Download Biology Chapter 4

Section One: Chemical Energy and
ATP
 ATP
 A molecule that transfers
energy from the breakdown
of food molecules to the cell
processes
 The chemical energy used for
most cell processes
 Energy is released when a
phosphate group is removed


ATP
ADP
ADP is a lower energy molecule
that can be converted to ATP by
the addition of a phosphate
group
Section One: Chemical Energy and
ATP
 ATP
 Digestion of food breaks it down into smaller molecules
that can be used to make ATP
 The number of ATP created depends on the type of food
broken down



Carbohydrate
Lipid: yield the most ATP
Protein: needed to build amino acids and are rarely broken
down for ATP
Section One: Chemical Energy and
ATP
 Chemosynthesis
 The process by which
some organisms use
chemical energy instead
of light energy to make
energy storing carbon
based molecules.
 The organism still
require ATP
Section Two: Overview of
Photosynthesis
 Photosynthesis: the process that captures energy from
sunlight to make sugars that store chemical energy
 Used by producers
 Occurs in chloroplasts

Chlorophyll is a molecule in chloroplasts that absorbs light
energy
 Two MainTypes: chlorophyll A & B
Section Two: Overview of
Photosynthesis
Section Two: Overview of
Photosynthesis
 Photosynthesis
 Occurs in chloroplasts





Most found in leaf cells
Two main parts are the
grana and stroma
Grana: stacks of coin
shaped membrane
enclosed compartments
called thylakoids
Thylakoid membranes
contain chlorophyll
Stroma: fluid that
surrounds the grana
Section Two: Overview of
Photosynthesis
 Photosynthesis
 2 Parts: Light-dependent reaction and lightindependent reactions

Light-dependent reactions: capture energy from sunlight
 Take place in and across the membrane of thylakoids
 Uses water and sunlight
 Steps
1.
Chlorophyll absorbs energy from the sunlight. The
energy is transferred from the thylakoid membrane.
Water molecules are broken down and oxygen is released.
2.
Energy carried along the thylakoid membrane is
transferred to molecules that carry energy, such as ATP
Section Two: Overview of
Photosynthesis
Section Two: Overview of
Photosynthesis
 Photosynthesis
 Light-independent reactions




Use energy created during the light-dependent reactions to
make sugars
Occurs in the stroma
Needs carbon dioxide molecules
Steps
1.
Carbon dioxide is added to a cycle of chemical reactions to
build larger molecules. Energy from the light-dependent
reactions is used in these reactions
2.
A molecule of simple sugar is formed. The sugar, usually
glucose (C6H12O6), stores some of energy that was captured
from sunlight.
Section Two: Overview of
Photosynthesis
 Photosynthesis
 Light energy, carbon dioxide from the atmosphere, and
water are used to create sugar and oxygen
 Only one molecule of carbon at a time is used to create a
six carbon sugar
Section Three: Photosynthesis in
Detail
 Light-dependent Reactions
 Energy is captured and transferred in the thylakoid
membranes by molecules called photosystems


Photosystem I and Photosystem II
Steps: Photosystem II and Electron Transport
1.
Chlorophyll and other light absorbing molecules in the
thylakoid membrane absorb the light energy from sunlight.
The energy is transferred to electrons (e-). These high energy
electrons leave the chlrophyll and enter the electron
transport chain, which is a series of proteins in the
membrane of the thylakoid
Section Three: Photosynthesis in
Detail
 Light-dependent Reactions
2. Enzymes break down water molecules. Oxygen,
hydrogen ions (H+), and electrons are separated from
each other. The oxygen is released as waste. The
electrons from water replace those electrons that left
chlrophyll.
3. Electrons move from protein to protein in the electron
transport chain. The energy used to pump hydrogen
ions from the outside of the thylakoid to the inside,
which is against the concentration gradient. Hydrogen
ions build up inside the thylakoid. Electrons move to
photosystem I.
Section Three: Photosynthesis in
Detail
Section Three: Photosynthesis in
Detail
 Light-dependent Reactions
 Photosystem I
4. Chlorophyll and other light absorbing pigments absorb
energy. Electrons are energized and leave the thylakoid
molecule
5. The energized electrons are added to a molecule called
NADP+. It functions like ADP. A molecule of NADPH is
made. NADPH works like ATP. The NADPH molecules
made will enter the light-independent reactions.
Section Three: Photosynthesis in
Detail
 Light-dependent Reactions
 ATP Production
6. Hydrogen ions flow through the protein channel in the
thylakoid membrane. The concentration rises inside the
membrane. The difference between the outside and
inside concentrations is called chemiosmotic gradient. It
stores potential energy. The ions flow through the
membrane by diffusion.
7. The protein channel in step 6 is part of a complex
enzyme called ATP synthase. As the ions flow through
the channel, ATP synthase makes ATP by adding a
phosphate group to ADP.
Section Three: Photosynthesis in
Detail
Section Three: Photosynthesis in
Detail
 Light-independent Reactions
 Take place in chloroplast in the stroma
 Light is not required
 Also called the Calvin Cycle

1.
2.
Use carbon dioxide gas from the atmosphere and the energy carried
by ATP and NADPH to make simple sugars
Carbon dioxide is added to a five carbon molecule already in
the carbon cycle, forming a six carbon molecule
Energy from the light dependent reactions (ATP & NADPH)
is used by enzymes to split the six carbon molecules into 2
three carbon molecules
Section Three: Photosynthesis in
Detail
 Light-independent Reactions
3. Most of the three carbon molecules stay in the Calvin
Cycle, but one leaves. After two leave they are bonded
together to form a six carbon sugar molecule like
glucose.
4. Energy from the ATP is used to change the three carbon
molecules back into five carbon molecules. The five
carbon molecules stay in the cycle and are added to new
carbon dioxide molecules that enter the cycle.
Section Three: Photosynthesis in
Detail
Section Three: Photosynthesis in
Detail
 Photosynthesis
 Functions
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Allows food production for plants and other organisms
Provides material for plant growth and development
Removes carbon dioxide from the atmosphere
Creates oxygen for organisms that breathe it
Section Four: Overview of Cellular
Respiration
 Cellular Respiration
 Releases chemical energy from sugars and other carbon
based molecules to make ATP when oxygen is present
 Aerobic: needs oxygen to take place
 Needs glycolysis: splits glucose into two 3 carbon
molecules and makes two molecules of ATP
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
Takes place in the cytoplasm
Anaerobic: does not need oxygen
Section Four: Overview of Cellular
Respiration
 Cellular Respiration
 Occurs in the
mitochondria
 Occurs through 2
stages: Krebs Cycle and
Electron Transport
 Up to 38 ATP are made
from one glucose
molecule
Section Four: Overview of Cellular
Respiration
 Cellular Respiration
 Stage One: Krebs Cycle
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
1.
2.
Krebs Cycle: produces molecules that carry energy to the second
part of cellular respiration
Takes place in the matrix of the mitochondria
3 carbon molecules from glycolysis are broken down. A small
number of ATP are made, along with other types of energy
carrying molecules. Carbon dioxide is given off as a waste
product.
Energy is transferred from the second stage of cellular
respiration.
Section Four: Overview of Cellular
Respiration
 Cellular Respiration
 Stage Two: Electron transport
Takes place in inner mitochondrial membrane
 An electron transport chain made of proteins needs energy
carrying molecule from the Krebs cycle and oxygen to make
ATP.
3. Energy is transferred to a chain of proteins in the inner
membrane of the mitochondria
4. A large number of ATP molecules are made and oxygen enters
the process and is used to make water molecules. Water and
heat are given off as waste products

Section Five: Cellular Respiration in
Detail
 Glycolysis
 Take place in the cytoplasm before cellular respiration
 Anaerobic
 Steps:
1.
2.
Two ATP are used to energize a glucose molecule. The
glucose is split into 2 three carbon molecules, and then
through enzymes and chemical reactions is rearranged.
Energized electrons from the three carbon molecules are
transferred to molecules of NAD+. Molecules of NADH are
formed. A series of reactions converts the three carbon
molecule to pyruvate, which enter cellular respiration, and
four ATP are made.
Section Five: Cellular Respiration in
Detail
 Cellular Respiration
 Stage One: Krebs Cycle (Citric Acid Cycle)

1.
2.
3.
Makes more ATP than glycolysis
A pyruvate molecule is split into a 2 carbon molecule and a
molecule of carbon dioxide (waste product). High energy
electrons are transferred from the 2 carbon molecule to NAD+
producing NADH. NADH moves to the electron transport
chain.
A molecule called coenzyme A bond to the 2 carbon molecule
and the intermediate molecule they form enter the Kreb cycle
The intermediate is added to a 4 carbon molecule to form
citric acid ( 6 carbon molecule). Coenzyme A will return to
step 2.
Section Five: Cellular Respiration in
Detail
 Cellular Respiration
 Stage One: Krebs Cycle (Citric Acid Cycle)
4. The citric acid is broken down by an enzyme into a 5 carbon
molecule. A molecule of NADH is formed and leaves the
Krebs cycle. A molecule of carbon dioxide is given off as a
waste product.
5.
The 5 carbon molecule is broken down by an enzyme,
forming a 4 carbon molecule, NADH, and ATP. NADH
leaves and carbon dioxide is given off as a waste product.
6.
Enzymes rearrange the 4 carbon molecule and high energy
electrons are released. NADH and FADH2, an electron
carrier, are made. They leave Krebs and the 4 carbon
molecule stays.
Section Five: Cellular Respiration in
Detail
Section Five: Cellular Respiration in
Detail
 Breakdown of Krebs
 3 molecules of carbon dioxide created as waste
 1 molecule of ATP made
 4 molecules of NADH sent to ETC
 1 molecule of FADH2 sent to ETC
Section Five: Cellular Respiration in
Detail
 Cellular Respiration
 Stage Two: Electron Transport Chain (ETC)
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Takes place in and across inner membrane of mitochondria
Made of proteins
Uses the energy from NADH and FADH2 to pump hydrogen
ions against their concentration gradient, and across the inner
mitochondrial membrane.
As hydrogen ions move out of the inner membrane back to
outer membrane they produce ATP
Section Five: Cellular Respiration in
Detail
 Cellular Respiration
 Stage Two: ETC
1.
2.
3.
4.
Protein in the inner mito. membrane take electrons from NADH
and FADH2. (Uses 2 NADH and one FADH2)
The electrons travel through proteins in the ETC and the
proteins use the energy from the electrons to pump hydrogen
ions into the inner mito. membrane. The hydrogens build up in
the membrane and are pumped against the concentration
gradient.
Hydrogens leave the inner mito. membrane through a protein
channel that is part of the ATP synthase enzyme. As they leave it
allows ATP synthase to add a phosphate group to ADP creating
ATP.
Oxygen picks up the hydrogens and electrons finished with the
process and creates water as a waste product.
Section Five: Cellular Respiration in
Detail
Section Five: Cellular Respiration in
Detail
 Breakdown of Cellular Respiration
 Carbon dioxide is created
 Water is created from the ETC
 A net gain of 38 ATP
Section Six: Fermentation
 Fermentation
 Does not make ATP but allows glycolysis to continue
when no oxygen is present
 Occurs when your body cannot get enough oxygen fast
enough to perform cellular respiration
 Removes electrons from NADH and recycles NAD+
molecules for glycolysis
 Lactic acid fermentation occurs when your body is
fatigued and can’t get oxygen
Section Six: Fermentation
 Lactic Acid Fermentation
 Latic Acid: is what causes your muscles to feel sore or
burn during exercise
1. Pyruvate and NADH from glycolysis enter
fermentation. NADH provide energy to turn pyruvate
into lactic acid. NADH forms NAD+ after usage.
2. The NAD+ goes to glycolysis, allowing it to continue.
Section Six: Fermentation
 Fermentation
 Used to make cheese, bread, yogurt, and alcohol
 Bacteria in animal stomach use it to get energy