Question

Purpose

        The clear understanding of energy transformations (Bioenergetics and Photosynthesis) by cells explains how cells can maintain their homeostasis in a continuously changing world. Completing this assignment will assist you in developing clarity of how cells function energetically on the planet and how some cells capture sunlight to build organic molecules. These principles of Bioenergetics and Photosynthesis will help clarify the Course Content Learning Outcomes number 2 (Understand the basic principles and ideas of chemistry and organic chemistry) and 4 (Able to explain the concept of a cell and describe the functions of its parts) for this course. This exercise will also clarify the Campus Wide Outcome of Critical Thinking (See page 3 (Critical Thinking) of the syllabus). The knowledge gained could assist students in other related science courses and courses in Psychology, Criminal Justice, and others.

Task

        Armed with a textbook (Chapters 5 & 6), the Bioenergetics and Photosynthesis Power Point presentations, or other reliable sources answer the following questions about Bioenergetics and Photosynthesis. Be creative in how you approach and answer each question. Do not just copy and paste information from another source. Read the source and then write your answer in your own words so that it becomes your answer. Remember in science there are no “correct” answers but rather explanations of phenomena. This assignment will be due .....

Criteria

        This assignment is worth .... total. The possible points for each question are in parenthesis after the question number. A complete answer to each question will involve being cognizant of the principles of Bioenergetics (The energy flow through a biological system.) and Photosynthesis (The harvesting of sunlight energy to build organic molecules.). Clear answers will have the involved cellular parts and molecules labeled clearly with descriptions and definitions that are clear, concise, and will contain enough detail that anyone reading your answer could potentially draw the same conclusions that you have by answering the questions.

1. (5) Define the following terms as they relate to an enzyme: activation energy, active site,

conformation, denaturation, and coenzyme/cofactor binding site.

2. (5) How are enzymes inhibited by competing and by non-competing molecules?

3. (5) Draw a graph that would represent enzyme function at various temperatures and draw a

graph that would represent enzyme function at various pH levels.

4. (5) Describe and give an example of the concept of energy coupling reactions in regards to cellular

ATP usage.

5. (10) Describe the light dependent reactions of photosynthesis in five steps or less.

6. (10) Describe the light independent reactions (Calvin cycle) of photosynthesis in five steps or less.

Divide the cycle into two halves: Molecule Building and Rearrangement before listing your steps to help focus your thoughts.

Answer 1

1.The energy required to start a reaction is called the activation energy. The lower the activation energy, the faster a reaction happens.The active site is the region of an enzyme where substrate molecules bind and undergo a chemical reaction.Interactions between the substrate and the active site are sometimes called "induced fit". This fit leads to the formation of a new product ,called conformation.Denaturation is the process of partial or total alteration of the native secondary, and/or tertiary, and/or quaternary structures of proteins or nucleic acids resulting in a loss of bioactivity. coenzymes are type of cofactor, and are organic molecules that bind to enzymes and help them function.The first type of enzyme partner is a group called cofactor or molecules that increase the rate of reaction or are required for enzyme function.

10.Light dependent reaction:

• Step 1: Photosystem II.
• Step 2: Electron Transport Chain.
• Step 3: Photosystem I.
• Step 4: Hydrogen Ion Movement.
• Step 5: ATP Formation. As hydrogen ions pass through ATP synthase, their energy is used.

Step 1.photosystem ll

Light absorbed by photosystem ll is used for breakdown of water molecules into energized molecules.

Step 2.Electron transport chain

High - energy electron moves to photosystem l

Step 3 .photosystem l

Electrons again energised.electron converted to NADPH

Step 4 . Hydrogen ion movement

Inside of thylakoid fills with positively charged hydrogen ion.

Step 5.ATP formation

As hydrogen ion pass through ATP synthase,their energy used to convert ADP to ATP.

Light independent reaction :

Step 1: fixation

Step 2 :Reduction

Step 3 : Regeneration

Step 1 . Fixation

In first stage CO2 is fixed from an inorganic to an organic molecule. In the second stage, ATP and NADPH are used to reduce 3-PGA into G3P;.

Step 2. Reduction

A reduction is the gain of an electron by an atom or molecule. Six molecules of both ATP and NADPH are used.for ATP energy is released with the loss of terminal phosphate, converting it into ADP.

Step 3 . Regeneration

In regeneration only one of the G3P molecules leaves the Calvin cycle and is sent to the cytoplasm to contribute to the formation of other compounds needed by the plant.

Three more molecules of ATP are used in these regeneration reactions.

(5) .competing and non competing molecule in enzyme inhibition.

The enzyme may react with the inhibitor and release the products as it would usually do to its substrate, thus the inhibitor and substrate compete for the active site. Non-Competitive inhibitors bind to an allosteric site of the enzyme (A site on the enzyme which is not the active one).