BICH 410 TAMU Carr Chapter 1 Questions

Which 4 elements occur in virtually all biological molecules?

H, O, C, N

Explain why complementarity would have been necessary for the development of self-replicating molecules

Bc it allowed complementary functional groups to associate and form new, more complex molecules by replicating. Once macromolecules could self-replicate, the ones that were more organized would enrich the environment/survive due to natural selection.

-transcription of DNA into RNA, translation of RNA into protein are examples of complementarity

What are the first 2 laws of thermodynamics

1) energy is conserved; it can neither be conserved nor created but can take on many different forms

2) the entropy of the universe always increases

Explain why changes in both enthalpy and entropy determine the spontaneity of a process

-An increase in entropy and decrease in enthalpy increase the spontaneity of a process

-Reactions with positive entropy change are favorable

-Reactions with positive enthalpy change are favorable

Enthalpy

the total internal energy of a system

negative enthalpy

heat is given off by the system

positive enthalpy

heat must be supplied from the surroundings to the system

entropy

disorder or the degrees of freedom in a system

positive entropy

system is becoming more disordered, more degrees of freedom

negative entropy

fewer degrees of freedom, system is becoming more ordered and surroundings more disordered.

standard state

a temperature of 25C, 1 atm pressure, pH of 7.0

Many biochemical reactions that form biopolymers from monomeric units involve the

release of______.

water

The principle component of a biological membrane is a

phospholipid

The chemical element ________ has a role in both transfer of energy as well as in the

structure of nucleic acids.

phosphorus

List the four building blocks of biological

macromolecules:

lipids, carbohydrates, proteins (amino acids), nucleic acids (nucleotides)

An amphipathic molecule provides the foundation for biological membranes because it

has both ________ and ________ functional groups

hydrophobic, hydrophilic

Genomics is concerned with the entire ________, while ________ is focused on

identifying all of the proteins of a cell.

genome, proteomics

The most abundant molecule in the human body is

H2O

The symbol for free energy under standard biochemical conditions is

DeltaG°'

Living creatures can be described thermodynamically as ______ systems.

open

Draw a carboxyl group in its un-ionized form:

C double-bond O, OH

What does DeltaG tell biochemists about a reaction?

Gibbs free energy, also called the free-energy change, is used to describe the

energetics of a reaction. This symbol is used to determine if particular reactions will be

spontaneous or biologically feasible.

If the First Law of Thermodynamics is true, how can biological processes be carried out?

Although energy cannot be created or destroyed, it can take on different forms, such as heat or chemical energy. Thus, the energy can be stored as chemical bond energy, which can be used to do work.

How can a cell exist if the Second Law of Thermodynamics is true?

Cells are open systems. Entropy in a local area (cell) can be decreased, but only at the

expense of increased entropy in the larger area (outside the cell, or the universe).

deltaH is negative, deltaS is positive

-enthalpically (exothermic) and entropically favored.

-spontaneous (exergonic) at all temps

delta H is negative, deltaS is negative

-enthalpically favored

-entropically opposed.

-spontaneous only at temps. below T=deltaH/deltaS

deltaH is positive, deltaS is positive

-enthalpically opposed (endothermic)

-entropically favored

-spontaneous only at temps above T=deltaH/deltaS

deltaH is positive, deltaS is negative

-enthalpically and entropically opposed.

-nonspontaneous (endergonic) at all temps.

The free energy change for a reaction can be calculated from the ______ and the _______ and ______ of the reactants and products.

temperature, concentrations, stoichiometry

organisms are non-equilibrium, ______ systems that constantly exchange matter and energy with their surroundings

open systems

______ increase the rates of thermodynamically favorable reactions

enzymes

For a biochemical reaction, the biochemical standard state free-energy change, DG°'

, pronounced, "delta G naught

prime," is the value of DG (kJ/mol), when:

1. Temperature: 25 °C (298 K)

2. Pressure: 1 atm

3. Concentrations of each reactant and product: 1 M

4. pH: 7 ßThis is why you don't count [H+]

5. The concentration of water (55.5 M) is constant

So, you don't include [H2O], either.

Ø Prime ( ' ) = constant [H+] and [H2O]