3.1 Metabolism and Energy Flashcards
All living things require energy
EX:
Ex. to skate, to sing, to dance, to mvmt of your
eye muscles as you read this slide
Energy is required not just for mvmt, but for also:
✓Growth
✓Maintenance
✓Repair
Brain is 2% of your body mass and does not have large moving parts, BUT
uses 20% of energy!
Many ______ and ______consume large amounts of energy
Plants and Animals
Living organisms must ________, _______ and ___ ______
capture, store and use
energy
ATP is made by
mitochondria in Eukaryotes
Metabolism
the sum of the chemical
reactions (anabolic, to
build and catabolic, to
breakdown) taking place
within an organism
Most living organisms
obtain energy via:
- Directly from the sun
through photosynthesis - Consuming energy-rich
molecules within food
All energy exists in one of two states:
- Kinetic energy
- Potential energy
Kinetic Energy
▪ Occurs as a result of motion
▪ (e.g., waves in the ocean or heart muscles contracting)
▪ Useful b/c it can perform work by making other objects move
Potential Energy
▪ Stored within an object; depends on location and/or chemical structure
▪ Ex. Chemical potential energy stored in food molecules
▪ Ex. Gravitational potential energy of Earth at high elevations gives the diver potential energy
The First Law of Thermodynamics
a.k.a. “The Law of Energy Conservation”
- Energy cannot be created nor destroyed; it can only be changed from one form to another
- Light energy comes from the sun
- Converted to chemical energy by plants
- Stored in plant cells as carbs
- Pass on to other organisms when they eat the plants
- Converted to other forms of energy (e.g., mechanical)
Converting energy from one form into another depends on
the breaking and
forming of chemical bonds
During a chemical reaction the
amount of __________ ______ that is available changes
potential energy
Ex. Electrons have more potential energy the farther they are from the nucleus
For bonds to break (in
reactants), energy is
absorbed, b/c
energy is required to pull an electron away
When bonds are formed (in
products),
energy is released
Bond Energy
Is a measure of strength/stability of a covalent bond measured in kJ/mol
All chemical reactions require ______ to start, even if it ultimately produces energy
energy
Activation Energy (Ea)
Minimum amount of energy needed to break bonds in reactants to start a chemical rxn
Transition State
Temporary condition in which bonds have reached their breaking point (in reactants)
and new bonds are ready to be formed (in products)
Exothermic Reactions
Net release of E
Endothermic Reactions
Net absorption of E
The Second Law of Thermodynamics
Every time energy is converted to another form, some of the useful energy becomes unusable (usually in the form of thermal E) and increases the
Entropy of the universe
Even cells only convert about __ __ __________ _______ in glucose into a form usable for
metabolism, the rest is lost as thermal E to the env.
40% of potential energy
