Transcript 8.1 Energy and Life

Chapter 8
8.1Energy and Life
Energy
• Energy = the ability to do work
– ex. light, heat, electricity, stored in bonds of
chemical compounds
• Living things depend on energy
– Even when sleeping, your cells use energy to
build new proteins and amino acids.
Autotroph vs. Heterotroph
• Autotroph (auto = “self”, trophe = “food”)
Organisms that make their own food
•Plants and some other organisms use light
energy from the sun
• Heterotroph (hetero = “other”, trophe =
“food”)
Obtain energy from the foods that they
consume
•Eat autotrophs or other heterotrophs
Example
Grass gets energy
from the sun.
The impala gets energy
from eating the grass.
The leopard gets
energy from
eating the impala.
Fuel of Life
• Glucose is called the fuel of life
– Monosaccharide
C6H12O6
• Contains too much energy for
cells to use all at once
Must convert this large
amount of energy into a
usable form
ATP Parts
• ATP  Adenosine Triphosphate
– Chemical compound that cells use to store
and release energy
• Basic energy source of the cell
• 3 main parts:
– Adenine
– Ribose (5 C sugar)
– 3 phosphate groups
ATP and Energy
The energy that ATP carries is found in the
bonds between the phosphates
Energy is released when these bonds are
broken; energy is stored when these bonds are
formed
Section 8-1
ADP
ATP
Energy
Adenosine diphosphate (ADP) + Phosphate
Partially
charged
battery
Energy
Adenosine triphosphate (ATP)
Fully
charged
battery
Comparison of ADP and ATP to a Battery
ATP vs. ADP / AMP
• ADP = adenosine
diphosphate
– 2 phosphate groups
Has less potential
energy than ATP
• AMP = adenosine
monophosphate
– 1 phosphate group
Has less potential
energy than ADP
• Both of the above are
recyclable
Using Biochemical Energy
– One way cells use the energy provided by
ATP is to carry out active transport.
Using Biochemical Energy
– ATP powers movement, providing the energy
for motor proteins that contract muscle and
power the movement of cilia and flagella.
Using Biochemical Energy
– Energy from ATP powers the synthesis of
proteins and responses to chemical signals at
the cell surface.
Using Biochemical Energy
– ATP is not a good
molecule for storing large
amounts of energy over
the long term.
– It is more efficient for
cells to keep only a small
supply of ATP on hand.
– Cells can regenerate ATP
from ADP as needed by
using the energy in foods
like glucose.
Review Questions
• 1. What is energy?
• 2. What is the difference between an autotroph
and a heterotroph?
• 3. What is the fuel for life? Why must it be
converted into another form?
• 4. What is ATP? What are its 3 main parts?
• 5. How is ATP used to store and release
energy?
• 6. What is the difference between an endergonic
reaction and an exergonic reaction?