Photosynthesis

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Photosynthesis
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Law Of Conservation of Matter and Energy

• Matter and energy can neither be created of
  destroyed, only transformed.

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• Total amount of energy in the universe is
  constant-its stored in the bonds of matter.
• Potential energy stored energy
• Kinetic energy released(bonds broken)energy.
• (Released energy is NOT lost energy, its just
  transformed)

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http//www.youtube.com/watch?vjRm-otFKWLIhttp//
www.youtube.com/watch?vEl6El4iapO4
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Carbon Bonding

• Organic molecules are made mostly of carbon
  atoms. Most matter in living organisms is made of
  organic molecules.
• Use pg. 51-52 to answer the following
• QUESTION How do carbons bonding properties
  contribute to the existence of a wide variety of
  biological molecules?

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Carbon

• ANSWER One of the most important elements found
  in living things
• Has 4 valence electrons which means it can form 4
  bonds with other carbon atoms or other elements
  such as hydrogen (H), oxygen (O), phosphorous (P)

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Reactions

• A condensation reaction is a chemical reaction
  that links/joins monomers to form polymers and
  release water
• Hydrolysis is a chemical reaction
• that uses water to break down polymers back into
  monomers .

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Macromolecules (polymers)

• Large Carbon Molecules-- are made from simpler
  molecules
• Monomers small, single molecules
• Polymer made of monomers linked in a long
  chain
• Macromolecules large/GIANT polymers(can be
  thousands long)

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Type 1 of 4 macromoleculesCarbohydrates
(polysaccharides)

• Carbohydrates provides energy (glucose is energy
  source) for cells
• Monomers MONO (single) SACCHARIDE (sugar)
• Ex glucose, fructose

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Monomer-monosaccharide

• Polymer polysaccharides

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Energy Currency

• Life/cellular processes need constant energy. ATP
  (adenosine triphosphate) has energy stored in
  covalent bonds between phosphates.

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Chemical Reactions
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2Fe 3H2O-? 2FeO3 3H2
Chemical reactions
A chemical reaction is a process that changes one
set of chemicals into another set of chemicals by
creating/breaking bonds


Products
Reactants
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What is Photosynthesis?

• Photosynthesis is when autotrophs make their own
  food/glucose.
• Photosynthesis takes light energy, water, and
  breaks apart carbon dioxide and converts it into
  stored energy in glucose.

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What is Photosynthesis?

• http//www.mhhe.com/biosci/bio_animations/02_MH_Ph
  otosynthesis_Web/

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Where does Photosynthesis happen? (read)
It happens inside the CHLOROPLAST, with dozens
in the cells of each leaf.
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What are the Parts of the Chloroplast?

• 1. Thylakoidssaclike photosynthetic membranes
  -Arranged in stacks called 2. Granum.
• solution surrounding them 3. Stroma.

Single thylakoid
Stroma
Granum
Chloroplast
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A
B
C
D
A
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Why are Most Plants Green?
Light travels in waves. In order to capture the
energy in light, plants use a main pigment called
chlorophyll. This pigment reflects green light
making plants look green.
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• Visible Light Spectrum
• The suns energy travels in waves
• The distance between waves wavelength

Different wavelengths of light are visible as
different colors
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ROY G BIV
Longest wavelength Least amount of energy
Shortest wavelength larger amount of energy
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What colors do chlorophyll a,b absorb best?
Worst? What colors do caretenoids absorb best?
Worst
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• -Chlorophyll does not absorb light well in the
  green region of the spectrum. (absorbs
  blue/violet best)
• -Green light is reflected by leaves, which is
  why plants look green.

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Why Do Leaves Change Color in the Fall

• The chlorophyll breaks down, leaving only
  carotenoid pigments that reflect orange, red, and
  yellow..

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8-1

• Why do plants look Green?
• There is much more chlorophyll than the other
  pigments (the other colors are masked).
• In the Fall, chlorophyll is broken down and
  the accessory pigment colors are shown.
• Why do trees lose leaves in the winter?
• Its difficult to absorb H2O from frozen ground
  so leaves drop off to save water.

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Reactants of photosynthesis?
LIGHT
Carbon Dioxide
GLUCOSE
Water

• Carbon Dioxide Water

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Products of photosynthesis?
LIGHT
Oxygen
Glucose
GLUCOSE

• Oxygen Glucose

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The GOAL of photosynthesis?
LIGHT
WASTE PRODUCT
GLUCOSE
GOAL

• -Oxygen is a waste product-
• GLUCOSE is the goal!

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The Equation!

• Word Form
• Carbon Dioxide Water Glucose Oxygen
• Balanced Chemical Equation
• 6CO2 6H2O C6H12O6 6O2

Light Energy
Light Energy
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What are the Reactions?

• Photosynthesis is 2 reactions happening
  simultaneously in the chloroplast!
• -1st- Light Dependent Reaction.
• 2nd Calvin Cycle a.k.a. Light Independent
  reaction
• The 2nd reaction can not happen without the
  first.

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Light Dependent Reaction
Water molecule is split by water splitting
enzyme-Oxygen is released and Hydrogen is sent to
Calvin cycle
Light
Calvin Cycle
Light- dependent reactions
Chloroplast
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Light dependent reaction(Step 1)

• a.)Occurs in the thylakoids of chloroplast
• b.)Starts w/water (H2O) and sunlight light
  absorbed by chlorophyll molecules
• c.)Makes Oxygen (O2) ,ATP energy and NADPH energy
• The ATP and NADPH will be used in reaction 2

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Light Dependent Reaction
H2O
CO2
Light
NADP
ADP P
Light- dependent reactions
Calvin cycle
Calvin Cycle
Chloroplast
Glucose
O2
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• With your shoulder partner explain
  when/what/where happens to each of the following
  when they enter the thylakoids of the Light
  Dependent Reaction
• Water
• NADP
• ADP

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Light- dependent Reactions

• Light energy is absorbed by chlorophyll molecules
• This light energy excites electrons (excited
  electrons supply energy) and boosts them to
  higher energy levels.
• The electrons fall to a lower energy state,
  releasing energy that is harnessed to make ATP

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Energy Shuttling

• ATP superb molecule for shuttling energy around
  within cells.
• Other energy shuttles-coenzymes (nucleotide based
  molecules) move electrons and protons around
  within the cell
• NADP, NADPH NAD, NADP FAD, FADH2

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Silently and Independently

• Q Explain why the splitting of water is
  important the continuation of the calvin cycle
  and to our survival?
• Provides Hydrogen the Calvin Cycle requires to
  make glucose and oxygen we need to breathe.
• Q Explain how oxygen is generated in
  photosynthesis(p.117 Paragraph 5,6)
• Water is split in light dependent reaction, and
  the oxygen is released as a waste product

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The Calvin Cycle (light-independent) (2nd Step)

• Occcurs in the stroma of the chloroplast
• Uses ATP from the light dependent reaction and
  CO2 to produce high energy glucose

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Calvin Cycle -aka-Light Independent Reaction
H2O
CO2
STROMA
Light
NADP
ADP P
Light- dependent reactions
Calvin cycle
Calvin Cycle
Chloroplast
Glucose
O2
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Glucose is used for what?

• Glucose is
• 1) Broken apart and used to make ATP energy(easy
  to use) in cellular respiration-ATP is used for
  active transport and protein synthesis.
• 2) Chained together to make the plants
  body-(cellulose for cell walls)
• 3.) Stored as starch(another carb-
• ex.potatoes) to be used later

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Factors Affecting Photosynthesis

• 1) Light Intensity
• in light ____ in the rate of
  photosynthesis
• 2)Temperature
• best between 0 C and 35 C
• If the temperature is too high/low,
• this changes the shape of the
• enzymes involved in photosynthesis.
• 3) Carbon Dioxide Levels
• in CO2 ____ in the rate of photosynthesis

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Why does the RATE of photosynthesis plateau/peak
even though light intensity continues to
increase?
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