Chapter 8 Flashcards
1
Q
Catabolism
A
- releasing energy by breaking down complex molecules into simpler ones
- energy is stored or released as heat; needed for anabolic processes
2
Q
Anabolism
A
- consuming energy to build complex molecules from simpler ones
3
Q
Bioenergetics
A
- the study of how organisms manage their energy resources
4
Q
Cellular metabolism
A
- the processes of sustaining a cell
- each step is catalyzed by a SPECIFIC ENZYME, ends with a product
- two types: anabolism and catabolism
- almost all metabolic reactions take place non-spontaneously (why they need enzymes)
5
Q
What type of molecule is an enzyme?
What dictates the structure of this type of molecule?
A
- catalytic protein
- sequence of amino acids in polypeptide chain, during primary structure ; including active site shape
6
Q
Energy
A
- the capacity to change
- exists in various forms, some can perform work
- 2 types: Kinetic Energy and Potential Energy
- can be converted from one form to another (i.e. cellular respiration)
7
Q
Kinetic energy
A
- associated with motion
- includes thermal energy (heat) which involves random movement of molecules
8
Q
Potential energy
A
- energy in matter because of its location/structure (height usually)
- includes chemical energy as energy available to be released during reactions
- cells convert chemical energy for heat
9
Q
Thermodynamics (and its 3 laws)
A
- the study of energy transformations
1) the energy of the universe is constant (principle of conservation of energy) - it can be transformed or transferred but not created or destroyed
2) unusable energy, usually lost in heat, is a product of energy transformations or transfers - every transformation/transfer increases universal entropy
3) irrelevant ig
10
Q
Entropy (S)
A
- entropy = disorder
- may decrease in an organism, but universe’s total entropy increases
- decreased entropy makes an organism “lower” and unstable (more reactive)
11
Q
Closed system
A
- a system that is isolated from its surroundings
- self sufficient
- like an aquarium (even if its not technically fully self sufficient)
- reactions eventually reach equilibrium and do no work (death…?) ; not in equilibrium = constant flow of materials (good! alive!)
12
Q
Open system
A
- a system open to its surroundings
- energy and matter can be transferred between system and surroundings
- example: organisms
13
Q
Spontaneous
A
- a reaction that occurs without energy
- happens quickly or slowly
- increases the entropy (disorder)
- have a negative delta G
- harnessed to perform work only when it is moving toward equilibrium
14
Q
Nonspontaneous
A
- a reactions that must have an energy input
- increases enthalpy (order)
- positive delta G
15
Q
Cells make ordered structures from —- ——- materials. Organisms replace ordered forms of —— and —— with less ——- forms.
A
1) less ordered
2) matter, energy, ordered
16
Q
Enthalpy (H)
A
- order
- sum of the system’s internal energy and the product of its pressure and volume
- decreased enthalpy makes an organism “higher” more stable (which means less reactive)
17
Q
(Gibbs) Free energy
A
- energy that can do work when temperature and pressure are uniform (like in a cell)
- how energy changes are studied to see if a reaction is spontaneous or not
- relates to change in enthalpy (aka total change in energy, delta H) and change in entropy
- ∆G = ∆H - T∆S
- measure of a system’s instability
18
Q
Stability and instability
A
1) equilibrium is a state of MAXIMUM stability, less reactive
2) the tendency to change to a more stable state, more reactive
19
Q
Exergonic
A
- exothermic
- releases energy, so reactants have more energy than products
- net release of free energy
- is spontaneous
- delta G is negative (i.e.: -7.3 kcal/mol)
20
Q
Endergonic
A
- endothermic
- intakes free energy from surroundings, so reactants have less energy than products
- nonspontaneous
- delta G is positive (i.e.: 3.4 kcal/mol)
- after atp drives an endergonic reaction, adp is left
