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IP Week 7: Energy Metabolism & Enzymes
Nicole Houchins
Created on December 19, 2024
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Course Competencies: 11. Describe the laws of thermodynamics and their relationship to the energy dynamics of living things. (V) 12. Explain the importance of enzymes to metabolic processes and their mode of action. (V) 13. Explain the importance of adenosine triphosphate (ATP) to living things. (V)
- Examine cellular metabolism and its components
- Understand the mechanisms of biological reactions
- Examine the role of enzymes in biological reactions
Lecture Goals:
Energy, Metabolism, and Enzymes
Sources and Types of Energy
Presentation Links
Enzymes and Energy
Reactions
Life's Need for Energy
Recall Theme of Life: Life depends on a continuous input and transfer of energy.
- Energy cannot be created or destroyed
- First law of thermodynamics
- The energy living things use has to come from and go somewhere.
- How organisms acquire energy varies:
- Autotroph: gains energy through photosynthesis or chemosynthesis
- Heterotroph: gains energy be eating other living things
- Decomposer: gains energy from breaking down organic matter
- Detritivore: gains energy from eating dead organisms and waste
Life's Need for Energy
What is Metabolism?
Metabolism is all of the chemical reactions occuring in a living thing.
- Chemical reactions either require energy or release energy (typically the transfer of electrons)
- Photosynthesis - energy originates from light from the sun and is converted to biological energy (ATP)
- Chemosynthesis - energy originates from chemical bonds (often methane or sulfide based) and is converted to biological energy (ATP)
Life's Need for Energy
Adenosine Triphosphate
ATP is the form of biological energy used by all living things.
- Nucleic acid
- Ribose sugar
- 3 phosphate groups (triphosphate)
- Nitrogenous base (adenine)
- Phosphate bonds store chemical energy
Life's Need for Energy
Watch: Amoeba Sisters Video
Life's Need for Energy
Catabolic
- Large molecules break down into small ones
- Releases energy
- Tip to remember: catabolic cuts
Metabolic Pathways
Anabolic
- Small molecules assemble into larger ones
- Requires energy
- Tip to remember: anabolic adds
Life's Need for Energy
Test your Knowledge
Watch: Crash Course video (until 2:30)
Laws and Concepts of Energy that Apply to Life
Entropy
- All things naturally move toward disorder
- Second law of thermodynamics
- Maintaining order requires energy
- Recall - order is a characteristic of life
- Life requires energy to maintain order
- Different forms of energy
- Not all energy is automatically usable by all living things
- Life needs to access energy in order to change it into a usable form
Life's Need for Energy
- Define metabolism
- What is the difference between an anabolic pathway versus catabolic pathway?
- Why does life require energy to maintain order?
02:00
Check your notes
Potential Energy
Potential energy is stored energy. Four types of potential energy:
- Chemical - stored in the chemical bonds between atoms and molecules (very important for living things!)
- Nuclear - energy stored within the nucleus of an atom (what holds the protons and neutrons together)
- Gravitational - energy stored in an object's height
- Elastic/mechanical - energy stored by tension (like a rubberband)
Types of Energy
Watch: Chemical Energy Videos
Types of Energy
Watch: Nuclear Energy Video
Types of Energy
Watch: Gravitational Energy Video
Types of Energy
Watch: Elastic/Mechanical Energy Video
Types of Energy
Kinetic Energy
Kinetic energy is motion energy. 5 types of kinetic energy:
- Radiant - energy from electromagnetic waves (in other words light)
- Thermal - energy from the speed of atoms or molecules that are moving (heat)
- Motion - energy from the speed of anything larger than atoms or molecules that are moving
- Sound - energy of compression/rarefaction waves (vibrations)
- Electrical - energy of electrons moving through metal
Types of Energy
Virtual Pendulum Lab
- Click the "energy" tab in the Virtual Pendulum Lab to examine the relationship between potential and kinetic energy
- Also available in Chapter 6, Section 2 of the textbook
Activity: Potential vs Kinetic Energy
Types of Energy
Measuring Energy
calories vs kilocalories vs Calories
- calorie - energy required to raise the temperature of 1 mL of water by 1 degree Celsius
- 1,000 calories = 1 kcal = 1 Calorie
- Nutrition is discussed in kilocalories or Calories
- All of your cells need that much energy by breaking chemical bonds (like in food molecules) in order to maintain their metabolism
Types of Energy
Can you explain what each arrow means in terms of cell metabolism and/or what each nutrient does for the body using what we have learned in class thus far?
Test your Knowledge
- List the four types of potential energy
- List the five types of kinetic energy
- What is the difference between cal vs kcal vs Cal?
02:00
Check your notes
On a sticky note, write down...
- A concept you still don't understand OR
- One question
End-of-Lecture Questions
02:00
OIL RIG: oxidation is loss (of electrons), while reduction is gain (of electrons).
Redox Reaction
A redox reaction occurs when electrons are transferred from one molecule to another. Two parts of a redox reaction:
- Oxidation reaction
- Atom "loses" electrons and is oxidized
- Named because oxygen is usually the electron taker between two atoms
- Reduction reaction
- Atom "gains" electrons and is reduced
- Named because the charge became more negative because it now has more electrons
Reactions
Enthalpy, Entropy, and Free Energy
Enthalpy - total energy present with a system (such as a chemical bond)
- All energy transfers involve losing some energy into an unusable form (such as heat), resulting in entropy
- Life needs a continuous input of energy since some energy is always "lost" (no longer in a useable form)
Reactions
Endergonic and Exergonic Reactions
Free energy equation: ΔG = ΔH − TΔS Change in free energy = Change in total energy - Temperature(Change in entropy)
- Endergonic reaction
- Positive ∆G - reaction uses energy
- Anabolic pathways contain endergonic reactions
- Exergonic reaction
- Negative ∆G - reaction releases energy
- Catabolic pathways contain exergonic reactions
Reactions
Test your Knowledge
Spontaneous and Non-Spontaneous Reactions
Chemical reactions are either...
- Spontaneous
- Happens without external energy input
- Example: exergonic reactions
- Non-spontaneous
- Requires external energy input
- Example: endergonic reactions
Reactions
Activation Energy
Activation Energy
Activation Energy
Every chemical reaction needs a small amount of energy to begin. This energy is called the activation energy. Enzymes serve as biological catalysts to speed up chemical reactions by lowering activation energy!
Reactions
Activation Energy, Reaction Types, and Enzymes
Reactions Summary
- What are the two parts of a redox reaction? When is an atom oxidized and when is an atom reduced?
- What is an endergonic reaction? Is it spontaneous?
- What is an exergonic reaction? Is it spontaneous?
- How do enzymes speed up chemical reactions?
03:00
Check your notes
Watch: Introduction to Enzymes
Enzymes
Structure and Function
- Made from proteins
- Acts as a biological catalyst - help speed up a chemical reaction by lowering the reaction's activation energy
- Contains an active site
- Where the chemical reaction takes place
- Shaped so that only a specific molecule can bind (the substrate)
- Substrate temporarily binds to the active site and undergoes a reaction
- After the reaction, the substrate is released and the enzyme returns to its original state
Enzymes
Enzyme Inhibitors
Some molecules are inhibitors.
- Stop or slow the function of enzymes
- Competitive
- Physically block the active site
- Non-competitive
- Bind to the enzyme at a non-active site, causing a shape change that removes the active site
- Substrate can no longer bind to the active site
Enzymes
Enzyme Activators
Some molecules are activators.
- Increase the activation or speed of the enzyme
- Can be an organic or inorganic molecule
- If organic, typically called a co-enzyme
- If inorganic, typically called a co-factor
- Bind to the enzyme, causing a shape change that reveals the active site
- Substrate can now bind to the active site!
Enzymes
- What is the active site of an enzyme?
- What is a substrate?
- What is the difference between enzyme inhibitors and enzyme activators?
02:00
Check your notes
Not required, but highly recommended (it can be very helpful to see the material again but phrased a little differently!)
OpenStax Biology 2e: Chapter 6
Recommended Textbook Reading
On a sticky note, write down...
- A concept you still don't understand OR
- One question