*Chapter 8- section 1 notes*

Tronsformation of energy

- Energy - the abulity to work.
- Thermodynamics - the study of the flow and transformation of energy in the universe.

Laws of Thermodynamics

- First law - energy can be converted from one form to another, but it cannot be created nor destroied.
- Second law - energy cannot be converted without the loss of usable energy.

Autotrophs and Heterotrophs

- Autotrophs - orgamisms that make their own food. Examples: plants some protists (algae), and some bacteria.
- Heterotrophs - organisms that need to ingest food to obtain energy. Examples: animals fungi, some protists (amoeba, paramecia).

How Organisms Obtain Energy

- Petabolism - all of the chemical reactions in a cell.
- Photosynthesis - Light energy fron sun is converted to chemical energy (glucose) for use by the cell.
- Cellular Respiration - organic molecules (glucose) are broken down to release energy for use by cell.
- ATP - the " energy currency" of the cell
- ATP - stores and releases a small amount ($1) of energy for movement, transport and other active processes in the cell.
- ATP - both heterotrophs use ATP as an energy storage molecule in their cells.
- ATP - used to power processes in the cell such as the Calvin Cycle of Photocynthesis in which CO2 is converted into glucose.

*Chapter 8- Section 2 Notes*

Section 2 -Photosynethesis

-Photosynthesis - the process by which the energy of the sun is used to convert H2O and CO2 into high enrgy sugars (glucose).
-Importance - We need glucose and other carbnohydrates for energy but we cannot produce them oursleves. We also need oxygen and this is produced during photosysnthesis by plants and algae.

  • Light Energy:
-Light is a form of energy that travels in the form of particles or waves. The waves are measured in wavelengths, which vary in length. Humans can see violet through red wavelengths. (Remember "ROY G BIV")
-Color - Reflected light. We see color.
-Pigment - a molecule that absorbs light.
-Whatever colors the pigment does NOT absorb are what we see.

  • Pigments:
-Cholorphyll A is a pigment that ABSOBS violet, ted, and vlue wavelegnths of light.
-Green is REFLECTED by cholorphyll A. That's why most leabes appear green to us.
-Other pigments called Accessory Pigments (cholorphyll B, xanophyll, and carotene) help cholorphylll A absorb a greater spectrum of light.

  • Chloroplasts:
-Photosynthesis takes place in the chloroplast.
-A chloroplast is a double-membraned, disk-shaped organelle.
-located inside this disk are stacks of stacks.
-Each sack is called a thylakoid.
-Inside each thylakoid is chlorophyll and other pigments.
-Stacks of sacks are called grana.
-Surrounding the grana is a fluid called stroma.

Things to know...
Balanced Photosynethesis Equation:
- 6CO2 + H2O --(light)---> C6H12O6 + 6O2
- Photosynthesis occures in two phases.
1. Light- dependent reactions
2. Light- independent reaction

Phase One: Light Reactio-The absorbtion of light is the first step in photosynthesis.
-Choloroplasts capture light energy.

Light Reactions

-Goal: convert light energy into chemical bond energy. (ATP, NADPH)
-What goes in: H2O, light pigments (cholorphyll), ADP, P, NADP+
-What comes out: O2, ATP, NADPH
-Location: In the thylakoids.

Electron Transport

-Light energy excites electrons in photosystem 2 and also causes a water molecule to split, releasing an electron into the electron transpory system, H+ into the thylakoid space, and O2 as a waste product.
-The excited electrons move from photosystem 2 to an electron-acceptor moleculein the thylakoid membrane.
-The electron-acceptor molecule transfers the electrons along a series of electron-carriers to photosystem 1.
-As electrons are passed down photosystem 2 (PS2), energy is released to make ATP.
-Light then strikes photosystem 1 (PS1) and electrons are captured by a 2nd electron accceptor.
-The electron acceptor of photosystem 1 sends the electrons down ITS electron transport chain (E.T.C.).
-As the electrons get passed down the ETC, their energy is used to "charge" an NADP+ into NADPH (adding two H)

Phase Two: The Calvin Cycle

-In the second phase of photosynthesis, called the Calvin Cycle, energy is stored in glucose.
-"light independent reactions" is another name for the Calvin Cycle.
-Goal: Use the ATP and NADPH from the light reaction to convert carbon dioxide into carbohydrate (glucose).
-What goes in: ATP, NADPPH, CO2, RuBP (a sugar)
-What comes out: Glucose (stored by the plant).
-ADP, P, NADP+: (shuttle back to the light reactoins to get "charged up" again.

4 Steps in the Calvin Cylcle

1. Six CO2 molecules combine with six RuBP's to form twelve 3-carbon molecules called 3-PGA
2. ATP provides energy and NADPH provides H+ to tranfowm the 3-PGA molecules into twelve high-energy molecules called G3P. One molecule of G3P is essentially a "half glucose". Two G3P's (half glucoses) leave the cycle to become glucose.
3. An enzyme called rubisco converts the remaining ten G3P molecules back into molecules of RuBP.

Factors influencing the rate of photosynthasis:

1. Availability of water.
2. Intensity of sunlight.
3. Temperature.

C4 plants

-Adaptation to conserve water in hot regions
-Instead of 3 carbon stages (3-PGA and G3P), these planrs fix C02 into a 4-Carbon molecule.
-Able to keep stomata on hot days and Calvin cycle occures only in special
-Used by suger cain and corn.

CAM plants

-Conserves water in dry regions.
-Only open stomata for CO2 until daytime. calvin cycle proceeds while stomata are closed.
-Used by pineapple and cacti.

*Chapter 8- Section 3 Notes*

  • Cellular Respiration
-Overall Goal: To completley break down glucose and transfer the energy to ATP.
-Location: In the cytoplasm and mitochondria of all eukaryotic cells.
-Balanced Equation: C6H12O6 + 6O2 ----> 6CO2 + 6H2) + Energy
-Cellular Respiration occurs in two main parts:
1. Glycolysis
2. Aerobic respiration
  • Glycolysis
-Glucose is broken down in the cytoplasm through the process of glycolysis.
-Two molecules of ATP and two molecules of NADH are formed for each molecule of glucose that is broken down.
-Location: Cytoplasm
-Goal: To break glucose ($100) into 2 pyruvates ($50). Does not require Oxygen therefore it is Anaerobic
-What goes in: Glucose + 2 ATP's ("invested").
-What comes out: 2 pyruvates ($50 each), 2 ATP's ($1) (net), 2 NADH's ($10)
-9 step processes with 2 phases:
1.energy consuming/investing
2.energy releasing
3. 2 ATP's phosphorlylate glucose which makes it more
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12-1 Griffith and Transformation
  • Only 1 strain caused pnuemonia
  • smooth edged colonies caused pneumonia, Rough edge colonies did not cause pneumonia.
  • Mice injected with smooth edged bacteria died, those injected with rough edged bacteria lived (surprise,surprise!)
  • Griffith heat killed some smooth bacteria and then injected it into the mice, the mice lived.
  • He also had a rough plus a heat killed smooth and the mice died. A good colonie and a good material were mixed together to kill the mouse, this process is called Transformation.
  • The mysterious bacteria that was in the rough, and heat killed smooth was answered by Oswald Avery in 1944.
  • Avery made an extract from the heat-killed bacteria and subjected samples of it to enzymes that would break down carbs, lipids, or proteins. He mixed each sample with living rough bacteria and injected one type of sample inot each group of mice.(all of the mice died)
  • Conclusion: Transformation had occured and the genetic material is not composed of carbs, lipids or proteins.
  • In experiment 2, Avery subjected te extract to enzymes that broke down DNA. He mixed this sample with living rough bacterua and injected it into the mice. (the mice LIVED.)
  • Conclusion: DNA was the transforming factor and is responsible for passing on traits.
Hershey and Chase
  • Avery's conslusion were not widely accepted by other scientists. Hershey and Chase attempted to verify in 1952.
  • They used bacteriophages,( viruses that infect bacteria) to confirm that DNA and not protein was responsible for the infection.
  • Viruses (strands of DNA or RNA surrounded by a protein coat or capsid) were grown in cultured with radioactive isotopes ( 32P and 35S)
  • Proteins do not contain much P and DNA has no S. So if S was found inside the bacterium it could be concluded that the infecting agent was a protein.
  • If P was found inside the bacterium, then it was DNA
  • Nearly all radiocativity in the bacterium was P. Hershey
  • Once it was confirmed taht DNA was the genetic material, the next step was to determine the structure of DNA and to determine how:
    -DNA could carry information
    -DNA could replicate easily
    -Dna could code for specific traits
  • Definition: the actual synthasys of polypeptide which occures under the direction of mRNA
  • 1. The mRNA molecule attaches to the ribosomes at its codon (AUG).
  • 2. The tRNA bearing the anticodon UAC on one of its ends and carring the amino acids methionine on its other end, binds to the mRNA at AUG
  • 3. As the ribosome moves along the mRNA codon is paired with its tRNA anticodon and amino acid. this will contenue until one of the stop codons(UGA,UAA, and UAG) is reached.
  • 4. The amino acids attach to one another with peptide bonds.
  • 5. When the ribosone reaches the end
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