Biology 12

Chapter 3 Cellular Energy • MHR 95

CHAPTER 3 REVIEW

Summary of Expectations

Briefly explain each of the following points.

• Stages of aerobic cellular respiration include
  glycolysis, transition reaction, the Krebs Cycle,
  and the electron transport chain. (3.1)


• Glycolysis occurs in the cytoplasm of all cells
  and produces two pyruvate molecules and two
  ATP molecules. (3.1)


• Substrate-level phosphorylation involves the
  transfer of a phosphate group to ADP to form
  ATP. (3.1)


• The transition reaction links the processes of
  glycolysis and the Krebs cycle. (3.2)


• The Krebs cycle is a cyclical metabolic
  pathway that oxidizes acetyl-CoA to carbon
  dioxide and water, forming two molecules of
  ATP. (3.2)


• The electron transport occurs in the cristae
  of the mitochondrion and involves a series of
  electron carriers and multienzyme complexes.
  (3.2)


• Oxidative phosphorylation requires oxygen in
  order to form ATP molecules. (3.2)


• Most ATP molecule production takes place
  during the reactions of the electron transport
  chain. (3.2)


• Chemiosmosis involves the production of ATP
  molecules when a hydrogen ion gradient is
  formed across a membrane by an electron
  transport chain. (3.2)


• When oxygen is not present, cells use
  anaerobic cellular respiration to produce
  ATP molecules. (3.2)


• Photosystems are made up of a network of
  chlorophyll pigments. (3.3)


• In cyclic photophosphorylation, electrons are
  cycled back into the photosystem. (3.3)


• ATP synthesis occurs within the thylakoids.
  (3.3)


• The Calvin cycle has three distinct stages —
  fixation of CO 2 , reduction of CO 2 , and
  re-formation of the molecule RuBP. (3.3)
  
  
  • The Calvin cycle produces one molecule of
    PGAL for every three molecules of CO 2 that
    enter the cycle. (3.3)
  
  
  • There are three methods of carbon dioxide
    fixation in plants — C 3 , C 4 , and CAM fixation.
    (3.3)
  
  
  
  

Language of Biology

Write a sentence including each of the following

words or terms. Use any six terms in a concept map

to show your understanding of how they are related.

• aerobic cellular • proton pumps
  respiration • anaerobic cellular


• aerobic respiration


• glycolysis • deamination


• anaerobic •β-oxidation


• pyruvate • photosynthesis


• fermentation • chloroplast


• transition reaction • thylakoids


• acetyl-CoA • chlorophylls


• Krebs cycle • photosystem


• electron transport chain • antenna pigment


• oxidative phosphorylation • reaction centre


• chemiosmosis • photosynthetic unit


• substrate-level • electron acceptor
  phosphorylation • electron transport


• PGAL system


• PGAP • cyclic


• PGA photophosphorylation


• PEP • non-cyclic


• porin photophosphorylation


• cardiolipin • photolysis


• pyruvate dehydrogenase • Calvin cycle
  complex • carbon fixation


• ATP synthase complex • RuBP carboxylase


• NADH dehydrogenase • photorespiration
  complex • PGAP


• cytochromes

1.Why do cells use energy?

2.What are the four steps of aerobic cellular
respiration?

3.Which of the four steps of cellular respiration
acts on glucose?

4.Which of the four steps of cellular respiration

take place in the mitochondrion?

5.Where is pyruvate produced?

6.Glycolysis I involves substrate-level

phosphorylation.

(a)What is substrate-level phosphorylation?

UNDERSTANDING CONCEPTS