Class notes
Biology Midterm Notes
- Course
- BIOL 1004
- Institution
- Arkansas Tech University
Basics of biology covering enzymes, law of thermodynamics, energy, catabolism vs anabolism, ATP's, photosynthesis and cellular respiration.
[Show more]
Seller
Follow
Content preview
10/1Enzymes
• help chemical reactions get done faster; at a temp that’s lower. Chemical reactions
require a flame, typically/higher pressure.
• Enzyme substrate reaction like a key and lock; relationship is very specific;
demonstrates that structure determines function. Active site, key spot (substrate
bonding)
• Enzymes lower energy by positioning reactants together
• High specification
• Induce fit phenomenon – interaction also involves conformational changes
• Proteins that are affected by environment; work in narrow range of temp and pH
• Biocatalyst
• Takes less energy to cause reaction
Enzyme Requirements
- Prosthetic groups: small molecules permanently attached to the enzyme
- Cofactor: usually inorganic ion that temporarily binds to enzyme
- Coenzyme: organic molecule that participates in reaction but is left unchanged
afterward
Enzyme Reactions
- Affinity: degree of attraction between an enzyme and its substrate
- Saturation: plateau where nearly all active sites are occupied by substrate
- Michaelis constant Km : substrate concentration where velocity is half max value,
constant in enzyme-substrate reaction
Proteins are made from polypeptides; polypeptides are made of amino acids (glycine
smallest, different types of amino acids)
Reaction spontaneous: does not require outside energy, increases entropy; free energy is
always negative
Energy: ability to promote change, and do work
- Kinetic vs Potential energy
Thermodynamics
First law:
, • law of conservation of energy
• energy cannot be created or destroyed, but can be transformed from one tup to
another
Second law:
• Transfer of energy from one form to another increases the entropy of a system
• As entropy increases, creates more disorder (less energy available to promote
change)
Gibbs free energy:
• change in free energy determines direction of chemical reactions: Total energy =
usable energy + unusable energy
• H = G + TS:
- H = enthapy
- G = free energy
- S = entropy
- T = constant, absolute temp in Kelvin (K)
Hydrolysis of ATP:
• adenosine triphosphate
• comes from RNA
• OH sugar is only present in RNA
• 3 phosphates + water
• Use this to drive reactions
• Energy currency of cells
Spontaneous Reaction:
• Fast/slow
• Gives free energy/doesn’t need excess energy
• Triangle G is negative, free energy change
Activation energy
• Minimum energy that’s required for a reaction to happen
• Can now achieve transition state where bonds are stretched
• Common ways to overcome activation energy: large amounts of heat, using
enzymes to lower activation energy
ATP
, • Typical cell uses millions of ATP/second to drive endergonic processes
• 10k cycles/day
• 20% of all proteins bind ATP
• particular amino acid sequences in proteins function as ATP-binding sites, make
ATP, substrate level phosphorylation, chemiosmosis
Proteins that use ATP energy: metabolic enzymes, transporters, motor proteins,
chaperones, DNA-modifying enzymes, aminoacyl-tRNA synthetases (important), protein
kinases
Inhibition:
- Competitive Molecule binds to active site, inhibits ability of substrate to bind
- noncompetitive - Lows Vmax without affecting Km, inhibitor binds to allosteric site,
not active site
- Irreversible - Usually bind covalently to an enzyme to inhibit its function, not a
common way for cells to control enzyme function
Types of energy
- Light
- Heat
- Mechanical
- Chemical
- Potential
- Electrical/ion gradient
Terms
Chemical potential energy: energy in molecular bonds
Feedback inhibition: process where the product blocks the initial process
Energy: ability to promote change or do work; kinetic vs potential energy; all reactions have
a threshold of energy, transition state
Entropy: randomness
Enzymes: protein catalysts in living cells
Ribozymes: RNA molecules with catalytic properties
Catalyst: an agent that speeds up the rate of a chemical reaction without being consumed
during the reaction.
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller reedhunter. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $8.79. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
53068 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now