Download Energy - My CCSD

QUIZ
1.
2.
3.
4.
T/F Energy is the ability to do work.
T/F One way cells use energy is to maintain
homeostasis.
T/F ADP is recharged into ATP by adding a
phosphate group.
Where do autotrophs get their energy?
Cell Energy Notes
Photosynthesis and
Cellular Respiration
Energy
 Energy
= the ability to do work
 Energy is usually released when bonds are
broken and needed to put bonds together
 All living organisms must be able to produce,
store, and use energy.
 Our food energy must always be converted
to ATP energy to be useful to our cells
Energy
2
types of organisms
 Autotrophs- use energy
from sun or inorganic
compounds to make
organic compounds
(like sugar). They use:
Photosynthesis
Chemosynthesis
 Heterotroph- organisms
that get energy from
food
Energy
 The
main source of cell energy is called ATP
(adenosine triphosphate)
 ATP is made of an adenosine molecule with
three (tri =3) phosphate groups attached.
 The energy is stored in the bonds of the
molecule as “potential energy” (energy
available for potential, or future, use)
Energy
 The
energy of ATP is
released when the
covalent bond between
the 2nd and 3rd P
(phosphate group) is
broken.
 Energy is released and the
resulting molecule is ADP or
adenosine diphosphate;
di=2
Energy
 ADP
and P can form
ATP again when
energy is added back
in and the P bonds to
the ADP
 Cells can make more
when needed
 ATP is a short term
energy storage
molecule- once it is
made, it is used pretty
quickly (the bonds are
unstable)
How do cells use the Energy
stored in ATP?
 When
ATP is broken down and the energy is
released, cells must have a way to capture the
energy and use it efficiently or it will be wasted


Cell proteins have specific sites where ATP can bind,
then the phosphate bond is broken and energy is
released
The cell can use the energy for activities such as
making a protein or transporting molecules through
the plasma membrane (active transport)
How do cells use the Energy stored
in ATP?
 Nerve
cells transmit signals by using ATP to
power the active transport of certain ions
 Making enzymes that help carry out
chemical reaction
 Build membranes and cell organelles
 Kidneys use energy to move molecules and
ions in order to eliminate wastes while
keeping needed substances in the blood
stream
 Cells use energy to maintain homeostasis
Enzymes
 All
of the chemical reactions that occur in
your body are called your metabolism.
 Most of these reactions require energy
 Enzymes lower the amount of energy needed
for a reaction to occur
 This means more reactions can happen in a
shorter amount of time because they need
less energy
 Without enzymes, our metabolism would be
too slow for us to live!!
Enzymes
•Key terms
•Substrate = substance enzyme acts on
•Active site = region where enzyme binds
•“Lock and Key” Model = one specific
enzyme for one reaction
Enzymes
 Enzymes…
 Are
proteins that act as catalysts
 Speed up reactions without being
changed (so one enzyme can catalyze
many reactions)
Ex: break down toxins in liver, digest your
food in your stomach
Enzyme reactions happen at an
average rate of 1000 reactions per
second!
 Only work with ONE TYPE of reaction
What can affect the
functioning of Enzymes?
 Heat

Higher temps increase the collisions of substrates
and enzymes, which makes the reactions happen
faster
So,
lower temps DECREASE reaction
rates


BUT, if temp is too high, enzymes can be denatured
(change shape) and not work
Our enzymes work best at 35-40OC (body temp is
normally 37OC)
What can affect the
functioning of Enzymes?
 pH
 Large
changes in pH also denature enzymes
 Some enzymes, like the ones in our stomachs,
work best in acidic conditions
 Best pH for our enzymes is 6-8
 So, heat and pH can denature (change the shape
of) enzymes, which makes them no longer able to
function
Catalase
 Other factors:
 Radiation, Electricity, Chemicals
Photosynthesis
Photosynthesis
 Cell
Equipment:
 Stomata
 Chloroplasts
 Electron carriers
2
Parts
 Light Reactions
 Calvin Cycle
(also called
Dark or light
indepepndent
Reactions)
Equipment for Photosynthesis
 Stomata
are like pores, plants use them to take in
CO2 and release O2
 Water is also be released when they are open
Stomata
Electron Carriers
 Used
in many places
throughout
photosynthesisthere job is to carry
electrons from one
place to another
Light Reactions
 Require
light to happen
 Also called light dependent reactions
 Light is absorbed by the chloroplasts
Light Reactions
 There
are pigments in the thylakoid
membrane of the chloroplasts that absorb
light
 The color you SEE is NOT the color absorbed,
all other colors are absorbed
 When you see a green leaf, it is because
the leaf absorbs all other colors and
REFLECTS green (so that green hits your
eyes).
Light Reactions
 There
are several pigments found in the
membrane of the thylakoids, the most prominent
is chlorophyll a and b which absorb most colors
except green.
 Chlorophyll a is directly involved in photosynthesis,
and other pigments assist it in absorbing other
colors of light.
 More colors absorbed
means more energy!
Light
Reactions
 Pigments
that
assist
chlorophyll
are called
accessory
pigments
Light Reactions
So,
what happens in the fall?
 Normally, the green color of chlorophyll
masks all other colors
 In the fall, many plants lose their chlorophyll
 So you are able to see the colors of the
carotenoids instead (yellow, brown, and
orange)
Light Reactions
 Turns
(ATP)
light energy into chemical energy
 Involves
 Takes
an enzyme called ATP synthase
place in the thylakoid membranes
 H2O molecules and light energy make
ATP, an e- carrier, and O2
 The oxygen leaves the cell, the ATP and
e- carriers move to the Calvin Cycle
Calvin Cycle
 Powered
by ATP & e- carriers made by
light reactions.
 Needs CO2
 Happens in stroma of a chloroplast
 Sugars are mainly built in this cycle, but
lipids, proteins, and nucleic acids can also
be made
Other paths
 When
stomata are open, water is lost
 This is BAD for desert plants which need
to conserve water
 C4 plants keep there stomata half closed
during the hottest part of the day
 They are able use the small amount of
CO2 that enters
 CAM plants keep there stomata closed
during the day.
 They hold on to the CO2 that they get at
night and use it during the day
Photosynthesis- Summary

Photosynthesis has 2 main parts
1. Light
reactions - where light energy is
absorbed and converted into ATP and
e- carriers
2. Calvin Cycle – where organic
compounds are formed using the
chemical energy in ATP and e- carriers
6CO2 + 6H2O + light  C6H12O6 + 6O2
PhotosynthesisSummary Reactants (what is
Products (what
needed?)
is produced?)
Light
1. Light
1. O2
Reactions
2. Water
2. e- carrier
3. ATP
Calvin Cycle 1. CO2
2. e- carrier
3. ATP
1. Organic
compounds
2. e- carrier
3. ADP + P
Cellular
Respiration
Cellular Respiration
 The
energy stored in
the chemical bonds
of organic molecules
(carbs, lipids, etc)
must be released
and turned in to ATP
to be useful to your
cells
 The process by
which this is done is
called cellular
respiration
Cell Respiration
 Cell
Equipment:
 Cytoplasm
 Mitochondria
 Electron carriers
(NADP/NADPH)
3
Parts
 Glycolysis
 Krebs Cycle
 ETC
Equipment
for Cellular
Respiration
Equipment for Cellular Respiration
 Electron
Carriers- Cell respiration has them
too, they are just different kinds of
molecules
Anaerobic Respiration-Glycolysis
 Anaerobic
means WITHOUT oxygen
 Takes place in the cytoplasm
 Uses 2 ATP & glucose, to make a
total of 4 ATP (net gain of 2 ATP), 2
pyruvate, & e- carriers.
 Since few ATP are produced, only
VERY SMALL organisms can live by
glycolysis alone
Anaerobic Respiration- Fermentation
 When
oxygen is not present, fermentation
occurs after glycolysis
 It occurs in the cytoplasm
 Fermentation allows glycolysis to continue
 So, SMALL amounts of ATP can continue to
be produced without oxygen
Anaerobic RespirationLactic Acid Fermentation
 This
type of respiration is used by
many kinds of bacteria and is
responsible for cheese,
buttermilk, sour cream, and
yogurt
 During strenuous activity, lactic
acid fermentation is used by our
muscle cells.
 Produces lactic acid and CO2
 The build up of lactic acid in
our muscle cells is what causes
pain, fatigue, and cramps after
strenuous activities
Anaerobic RespirationAlcoholic Fermentation
 Creates
ethyl alcohol and
CO2
 This type of fermentation is
used in plants and some
microorganisms, such as yeast.
 This type of fermentation is
used in the beer and wine
industry
 It is also used in the bread
industry, because yeast give
off CO2 when they ferment
(this creates fluffy bread)
Aerobic Respiration
 Happens
after
glycolysis IF OXYGEN
IS PRESENT
 2 major stages
 Krebs Cycle
 ETC
 Pyruvic acid created
in Glycolysis diffuses
into the mitochondrial
matrix
Aerobic RespirationKrebs Cycle
 Occurs
within the
mitochondrial matrix
 Starts with pyruvate
molecules from
glycolysis
 Produces ATP, ecarriers, & some CO2
molecules (CO2 is
released from the cell).
ETC (Electron Transport Chain)
 The
ETC is in the inner membrane of the
mitochondrion in the folds called cristae
 It uses the e- carriers made by Krebs
Cycle and O2 to make H2O and 32 ATP.
 Lots of energy! 32 ATP just from 1
glucose using these ETC reactions.
 Produces way more ATP than any of
the other reactions.
Cellular RespirationSummary
C6H12O6 + 6O26CO2 + 6H2O + ATP
 In the anaerobic process of glycolysis,
organic compounds are converted into
pyruvic acid, producing a small amount
of ATP and e carriers in the process
 In aerobic respiration pyruvic acid is
broken down using oxygen into CO2 and
water, which produces a large amount of
ATP
 This process is 39% efficient (means 39% of
the stored energy in your food is used)
Reactants
Respiartion- Summary
Products
Glycolysis
1. 2 ATP
1. 4 ATP
2. Glucose
2. e- carrier
3. Pyruvate
Krebs Cycle
ETC
1. Pyruvate
1. CO2
2. e- carrier
2. 2 ATP
3. ADP
3. e- carriers
1. e- carriers
1. Water
2. Oxygen
2. 32 ATP
3. ADP
Cellular RespirationSummary
 But
remember that 2 ATP were used in Glycolysis,
so cellular respiration produces 36 NET ATP
Energy
Cycle
sun
Photosynthesis
light
CO2 + H2O + energy  C6H12O6 + O2
plants
CO2
H2O
glucose
animals, plants
ATP
C6H12O6 + O2  energy + CO2 + H2O
Cellular Respiration
ATP
O2