Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Chemistry Of Biological Interactions: > Biomolecular Reactions: > Flashcards

Biomolecular Reactions: Flashcards

1
Q

What is an endothermic reaction?

A

A reaction in which the products have a greater chemical potential energy than the reactants

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

What is required to start an endothermic reaction?

A

The input of energy in the form of heat

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

What is an exothermic reaction?

A

A reaction where the reactants have a chemical potential energy than the products

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

What is required to start an exothermic reaction?

A

Energy must be given out in the form of heat

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

What is the equation for Gibbs energy ? State what each symbol means:

A

G = H-TS

  • H is enthalpy
  • T is temperature
  • S is entropy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the change in Gibbs energy equal to?

A

The enthalpy change of the system minus the product of the temperature and the change in the entropy of the system
△G = △H - T△S

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a catalyst?

A

A substance that increases the reaction rate without being consumed

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do catalysts work?

A
  • Catalysts provide an alternative reaction pathway with a lower activation energy
  • Provides an alternative reaction mechanism in which the transition state is more stabilised
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a nucleophile?

A

An electron-pair donor that participates in bond formation by donation of an electron pair to an electron acceptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is an electron acceptor?

A

An electrophile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is an electrophile?

A

An electron-pair acceptor that participates in bond formation by accepting an electron pair from an electron donor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is an electron donor?

A

A nucleophile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is a system?

A

The system is simply the set of biochemical reactions and interactions we are interested in studying within a particular boundary

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are examples of a system?

A

The reactants and products in a reaction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are surroundings?

A

Everything else that is outside the system of interest that is in contact with the boundary of the system (usually the rest of the universe).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is a boundary?

A

Where the system and surroundings meet

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the three main ways a system and its surroundings are described?

A
  • Open
  • Closed
  • Isolated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe the energy transfer in an open system and its surroundings:

A

Energy and mass is transferred both ways between a system and it’s surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe transfer between a closed system and it’s surroundings:

A

A transfer of energy (only) between the system and the surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Describe the energy transfer between an isolated system and it’s surroundings:

A

There is no transfer of energy or mass between the system and surroundings

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

What effect does the boundary between the system and it’s surroundings have?

A

The boundary plays no part (does not affect or is affected by) interactions between, or behaviours of, the system and the surroundings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the law of conservation of energy?

A

Energy can neither be created nor destroyed but changed from one form to another

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the law of conservation of energy the basis of?

A

The First Law of Thermodynamics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What does it mean that energy can only be transferred from one form to another, and not created or destroyed?

A
  • The total energy of an isolated system doesn’t change

- The total energy of a system and its surroundings does not change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Describe energy transfer when an object is dropped from a height:
Stored (potential) energy in the form of gravitational potential energy is transformed into kinetic energy
26
Why is energy transformed from potential energy to kinetic energy when an object is dropped?
The gravitational potential energy does work, upon release, to give the object kinetic energy as it falls
27
What are the two types of stored (potential) energy?
- Gravitational potential energy | - Chemical energy
28
What is chemical (potential) energy?
A type of potential energy related to chemical bonds
29
What is thermodynamic temperature?
An absolute measure of the average total internal energy of an object or objects (mainly the kinetic energy and other other contributing factors)
30
What is the normal measure of temperature?
A direct comparison of how cold/hot something is relative to another
31
What is thermodynamic temperature defined by?
The third law of thermodynamics
32
What in the third law of thermodynamics defines the thermodynamic temperature?
The theoretically lowest temperature is 0 K which is equivalent to -273.15 °C
33
What is thermodynamic temperature measured in?
Kelvin (K)
34
What is thermodynamic temperature proportional to?
The average of all energies in all the ways in which it is possible for an object to move
35
what is the name given to the average of all the energies in all the ways in which it is possible for an object to move?
Degrees of Freedom
36
Explain why a helium atom only has 3 degrees of freedom:
It can move in the up and down plane, left and right plane and the front and back plane
37
How many degrees of freedom does a two atom molecule (like nitrogen) have?
Five degrees of freedom
38
Why do two-atom molecules have five degrees of freedom?
They can move: - Front and back - Left and right - Up and down - Rotate - Vibrate
39
What effect does the size of a molecule have on the degrees of freedom?
The more components (increasing the complexity of the molecule), the greater the number of possible motions (degrees of freedom).
40
What happens when two objects with different temperatures come into contact?
They will eventually reach the same temperature
41
Why do two touching objects eventually end up having the same temperature?
Heat is transferred from one object to other in order to reach this thermal equilibrium
42
What is enthalpy? Define both terms:
- The internal energy of a system plus the amount of pressure and volume - The total amount of energy (the sum of the heat/kinetic and chemical potential energy) that a chemical system possesses
43
What is the enthalpy change in a system equal to?
The heat brought in or released to the system at constant pressure
44
What can kinetic energy be in the form of?
- Moving electrons within an atom - The vibrations of atoms connected by chemical bonds - The rotation and translation of molecules made up of these atoms
45
What can chemical potential energy be in the form of?
- Covalent or ionic bonds between atoms/ions | - Intermolecular forces between molecules
46
What is the symbol for enthalpy?
H
47
How do we work out the enthalpy change of a reaction?
- Add up the bond energies for all the bonds in the reactants and products - Take away the total bond energy of the products from the bond energy total of the reactants
48
What is bond energy?
The average amount of energy required (when substance is a gas and under standard conditions) to break 1 mol of all bonds of the same type within the same chemical species
49
What makes bonds between atoms differ in bond energies?
- Types of atoms involved - Types of bonds that exist - The surrounding atoms/ the molecule the bond is in
50
What is the average bond energy of a C-H single bond?
412 kJ mol^-1
51
Why are bond energies important?
- Tells us how much energy is required to break a particular bond - Tells us how much energy will be released when a particular bond is made
52
What can you work out from the total bond energies of the reactants and products?
Whether the reaction will take in or release energy when it occurs
53
What is the symbol for enthalpy change?
△H
54
What is the equation for calculating the enthalpy change for a chemical reaction?
△H = H (products) - H (reactants)
55
What does the symbol △H° mean?
The change in enthalpy under standard state conditions
56
What is the standard temperature?
298.15 K
57
What is the standard pressure?
- 1 atmosphere (atm) | - 101.325 kPa (SI units)
58
What does △H > 0 show?
That a reaction is endothermic
59
Why do endothermic reactions have a positive value for the change in enthalpy?
- Endothermic reactions require energy input in the form of heat. - The products have a greater chemical potential energy than the reactants as more energy was taken in for bond breaking in reactants than released for bond making in products
60
What does △H < 0 show?
An exothermic reaction
61
Why do exothermic reactions have a negative value for enthalpy change?
- The reactants have a greater chemical potential energy than the products - This is as more energy is given out during bond making in the products than bond breaking in the reactants
62
What is more stable, reactants or products, in an exothermic reaction? Why?
The products are more stable as their total bond enthalpy is greater
63
What law supports that how or how fast a reaction happens doesn't influence the overall change in enthalpy for the reaction?
Hess's law
63
What law supports that how or how fast a reaction happens doesn't influence the overall change in enthalpy for the reaction?
Hess's law
64
What is Hess's law?
The total enthalpy change that occurs for a given reaction is independent of the reaction pathway
65
What diagram is used to show the enthalpy change between reactants and products of exothermic and endothermic reactions?
Reaction profiles
66
What does energy spontaneously do?
Disperse from being localised to becoming spread out if not hindered from doing so
67
What is entropy?
The thermodynamic measure of the randomness of a system
68
What is entropy described as? Why?
The thermal energy not able to do work since energy becomes more evenly distributed as the system becomes more dispersed
69
When is entropy important in biomolecular reactions

Chemistry Of Biological Interactions: (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions