Possible Essay Questions for Chapters 8 and 9



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Possible Essay Questions for Chapters 8 and 9

1. 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. (In other words, compare and contrast aerobic versus anaerobic respiration.)

2.  Describe the chemical composition and configuration of enzymes and discuss the factors that modify enzyme structure and/or function.

3. Describe the ways that enzymes can be regulated.

4. Describe the factors that affect the rate of enzyme catalyzed reactions.

This is a sample question taken from an old AP exam. Also provided is a grading rubric showing what should be discussed. I won’t ask this question, but I am providing it as an example of an AP Test question and for you to study from.
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 ETS

___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/AP BIOLOGY


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