Photosynthesis, Respiration, Etc.

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Photosynthesis, Respiration, Etc.
Metabolism
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Introduction

• Definitions
• Growth - the irreversible increase in size
• Reflects a net increase in protoplasm
• Due to cell division and elongation
• Development - a higher order of change involving
  both anatomical and physiological organization
  and specialization
• Metabolic Processes
• Photosynthesis
• Respiration
• Other

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Introduction

• Photosynthesis
• The process of converting CO2 and H2O into a
  sugar (chemical energy ) using light energy. In
  the process, O2 is given off.
• 6CO2 6H2O C6H12O6 6O2

Light
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Light Reactions

• First phase of photosynthesis
• Functions to temporarily store energy as ATP and
  NADPH
• Occurs in the chloroplasts, specifically in the
  grana

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Light Reactions

• Chlorophyll - pigment in chloroplast
• Large head
• Loosely held pi electrons
• Light expels electron - excitation

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Light Reactions

• Electron Transport Chain
• PSII
• PSI
• Ferredoxin final step
• Passes electron off to NADP turns into NADPH
  or
• ATP Synthase - combines ADP inorganic
  phosphate turns it into ATP

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Light Reactions

• In order for chlorophyll to remain functional it
  must replenish the electrons
• chlorophyll PSI
• accept electrons from chlorophyll in PSII or
• recycling its own electrons
• chlorophyll PSII
• Photolysis of water (Hill reaction)

http//www.stolaf.edu/people/giannini/flashanimat/
metabolism/photosynthesis.swf http//www.fw.vt.edu
/dendro/forestbiology/photosynthesis.swf http//ww
w2.kumc.edu/netlearning/examples/flash/photosyn2.h
tml http//highered.mcgraw-hill.com/sites/00724373
16/student_view0/chapter10/animations.html
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Light Reactions

• Influences
• Seasons
• Chlorophyll breaks down other pigments show
  through.
• Amount of light
• Fates of light
• reflected
• absorbed
• transmitted through leaf
• Quality of light
• Visible light range
• Red blue bands best utilized

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Dark Reactions

• Process of CO2 fixation into a sugar (CH2O)
  utilizing H from NADPH and energy from ATP
• Occurs in the stroma of chloroplasts

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Dark Reactions

• Carbon fixation
• Type according to of carbons in first stable
  intermediate
• C3 type
• Rubisco enzyme
• 3RuBP (5 Carbon atom) 3 CO2 ? 6 PGA
• PGA is converted to Glyceraldehyde-3-phosphate
• (G3P) using NADPH and ATP
• Protons extracted from NADPH P from ATP
• G3P formed (three carbon sugar phosphate)
• G3P is used to form sugar

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Dark Reactions

• Carbon Fixation
• C4 type
• Mesophyll cells
• CO2 converted into bicarbonate (HCO3)
• HCO3 PEP ? OAA by PEP carboxylase
• OAA ? Malate
• Bundle sheath cells
• Malate ? Pyruvate
• C3 path proceeds

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C 4 pathway
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C 4 pathway
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Light and Dark Reactions
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Influences on Photosynthesis

• Temperature
• Amount of CO2
• Amount of energy (ATP NADPH)
• Water
• Nutrients

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Respiration

• Definition
• Burning (oxidation) of food (carbohydrates) to
  yield energy (ATP NADPH) for cellular activity
• Overall reaction
• C6H12O6 6O2 ? 6CO2 6H2O energy
• Processes
• Glycolysis
• Citric acid (Kreb's) cycle
• Electron transport system

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Glycolysis

• Carbohydrate (CH2O) is broken down to pyruvic
  acid.
• Formation of ATP NADPH
• Occurs in the cytoplasm

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Krebs Cycle

• Pyruvic acid derivative is cycled through several
  steps to yield
• CO2
• energy (NADH FADH2)
• ATP
• Occurs in the mitochondria

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Electron Transport System

• Hydrogen atoms are removed from NADH FADH2 and
  energy is released (ATP formed)
• Hydrogen atoms then combine with O2 to form H2O
• Occurs in the mitochondria

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Respiration

• Types
• Aerobic
• Requires oxygen
• Glycolysis Krebs cycle ETS
• Anaerobic
• Occurs in the absence of O2
• Carbohydrate (CH2O) pyruvic acid
  lactic acid
• alcohol

Animals
Plants
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Respiration

• Types
• Photorespiration
• Organic compound is oxidized without the
  formation of any energy.
• Non-beneficial process
• Occurs only in C-3 type plants

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Respiration

• Affected by
• Temperature
• Tissue state - active vs. dormant tissue
• Availability of carbohydrate (CH20) oxygen (O2)
• Age and condition of the cells

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Metabolism
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Definition

• The building (anabolism) or breaking down
  (catabolism) of organic molecules
• Organic molecules
• Carbohydrates
• Proteins
• Lipids
• Nucleic acids
• Hormones

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Proteins

• Formed from combination of 20 amino acids
• Amino group
• Acid group
• (Carboxyl group)
• Peptide bond

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Proteins

• Functions
• Enzymes catalyze biological reactions
• Import export
• Structure
• Storage

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Lipids

• Limited ability to dissolve in water
• Triglycerides
• Glycerol fatty acids (1-3)
• Fatty acids 18-20 carbons, unsaturated
• Phospholipids
• Phosphate group replaces one fatty acid
• Dual solubility cell membranes
• Uses
• Storage of energy
• Cuticle
• Pigments

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Nucleic Acids

• DNA
• Deoxyribose sugar (5 carbon)
• Phosphate group
• Bases AGCT
• Double stranded
• RNA
• Ribose sugar
• U replaces T
• Single stranded

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Hormones

• Chemical messengers
• Auxins
• Gibberellins
• Cytokinins
• Abscisic acid
• Ethylene