Question

Chapter 5: Ground Rules of Metabolism

* Section 5.1 – Life Runs on Energy

o Describe what energy is (definition). Explain how this definition applies to life. Use a cell as an example. Use an entire organism as an example.

o What are the first and second law’s of thermodynamics? What does each one mean for life, from the perspective of a cell?

o Compare kinetic versus potential energy. How does life obtain potential energy?

* Section 5.2 – Energy in the Molecules of Life

o Interpret a chemical formula (just identify which are products, which are reactants)

o Explain activation energy. After defining it, explain what life does to deal with activation energy (hint: think enzymes)

* Section 5.3 – How Enzymes Work

o What is an enzyme? First, which macromolecule is it? Then, what does an enzyme do?

o How does an enzyme accomplish its job? (Read about induced fit model)

o What is a substrate?

* Section 5.4 – Metabolic Pathways

o Describe allosteric regulation

o Describe feedback inhibition

o What is an electron transfer chain?

* Section 5.5 – Cofactors and Coenzymes

o Define cofactor and coenzyme. What is the difference in the two?

o What does ATP stand for? Explain what about ATP gives it lots of energy.

o Explain what ADP is and how it is related to ATP

* Section 5.6 – Diffusion and Membranes

o Describe what diffusion is. Give an example

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o Explain the factors that can affect the speed (rate) of diffusion. Most importantly, HOW do each of these factors cause a change in the rate of diffusion?

o Describe what osmosis is. How does this compare to diffusion?

* Hint – in osmosis, water will move across a membrane to dilute the concentrated side, since the solute cannot always move on its own by diffusion

o Define the terms hypotonic and hypertonic. If I were to give you the salt concentration, for example, inside a cell versus outside a cell, be able to state whether the solution outside the cell is hypotonic or hypertonic to the cell. Also, what is isotonic?

o Explain turgor, and how this term applies to wilting (think of how a cut flower will wilt out of water)

o Critical thinking regarding turgor and osmosis – think of a leftover salad. You have salad dressing on the salad, which is typically salty and concentrated so that it is flavorful. Can you link osmosis and turgor to the fact that salads do not stay fresh very long after they are dressed?

* Section 5.7 – Membrane Transport Mechanisms

o Compare passive transport versus active transport in a simple definition of the two.

* What is the cellular form of energy that active transport requires?

* How are membrane proteins important for active and passive transport?

* Section 5.8 – Membrane Trafficking

o Define phagocytosis. What sorts of molecules might a cell ingest, and why would the want to ingest such things?

Answer 1

Energy is the ability to perform a .work or an activity.

Life is flow of energy. In order to prevent damage or breakdown or to keep the intact structure of the living cell or an organism many biochemical activities have to take place in the living cells of living organisms.

These biochemical activities involve many molecular movements. These movements require energy to move through out the survival of an organism.

Thus life or flow of energy has to be maintained in the living organisms throughout their life.

The first law of thermodynamics states that "energy neither be created nor be destroyed and it is only converted from one form to the other",

thus, the total energy of a system is maintained constant.

In the living system also the light energy is converted into chemical energy by the producers, later it is transferred to consumers in only10%rate from one level to next level, remaining energy is not destroyed, instead it is released in the form of heat into their surroundings.

Thus as per the first law of thermodynamics every living cell is living by using energy transformed from light energy.

Second law of thermodynamics states that "total entropy of a system cannot decrease over a period of time"

Entropy is the random ness. If no randomness or molecular movement is there then flow of energy is completely stopped.

Thus if a living organism has to be .in survival state, then it needs its entropy be maintained.