Mixotrophic Metabolism
* Autotrophic + Heterotrophic
* Autotrophic: Photosynthesis, lack glucose transporters so no growth in the dark
* Heterotrophic: External food source, cannot use light
What are the two energy sources for chlamy? How does this benefit it?
Light (autotrophic) and acetate (heterotrophic), allows for highest growth rate
What process does photosynthesis involve?
Gas exchange
6CO2 + 6H2O (photosynthesis) C6H12O6 + 6O2
CO2 consumption occurs in:
O2 production occurs in:
CO2 consumption occurs in the Calvin Cycle
O2 production occurs in the Photosynthesis Electron Transport
Explain:
How to measure photosynthesis
- Put a culture of chalmy into Co2 analyzer
- Expose the culture to varying light intensities
- Assess changes in CO2 levels
Unit for CO2 fixation rate
CO2 fixation rate = μMol CO2 consumed/min/cell
On the light response curve:
What occurs when the light intensity is 0?
- No light = No photosynthesis
- BUT cellular respiration is not light dependent
- Thus, net CO2 release (net negative CO2 fixation rate)
On the light response curve:
What is the light compensation point?
- The rate of carbon loss (respiration) is equal to rate of carbon gain (photosynthesis)
- Net CO2 fixation rate = 0
On the light response curve:
What does the x-axis and y-axis represent?
- X-axis: Light intensity
- Y-axis: NET CO2 fixation rate
On the light response curve:
What is the light-limited region?
A region where there is an approximate linear relationship between light intensity and rate of photosynthesis
* There is a net carbon gain = growth
On the light response curve:
What is the light saturated point?
- Rate of photosynthesis reaches maximum
- Pmax = Maximum net rate of CO2 fixation
What is the maximum rate of photosyntehsis/net rate of CO2 fixation limited by?
Maximum trunover rate of enzymes in the Calvin cycle, not substrates
State:
The measure of carbon gain
Net Photosynthesis = Pmax = Gross Photosynthesis - Respiration
What limits the rate of carbon fixation as a function of light?
- Enzymes: Rubisco has a limit to how fast it can turnover product, even with an abundance of NADPH and ATP
- Available CO2
In enzyme kinematics:
What does no substrate equal?
Zero velocity
In enzyme kinematics:
What is increasing velocity caused by?
Increasing substrate concentration
In enzyme kinematics:
What is Km?
Measure of affinity
* It is the substrate concentration at which half of maximum velocity is reach (1/2 Vmax)
* Vmax is a measure of the max velocity
In enzyme kinematics:
How do we interpret Km values?
- Low Km = high affinity for substrate
- High Km = low affinity for substrate
What is a competitive inhibitor?
- Resembles original susbtrate
- Binds to active site
- Binding can be reversible or irreversible
What is the effect of an competitive inhibitor?
Increased Km (no change in 1/2 Vmax or Vmax)
True or False:
Increasing substrate concentration can reduce effects of reversibly-bound inhibitors
True
What is an inhibitor/activator in non-competitive (allosteric) regulation?
Can be inhibitor or activator
* Binds to allosteric site distant from active site
* Changes enzyme affinity for substrate
* Faster regulation than transcription
* ATP/ADP, NADH/NAD+ can act as allosteric inhibitors/activators of metabolism
What is the advantage of enzyme regulation via non-competitive (allosteric) regulation?
It is FASTER to regulate at the level of enzyme activity versus transcription of translation
What is a noncompetitive inhibitor?
- Does not bind to active site; binds elsewhere
- Causes a conformational change that makes the subtrate unable to bind
What is the effect of a noncompetitive inhibitor?
Change in 1/2 Vmax or Vmax (no change in Km)
