You may download this entire file in Microsoft Word Format, or you may preview the questions and standards by year through your web browser by selecting the appropriate year.
1977 1982 1989 1990
CELLULAR RESPIRATION QUESTION 1977: L. PETERSON/ECHS
Explain how the molecular reactions of cellular respiration transform the
chemical bond energy of Krebs Cycle substrates into the more readily available
bond energy of ATP. Include in your discussion the structure of the mitochondrion
and show how it is important to the reactions of the Krebs Cycle and the Electron
Transport Chain.
STANDARDS: 1/2 point for each of the following
___Krebs and ETS occur within mitochondria
___Krebs - enzymes freely present in matrix fluid
___ETS - respiratory chain (respiratory assembly) arranged in order
inner membrane of mitochondria (Diagram OK)
___more active cells - more respiratory assemblies & more cristae
___Aerobic - O2 necessary as final H acceptor (-> H2O)
(most eukaryotic cells all of the time)
___Glycolysis is 1st required (outside mitochondria)
___Glucose (6C) is broken down into 2 Pyruvic Acid (3C) molecules
___Phosphorylation must 1st occur
___Net production: 2 ATP & 2 NADH
MITOCHONDRIA
___Pyruvic Acid & 2NADH enter mitochondria
___2 NADH will transfer H (electrons) into ETS
___yields 2 x 2 ATP = 4 ATP (some loss due to point of entry into ETS)
KREBS CYCLE SUBSTRATES
___2 Pyruvic Acid loses CO2 & H -> 2 NADH & combines w/CoA -> Acetyl CoA
___(2C) Acetyl CoA + (4C) Oxaloacetic Acid -> (6C) Citric Acid
___Citric Acid -> Isocitric Acid
___(6C) Isocitric Acid - DEHYDROGENATION & loss of CO2 -> (5C) Ketogluatric Acid
NAD -> NADH
___(5 C) Ketoglutaric Acid - DEHYDROGENATION & loss of CO2 -> (4C) Succinic Acid
NAD -> NADH
___(4C) Succinic Acid - DEHYDROGENATION -> (4C) Malic Acid
FAD -> FADH2
___(4C) Malic Acid - DEHYDROGENATION -> Oxaloacetic Acid
NAD -> NADH
___specific mention of 2 x 3 NADH & 2 x 1 FADH2 produced during Krebs
___ATP (1) produced in Krebs
ETS RECEIVES THE FOLLOWING:
NADH or FADH2 WHICH RESULTS IN ATP PRODUCTION
___Glycolysis -> 2 NADH x 2 ATP = 4
___Pyruvic Acid -> Acetyl CoA + 2 NADH x 3 ATP = 6
___Krebs -> 8 NADH (FADH2) x 3 ATP = 24
Total = 34
___34 ATP gained through ATS
___Respiratory Assembly: CoQ, cytochromes b, c, a, a3
___Ring Compounds w/Fe (porphyrin ring)
___Changing Oxidation states as "go down" assembly
___Fe III -> Fe II change ionic state as accept electrons
___Release energy in "packets" - small amounts sufficient to produce ATP (about 7 kcal/mole)
___Occurs at 3 places in the chain for each NADH, FADH2
___mention of various hypotheses: Chemiosmotic, Conformational, Chemical Coupling
___O2 final acceptor ( -> H2O)
CELLULAR RESPIRATION QUESTION 1982: L. PETERSON/ECHS
Describe the similarities and differences between the biochemical pathways of aerobic respiration and photosynthesis in eukaryotic cells. Include in your discussion the major reactions, the end products, and energy transfers.
STANDARDS: 7 points Maximum for Photosynthesis section
7 points Maximum for Respiration section
PHOTOSYNTHESIS:
___Conversion of light energy to chemical energy
___Fixation of CO2
___Occurs in chloroplasts
___Split H2O (photolysis)
___Chlorophyll needed
___ATP in light reaction
___NADPH2 produced
___Anabolic (Constructive)
___Oxygen released
LIGHT REACTION (Diagram and/or Discuss)
___Photosystem I & II
___Energy "input" (electron flow)
___Chemiosmotic
DARK REACTION (CO2 FIXATION)
___Carboxylative phase
___Reductive phase
___Regenerative phase
NET REACTION
___ENERGY + CO2 + H20 -> C6H12O6 = O2
___"Uphill" Reaction - possess more free energy and/or stores 686,000 cal/mole glucose
___Coupling of light and dark reactions
RESPIRATION
___Conversion of chemical energy to metabolic
___Release of CO2
___Occurs in mitochondria
___Form H2O (reduction)
___Cytochromes needed
___ATP in oxidative phosphorylation
___NADH produced
___Catabolic (destructive)
OXIDATIVE PHOSPHORYLATION (Diagram and/or Discuss)
___ETS (NAD, FAD, cytochromes)
___Energy "release" (electron flow)
___Chemiosmotic
___Glycolysis
___Krebs Cycle
NET REACTION
___O2 + C6H12O6 -> CO2 + H2O + ENERGY
___"Downhill"Reaction - possess less free energy and/or releases 686,000 cal/mole glucose
BONUS POINTS 3 points MAX
___Dark reaction is reverse of anaerobic glycolysis
___Both processes are complementary and/or supply materials for each other
___Thorough contrast of photosynthesis and cellular respiration
CELLULAR RESPIRATION QUESTION 1989: L. PETERSON/ECHS
Explain what occurs during the Krebs (citric acid) cycle and electron transport
by describing the following:
a. The location of the Krebs cycle and electron transport chain in the mitochondria
b. The cyclic nature of the reactions in the Krebs cycle
c. The production of ATP and reduced coenzymes during the cycle
d. The chemiosmotic production of ATP during electron tranpsort
STANDARDS: 3 points Maximum for each of the four sections
1 point for any of the following:
LOCATION
___Description of internal structure (compartmentalization) of mitochondrion
___Krebs in matrix (inner or M compartment)
___Krebs' enzymes mostly dissolved in matrix
___ETS in cristae (inner membrane)
___ETS components are embedded in the inner membrane
5 pts MAX 3
CYCLIC NATURE OF KREBS
___Acetyl CoA (C2) starts Krebs
___C2 joins with OAA (C4) to form citric acid (C6)
___2 CO2 removed during Krebs
___OAA is recycled or overall cycle concept (diagram OK)
___Position of Krebs in Aerobic Respiration (2 cycles/glucose, uses products of glycolysis)
5 pts MAX 3
PRODUCTION OF ATP AND REDUCED COENZYMES
___ 1 ATP/cycle
___NADH and/or FADH2 formed (or NADH2, NADH + H+, NAD red)
___Amount of NADH (3) and/or FADH2 (1) per cycle
___ATP formed from released energy; substrate level phosphorylation
___ATP specific reaction: Succinyl CoA -> Succinic Acid; GTP --> GDP
ADT -> ATP
___NADH or FADH2 formed by H or e-
6 pts MAX 3
CHEMIOSMOTIC PRODUCTION OF ATP
___Electron transfer (redox) through carriers; O2 final acceptor
___Gradient drives ATP formation or battery (electrochemical, charge separation, etc.)
___Protons pumped to inter-membrane space;
proton carriers alternate w/electron carriers;
charge separation; gradient established;
lowers pH in inter-membrane space;
+ between membranes; - matrix
___Inner membrane impermeable to H+ except for and/or proton channel (ATP synthetase;
ATPase) is permeable
___ATP synthetase structure F0 + F1
___Specifics of # of ATPs formed (ETS = 32 ATP; 2 ATP/FADH2; 3ATP/NADH)
6 pts MAX 3
CELL RESPIRATION QUESTION 1990: L.PETERSON/ECHS
The results below aer measurements of cumulative oxygen consumption by
germinating and dry seeds. Gas volume measurements were corrected for
changes in temperature and pressure.
Cumulative Oxygen Consumption (mL)
Time (minutes) 0 10 20 30 40
220 C Germinating Seeds 0.0 8.8 16.0 23.7 32.0
Dry Seeds 0.0 0.2 0.1 0.0 0.1
100 C Germinating Seeds 0.0 0.0 0.2 0.1 0.2
Dry Seeds 0.0 0.0 0.2 0.1 0.2
a. Using the graph paper provided, plot the results for the germinating seeds
at 220 C amd at 100 C.
b. Calculate the rate of oxygen consumption for the germinating seeds at 220 C,
using the time interval between 10 and 20 minutes.
c. Account for the differences in oxygen consumption observed between:
(1) germinating seeds at 220 C and at 100 C.;
(2) germinating seeds and dry seeds.
d. Describe the essential features of an experimental apparatus that could be used
to measure oxygen consumption by a small organism. Explain why each of these
features is necessary.
STANDARDS: Parts a, b, and c together = 8 pts MAX
one point for each of the following:
a. GRAPH(S)
___Correct orientation of x (independent) and Y (dependent) axes
___Scale and label axes
___Curves plotted (both lines drawn and identified as 100/220).
Histograms accepted if correctly drawn.
___Title of graph
b. RATE CALCULATION
___Setup (16 - 8.8)/(20 -10) or number 7.2 or 0.72
___Rate Concept - units (volume/time)
7.2 mL/10 min. or 0.72 mL/min.
c. EXPLANATIONS
1. TEMPERATURE VARIATION
___Seeds show no temperature regulation (at environmental temperature);
do not increase O2 consumption to maintain preset temperature
___Temperature increase causes increased activity (or increased respiration or metabolism)
___Extended explanation of respiratory enzyme reaction rate, rate increases (to limit) with
increased temperature (enzymes generally have Q10 about 2.)
___220 vs. 100 rates reversed in cold hardiness (genetically determined) seeds
2. GERMINATING SEEDS VS. DRY SEEDS
___Dry seeds dormant and/or germinating seeds metabolically active
___Extended explanation of dormancy and/or metabolism
___Explanation of water based chemistry of respiratory enzyme reactions
d. EXPERIMENTAL APPARATUS 3 pts MAX
___ Method to separate O2 consumption vs. CO2 release
Something (KOH, etc.) to remove CO2 (gas -> solid)
___Closed System
___Method to measure pressure/volume change = graduated tube/pipet,
containing bubble/water/Brodie
___Method to control temperature = water bath
___Method to control volume = glass beads or some other inert material vs. seeds
___Timing device
___Equal numbers of organisms in experimental and control
Other techniques/methods for measuring O2 consumption
one point for any of the following:
Winkler titration to determine O2 concentration before and after
Polarographic, oxygen electrode, Clark-type electrode
EPR measurement of O2 concentration changes, in gas flow-thru system
one point for a detailed explanation for any one of the above techniques
None of these require special techniques to distinguish volume of CO2 from volume of O2;
all are specific for O2. None of these depend on pressure changes. Other features of
procedure (constant temperature, appropriate controls, etc.) remain the same.