Download Name: Date: Period: Cell Energy Review Glucose is the main

Name:
Date:
Period:
Cell Energy Review
1. Glucose is the main energy fuel for the cell. Its chemical formula is C6H12O6. Because it is a form of
energy storage, in terms of money, it is known as the savings account for energy. The total amount
of energy released from breaking all the bonds is 686 kcal/mol (include units). In the process of
cellular respiration, however, only 40% of energy is broken down to form 36-38 ATP.
2. The money in your pocket type of energy is ATP because it is easily usable. In order to get the energy
out one phosphate group is taken off to form ADP. In order to be usable as a form of energy again,
this same group will be reattached with the addition of energy.
3. Aerobic cellular respiration requires oxygen. The three two main reactants are C6H12O6 and O2. The
three main products are CO2, H2O, and energy in the form of ATP. The purpose of aerobic cellular
respiration is to make ATP. All eukaryotes must go through this process in order to take energy out
of its storage form into its easily usable form.
4. The first step of cellular respiration is glycolysis. Using the reactants C6H12O6 and ATP, it takes place
in the cytoplasm of the cell. This is an anaerobic reaction (oxygen requirement) and produces ATP,
NADH, and pyruvic acid.
5. The second step of aerobic cellular respiration is Kreb’s Cycle in the matrix of the mitochondria. This
is an aerobic reaction although it does not directly require O2. It uses pyruvic acid to make ATP,
NADH, and FADH2. Glucose is completely broken down in this process.
6. The last step of aerobic cellular respiration is the Electron Transport Chain (aka as the ETC) in the
cristae of the mitochondria. In this process the large energy check NADH will be converted into 3
ATP while the smaller energy check FADH2 will be converted into 2 ATP. The proteins in this process
take off the H+ and the electrons from the energy checks and pump the ion H+ into the outer
compartment of the mitochondria. This builds up a chemical gradient which can only move towards
equilibrium when the same ion is passed through the protein ATP Synthase which makes ATP using
the chemical energy gradient. Ions are unable to pass through the cell membrane because their
charge cannot go through the nonpolar tails of the phospholipid bilayer. In this process, both energy
checks lose electrons and are oxidized which makes them reducing agents. Meanwhile, the
electrons and H+ ions are picked up by the last reactant O2 to form H2O. This last reactant is an
oxidizing agent because it is reduced. All the energy removed from glucose is now converted into
the money in your pocket energy known as ATP.
7. If H2O is not present, the cellular respiration will continue as an anaerobic reaction (oxygen
requirement). This process takes place in obligate anaerobes which can not use O2 and in facultative
anaerobes which can use H2O if it is available. Picking up after glycolysis, this process will allow the
cell to continue making 2 (#) ATP per glucose by recycling NADH to make NAD+. Yeasts go through
alcoholic fermentation while muscle cells go through lactic acid fermentation. This process is not
very favorable because it makes 2 ATP compared to 36-38 ATP with aerobic cellular respiration.
8. In the electromagnetic spectrum, humans can only see visible light. The color white in light contains
all the colors. When a shirt is black in color that means that it absorbed all the colors which makes it
very hot on a summer day. White shirts, however, reflect all the colors which makes it cooler to
wear. Plants are green in color because they reflect green. In the process of photosynthesis, they
absorb the colors red and blue to capture light energy.
9. Most of the energy for life on earth comes from the sun. Organisms that feed themselves are known
as autotrophs such as trees and algae. On the other hand, organisms that eat others are known as
heterotrophs such as humans and fungi.
10. The process of converting light energy from the sun into chemical energy is known as
photosynthesis. The three main reactants are light, CO2, and H2O. These are used to make the
products C6H12O6 and O2. All of these reactions take place in the chloroplast.
11. In the first reaction, known as the light reaction, takes place in the thylakoid space. Light excites H2O
which makes it lose electrons and H+ ions in Photosystem II. This creates energy in the form of ATP
and a product O2. The second part takes place in Photosystem I where the electrons and H+ ions are
picked up by NADP (an energy check only used in photosynthesis) to make NADPH.
12. The energy produced from the previous reaction is now used in the dark reaction which takes place
in the stroma. This is known as the carbon-fixing cycle because the reactant CO2 is changed into
C6H12O12 with the addition of energy.