Chapter 8 Flashcards

You may prefer our related Brainscape-certified 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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Anabolism

A
  • consuming energy to build complex molecules from simpler ones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Bioenergetics

A
  • the study of how organisms manage their energy resources
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Kinetic energy

A
  • associated with motion
  • includes thermal energy (heat) which involves random movement of molecules
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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!)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Open system

A
  • a system open to its surroundings
  • energy and matter can be transferred between system and surroundings
  • example: organisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Nonspontaneous

A
  • a reactions that must have an energy input
  • increases enthalpy (order)
  • positive delta G
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
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
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

3 kinds of cellular work

A
  • mechanical, transport, and chemical
  • powered by hydrolysis of atp (breaking apart phosphate group)
22
Q

ATP

A
  • adenosine triphosphate
  • powers work by using exergonic processes to drive endergonic ones ; overall EXERGONIC (delta G = negative)
  • the cell’s energy shuttle
  • provides energy for cellular functions
  • nucleic acid
  • renewable resource ; regenerated by addition of a phosphate group to ADP
23
Q

One example of how atp uses an exergonic process to drive an endergonic one

A
  • bonds between ATP tail phosphate groups can be broken by hydrolysis which RELEASES ENERGY
  • energy comes from chemical change to a state of lower free energy, not the phosphate group
24
Q

Phosphorylation

A
  • transferring a phosphate group to some other molecule, such as a reactant
  • how atp drives endergonic reactions
  • if phosphorylating adp, the energy comes from catabolic reactions
25
Q

Enzymes

A
  • speeds up metabolic reactions by lowering energy barriers
  • can be denatured and permanently unusable because of temperature, pH, inhibitors, specific chemicals, etc.
  • example of enzyme-catalyzed reaction: hydrolysis of sucrose by sucrase enzyme
  • do not affect the change in free-energy
  • reusable
  • each enzyme has an optimal pH and temperature it can function at
26
Q

Activation energy

A
  • initial energy needed to start a chemical reaction
  • the energy used bond breaking and bond forming (every chemical reaction)
  • often supplied as heat from surroundings
  • enzymes catalyze by lowering this activation energy barrier
27
Q

Substrates

A
  • reactant that an enzyme acts on
  • when it binds to an enzyme on its active site, its an enzyme-substrate complete
  • usually only 1 or 2 substrates can fit into their enzyme’s active site
  • converted into products in enzyme
28
Q

induced fit of the substrate

A
  • enhances chemical groups’ ability to catalyze the reaction by putting them in certain positions
29
Q

Cofactors

A
  • nonprotein enzyme helpers
  • examples: ions - Ca+2, Mg+2, etc.
  • coenzymes are organic cofactors (i.e. vitamins)
  • can determine how quickly reactions proceed from their reactant to their product
30
Q

Inhibitors

A
  • two types: competitive and noncompetitive
  • competitive: binds to the active site of an enzyme thus competes with substrate for it
  • noncompetitive: binds to another part of an enzyme which makes it change shape which decreases the active site’s efficiency
31
Q

Why is enzyme regulation important?

A
  • chemical chaos would result if metabolic pathways are not tightly regulated
  • although enzymes can help make materials, making TOO much can hurt the cell just as much as having too little
  • reduces material waste
32
Q

Enzyme regulation

A
  • the cell switches on or off the genes that encode the synthesis of specific enzymes to regulate them
33
Q

Allosteric regulation

A
  • cases where an enzyme’s function at one site is affected by a regulatory molecule binding at another site (of the same enzyme, again just at different places or sites)
  • may either inhibit or stimulate an enzyme’s activity
  • essential for enzymatic regulating
  • allosterically regulated enzymes are made from polypeptide subunits
34
Q

Allosteric regulation

A
  • cases where an enzyme’s function at one site is affected by a regulatory molecule binding at another site (of the same enzyme, again just at different places or sites)
  • may either inhibit or stimulate an enzyme’s activity
  • essential for enzymatic regulating
  • allosterically regulated enzymes are made from polypeptide subunits
35
Q

Active and inactive enzyme forms

A
  • all enzymes have a form of both
  • being binded to an activator stabilizes the active form (functioning)
  • being binded to an inhibitor stabilizes the inactive form (not functioning)
36
Q

Feedback inhibition

A
  • where the end product of a metabolic pathway shuts down the pathway
  • prevents a cell from wasting chemical resources by synthesizing more product than is needed
  • the product realizes enough of itself is made and then acts as the inhibitor to cut off production
37
Q

Structures and enzymes

A
  • some enzymes are structural components of membranes
  • some enzymes reside in specific organelles
  • example: enzymes for cellular respiration being located in mitochondria
38
Q

Chemical potential energy

A
  • energy that can be absorbed or released due to a change of the particle number in a chemical reaction or phase transition
  • stored in the chemical bonds of a substance (ATP!!!)
39
Q

Catalyst

A
  • a substance that increases the rate of a chemical reaction without undergoing any permanent chemical change itself
  • enzyme
40
Q

Why do highly ordered living organisms do violate the second law of thermodynamics?

A
  • because the earth is an open system, not a closed system
41
Q

Why cant most cells harness heat to perform work?

A

Because the temperature is usually consistent throughout the cell

42
Q

Some bacteria are metabolically active in hot springs because?

A

They have high optimal temperatures

43
Q

Which statements is a logical consequence of the 2nd Law of Thermodynamics?

A

Every chemical reaction must increase the total entropy of the universe

44
Q

true or false: hydrolysis decreases the entropy of a system

A

FALSE
dehydration reactions do

45
Q

true or false: rna nucleotides are the most similar to atp structure

A

true

46
Q

Increasing the substrate concentration in an enzymatic reaction could overcome what?

A

competitive inhibition

47
Q

How does zinc affect enzymes

A

it is a cofactor necessary for enzyme function

48
Q

structure of atp

A

a ribose sugar, the nitrogenous base adenine, and a chain of three phosphate groups.

49
Q

When a cell uses an energy releasing process to drive an energy consuming process, this is known as?

A

energy coupling

50
Q

allosteric regulation

A

a molecule that impedes enzymatic action by binding to the enzyme outside of the active site casing a conformational shape change that renders the active site less effective.

51
Q

If an enzyme is added to a solution where its substrate and product are in equilibrium, what will occur?

A

nothing, the reaction will stay the same