Photosynthesis and Cellular Respiration

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Photosynthesis and Cellular Respiration
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Why do we need energy in the first place?

• Main source of energy for ALL life is the sun.
• Remember autotroph vs heterotrophs.
• ALL organisms need energy for life processes
• active transport
• movement
• protein synthesis
• cell division

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QUICK SUMMARY Photosynthesis

• The process that uses light energy to make
  glucose
• this glucose can be used to make ATP
• Photosynthesis is carried out by plants and some
  bacteria
• occurs in the chloroplast
• divided in to light dependent reactions and the
  Calvin Cycle

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Structures to Know of the Leaf

• Cuticle thin waxy outer surface of leaf. Aids
  with H20 conservation.
• Vascular Tissue veins of plant.
• Xylem brings water and nutrients from roots to
  leaves of plant.
• Phloem transports glucose from leaves to stem
  and roots of plant.
• Mesophyll middle of the leaf where the cells
  are packed with chloroplasts
• Palisade layer spongy layer (air spaces for gas
• exchange)
• Stomata tiny holes within the epidermis on the
  underside of leaf, surrounded by guard cells
  (these cells open and close the stomata to allow
  for gas exchange and transpiration.
• Chloroplast membrane bound organelle of plants
  that converts sun (light) energy into chemical
  energy (glucose).

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The Chloroplast

• Stroma space inside the chloroplast where the
  Dark reactions take place
• Thylakoid green disc (because the contain
  chlorophyll) in the chloroplast where light
  reactions take place
• Chlorophyll is the green pigment that absorbs
  light energy
• Lumen inside of a thylakoid
• Granum (plural grana) a stack of thylakoids
  where the
• light dependent reaction
• occurs.

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Pigments are molecules that absorb visible
light Chlorophyll a absorbs violet and red
light Chlorophyll b absorbs violet-blue and
red-orange light Both pigments reflect green
light
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Accessory Pigments

• Carotenoids are yellow and orange
• Increase the spectrum of light that drives
  photosynthesis
• Absorb and reflect excess light energy
• Visble in the fall as chlorophyll production
  slows down

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Usable energy

• The energy we use for these various processes is
  stored in the bonds of the ATP molecule
• This is produced in the Mitochondria during
  Cellular Respiration (next topic)
• ATP adenosine triphosphate
• each bond between phosphates stores a lot of
  energy and when these bonds are broken the energy
  is released

Remember ATP is a nucleotide. Contains the
following Nitrogenous Base (Adenine) 5
carbon sugar (pentose) 3 Phosphate groups
instead of 1
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Breaking and creating bonds for energy production
and energy storage

• Two processes convert ADP into ATP
• 1) substrate-level phosphorylation. Occurs in the
  cytoplasm when an enzyme attaches a third
  phosphate to the ADP (both ADP and the phosphates
  are the substrates on which the enzyme acts).
• 2) Chemiosmosis is the movement of ions across a
  selectively permeable membrane, down their
  electrochemical gradient. More specifically, it
  relates to the generation of ATP by the movement
  of hydrogen ions across a membrane during
  cellular respiration or photosynthesis.

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END LECTURE 1!!

• Create a
• Super Hero/Villain
• Be creative and be sure that your Super Hero
  depicts the cycle of ATP.
• Things to remember
• 1. What is released from ATP
• 2. How is the energy released
• 3. Can ATP be recycled?

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Formula for Photosynthesis

• 6 CO2 6 H2O light ? C6H12O6 6 O2
• MUST KNOW!!!
• carbon dioxide water light ? glucose (sugar)
  oxygen

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Steps of Photosynthesis

• Light reactions (thylakoids)
• traps sunlight and makes electrons and ATP to run
  the Dark reactions
• Light energy is absorbed by chlorophyll causing
  electrons to leave the chlorophyll
• these electrons move down a chain (Electron
  Transport Chain) and are caught by the NADPH
  compound so ATP can be made
• water breaks down into oxygen and electrons

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Electron Transport Chain

1. Light strikes chlorophyll of the chloroplast an
   electron is excited.
2. The electron falls from photosystem II to
   photosystem I via an electron transport chain
   the energy of the fall is used to make ATP
3. Photosystem I excites the electron again
4. Hydrogen is trapped by NADP (electron carrier
   that provides the high energy electrons needed to
   make C-H bonds), forming NADPH (requires 2
   electrons)

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ATP Synthesis in the Light Reactions

• Protons (H) are pumped into the thylakoid space,
  creating a gradient
• Protons (H) flow through ATP synthase, which
  makes ATP from ADP

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Steps of PhotosynthesisDark reactions or Light
Independent Reactions aka the Calvin Cycle

• occurs in stroma
• Carbon fixation CO2 molecules are incorporated
  into organic compounds. Atmospheric CO2 combines
  with a 5 carbon sugar, RuBP (ribose biphosphate)
  to produce an unstable 6-carbon sugar.
• ATP energy is used, and electrons from NADPH are
  used, to make simple sugars by splitting the
  6-carbon sugar. These are 2 molecules of
  Phospholgylceric Acid (PGA). Then adding a H from
  NADPH to form PGAL (Phosphoglyceraldehyde) and
  water.
• ATP energy is used to regenerate the CO2
  acceptor, which starts the cycle over again
• ADP and NADP leave the calvin cycle and return
  to the thylakoids to be used by the light
  reactions again
• Two turns of the Calvin cycle make one
  glucose!

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Fates of the Sugars

• 50 is used for cellular respiration in the
  mitochondria of the plants cells
• Used to synthesize proteins and lipids
• Used to build cell walls cellulose
• Stored for later energy use as starch
• Plants feed the planet and make the oxygen that
  we need for cellular respiration!

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Photosynthesis and Water Loss

• CO2 enters plant leaves through stomata
• Every time the stomata open, water vapor can
  escape. This is called transpiration.
• Plants often keep stomata closed on hot days,
  which limits photosynthesis

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End Lecture 2
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ATP is the energy molecule of the cell
How ATP is made in glycolysis
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Cellular Respiration

• process where mitochondria break down glucose
  (chemical energy) to make ATP
• C6H12O6 O2 ? CO2 H2O ATP
• two types of respiration are
• aerobic with oxygen...requires oxygen and occurs
  in plants, animals and some bacteria
• anaerobic without oxygen....carried out by
  yeast, some bacteria and sometimes animals

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Respiration.the branching

• GLYCOLYSIS
• Used by both prokaryotes and eukaryotes
• Glucose will break down to form 2 pyruvate
  molecules (happens in the cytoplasm of cells)
• IF oxygen is available or not will determine what
  happens next
• Oxygen NOT available ? branch off into Anaerobic
  respiration
• Oxygen IS available ?branch off into Aerobic
  respiration

From POGIL activities
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Anaerobic respiration

• if there isnt any or enough oxygen available we
  have anaerobic respiration
• also called fermentation
• anaerobic respiration stops with glycolysis
• Alcoholic fermentation
• yeast and some bacteria
• used to brew beer, make bread
• Lactic acid fermentation
• in muscles when you cant get oxygen fast enough

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Respiration or Fermentation?Following
glycolysis, if oxygen is present, pyruvate enters
the mitochondria for aerobic respirationKnow
this picture
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Steps of Aerobic respiration

• Glycolysis occurs in the cytoplasm
• glucose breaks down into 2 pyruvate (make 2 ATP)
• Intermediate Step (needs oxygen)
• pyruvate changes into acetyl CoA
• Krebs Cycle (citric acid cycle)
• occurs in mitochondria
• acetyl CoA goes through the cycle to make ATP,
  NADH FADH2 carry electrons to next step

KNOW THIS PICTURE
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Steps of Aerobic respiration

• Last step Electron transport chain
• occurs in mitochondria
• electrons from NADH move down chain
• these combine with oxygen and we get 34 ATP

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Electron Transport Chain
ATP Synthase

• NADH (electron carrier) in the inner membrane of
  mitochondria
• Proteins (fixed and mobile) line the inner
  membrane and will help move electrons(e-) down
  chain
• In order to accept electrons, H (hydrogen ions)
  must be moved across the inner membrane
• H will diffuse (high to low concentration) back
  into inner membrane via ATP synthase. Oxygen will
  be final electron acceptor , binding with 2 H to
  make H20
• As H flow through membrane they will power ATP
  synthase and ATP will be formed

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Proteins in the electron transport chain release
H into the inter-membrane space as they
release electrons this creates a
gradientKnow how/where to label the H,
proteins, ATP Synthase and ATP
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ATP SynthaseA membrane protein of the inner
membrane of the mitochondriaMakes ATP by adding
phosphate to ADPPowered by the flow of protons
(H) across the inner membrane
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• so 1 glucose will provide 36 ATP for us to use!

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Photosynhesis/Respiration Review
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• Energy Matter

• All living things use energy
• Autotrophs can capture energy from the
  environment
• Heterotrophs must consume other organisms
• Matter cycles through ecosystems
• Constantly recycled and reused
• Energy flows through ecosystems
• In from the sun
• Transferred between organisms
• Out as heat

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• Photosynthesis

• Photosynthesis process by which some autotrophs
  capture energy from the environment

• carbon dioxide
• solar energy
• water
• sugars
• oxygen

• Stores Energy

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• Photosynthesis

• Can be expressed chemically
• 6CO2 6H2O energy ? C6H12O6 6O2

Products
Reactants
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• Respiration

• Cellular Respiration process by which organisms
  convert sugars into usable energy and waste
  products

• sugars
• oxygen
• carbon dioxide
• energy
• water

• Releases Energy

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• Respiration

• Can be expressed chemically
• C6H12O6 6O2 ? 6CO2 6H2O energy

Products
Reactants
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• Photosynthesis Respiration

• Photosynthesis
• Autotrophs
• Captures energy
• Uses carbon dioxide, water, and solar energy
• Creates sugar and oxygen

• Respiration
• Autotrophs heterotrophs
• Releases energy
• Uses sugar and oxygen
• Creates carbon dioxide and water, converts energy

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• Photosynthesis Respiration

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• Photosynthesis Respiration

• Photosynthesis
• 6CO2 6H2O energy ? C6H12O6 6O2
• Respiration
• C6H12O6 6O2 ? 6CO2 6H2O energy

Products
Reactants
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• Photosynthesis Respiration

• Learning Objectives
• Understand photosynthesis
• Understand respiration
• Relate photosynthesis and respiration