cell energy (photosynthesis and respiration) notesstaff.katyisd.org/sites/khspapbio/preap biology...
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Cell Energy (Photosynthesis and Respiration) Notes
I. Energy – ability to do work; forms of energy: heat, light, chemical, electrical, mechanical, kinetic, potential
A. Energy for living things comes from - foodOriginally the energy in food comes from - sun
B. Uses light energy from the sun to produce food –autotrophs
Examples: plants + some microorganisms (bacteria and protists)
C. Cannot use the sun’s energy to make food –heterotrophs; obtain energy from food they consume
Examples: animals, fungi, most microorganisms
II. Cell Energy – needed for active transport, making proteins and nucleic acids, chemical signals (fireflies’ light)
A. Cells usable source of energy – ATP
1. ATP stands for adenosine triphosphate
adenine3 Phosphate groups
ribose
ATP
2. ADP stands for – adenosine diphosphate
2 phosphate groups adenine
ribose
ADP
B. All energy is stored in the bonds of the compoundBreaking the bond releases energy
C. When cell has energy available it can store this energy by adding a phosphate group to ADP, producing ATP
D. Example:
ATP ADP + P + E from breaking bond
ADP + Energy + P ATP
http://www.youtube.com/watch?v=bbtqF9q_pFw&NR=1
III. Photosynthesis – energy of sunlight is converted to energy of glucose
A. General Formula:
H2O + CO2 + light C6H12O6 + O2
water + carbon dioxide + light glucose + oxygen
B. 2 parts of photosynthesis:
1. light reaction – forms ATP and NADPH – contain chemical E, but are unstable
2. Calvin cycle (dark reaction) – uses E from ATP and NADPH to produce glucose
C. Photosynthesis occurs in the organelle –chloroplast
D. Light absorbing (and reflecting) compounds – pigments
Most common photosynthetic compound –chlorophyll (a + b)
Absorbs light energy needed for photosynthesis to work
Absorption of Light by Chlorophyll a and Chlorophyll b
F. Sun’s energy is stored in – glucoselight energy chemical energy
CO2 + H2O + light C6H12O6 + O2
H2O CO2
O2
released
C6H12O6
produced
Light
Light Dependent Reactions
Calvin Cycle
ATP
NADPH
NADP+
ADP+P+
Light Dep. Reactions:
•Trap E of sun in chemical form•Produces O2,
ATP, NADPH
high E cmpds.
Chloroplast
Light Dep. Reactions occur in thylakoid
stroma—Calvin Cycle occurs here
Calvin Cycle:
•Uses E from Light Dep. Reactions and CO2 to make glucose
IV. Cellular Respiration – process by which E of glucose is released in the cell to be used for life processes (movement, breathing, blood circulation, etc…)
A. General Formula:
C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP
B. Cellular respiration occurs in all cells of all organisms –plants, animals, bacteria
C. Energy stored by photosynthesis in glucose is converted into the energy of – ATP
E. Respiration requiring oxygen – aerobic respiration
C6H12O6 + 6O2 6CO2 + 6H2O + 36 ATP
1. organelle occurring in – mitochondria
Human cells contain a specialized structure – the
mitochondrion – that generates energy.
E. Respiration NOT requiring oxygen – anaerobic respiration (an = without)
Also called – fermentation
1. Alcoholic Fermentation: glucose ethyl alcohol + CO2 + 2 ATP
a. organisms -- yeast, bacteria
b. industries – baking, brewing, wine-making
2. Lactic acid fermentation: glucose lactic acid + 2 ATP
a. lactic acid is produced in the muscles during rapid exercise when the body cannot supply enough oxygen to tissues (burning painful sensation)
3. occurs in – cytoplasmSore Muscles and
C6H12O6 + O2 CO2 + H2O + 36 ATP
**E transferred from glucose to ATP
3 stages of aerobic respiration:1. Glycolysis – cytoplasm, 2 ATP2. Krebs cycle – mitochondria, 2 ATP3. Electron Transport Chain – mitochondria, 32 ATP
36 ATPtotal
Glucose1 6-C molec.
Glycolysis
Pyruvic Acid2 3-C molec.
Cytoplasm
2 322
MitochondriaCO2
released
Krebscycle
E. T. C.
High E e- carried in NADH
High E e-
carried in NADH and FADH2
H2O released
O2
AEROBIC
Glucose1 6-C molec.
Glycolysis
Pyruvic Acid2 3-C molec.
Fermentation
Alcoholic Lactic Acid
YeastBacteria
muscles
2
Cytoplasm
ANAEROBIC
Mitochondria
ANAEROBICalcoholic fermentation = 2 ATP
glucose 2 pyruvic acid lactic acid fermentation = 2 ATP
cytoplasm
mitochondriaAEROBIC
Krebs cycle ETC = 36 ATP