Bio 211
Chapter 6-8

 
 
 
1. Define the 1st and 2nd Laws of Thermodynamics. What are the consequences of these laws?
· 1st law: Energy is neither created nor destroyed. The amount of energy in our galaxy has always been here and will continue to always be here. It is merely transformed from one form to another-example is the conversion of radiant (light) E to the E tied up in chemical bonds. Different forms of energy include: radiant, chemical, mechanical, electrical, & nuclear. (3 pts)

· 2nd Law: At any transformation, some of the energy is wasted as heat (a non useable form). You don't get 100%. The world starts in an ordered state and moves to a less ordered state (more disorder). The measurement of this disorder is called entropy. (3 pt)

· The sun releases radiant energy, plants take that energy and convert it to energy bound in chemical bonds. 1st law—same amount of energy, just a transfer from radiant to chemical energy. The animal eats the plant, releases some of the energy in those bonds and uses it for metabolism—2nd law—some energy is wasted as heat, the animal doesn’t get to convert all the chemical energy for its own uses (4 pt).

All of the sun's radiant energy will one day be converted to heat, and at that time we will no longer have our ultimate energy source-don't worry-it won't happen in your lifetime!
 

 
 
2. What is "ATP" the abbreviation for? Tell why ATP is so important. Use a diagram to show the ATP – ADP cycle. Show the energy source and energy flow of plants and animals in your diagram.
ATP is adenosine triphosphate and is the energy source for all living things.  The cycle must contain: ATP (an adenosine plus 3 phosphates linked to show bonds), Energy being released (exergonic), ADP (adenosine plus 2 linked phosphates and a free floating phosphate) and Energy going in (endergonic). Takes energy to make ATP and energy is released when the last phosphate bond is broken. Show how energy moves through a simple food chain (light energy from sun to chemical energy in plant to animal that eats the plant, etc.).

 
 

 

3. With the aid of diagrams, trace the major steps in an overview of photosynthesis.
(can use the diagrams on page 161, 157 or the diagram in the lab manual)

Carbon dioxide + Water + Sunlight --> Oxygen + Glucose


Must include:
i. Light Dependent reaction: occurs in the thylakoid

  1. Water provides electrons, oxygen is released and protons (H+) go to NADP at end of this reaction.
  2. The sun provides the Energy for the electron to become "excited" (the electron moves to another orbital) where it is picked up by an electron acceptor molecule from the photosystem (where the pigment chlorophyll is located), and delivered to ETS and ATP is formed.
  3. The electron returns to its energy state and once again becomes excited (by sun’s energy), picked up by an electron acceptor molecule from another photosystem, delivered to ETS where NADP and H+ (from water splitting) is formed—NADPH+. The purpose of the light dependent reaction is the production of ATP & NADPH+, which go to the second part of photosynthesis. (5 pt)

    In: Water & Sunlight

    Out: Oxygen, ATP, NADPH+

ii. Light Independent Reaction: occurs in the stroma

  1. This reaction takes the carbon from the inorganic molecule,carbon dioxide in the atomosphere and uses it to produce an organic molecule, sugar. It takes a tremendous amount of E and the ATP & NADPH+ from the light dependent reaction fuel this cycle.
  2. Also known as the Calvin cycle (named after Melvin Calvin).
  3. The reactants ADP & NADP go back to the light dependent reaction (5 pt).

    In: Carbon Dioxide, ATP, NADPH+

    Out: Glucose, ADP & NADP
     

Be sure to include a drawing!!

 
 
 
 

4. List and define the 3 major stages of the process of aerobic respiration. What are the major inputs and products of each major stage? (p. 145)
· Glycolysis: The breakdown of glucose (6 carbon compound) into two molecules of pyruvic acid (3-carbon compound). Nets 2 ATP molecules. Occurs in the cytoplasm.
i. Inputs—glucose
ii. Output—pyruvic acid, ATP

( 3pt)

· Krebs: Pyruvic acid is modified and enters the Krebs cycle (if oxygen is present) as aceytlCoA, releases CO2, ATP, NADH, and FADH2. Nets 2 ATPs per molecule of glucose. (one molecule of glucose cycles two times) Occurs in the matrix of the mitochondria.
i. Input—aceytlCoA
ii. Output—CO2, ATP, FADH2, NADH

( 3pt)

· Electron Transport System: Electrons carried by NADH & FADH2, are released into the electron transport chain. (when NADH runs into a particular protein, the NADH is oxidized and donates its electron and proton to ETS) The movement of electrons along the ETS gives off enough energy to drive protons against their concentration gradiant across the membrane into the outer compartment. The fall of the H+ energy back into the inner compartment through the ATP pump is what drives the ATP sysnthesis (ATP synthase). Oxygen is the final electron acceptor and combines with 2 protons to become water.
i. Input—Electrons & protons from NADH & FADH2, oxygen
ii. Output—ATP (32!!), water ( 4pt)