Ground rules of Metabolism- Unit 2 Flashcards
Alcohol Dehydrogenase
Alcohol breakdown directly damages liver cells and interferes with normal metabolic processes
Called inTOXICation for a good reason
Puking is best way to get out
Metabolism
Build and break down organic molecules (ethanol and other toxins)
Energy Types
Kinetic, potential, light, heat, electricity, and motion
First law of thermodynamics
Energy cannot be created or destroyed
Can be converted from one form to another and thus transferred between objects or systems
Second law of thermodynamics
Energy tends to disperse spontaneously.
A bit disperses at each energy transfer, usually as heat
All work is a result of this energy transfer
Entropy
Measure of how dispersed the energy of a system has become.
Entropy can increase but the total amount of energy always stays the same (just more spread out rather than compact)
Work
Occurs as a result of an energy transfer.
A plant converts light energy to chemical energy (this is work)
Most cellular work occurs by transfer of chemical energy from one molecule to another (transferring chemical energy from ATP to other molecules)
Energy’s one way flow
Living things maintain their organization only as long as they harvest energy from someplace else. An organism that stops harvesting energy is dead/dying
Energy flows in one direction through the biosphere starting mainly at the sun and then in and out of ecosystems
Producers and then consumers use energy to assemble, rearrange, and break down organic molecules that cycle throughout the ecosystem
Energy flows into and out of biological systems
Materials recycle among producers and consumers
Energy Conversion
It takes 10000 pounds of feed to raise a 1000 pound steer.
About 15% of energy in food builds body mass, the rest is lost as heat during energy conversions
Potential Energy
Chemical bonds prevent energy’s spontaneous dispersal
Energy in chemical bonds is stored energy. Life exists because energy can be stored chemically binding elements together and released when unbinding them
Every chemical bond holds energy- the amount of energy depends on which elements are taking part in the bond
Cells store and retrieve free energy by making and breaking chemical bonds in metabolic reactions, where reactants are converted to products
ATP
The main currency in a cell’s energy economy. Nucleotide with 3 phosphate groups linked by high energy bonds
High energy bonds means easier to do work
ATP/ADP cycle
Cells constantly use ATP to drive reactions to they constantly replenish it
ADP forms when ATP loses a phosphate, then ATP forms again as ADP gains a phosphate
Enzymes
Make a reaction run much faster than it would on its own without being changed by the reaction
Cheerleaders step in and give player red bull and leave
Catalysis
The acceleration of a reaction rate by a molecule that is unchanged by participating in the reaction. In biology the molecules are enzymes (usually proteins, but some are RNAs)
Effects of Temperature, pH, and salinity on Enzymes
Each type of enzyme works best within a characteristic range
Adding heat- boosts free energy, increasing reaction rate (within a given range
Optimal pH of between 6-8, pepsin functions only in stomach of pH 2
Too much or too little salt disrupts hydrogen bonding that holds an enzyme in its 3D shape
Turgor
Cell walls of plants and many protists, fungi, and bacteria can resists an increase in the volume of cytoplasm even in hypotonic environments
Outward directed fluid pressure against a cell membrane or wall
If turgor inside plant cell decreases, the plant wilts
Osmotic pressure
The amount of turgor that stops osmosis
Membrane crossing mechanisms
Gases, water, and small nonpolar molecules can diffuse against a lipid bilayer,
other’s only cross with help of transport proteins (allow organelle or cell to control what enters and exits)
Each type of protein can move a specific ion or molecule
Passive Transport
Work without energy input, concentration gradient drives movement of a solute across a cell membrane through a transport protein
Needs to energy
Glucose binds to glucose transporter, binding causes the protein to change shape and the glucose detaches after squeezing through, then protein resumes shape
Active transport
Transport proteins use energy ATP to pump a solute against its concentration gradient
Two calcium ions bind to transporter protein, energy is transferred from ATP to protein, transfer causes protein to change shape and eject calcium ions to opposite side, then resumes shape
Exocytosis
A cytoplasmic vesicle fuses with the plasma membrane and contents are released outside of the cell. Moves a bulk substance and large particle across plasma
Endocytosic processes
A patch of plasma membrane balloons into the cell forming a vesicle that sinks into the cytoplasm
Phagocytosis
Cell eating
An endocytic pathway by which cell engulfs particles such as microbes or cellular debris
