Transcript Energy and Cycles of Matter

Energy and Cycles of
Matter
Mr. I
Why do we need energy?
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All living things need energy to do work,
Energy is the ability to do work.
In terms of energy there are two types of organisms :
1)Autotrophs
2) Heterotrophs
Autotrophs
• Autotrophs make their own food through either photosynthesis or
chemosynthesis.
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Examples of such organisms are plants, algae, and bacteria.
They are the foundation of all ecosystems.
Without autotrophs no ecosystem can flourish
Also called producers
Heterotrophs
• Cannot make their own food, rely on autotrophs.
• Also known as consumers.
• Include all animals and fungi.
Energy Molecules
• Glucose – This is a sugar molecule made by plants through photosynthesis
and it is broken down in cellular respiration in the mitochondria of all cells.
• ATP – This is a high energy molecule that is needed for all cell processes.
Chemosynthesis
• This is the formation of organic material by bacteria using energy derived from
simple reactions.
• Micro-organisms in dark regions of the ocean can produce energy from single
carbon molecules
• It was first discovered at hydrothermal vents, places where the temperatures are
thought to be too hot for life to exists.
• Large populations of animals can be supported by chemosynthetic secondary
production at hydrothermal vents, methane clathrates, cold seeps, whale falls, and
isolated cave water
Photosynthesis
• This is the fundamental process that all life depends on.
• It is the conversion of light energy to glucose in the chloroplasts of plant
cell.
• It is the conversion of radiant energy to chemical potential energy stored
within the bonds of carbon sugars. (glucose)
• It uses carbon dioxide from the atmosphere, water, and sunlight and converts
it to glucose and oxygen.
Respiration
• Takes place in the mitochondria of cells.
• the release of chemical energy from food molecules for use by the cell.
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Most organisms depend on respiration and/or photosynthesis to provide
energy directly or indirectly.
Aerobic Respiration
• Takes place in the mitochondria of all eukaryotic cells, conversion of glucose
to ATP (energy) for all life sustaining processes.
• It is the release of chemical potential energy from sugars.
• Uses oxygen and glucose and converts it to carbon dioxide, water, and 38
ATP molecules. (ATP= Adenosine Triphosphate)
• The products of photosynthesis are the reactants of respiration and vice
versa.
Relationship Between Photosynthesis and
Respiration
• 6H2O +6 CO2 → C6H12O6 + 6 O2
• Carbohydrates and oxygen are products in photosynthesis, BUT
reactants in respiration.
• Carbon dioxide and water are reactants of photosynthesis, BUT
products of respiration.
• C6H12O6 + 6 O2 →6H2O +6 CO2+ ATP
Lets look at these processes in more detail!
We will look at the biochemical pathway of
each process
• Biochemical pathway – Complex series of reactions that involve the specific
series of reactions, perform a specific function, and occur at different sites.
Photosynthesis
• Photosynthesis
• Divided into 3 sets of reactions :
• 1.Light absorption in chlorophyll
• 2.Light-dependent reactions.
• 3.Light-independent reactions.
Light absorption in chlorophyll
1.Light absorption by chlorophyll
Chloroplasts found in the cells of green plants absorb
chlorophyll from sunlight.
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Thylakoid- site of light absorption found in
chloroplasts.
2. Light Dependent Reactions
• Main Stages :
electrons.
1.Converts sunlight to electrical energy, which is the flow of
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Electron transport chain – Passage of electrons from a high
energy level to a lower energy level. – Generates electrical energy
2. Electrical Energy is changed to chemical energy through a
membrane, resulting in ATP formation that is used to drive the
process of photsythesis
Chemiosmosis – diffusion of chemicals through a membrane,
forming ATP.
Light Independent Reactions
3. Light Independent Reactions – reactions that form organic compounds by
using energy stored during light-dependent reactions.
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During these reactions carbon fixation produces organic compounds
through carbon-carbon bonding.
Here the ATP created in the light dependent reactions is stored within the
bonds of the sugar (carbon-molecules)
Carbon Fixation
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Most plant species in moderate climates fix carbon through lightindependent reactions called the CALVIN CYCLE.
Other pathways that fix carbon: C4 and CAM pathways.
C4Pathway is an adaptation for plants in environments having high
temperatures, dry conditions and abundant light.
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Allows plants to grow quicker in hot dry climates
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ex... corn, sugar cane etc...
Carbon Fixation
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CAM pathways takes in CO2during the night then releases it during the day
for use in photosynthesis.
These plants lose less water due to collection CO2 at night, giving them a
survival advantage over other plants in hot, dry environments.
Ex. - cactus, pineapple, etc...
OGT Review Question
• What does the process of photosynthesis release to the
atmosphere?
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a- carbon dioxide
b- hydrogen
c- nitrogen
d- oxygen
OGT Review Question
• For many years scientists debated whether viruses should be considered living
organisms.
• Which statement could a scientist use to support the position that viruses are not
living?
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A-Viruses have genes encoded in DNA
B- Viruses require a host cell in order to reproduce.
C- Viruses infect both plant and animal cells.
D-Viruses replicate to produce more viruses.
OGT Review Question
• What Structure is absent in the cells of fungi thereby preventing them from
performing photosynthesis?
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a- Cilia
b- Nuclei
c- Chloroplast
d- Mitochondria
OGT Review Question
• A scientist uses a microscope to examine two slides of living bacteria. Each
slide has different bacteria. While the cells on the first slide are moving
rapidly, the cells on the second slide are stationary.
• Based on these observations, the cells on the second slide most likely have
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• a- nucleus
• c- chloroplasts
b- Flagella
d- Mitochondria
Cellular Respiration
• Cellular Respiration- a set of chemical reaction that
occurs inside every organism's cells and converts
nutrients to ATP (Energy Molecule).
• C6H12O6+ 6 O2→ 6 H2O + 6CO2 + ENERGY (ATP)
• Glucose + Oxygen → Water + Carbon Dioxide
+Energy
2 types of cellular respiration :
•1.Anaerobic Respiration
•2. Aerobic Respiration
• Aerobic Respiration – Respiration that requires
oxygen
• - Glycolysis is followed by Krebs Cycle then the
Electron Transport Chain.
• - Krebs Cycle – a Biochemical pathway that
releases CO2 AND H+(water) and results in the
formation of ATP.
• Takes place in the mitochondria of a cell.
• - Electron transport chain – passage of electrons
from high energy to lower energy level.
Types of Fermentation
• 1.Lactic acid Fermentation – converts Pyruvic acid to lactic acid.
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- Causes soreness in muscles.
• 2. Alcohol Fermentation – converts Pyruvic acid to ethyl alcohol.
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- Creates our beer, wine, and bread
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- Many calories in beer due to energy
alcohol and not being converted to ATP.
remaining in the ethyl
Anaerobic Respiration
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It is the incomplete breakdown of glucose in the ABSENCE of oxygen (NO
OXYGEN)
Consists of:
1- Glycolysis – glucose converted to Pyruvic acid without using oxygen. Produces a
small amount of ATP.
Takes place in the cytosol.
2- Fermentation – process of breaking down Pyruvic acid without the use of oxygen
to form Lactic Acid (Muscle soreness)
Energy Yields
• Aerobic Respiration
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-Glycolysis = 2 ATP
-Krebs Cycle = 2 ATP
- Electron Transport = 34 ATP
38 ATP Total
Energy Yields
• Anaerobic Respiration
• -Glycolysis = 2 ATP
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2 ATP total
• Aerobic Respiration is 19 times more effective that
anaerobic respiration in providing a cell with energy
for cellular activities.