Ch 6 Flashcards
What does the symbol ΔG represent? Explain what +ΔG and -ΔG mean in
respect to the energy of the system.
ΔG represents the change in the Gibbs free energy of a system.
-ΔG means the reaction is spontaneous and releases energy
+ΔG means the reaction is non-spontaenous and requires energy input
Which best describes the reaction below? AB → A + B + energy
Catabolic
Catabolic reactions break down complex molecules into simpler
ones and release energy. This matches the reaction where AB is breaking
down into A and B, releasing energy.
What is an enzyme? Describe the functions of an enzyme in regards to metabolic
pathways and how these affect the rate of reactions within the cells during
metabolism.
Enzyme is a protein that acts as a biological catalyst to speed up chemical
reactoins
Role in Metabolic Pathways:
1. Speed up reactions: They increase reaction rates by lowering the
actavation energy.
2. Specificity: Each enzyme is specific to a patricular reaction, ensuring
precise control.
3. Regulation: Enzymes can be turned “on” or “off”, directing metabolic flow.
Enzymes impact on reaction rate:
Enzymes bind to substrates, stabalize the transition state and provide the right
environment to make reactions happen faster.
In essence, enzymes ensure that cellular reactions proceed efficiently and
specifically, enabling life’s necessary processes.
Which of the following processes is endergonic?
a. Cellular respiration
b. Synthesis of glucose from carbon dioxide and water
c. Burning of wood
d. Release of heat from breakdown of glucose
Synthesis of glucose from carbon dioxide and water
Why: This process describes photosynthesis, where plants capture light energy
to convert carbon dioxide and water into glucose. Since it requires an input of
energy (from sunlight), it’s endergonic.
Describe the process of denaturation
It’s the process where proteins or nucleic acids lose their native structure and shape.
- Caused by external factors like heat, pH changes, or chemicals.
- Results in the breaking of hydrogen bonds and other non-covalent interactions.
- Leads to loss of biological function.
The final product of glycolysis is
2 pyruvic acid, 2 NAD+, and net gain of 2 ATP
State the differences between a Cofactor and a Coenzyme
Cofactor:
- A non-protein molecule that assists enzyme activity.
- Can be inorganic (like metal ions) or organic.
Coenzyme:
- A specific type of organic cofactor, often derived from vitamins.
- Helps enzymes by transporting certain components, such as electrons, between
reactions.
- Key Difference: All coenzymes are cofactors, but not all cofactors are coenzymes.
Coenzymes are specifically organic and often participate in transfer reactions.
Patricia notices that after hitting the gym for several weeks, she has put on weight by
developing more muscle as well as storing more fat. Her body must be undergoing a
(catabolic/anabolic) pathway.
anabolic
Anabolic processes are associated with synthesis and growth.
Anabolic Reactions: Build complex molecules from simpler ones, requiring energy
Feedback inhibition
Pathway: Initial substrate → Intermediate A → Intermediate B → End product.
Feedback inhibition is when the end product is Allosteric inhibitor of earlier enzyme in pathway , tells enzyme to stop further production
Use the following chemical reaction to answer the question below: (A+) + (B) = (A++) + (B-)
Which is being oxidized? Which is being reduced? Which is the oxidizing agent and which is the
reducing agent?
A+ -> A++ losses an electron (since an increase in positive charge indicates loss of a
nergatively charged electron) -> Reducing agent
B -> B- gains an electron, it went from having no charge to –1. (reduced) -> Oxidizing
agent
Oxidation: Loss of electrons.
Reduction: Gain of electrons.
Oxidizing agent: Causes another substance to be oxidized and is itself reduced.
Reducing agent: Causes another substance to be reduced and is itself oxidized.
(T/F) The Second law of thermodynamics states that entropy is always decreasing
False; In a closed system, entropy (or disorder) is always increasing or, in the best-case
scenario, it remains constant. It never decreases.
Second Law: In any energy transfer or transformation, the total entropy of a closed system will
always increase or remain constant. It never decreases.
Which of the following are NOT an enzyme?
A. Ribozymes
B. Amylase
C. Ligase
D. Starchzymes
D. Starchzymes
List factors that can affect the function of an enzyme. Do these factors affect all enzymes in
the same way? Give one example of an enzyme and how it works in its optimal and not optimal
environments.
Factors affecting enzyme function:
1. Temperature: Optimal activity at specific temperatures; too high or low can reduce activity.
2. pH: Each enzyme has a preferred pH. Deviation can decrease activity.
3. Substrate Concentration: Increased rate up to a point; too much can saturate the enzyme.
4. Inhibitors: Molecules that decrease enzyme activity.
5. Cofactors/Coenzymes: Some enzymes need these to work.
6. Salt Concentration: Extreme levels can alter enzyme activity.
Not all enzymes are affected the same way by these factors. Each has unique optimal conditions.
Example: Human Amylase
- Best environment: works at body temperature (37 C) and slightly acidic to neutral pH (6.8-7.2) to
break down startch
- Poor environment: Too acidic or off-optimal temperatures can hinder its function.
An object at rest has _____ energy and an object in motion has ______ energy.
c. Potential, kinetic
State the First Law of Thermodynamics.
The Law of Conservation of Energy: Energy cannot be created or destroyed, only transferred or
converted from one form to another
