Download Unit 4 (Bioenergetics - Photosynthesis and Cellular Respiration)

Bioenergetics Test Review - KEY
Enzymes and Metabolism
1. Define the following terms:
a. Anabolism – To build up using dehydration; requires energy; Remember by anabolic steroids
build muscle OR build up like an ant.
2.
b.
Catabolism – To break down using hydrolysis; gives off energy; Remember by: tear down like
a cat.
c.
Dehydration – Pull out water to build (Remember everything wants to have 8 valence
electrons. If we pull out water it is losing valence electrons so it wants to make a bond to get
back to 8).
d.
Hydrolysis – Put in water to break down (Remember everything wants to have 8 valence
electrons. If we put in water it now has more than 8 so it has to break to get back to 8).
e.
Endergonic – Requires energy (i.e. anabolism and dehydration)
f.
Exergonic – Gives off energy (i.e. catabolism and hydrolysis)
What is it about the shape of ATP that allows it to be used for energy?
Phosphates are negative. The phosphate-phosphate bonds repel each other. ATP has 3 phosphates so
they all push each other away (and is very unstable). It breaks and releases energy very easily. It
breaks into ADP (2 phosphates) which does not have lots of energy because the phosphates can bend
so that their negative charges do not repel as much.
3.
4.
5.
What is a substrate?
What an enzyme works on
What type of organic molecule are most enzymes? Proteins (although some are RNA)
What is the active site of an enzyme?
The spot where it binds with a substrate. This is where the enzyme is actively working.
6.
7.
8.
How do enzymes affect the reaction rate?
They speed up the reaction rate.
What is activation energy?
Lower the activation energy.
How does an enzyme affect activation energy?
It grab-grab-pairs (DEHYDRATION) or grab-grab-tears (HYDROLYSIS) the substrate. In other
words, it orients the substrate so that it can do the reaction faster/easier.
9.
In the diagram above, which is the activation energy with and enzyme? (A or B)
a. Reaction A requires (more or less) energy than reaction B?
Reaction A has a lower activation energy because enzymes GRAB-GRAB-PAIR OR GRABGRAB-TEAR the substrate (which means it orients it so the reaction happens EASIER)
10. What is the induced fit model?
The active site of the enzyme is induced (caused) to change shape to fit the substrate perfectly once
the substrate binds.
11. List 3 factors that can affect an enzymes ability to work optimally.
Temperature, pH, salinity
12. How is an enzyme affected by being outside its “range” (such as pH or temperature range)? It denatures
What does it mean when an enzyme is denatured? It loses its shape thus loses its function. The primary
structure (covalent bond) remains because they are very strong, but the secondary (and tertiary)
levels of protein structure fall apart.
13. Describe two types of inhibitors, how are they different?
Competitive and non-competitve (allosteric).
Competitive is shaped like the substrate and competes for the active site. It slows down reaction rate
by blocking the substrate from getting to the active site.
Non-competitive is not shaped like the substrate so it does not compete for the active site. It binds to
another site (called the allosteric site) which causes the enzyme’s active site to change shape so that it
can no longer bind with the substrate.
14. Explain what the diagram below is showing.
The reactions rate increase as the substrate increase because the enzyme has more material to work with (it
doesn’t have to wait on another substrate to react with after finishing with one). Remember enzymes are
reusable so when they finish one reaction they are automatically ready to do another. Eventually the reaction
rate reaches a peak because the enzyme is going as fast as it can go (so if you add more enzyme it won’t
matter because it already is going as fast as possible – there is no wait time).
Photosynthesis:
1. Draw a chloroplast and label the following: a) stroma, b)granum, c) thylakoid, d) thylakoid space
Thylakoid space
Green pancake = thylakoid
Stack of pancakes = grana
Syrup (sugar water) = stroma
2. Where is the majority of chloroplast located in a plant? Leaf (specifically the mesophyll of the leaf)
3. What is the name of the MAIN pigment that absorbs sunlight in chloroplast, and why is this pigment green
(NOTE: This is not the only pigment responsible for light absorption. It is just the main one)?
Chlorophyll A. It absorbs all colors BUT green (it reflects green).
4. How does a plant receive or release each of the following: a) oxygen, b) carbon dioxide, c) sunlight, d)
water?
a) Oxygen and b) carbon dioxide – stomata, c) sunlight – leaves, d) water – root hairs
5.
6.
7.
8.
9.
What is the green tissue in the interior of leaves where chloroplast are located called? Mesophyll (the
ground tissue of leaves). Remember there are 3 types of tissues in plants: dermal, ground (mesophyll
for leaves), and vascular.
What is the balanced equation for photosynthesis (Draw arrows between the reactants and products to show
what product each reactant becomes)?
What is being reduced in this equation? What is being oxidized?
L.E.O. (lose electrons oxidized) the lion says G.E.R. (gain electrons reduced). Look for the flow of
hydrogens (they are carrying the electrons).
Water loses hydrogens to become oxygen so it is oxidized.
CO2 gains hydrogens to become glucose so it is reduced.
What are the 2 stages of photosynthesis?
1) Light Reactions and 2) Calvin Cycle (Also called dark reactions or light independent reactions
because they do not directly require light. Even so, it happens during the day because it requires
the products of the light reactions that happen during the day).
Explain in detail the following for each stage: a) where the stage occurs, b) What are the reactants and
products of each stage, c) what is the “purpose” of each stage
1. Light reactions –
a) Thylakoid membrane (this is where light is absorbed)
b) Reactants – Light, Water (to provide hydrogens), ADP, NADP+ Products – O2 (after water loses
hydrogen), ATP, NADPH
c) To convert suns energy into chemical energy (ATP and NADPH) that will power the production of sugar
2. Calvin Cycle –
a) stroma (Calvin Cycle is making of sugar. Remember stroma is the “sugar water”)
b) Reactants – CO2 (which will become glucose), ATP and NADPH (the batteries to power the conversion of
CO2 to glucose)
Products – Glucose, ADP and NADP+ (because ATP and NADPH have been used)
c) to make sugar (food for the plant
10. What is the the purpose of NADPH?
Electron carrier. It physically takes the electrons that were on water to CO2 to turn it into sugar.
11. What is carbon fixation?
Rubisco converting CO2 to glucose. “Fixing” inorganic carbon into organic carbon that can be used
by the plant.
12. Use the following terms to complete the diagram below showing a summary of Photosynthesis: ATP and
NADPH (together as one number), ADP + P and NADP+ (together as one number, light, Light Reactions,
Calvin Cycle, H2O, CO2, O2, Glucose
1.
Light, 2. Water, 3. CO2, 4. Light Reactions, 5. Calvin Cycle, 6. ADP and NADP+, 7. ATP and
NADPH, 8. O2, 9. Glucose
Cell Respiration:
1. Which of the following make ATP for energy: prokaryotes, plants, animals?
All of them.
2. Explain your answer for #1.
Every living thing uses ATP for energy.
3.
4.
Which of the following USE MITOCHONDRIA to make ATP: prokaryotes, plants, animals?
Only plants and animals.
Explain your answer for #3.
Prokaryotes DO NOT have a nucleus or membrane bound organelles (the only thing inside them
would be cytoplasm, DNA, proteins, and ribosomes).
5.
What is the balanced equation for cellular respiration (Draw arrows between the reactants and products to
show what product each reactant becomes – Remember to look for the flow of hydrogens)?
6.
What is being oxidized in cellular respiration? What is being reduced?
Glucose loses electrons (oxidized) to become CO2.
Oxygen gains electrons to become water (reduced).
7.
Draw a mitochondria and label the following: a) outer membrane, b) inner membrane,
intermembrane space, d) cristae, e) mitochondrial matrix
c)
What are the 3 stages of cellular respiration? Glycolysis, Kreb’s (Citric Acid) Cycle, Oxidative
Phosphorylation
9. Which of these 3 stages produces ATP? All of them
10. Which of the 3 stages produces the most ATP? Oxidative phosphorylation (which is why we have to
breathe oxygen).
11. Describe in detail what occurs during all 3 phases. Be sure to include a) where the stage occurs, b) What
are the reactants and products of each stage, c) what is the “purpose” of each stage
1. Glycolysis
a. Cytoplasm (Which is why ALL organisms can make ATP. All organisms have cytoplasm so
all organisms do this stage).
b. Reactant – Glucose Product – Pyruvate (half of a glucose), 2 ATP, 2 NADH (electron
carrier like NADPH – think the P is for photosynthesis)
c. To break sugar (and to start cellular respiration). Glyc = sugar and lysis = to break
8.
Kreb’s Cycle
a. Mitochondrial matrix (inside of mitochondria). Only eukaryotes do this stage because only
eukaryotes have a mitochondria.
b. Reactant – Pyruvate Product – CO2 (because all of the hydrogens are pulled off), 2 ATP,
NADH, and FADH2 (another electron carrier)
c. To finish break down glucose to make electron carrier (NADH and FADH2)
3. Oxidative phosphorylation
a. Inner mitochondrial membrane (cristae – folded for more surface area)
b. Reactant – NADH, FADH2, O2 (to accept electrons from electron carriers) Product – H2O
(oxygen after it has accepted electrons) and ATP (LOTS of ATP – 32 or 34 per sugar)
c. To make lots of ATP
12. Oxidative phosphorylation involves the electron transport chain and chemiosmosis. Describe these 2
processes, and how they work together to produce ATP.
2.
Electron transport chain – The step by step movement of the electrons (from the electron carriers) through
the inner mitochondrial membrane. They move because each molecule is more electronegative than the one
before it. As they move, the kinetic energy created is used to power proton pumps that pump hydrogen to the
INTERmembrane space.
Chemiosmosis – All of the hydrogens are trapped (because they’re charged) in the intermembrane space.
They come back into the matrix through the ATP synthase. It spins as they come through to turn ADP into
ATP.
13. What is pyruvate, and what is its purpose?
Half of a glucose. Take hydrogens (and electrons) from glucose to the mitochondria
14. What is the purpose of NADH and FADH2?
Electron carriers. Take electrons from glucose to the electron transport chain.
15. Which stage finishes breaking down sugar all the way to CO2? Kreb’s cycle
16. Which process occurs in ALL organisms (prokaryotic/eukaryotic, aerobic/anaerobic)? Glycolysis because
it happens in the cytoplasm
17. All of the following questions concern fermentation.
a. What is it?
MAKING ATP WITH NO OXYGEN. Glycolysis over and over in the absence of oxygen. It
makes much less ATP, but it does not require oxygen (so a little ATP is better than none).
b. Where does it occur?
Just like glycolysis – so in the cytoplasm
c. Why do it? (Pros / Cons)
Pro - Makes 2 ATP so keeps organism alive when no oxygen is available
Con – makes much less ATP so organism doesn’t have as much energy
d. What organisms can do it?
Everyone (anaerobic organisms ONLY do fermentation)
e. Which organisms do Alcohol Fermentation? Yeast and bacteria
f.
Which organisms do Lactic Acid Fermentation? Animals
18. Use the following terms to complete the diagram below showing a summary of Cellular Respiration:
Glycolysis, Kreb’s Cycle (Citric Acid Cycle), Oxidative Phosphorylation (Electron Transport Chain),
NADH, NADH and FADH2 (as one number), ATP (will be used as multiple numbers), Pyruvate,
Mitochondria, Glucose
1.
NADH, 2. NADH and FADH2, 3. Glycolysis, 4. Glucose, 5. Pyruvate, 6. Mitochondria, 7. Kreb’s
(Citric Acid) Cycle, 8. Oxidative phosphorylation, 9-11. ATP