4/14/13
Introduction
Notes 1 for Cellular Energy
How Organisms
Obtain Energy
In order to survive, all
organisms must keep
their body systems
stable, even though they
live in changing
environments.
 Biochemical processes are the
For example, your body
temperature must stay near
98.60 F. If you become too hot
or too cold, the biochemical
processes that keep you alive
will fail.
Getting Energy
 All living things need energy.
They must be able to make
energy from the environment,
store energy for later use, and
use energy under
controlled conditions.
chemical reactions that occur in
all living things to maintain this
stability. Remember, they are
regulated by enzymes made
according to instructions in DNA.
Two very important enzyme-controlled biochemical processes
are photosynthesis and cellular respiration. These processes
are how your body gets, stores and uses energy.
All of the active characteristics of living
things (growing, developing, responding to
stimuli, reproduction, etc.) require energy.
The organelles in your cells need fast
energy after exertion the same way the
rest of your body does.
1
4/14/13
Energy is the ability to do work. Remember
the 1st Law of Thermodynamics? Energy
can’t be created or destroyed just
rearranged.
Autotrophs, like plants, make their own
food using energy from the sun and
and heterotrophs eat the
autotrophs to get their
energy.
Photosynthesis (changing smaller
molecules into bigger molecules using
light energy) is an anabolic pathway.
SMALL
Carbon
(added to make)
Metabolism
Metabolism is all of the chemical
reactions that go on inside a cell.
When you take smaller molecules to
make large ones this is known as an
anabolic pathway of metabolism.
When you take large molecules and
break them down into smaller ones
this is known as a catabolic pathway.
Cellular respiration (breaking
down large molecules into smaller
molecules) is a catabolic pathway.
BIG
LARGE
WATER
Sugars
Oxygen
_______________ + ____________
_____________
dioxide + ____________
6 CO2 + ____________
6 H2 O
_____________
→
CH O
(broken down to make) SMALL + ENERGY
6O
6 12 6 + _________
2
_____________
6 CO2
→________
6 H2O + __________
+ __________
C6H12O6 + ____________
6 O2
_______________
ATP
These 2 reactions make a cycle.
The products of one are the reactants for the other.
PHOTOSYNTHESIS
6 CO
6H O
___________
+ ___________
2 + _________
2
C6H12O6 + __________
6O2
→_______________
CELLULAR RESPIRATION
CH O
6O
6 12 6 + _________
2
_____________
6 CO2 + __________ + __________
→________
6 H2O
The two equations are exact opposites!
Your cells can’t grab a Snickers bar for
energy, they grab ATP. ATP stands for
adenosine triphosphate. ATP is a special
kind of nucleotide used by cells to store and
transport ENERGY. It contains one molecule
of an adenine base, a ribose sugar and 3
phosphate groups - P.
ATP
2
4/14/13
http://www.cat.cc.md.us/~gkaiser/biotutorials/energy/adpan.html
Because it takes energy
to add the P groups, the
energy is stored in the
bonds between the P s.
When a P is removed
energy is released.
When you take a P away
from ATP by breaking a
bond you get ADP plus
energy
ATP
ADP + ____ +
→ ____
Cells ________
STORE energy by adding the
phosphate back on to ADP to make ATP.
The energy to do this comes from
FOODS
GLUCOSE
____________
like _____________
It’s like recharging the battery !
ADP + ___ + ________
→ ATP
___
Cellular uses of energy include making
new molecules and cell parts,
maintaining homeostasis, and
transmitting nerve impulses.
3