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