Transcript Photosynthesis and Respiration

Competency 4
Chemical Cycling Between
Photosynthesis and Cellular Respiration
THE BASICS OF PHOTOSYNTHESIS
 Almost all plants are photosynthetic autotrophs, as are
some bacteria and protists
– They generate their own organic matter through
photosynthesis
(c) Euglena
(d) Cyanobacteria
(b) Kelp
(a) Mosses, ferns, and
flowering plants
Figure 7.2
The Overall Equation for
Photosynthesis
 The reactants and products of the reaction
Carbon
dioxide
Water
Light
energy
Glucose
Oxygen
gas
Unnumbered Figure 7.1
Chloroplasts: Sites of Photosynthesis
 Photosynthesis occurs in the chloroplasts
– Leaves are major site of photosynthesis because they
have more chloroplasts
– Chlorophyll is the pigment that actually absorbs light
energy for photosynthesis
 Carbon dioxide enters and oxygen exits the leaf through
stomata
 Water is absorbed by plant’s roots and travels to the the
leaves via veins
 Chloroplasts
– Are found in the cells of the mesophyll (green tissue in the interior of the
leaf)
– Contain stroma, a thick fluid
– Contain thylakoids, membranous disklike sacs
• Grana are the stacks that comprise the thylakoids
 In photosynthesis
– Energized electrons are boosted “uphill” and added
to carbon dioxide to make sugar
– Hydrogen is moved along with the electrons, so the
redox process takes the form of hydrogen transfer
from water to carbon dioxide
– Sunlight provides the energy needed for the
chloroplasts to split the water molecules
Photosynthesis is a two-step process:
Light reaction and Calvin Cycle
 The light reactions
convert solar
energy to chemical
energy (ATP and
NADPH)
Light
Chloroplast
NADP
ADP
+P
Light
reactions
• The Calvin cycle
makes sugar from
carbon dioxide
(carbon dioxide is
reduced to
glucose)
Calvin
cycle
Figure 7.4
Light reaction – Energy in sunlight is trapped, O2 is
released, and both ATP and the hydrogen-carrier molecule
(NADPH = H) are formed
THE CALVIN CYCLE: MAKING SUGAR
FROM CARBON DIOXIDE
 The Calvin cycle
– Functions like a sugar factory within the stroma of
the chloroplast
– Regenerates the starting material with each turn
– The inputs are carbon dioxide from the air and ATP
and NADPH produced in the light reactions
Input
Three CO2
1
Three RuBP
Six 3-PGA
Six
4
Three ADP
Six ADP + Six
Calvin
cycle
2
Six
Three
Six NADP
Six G3P
Five G3P
3
One G3P
Glucose and
other compounds
Output
Figure 7.13
The Overall Equation for Cellular
Respiration
 A common fuel molecule for cellular respiration is
glucose
– This is the overall equation for what happens to
glucose during cellular respiration
– Cellular respiration can make up to 38 ATP
molecules for each glucose molecule
Glucose
Oxygen
Carbon
dioxide
Water
Energy
Unnumbered Figure 6.1
The Metabolic Pathway of
Cellular Respiration
 Cellular respiration is an example of a metabolic pathway
(metabolism)
– A series of chemical reactions in cells
• All of the reactions involved in cellular respiration
can be grouped into three main stages
– Glycolysis
– The Krebs cycle
– Electron transport
A Road Map for Cellular Respiration
Cytosol
Mitochondrion
High-energy
electrons
carried
mainly by
NADH
High-energy
electrons
carried
by NADH
Glycolysis
Glucose
2
Pyruvic
acid
Krebs
Cycle
Electron
Transport
Figure 6.7
Stage 1: Glycolysis
 A molecule of glucose is split into two molecules of
pyruvic acid
 The enzymes for glycolysis are located outside the
mitochondria (dissolved in the cytoplasm)
 Glycolysis breaks a six-carbon glucose into two threecarbon molecules
• These molecules then donate high energy electrons to NAD+,
forming NADH
• Oxygen present – next step Krebs Cycle
• NO Oxygen present – next step Fermentation
 Glycolysis makes some ATP directly when enzymes
transfer phosphate groups from fuel molecules to ADP
Enzyme
Figure 6.9
Stage 2: The Krebs Cycle
 The Krebs cycle completes the breakdown of sugar
 The enzymes of this stage are found in the liquid inside
the mitochondria
 In the Krebs cycle, pyruvic acid from glycolysis is first
“prepped” into a usable form, Acetyl-CoA
 The Krebs cycle extracts the energy of sugar by breaking
the acetic acid molecules all the way down to CO2
– The cycle uses some of this energy to make ATP
– The cycle also forms NADH and FADH2
Stage 3: Electron Transport
 Electron transport releases the energy your cells need to
make the most of their ATP
 The molecules of electron transport chains are built into
the inner membranes of mitochondria
 Converts ADP into ATP
 Yields 34 ATP
Glycolysis = 2 ATP
Krebs Cycle = 2 ATP
Electron Transport = 34 ATP
TOTAL = 38 ATP
Fermentation
 When cells release energy in the absence of oxygen
(anaerobic respiration)
 Produces QUICK energy
 Two types:
 Alcoholic – produces ethyl alcohol, carbon dioxide, and
NAD from pyruvic acid and NADH (yeast and other
microorganisms
 Lactic Acid – takes place mainly in muscle cells, pyruvic
acid is turned into Lactic acid, makes you sore
F: converts light (solar) energy into chemical (glucose) energy
B: photosynthesis
F: Occurs in plants, some protists, and some bacteria
B: photosynthesis
F: occurs in the chloroplasts of eukaryotes
B: photosynthesis
F: green pigment that traps light energy to do photosynthesis
B: chlorophyll
F: stacks of disks in stroma of chloroplast
B: grana
F: fluid b/t double membrane of chloroplast
B: stroma
F: each individual disk that makes up the grana in a chloroplast
B: thylakoid
F: thylakoid (disk) of chloroplast is surrounded by membrane
called?
B: thylakoid membrane
F: thylakoid disk contains ___ which trap light energy
B: chlorophyll
F: chemical equation for photosynthesis
B: 6CO2 + 6H2O + light  C6H12O6 + 6O2
F: reactants for photosynthesis
B: 6 carbon dioxides, 6 waters, and light
F: products of photosynthesis
B: 1 glucose and 6 oxygens
F: once glucose is produced, the glucose leaves the chloroplast and goes
to the _
B: mitochondria
F: Oxygen leaves the plant as a waste product through the pores of the
leaves
B: stomata
F: 2 stages of photosynthesis
B: light dependent reaction (light reaction) & light independent reaction
(dark reaction)
F: stage of photo. that requires light to make ATP
B: light reaction
F: stage of photo that does not require light to make glucose
B: dark reaction
F: another name for dark reaction
B: Calvin cycle
F: requires oxygen
B: aerobic
F: does not require oxygen
B: anaerobic
F: converts chemical energy (glucose) into usable energy (ATP)
in the mitochondria
B: cellular respiration
F: ATP stands for ?
B: adenosine triphosphate
F: 3 stages of cellular respiration
B: glycolysis, Krebs cycle (citric acid cycle), electron transport
chain
F: stage of cell respiration that is anaerobic
B: glycolysis & fermentation
F: stage of cell resp that does not occur in the mitochondria.
Occurs in the cytoplasm
B: glycolysis
F: stages of cell resp that produces 2 ATPs
B: glycolysis and Krebs cycle (citric acid cycle)
F: stages of cell resp that is aerobic
B: Krebs cycle (citric acid cycle), and electron transport chain
F: stages of cell resp that occurs in the mitochondria
B: Krebs cycle (citric acid cycle), and electron transport chain
F: stage of cell resp that produces 34 ATPs
B: electron transport chain
F: folded membrane of mitochondria
B: cristae
F: chemical equation for cellular respiration
B: C6H12O6 + 6O2  6CO2 + 6H2O + 38 ATP
F: reactants for cell respiration
B: 1 glucose and 6 oxygens
F: products for cell respiration
B: 6 carbon dioxides, 6 waters, and 38 ATPs
F: How is energy is released from ATP?
B: when a phosphate breaks away forming ADP. When
phosphate breaks away, a chemical bond is broken releasing
energy.
F: our ATP must be recycled. Cell respiration adds ___ back to
ADP forming ATP
B: phosphate
F: 2 types of fermentation
B: alcoholic & lactic acid
F: produces ethyl alcohol
B: alcoholic fermentation
F: produces lactic acid in mammals during rapid exercise;
makes muscles burn
B: lactic acid fermentation