SBI4U Test 3 Flashcards
Distinguish between oxidation and reduction. (8 marks)
Oxidation: loss of electrons, loss of hydrogen, oxygen is added, also referred to as dehydration
Reduction: gain of electrons, gain hydrogen, oxygen is lost, also referred to as hydrogenation
Distinguish between substrate-level phosphorylation and oxidative phosphorylation.
Draw and label a mitochondrion.
Draw and label a chloroplast.
Must include: outer membrane, intermembrane space, inner membrane, thylakoid, lamella, DNA, ribosomes, granum, stroma
What evidence do scientists have to support the idea that chloroplasts and mitochondria were at one time independent organisms that became symbiotic?
- They have their own circular DNA like bacteria
- They have special ribosomes - 70s like bacteria (80S ribosomes are found in eukaryotic cells)
- They reproduce like bacteria through binary fission (mitosis)
Write the balanced chemical equation for cellular respiration.
C6H12O6 + 6O2 —> 6CO2 + 6H20 + 36ATP
For glycolysis, state the location, input & output materials, and whether or not it is an aerobic or anaerobic process.
Location: cytoplasm
Input materials: Glucose, 2ATP, 4ADP, 4Pi
Output materials: 2ATP (net), 2NADH (2H20, 2 pyruvate, 2ADP)
Aerobic/Anaerobic: Anaerobic
For Kreb’s Cycle, state the location, input & output materials, whether it is aerobic or anaerobic.
Location: in the matrix of the mitochondrion
Input Materials: 3 pyruvate/pyruvic acid, 4NAD, ADP, CoA
Output Materials: 2ATP, 8NADH, 2FADH2
Aerobic/Anaerobic: aerobic
For the Electron Transport Chain, state the location, input & output materials, and whether it is aerobic or anaerobic.
Location: across the inner mitochondrial membrane
Input materials: NADH, FADH2, H+, ADP, Pi, O2
Output materials: 32 ATP, NAD, FAD, H2O
Anaerobic/Aerobic: aerobic
What is the balanced equation for photosynthesis?
6CO2 + 6H2O + energy –> C6H12O6 + 6H2O
OR
6CO2 + 12H2O + energy –> C6H12O6 + 6O2 + 6H2O
Distinguish between carotenoids and chlorophylls
Chlorophyll
- green pigment used in photosynthesis
- consist of a metal atom (magnesium) in the centre of the porphyrin ring
- absorb photons in the 700nm (red) and 400nm (blue-violet) range
Carotenoids
- yellow & orange pigments
- accessory light absorbing pigments
- absorbs a wide range of photons (380nm - 750nm) but not efficiently
Distinguish between chlorophyll a and b.
Chlorophyll a - more crucial to photosynthesis, contains a -CH3 group (methyl), occurs less frequently
Chlorophyll b - less important to photosynthesis, contains a -CHO group (carbonyl aldehyde), occurs more frequently
Explain how a CAM plant has overcome the problem of low CO2 levels.
CAM plants open their stoma during the night and take in CO2, then converting it into organic acids (e.g. crassulacean acid) which is then stored in the vacuoles. During the day, when the guard cells are closed, organic acids are converted back into CO2 and used in the Dark Rx.
Name 5 factors that effect the rate of photosynthesis
- Light Intensity (Brightness)
- Light Quality
- Temperature
- CO2 Concentration
- Water Supply
What is the relationship between rate of photosynthesis and light intensity/brightness?
As intensity increases, so does rate of photosynthesis.
What is the relationship between rate of photosynthesis and light quality?
Photosynthesis functions most effectively in the blue/violet ranges of the visible spectrum.
What is the relationship between rate of photosynthesis and temperature?
As temperature increases, so does rate of photosynthesis (up to 34 degrees).
What is the relationship between rate of photosynthesis and CO2 concentration?
As concentration increases, so does photosynthesis rate until about 0.02% where it levels off.
What is the relationship between rate of photosynthesis and water supply?
Water supply is only a factor when it is very limited.
Why is a C-4 plant better able to connect to CO2 for the dark reaction than a C-3 plant?
This is because in C-4 plants, the compound PEP found in the mesophyll cell fixes carbon from carbon dioxide, forming the 4-carbon compound OAA. OAA is then converted into malate. Malate then leaves the mesophyll cell and takes its extra C to the bundle sheath cell where the Dark Rx occurs. CO2 is dropped off at the Calvin cycle and pyruvate is left, which then converts back into PEP and the cycle starts over again.
**The point of this is that there is no oxygen present in the bundle sheath cell where the Calvin Cycle occurs (only CO2) so Photorespiration (oxygen being fixed to RuBP instead of CO2) cannot happen because of the absence of oxygen. **
For the Light Rx, state the location, input materials and output materials.
Location: Thylakoids
Input: Light, NADP+, water
Output: Oxygen, NADPH, H+
For the Dark Rx, state the location, input materials and output materials.
Location: Stroma
Input: 6CO2, 18ATP, 12NADPH
Output: 18ADP, 18Pi, 12NADP+, 2PGAL
*amounts are for 2 turns of the Calvin Cycle
How do poisons affect respiration?
They inhibit cellular respiration by disrupting chemiosmotic mechanisms.
How does cyanide inhibit cellular respiration?
- It blocks the passage of electrons from cytochrome a3 to O2.
- It plugs the ETC as a result of protons not being pumped –> no ATP produced
How does dinitrophenol interfere with cellular respiration?
It “shortcircuits” the proton pump by allowing the membrande to leak H+ > no proton gradient > no ATP
How does oligomycin interfere with cellular respiration?
It interferes with the operation of ATPase
