Homework 7 Due 11/12

What is ATP? What is ADP? Give similarities
and differences between the two molecules.
Photosynthesis and
Cellular Respiration
ALL CELLS REQUIRE ENERGY
Some chemical reactions release energy
(what kind of rxn?) while others absorb
energy
 All chemical reactions consume activation
energy
 All cells require energy to perform
processes
 This is a requirement of life!

Two ways to get food

“troph” = food (nutrition)

Autotrophs
–
–

Auto = self
Autotrophs make their own food
Heterotrophs
–
–
Hetero = different
Heterotrophs get their food from something else (they
have to eat it)
Two ways to get food

Autotrophs
–
–

Producers
Plants, algae, some bacteria
Heterotrophs
–
–
–
Consumers
Animals, fungi, most protists most bacteria
(do you remember the vore terms?)
Cellular Respiration
Cells
Breathing
Cellular Respiration

Happens in all cells. Yes both plant and
animal cells

Overall Reaction:
–

C6H12O6 + 6O2 → 6CO2 + 6H2O + 36 ATP
Occurs in Cytoplasm and Mitochondria
Homework 7 Due 11/12

What is ATP? What is ADP? Give similarities and
differences between the two molecules.
ATP – when a PO4 is removed,
energy is released!
What kind of reaction is this?
Some energy is given off as heat.
How would you get back to ATP?
Which comparison between ATP
and ADP is correct
A.
B.
C.
D.
ATP stores less chemical energy than ADP and
phosphate
ATP stores more chemical energy than ADP
and phosphate
Less energy is used to form ATP than is
released from ATP and hydrolysis
More energy is used to form ATP than is
released from ATP and hydrolysis
Which comparison between ATP
and ADP is correct
A.
B.
C.
D.
ATP stores less chemical energy than ADP and
phosphate
ATP stores more chemical energy than ADP
and phosphate – which is released! This is it!
Less energy is used to form ATP than is
released from ATP and hydrolysis – NO, it
would be the same
More energy is used to form ATP than is
released from ATP and hydrolysis – see above
A protein in a cell membrane changed its shape
to move sodium and potassium ions against their
concentration gradients. Which molecule was
most likely used by the protein as an energy
source?
A. ATP
B. ADP
C. Catalase
D. Amylase
A protein in a cell membrane changed its shape
to move sodium and potassium ions against their
concentration gradients. Which molecule was
most likely used by the protein as an energy
source?
A. ATP – Ummm… yeah!
B. ADP – nope, no energy
C. Catalase – nope enzyme (peroxide)
D. Amylase – nope enzyme (digestion)
RESPIRATION


Process of taking ADP and making it ATP again.
Involves breaking down

Complicated molecules  into simple molecules
Cellular Respiration Overview

Depends on whether or not there is oxygen

Aero = oxygen
Aerobic Respiration – makes energy IN O2
Anaerobic Respiration – Fermentation – makes
energy WITHOUT O2


3 Stages of aerobic cellular
respiration
1.
2.
3.
Glycolysis
Krebs Cycle
Electron Transport System
For each glucose molecule, total ATP = 36
Only 39% efficient, rest is lost as heat.
HOMEWORK 8 – DUE 11/19
Describe the energy changes
occurring in each process of
photosynthesis.
Describe how energy transformations
involved in photosynthesis are
related to energy transformations
involved in cellular respiration.
Step 1: Glycolysis




Glycolysis makes 2 molecules of ATP (energy)
Glycolysis happens in the cytoplasm of the cell
Glycolysis is anaerobic
Glucose is broken down into smaller molecules
Step 1a: Check for Oxygen



If oxygen is present, two more steps occur in the
mitochondria
If no oxygen is present, fermentation occurs
Let’s go on as if there IS oxygen
Mitochondria





In ALL eukaryotic cells! (name some. What is
NOT?)
Are not original to cells.
Most likely a prokaryote of their own
Have their own DNA and Ribosomes
They take shelter in cells, and in return provide
ATP (cell currency) to their hosts.
Mitochondria Structure




The outer membrane to protect the organelle
The intramembrane space (the space between
the inner and outer membranes)
The inner membrane is folded into a series
cristae or long folds that greatly increase the
surface area of the inner membrane allowing
more area for energy production in electron
transport.
The matrix – inside the inner membrane
Steps 2 with oxygen:
Kreb’s Cycle





Kreb’s Cycle aka citric acid cycle
Takes place in matrix
Breaks down PRODUCTS from glucose
Produces much CO2
Produces 2 ATP
Kreb’s Cycle (Citric Acid Cycle)
Steps 3 with oxygen: Electron
Transport Chain





Electron Transport Chain – makes 32-34 ATP
H+ ions, FADH2 and NADH are used here.
These ions flow across the inner mitochondria
membrane
As they flow, they power ATP synthase (sits on
inner membrane)
This enzyme attaches PO4 to ADP, making ATP
Energy Tally AEROBIC


36 ATP for aerobic vs. 2 ATP for anaerobic
–
Glycolysis
2 ATP
–
Kreb’s
2 ATP
–
Electron Transport
32 - 34 ATP
36 - 38 ATP
Anaerobic organisms can’t be too energetic but
are important for global recycling of carbon
Step 2 without oxygen:
Fermentation



The cell must recycle the materials from
glycolysis. DOES NOT GIVE AS MUCH ATP.
This recycling process is called fermentation.
The product of fermentation is alcohol (ethanol)
and carbon dioxide (prokaryotes) OR lactic acid
(for us).
Which types of respiration are
useful in increasing the amount of
gas in a food product?
A.
B.
C.
D.
Fermentation producing lactic acid only
Fermentation producing carbon dioxide
and ethanol only
Aerobic respiration and fermentation
producing lactic acid
Aerobic respiration and fermentation
producing carbon dioxide and ethanol
Which types of respiration are
useful in increasing the amount of
gas in a food product?
A.
B.
C.
D.
Fermentation producing lactic acid only
– need CO2
Fermentation producing carbon dioxide
and ethanol only YES THIS IS IT
Aerobic respiration and fermentation
producing lactic acid
Aerobic respiration and fermentation
producing carbon dioxide and ethanol
All of the following are correct
about respiration except
A.
B.
C.
D.
All plants and animals carry out respiration all
the time
It consists of glycolysis, Krebs cycle, and the
electron transport chain
Oxygen molecules are pumped across the inner
membrane of the mitochondria
Most ATP is produced in the electron transport
chain
All of the following are correct
about respiration except
A.
B.
C.
D.
All plants and animals carry out respiration all
the time
It consists of glycolysis, Krebs cycle, and the
electron transport chain
Oxygen molecules are pumped across the inner
membrane of the mitochondria – nope, it’s H+
Most ATP is produced in the electron transport
chain
Glycolysis
A.
B.
C.
D.
E.
Produces water
Produces oxygen
Involves an electron transport chain
Is the breakdown of glucose to produce smaller
organic compounds
Produces carbon dioxide
Glycolysis
A.
B.
C.
D.
E.
Produces water
Produces oxygen
Involves an electron transport chain
Is the breakdown of glucose to produce smaller
organic compounds
Produces carbon dioxide
Photosynthesis
HOMEWORK 8
Describe the energy changes occurring in
each process f\of photosynthesis.
Describe how energy transformations
involved in photosynthesis are related to
energy transformations involved in
cellular respiration.
Used by producers to create
glucose
Reactants are 6 carbon dioxide and 6 water
 Creates 1 glucose molecule
 Glucose can be stored (?), used as structure
(?), or directly in respiration
 Some ATP is also directly produced

Though respiration occurs, more
O2 is generated than used
Which of the following best explains the
relationship between photosynthesis and
cellular respiration?
A.
B.
C.
D.
Both produce CO2 and O2
Both require energy from sunlight to occur
The products of one are the reactants of
the other
A plant can carry out one or the other
process
Photosynthesis


Takes place in specialized
structures inside plant cells
called chloroplasts
Chloroplasts surround the
central vacuole (water
storage) of the plant cell.
Why?
Photosynthesis



Chloroplasts are one of the
special structures in plants.
Chloroplasts are almost
certainly cyanobacteria that
have hopped into plant cells for
a symbiotic ride.
They get a home, the plant
gets sugar. What relationship
is this?
Chloroplast –vs- Mitochondria
• Both are surrounded by a double
membrane with an intermembrane space.
• Both have their own DNA .
• Both are involved in energy metabolism.
• Both have membrane reticulations filling
their inner space to increase the surface
area on which reactions with membranebound proteins can take place.
Structures of chloroplasts



Double membrane surrounds stroma – inner fluid
Stacks of disks called thylakoids
Thylakoids contain chlorophyll – a pigment that
absorbs light energy.
Light is absorbed by pigments


The primary pigment for photosynthesis is
chlorophyll a
It absorbs blue and red light, not green (green
light is reflected back!)
Absorption spectrum
of chlorophyll a
Chlorophyll a is the primary
photosynthetic pigment that drives
photosynthesis.
Accessory pigments absorb at
different wavelengths,
extending the range of light
useful for photosynthesis.
Leaves are where most
photosynthesis occurs




Leaves need direct access to CO2 and H2O
They take these in from atmosphere through
stomata
Plants can open stomata to take in CO2 and
release O2 (plural is stoma)
Plants also take in water through roots which
travels to leaves through vascular tissue called
xylem.
Chloroplast Structure &
Function


The chloroplast has different spaces: stroma
and thylakoid
These compartments and the membranes that
separate them serve to isolate different aspects
of photosynthesis.
Light reactions take place on the thylakoid
membranes.
 “Dark” reactions take place in the stroma.

Inside a Chloroplast
• Remember: Structure correlates to function!
Homework 9 Due 11/25
• When temperature becomes too warm,
leaves close their stoma to conserve
water. How will high temperature most
likely affect rate of photosynthesis?
• In the autumn, the amount of daily sunlight
decreases in time and strength.
Additionally, the amount of water in the air
decreases with temperature. Explain how
deciduous trees cope with the winter
season.
Photosynthesis
• 2 different
reactions
– Light Reactions
• Capture light
energy for
photosynthesis
– Calvin Cycle
• Produces glucose
sugar
The first stage – Light Dependent
1.
2.
3.
4.
5.
6.
Occur in Thylakoid – why?
Uses chlorophyll to split H2O
Captures sun energy
Produces ATP and other energy rich molecules
Splits water (H needed for next stage and O2)
Release O2 from leaf
Using a microscope, a student observes a small,
green organelle in a plant cell. Which energy
transformation most likely occurs first within the
organelle
A.
B.
C.
D.
ATP to light
Light to Chemical
Heat to electrical
Chemical to chemical
Using a microscope, a student observes a small,
green organelle in a plant cell. Which energy
transformation most likely occurs first within the
organelle
A.
B.
C.
D.
ATP to light
Light to Chemical of course. Come on.
Heat to electrical
Chemical to chemical
The second stage – Light
Independent
1.
2.
3.
4.
5.
The “Dark” or Carbon Reactions
Also called Calvin Cycle
Light independent (can occur in light or dark;
some enzymes require activation by light)
Occurs in stroma
Uses the energy from stage 1 (ATP; NADPH)
to “fix” carbon in sugar
Photosynthesis and cellular respiration are two
major processes of carbon cycling in living
organisms. Which statement correctly describes
one similarity between photosynthesis and
cellular respiration?
A. Both occur in animal and plant cells
B. Both include reactions that transform
energy
C. Both convert light energy into chemical
energy
D. Both synthesize organic molecules as
end products
Efficiency & Photosynthesis


Photosynthesis is not perfect.
Depending upon the plant type, it ranges
from being only 1 - 4 % efficient to having
7% efficiency
Without
photosynthesis,
virtually all
plants and
animals would
become extinct.
Photosynthesis
• Reaction:
CO2+H2O+sunC6H12O6+O2+H2O
Respiration
C6H12O6+O2CO2+H2O+36ATP
• Reactants: Carbon dioxide, water, sun
Glucose, oxygen
•
•
•
•
Energy
Products: Glucose
By-products: Oxygen
Cellular location: Chloroplasts
Energetics: Requires energy
• Chemical paths: Light reactions &
Calvin cycle
• Summary: Sugar synthesized using
energy from the sun
Carbon dioxide, water
Cytoplasm, mitochondria
Releases energy
Glycolysis, Krebs cycle
& Electron Transport Syst.
Energy released from
sugar breakdown
The oxygen that plants give off
A. Comes from the light dependent reactions
B. Comes from the dark reactions
C. Is a by-product of respiration
D. Comes from CO2 that plants absorb
E. Is carried from the Calvin cycle to the
light reactions.
The oxygen that plants give off
A. Comes from the light dependent reactions
B. Comes from the dark reactions
C. Is a by-product of respiration
D. Comes from CO2 that plants absorb
E. Is carried from the Calvin cycle to the
light reactions.
Name as Light Dependent or
Independent
A. Oxygen released - DEPENDENT
B. Carbon fixation occurs - INDEPENDENT
C. Calvin Cycle occurs - INDEPENDENT
D. ATP produced - DEPENDENT
Which is produced by both
respiration and photosynthesis?
A. Glucose
B. ATP
C. CO2
D. O2
Which is produced by both
respiration and photosynthesis?
A. Glucose
B. ATP
C. CO2
D. O2
•
•
•
•
•
•
•
Respiration, Energy & Carbon
Cycle
Energy
Virtually all organisms require energy of
food for:
Making chemicals
(proteins, carbs, etc.)
Movement
Cell division
Heat, electricity and light production
The way living organisms obtain energy is
through
Cell respiration
ENERGY: ability to do work
Newton’s First Law of Thermodynamics:
(1701)
“Energy cannot be created or
destroyed, it can only be transformed
from one form to another”
• Once a cell has used energy to do work, it
cannot be used again by any organism.
ENERGY
ENERGY FLOW IS LINEAR
Sun  Earth Producers 1o consumers  2o consum
heat
resp, heat
resp, heat
resp, heat
Energy flows into ecosystem from the sun
Energy travels in a straight line by way of
food chains.
ENERGY
However, much energy is lost as heat along
the way – as a result of respiration.
Approximately 90% energy is lost on each
step!
• Newton’s Second Law of
Thermodynamics:
“In any transfer of energy there is always
a loss of useful energy to the system,
usually in the form of heat”
Food Chains
Food chains demonstrate linear nature of
energy
• Producers are the base of the food chain,
they include photosynthetic organisms like:
• Plants
• Algae
• Certain bacteria
Food chains
• Primary
consumers –
all plant
eaters
(herbivores).
Secondary
consumers –
Eat primary
consumers,
(carnivores)
Food chains
• Decomposers – aka detritivores obtain energy by breaking down
remaining organic material of the other
members of the food chain.
• Fungi and bacteria.
Matter
• All important elements move in cycles;
Environment
Organisms
Cycles called biogeochemical cycles:
Water cycle
Carbon cycle
Nitrogen cycle
The Carbon Cycle
• Carbon from the atmosphere (CO2) enters the
biosphere by way of plants!
– CO2 used in photosynthesis
– Carbon moves into food chain
• Carbon is released to the physical
environment by respiration
– Release CO2 during respiration
– Amount CO2 fixed in photosynthesis = the amount
released by respiration
Carbon Cycle
• Carbon moves from atmosphere to
plants to animals and back to
atmosphere.
Venus doesn’t have a carbon cycle. It’s
hell.
“Look deep into nature,
and then you will
understand everything
better.”
Albert Einstein