Download Chapter 5 Study guide – pp. 72 – 78 Define: Energy

Chapter 5 Study guide – pp. 72 – 78
Define:

Energy -

Kinetic energy -

Potential energy -

Chemical energy – molecules can store and release energy in their chemical bonds – different
bonds have different amounts of energy stored in them - i.e. Carbon-hydrogen, carbon-carbon,
carbon- oxygen bonds are common ways to store energy in food – in digestion we break bonds
to release energy
Define and give examples of the laws of thermodynamics –


First Law of Thermodynamics Energy cannot be created or destroyed – only converted from one to another.
o Example:
photosynthesis does not create energy in a sugar molecule, it is a process that transfers
light energy to the chemical energy of bonds in sugar molecule.
Second Law of Thermodynamics –
Energy transfers or conversions are not 100% efficient and some “energy” is “lost” for useful
purposes and increases the entropy of universe.
o
o
Example Running – when you run/exercise, you are converting energy from food molecules into
kinetic energy of the contraction of muscles BUT also are “losing” a little of the potential
energy to heat which is why you get hot!
Explain how laws of thermodynamics apply to biological systems.
Label the following diagram:
Heat
energy
Glucose
Process of cellular respiration
Carbon
dioxide
Water
Oxygen
ATP
Give examples and distinguish between endergonic and exergonic reactions –

Endergonic – Chemical reactions that take in energy – the product of the reaction has more
potential energy than the original reactants. The source of that energy may be chemical, light,
electric….
o

Example – Photosynthesis – starts with carbon dioxide and water (relatively low energy
molecules) – but by using light energy, ends with glucose which is a higher energy
molecule – (more potential energy in its bonds)
Exergonic –Chemical reactions that release energy – the products have less potential energy
than the reactants and the energy released may have been used to work.
o
Example – wood burning – the product of burning the polysaccharides in wood is carbon
dioxide and carbon soot – the energy that was in the bonds of the wood was released as
heat and light and the products now have less potential energy. Cellular respiration is
another example.
Explain how the following diagrams show endergonic and exergonic reactions:
Endergonic reaction – potential energy diagram – on the left are the
reactants which have less potential energy than the products. The
gold star is ATP and shows energy being added to the system, the
products have more potential energy than reactants.
Exergonic reaction – potential energy diagram – on the left are the
reactants which have more potential energy than the products. The
gold star is ATP and shows energy being removed from the system,
the products have less potential energy than reactants.
Define:

Cellular respiration –step by step breakdown of food molecules to release energy in the cell –
series of chemical reactions that results in conversion of potential energy in food to the
potential energy of ATP.

Cellular metabolism – Involved chemical breakdown of molecules – catabolism – and build-up of
molecules – anabolism.

Energy coupling – your cell can link an exergonic reaction which releases energy to an
endergonic reaction which takes in energy.
Explain in a few sentences how the above terms relate to each other:
Label this diagram:
Using the terms endergonic, hydrolysis, phosphorylation explain how ATP can carry and transfer energy
within the cell to support cellular work. Use the diagram to show what kind of work it supports?
How does ADP interact with the above processes?
Use the terms energy of activation, reactants, and products to explain how enzymes help a reaction
occur.
Are enzymes used up in the reaction? Explain.
What kind of macromolecule are enzymes?
Why do we call enzymes the workers of the cell?
Explain the diagram:
Using the terms substrate and active site, explain how an enzyme works by its shape matching the shape
of its target.
Label the diagram:
What is induced fit?
What factors in the cell environment might affect an enzyme’s activity?
How do competitive and noncompetitive inhibitors work to regulate or block enzyme activity?
Label the diagram:
What does this have to do with feedback inhibition and why is feedback inhibition important?