Download Biol 178 STUDY GUIDE – ENERGY, RESPIRATION

Biol 178 STUDY GUIDE – ENERGY, RESPIRATION & PHOTOSYNTHESIS
Use the following questions/comments as a guide to prepare for the next exam.
ENERGY
Understand the concepts of oxidation and reduction, especially with respect to coenzymes like NAD or
NADP.
Exergonic and endergonic are basic types of chemical reactions. Understand them and the concept of
activation energy.
Be familiar with the role of enzymes and how the operate in a cell. In other words, how does an enzyme
speed up a chemical reaction? Why are enzymes very specific?
What is ATP and why is it important?
On a global scale, photosynthesis and respiration are interrelated. Explain.
It could be argued that life's ultimate source of energy is derived from the sun. Why?
Living organisms obey the First and Second Laws of Thermodynamics. What are these laws and how do
they relate to living organisms?
You should understand that NAD+ and FAD are electron carriers used in cellular aerobic respiration.
NADP is also an electron carrier used in photosynthesis. What are electron carriers?
CELLULAR RESPIRATION
Our study of cellular aerobic respiration considered four stages:
(1) glycolysis,
(2) pyruvate oxidation to Acetyl Coenzyme A,
(3) Krebs (citric acid) cycle and
(4) electron transport system or oxidative phosphorylation.
Be VERY familiar with these stages as discussed in class. For example, where are these pathways found
in a eukaryotic cell, what is the principal function of each pathway and where is ATP produced?
The concept of reducing power in the form of reduced coenzymes is important. What is a reduced
coenzyme and where do they come from in aerobic cellular respiration?
In the absence of oxygen, cells must respire anaerobically. What is the difference between fermentation
and anaerobic respiration? What anaerobic mechanism do we (animals) use? Yeast?
You must understand chemiosmosis and substrate-level phosphorylation. Where do they occur and why
are they important?
If a difference in H+ concentration on the two sides of the mitochondrial membrane is responsible for
chemiosmosis, how is the hydrogen ion gradient formed?
Know the equation for cellular aerobic respiration: C6H12O6 + O2 Æ CO2 + H2O + ATP
Know the equation for cellular anaerobic respiration in yeast: C6H12O6 Æ CO2 + Ethyl alcohol + ATP
Know the equation for cellular anaerobic respiration in animals: C6H12O6 Æ Lactic acid + ATP
Glycolysis occurs in all living organisms, but oxidative phosphorylation does not. Explain.
Be familiar with the basic aspects of glycolysis.
We breathe oxygen. What is the role of oxygen in cellular respiration?
The electron transport chain in mitochondria is a series of membrane-associated electron carriers. As
electrons flow through these carriers, they lose most of their energy by driving several proton pumps.
Where do the protons go and why is this important for ATP synthesis in the mitochondrion?
Most ATP synthesis during aerobic cellular respiration occurs through ATP synthase in the inner
mitochondrial membrane. Why is this location essential for ATP synthesis with this enzyme.
In an environment without oxygen, yeast cells respire anaerobically. What is the reactant and what are
the products for this type of respiration.
Fermentation occurs when an organic molecule accepts hydrogen atoms in order to recycle NADH back
to NAD+. Explain.
What respiratory pathways are required to produce ATP in an anaerobic environment?
PHOTOSYNTHESIS
What is visible light and what is the electromagnetic spectrum?
What are the pigments used by plants in photosynthesis?
What is an absorption spectrum and what does it tell us about pigments?
Why are leaves green?
Why is photosynthesis important?
What is the equation for photosynthesis?
What is the difference between an antenna complex, a reaction center and a photosystem?
Where are the reactants of photosynthesis used and where are the products of photosynthesis produced?
What is light-harvesting and sugar building in photosynthesis? Have a clear understanding of the
difference between light dependent and light independent reactions of photosynthesis.
After a photon of light energy is absorbed by a pigment in Photosystem I, what happens to it if it?
After a photon of light energy is absorbed by a pigment in Photosystem II, what happens to it if it?
Most plants incorporate carbon dioxide into sugars by means of a cycle of reactions called the Calvin
cycle. What are major stages of the Calvin cycle?
Chloroplasts have a structure giving them a division of labor between light-harvesting and sugar building.
Explain how the stroma and the thylakoids relate to light-harvesting and sugar-building.
What is RuBP and what is rubisco?
Chemiosmosis is common to both cellular respiration and the light reactions of photosynthesis. What is
the source of energy for chemiosmosis in respiration and what is the source in photosynthesis?
ATP and NADPH are the products of light reactions of photosynthesis and they are used in the Calvin
cycle. Explain.
What is C3 photosynthesis?
A different form of photosynthesis called CAM metabolism evolved in succulent desert plants to reduce
the problem of photorespiration. Briefly, how does CAM work?
Fall leaf color on deciduous trees becomes apparent because chlorophyll production stops and this allows
the accessory pigments to be revealed. This illustrates other pigments found in leaves are hidden by the
green chlorophylls.
ATP synthesis in a chloroplast occurs in a manner similar to ATP synthesis in the mitochondrion since
both use a proton gradient and ATP synthase enzyme. But, what is the source of energy to create a proton
gradient in chloroplasts and what is the source of energy in a mitochondrion. Think about the expressions
photophosphorylation and oxidative phosphorylation.
If photosynthesis suddenly stopped on a global scale, aerobic respiration would stop leading to the loss of
atmospheric oxygen and global food supplies. Most life as we know it would cease to exist!