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Celeste Roderno-Desingaño, MS
Atmosphere A mixture of gases surrounding a planet.
Prevented from escaping due to pull of gravity
Also includes water, carbon dioxide and ozone.
Plays a major part in the various cycles of nature (water cycle, carbon cycle and nitrogen cycle)
In the lowest layer, the Earth’s atmosphere consists of: nitrogen (78%) oxygen (21%) Argon (1%)
Layers of the Atmosphere
1. Thermosphere Highest layer (80km/50mi to about
700km/450mi)
The thermal structure of the Earth’s atmosphere is the result of: complex interaction between the
electromagnetic radiation from the sun;
radiation reflected from the Earth’s surface and
molecules and atoms in the atmosphere.
Temperature is higher because of collisions between ultraviolet photons and atoms of the atmosphere
Mesopause – base of the thermosphere
Ionosphere – acts as reflector of radio waves.enabling radio transmissions to “hop” between widely separated points on the Earth’s surface.
Layers of the Atmosphere
2. MesosphereTemperature
decreases with altitude of 50km/31mi to 80km/50mi.
Temperature ranges from 0oC/32oF to below -100 oC/212 oF
Stratopause found on top of the
stratosphere Production of ozone
(O3) from oxygen molecules (O2)
Layers of Atmosphere
3. Stratosphere Temperature decreases with
altitude of 10km/6mi to 50km/31mi.
Temperature ranges from -60oC/-140oF to near 0 oC/32
oF
Ozone better absorber of UV
radiation than ordinary oxygen atom
prevents lethal amounts of UV from reaching the Earth’s surface
Tropopause the mark between the
stratosphere and troposphere and marks the influence of the Earth’s warming effects
Layers of the Atmosphere 4. Troposphere
The lowest level of the atmosphere (altitude from 0-10 km)
With temperature of 150C by the Earth, which in turn is warmed by infrared and visible radiation.
• Carbon and oxygen found in organism are ultimately returned to the atmosphere via the carbon-oxygen cycle.
Cycle:1. Photosynthesis2. Respiration
Phases of Photosynthesis
Light Reaction/Light Dependent Phase
The first phase of photosynthesis involves reactions that occur only in light and require chlorophyll.
In these light reactions, water molecules are split and energy stored for later use.
The whole series takes place in split second.
Light Reaction Is absorbed by
Chlorophyll a (energy carrier)
Becomes energized chlorophyll that supplies energy to
Split H2O and
Add P
2H O2 ADP (energy
carrier)
Trapped by NADP released forming ATP- stores energy (H acceptor)
Forming
NADPH2
For use in the dark reaction
Dark ReactionCO2
Combines with RDP, a 5-C sugar in the chloroplast(CO2 acceptor)
To form a very unstable 6-C sugar
This splits quickly and forms 2 PGA, a 3-C compound
Combines with 2H supplied by NADPH2 from the light reaction
(energy supplied by conversion of ATP to ADP)
forms
PGAL H2O
Can be used as nutrient or converted
to
RDP Glucose
Used to combine with CO2
and
By combining 2 molecules of PGAL and substituting H for a
phosphate
Cellular Respiration: Chemical Reaction
C6H12O6 + O2 CO2 + H2O + Energy
Cellular Respiration
Cellular Respiration: Three Reactions1. Glycolysis Takes place in the cytosol and not in the organelles Does not require the use of oxygen Glucose is converted to ATP
2. Kreb’s cycle Takes place in the matrix of the mitochondria Requires the use of oxygen and releases carbon
dioxide
3. ATP synthesis/ ETC Takes place in the inner membrane of the
mitochondria Requires the use of oxygen These reactions pump H+ across the membrane
creating a gradient As H+ enters the matrix, ATP is formed.
ATP Synthesis/Electron Transport Chain
Energy Produced in Cellular Respiration In Glycolysis = 2 ATP
In Krebs Cycle = 2 ATP
In ATP synthesis/ ETC = 34 ATP
Total = 38 ATP
From 38 ATP, the 2 ATP are used to transport products of glycolysis into the mitochondria.
Therefore: 36 ATP are produced for the whole process
Types of Respiration1. Aerobic respiration Stage which requires molecular oxygen Water and carbon dioxide are given off and
energy is released.
2. Anaerobic respiration Do not require oxygen to regenerate NAD Occurs outside mitochondria Organisms depend on glycolysis to generate
ATP and on fermentation to generate NAD. Product of this reaction is ethanol. This alcohol is formed whenever fruits are
processed into wine through fermentation.
Comparison of Photosynthesis and Respiration1. Occurs only in the
chlorophyll-bearing cells of plant.
2. Needs the presence of light
3. Water and Carbon dioxide are used.
4. Oxygen is given off as a waste product.
5. Food is built or synthesized.
6. The weight of the plant is increased
7. Energy is stored.
1. Occurs in every living plant and animal cell.
2. Occurs at all times.
3. Water and Carbon dioxide are given off as waste products.
4. Oxygen is used in the process.
5. Food is destroyed to release its energy.
6. The weight of the plant is decreased.
7. Energy is released.
Nitrogen CycleOne of the basic elements that compose proteins. Proteins are the structural components of all living things.
All organisms are made up of proteins. Growth of plants will be limited if there is not enough nitrogen in the soil.
About 78% of the atmosphere is nitrogen gas (N2) but in this state, nitrogen cannot be used by organisms.
Nitrogen CycleThe Cycle:1. Nitrogen fixation Conversion of Nitrogen (N2) to
ammonia (NH3) or ammonium (NH4)
Before nitrogen can be made available to plants and animals, it must first be fixed by nitrogen-fixing bacteria. -found in nodules of legumes
(soybean, mongo, pea). when these bacteria die,
ammonia or ammonium is released and used by other bacteria as energy source.
Small portion of gaseous nitrogen is fixed in the air by lightning and the fixed nitrogen is brought down to the soil by rain.
2. Nitrification Ammonia and ammonium is
converted to nitrites (NO2) by nitrifying bacteria in the soil. Some of these bacteria convert nitrites to nitrates (NO3).
When ammonia and nitrates that are released in the soil are dissolved in soil water, they are absorbed by roots of plants and become incorporated into plant proteins. these plant proteins are
then eaten by animals by which animal proteins are formed.
3. AmmonificationMetabolic wastes (urea, uric
acid) and remains of plants and animals are broken down by decomposers releasing ammonia or ammonium in the process.
4. DenitrificationNitrates not used by plants are
converted by denitrifying bacteria to nitrogen gas which is released to the atmosphere
Nitrogen Cycle