Chapter 1 - The Chemical Basis of Life

Question 1

biochemistry

Answer 1

a study of the chemical processes and chemical transformations in living organisms

Question 2

what distinguishes life from death?

Answer 2

life - able to maintain a state that is different from the environment
death - in equilibrium with the environment

Question 3

what are the most abundant elements found in biological systems?

Answer 3

carbon, nitrogen, oxygen, hydrogen

Question 4

what are the 4 major types of biomolecules that cells contain?

Answer 4

amino acids, carbohydrates, nucleotides, lipids

Question 5

what are the 3 major kinds of biological polymers?

Answer 5

proteins, Nucleic Acids, polysaccharides

Question 6

major and minor functions of proteins

Answer 6

major functions: carry out metabolic reactions, support cellular structures
minor function: store energy

Question 7

major and minor functions of nucleic acids

Answer 7

major functions: encode information

minor functions: carry out metabolic reactions, support cellular structures

Question 8

major and minor functions of polysaccharides

Answer 8

major functions: store energy, support cellular structures

minor functions: encode information

Question 9

first law of thermodynamics

Answer 9

energy is conserved

Question 10

energy change of a system

Answer 10

heat (q) absorbed by the system from the surroundings - work (w) done by the system on the surroundings

Question 11

change in enthalpy

Answer 11

• the heat content of the system

- change in energy (U) + pressure*change in volume

Question 12

second law of thermodynamics

Answer 12

entropy tends to increase

Question 13

entropy

Answer 13

• a measure of the system’s disorder or randomness

- S=kB*W, where kB is the Boltzmann constant, W is the number of energetically equivalent ways

Question 14

Gibbs free energy

Answer 14

• a measure of the free energy of a system based on enthalpy and entropy
• change in Gibbs free energy (G)= change in enthalpy (H)-temperature*change in entropy (S)
• change in G < 0 is a spontaneous, exergonic reaction
• change in G > 0 is a non-spontaneous, endergonic reaction

Question 15

how do organisms acquire and use energy?

Answer 15

cells couple unfavourable metabolic processes with favourable ones so that the net change in free energy is negative

Question 16

reduction

Answer 16

• gain of electrons
• addition of hydrogen
• removal of oxygen

Question 17

oxidation

Answer 17

• loss of electrons
• removal of hydrogen
• addition of oxygen

Question 18

reduction and deoxidation of carbon compounds

Answer 18

using light energy, reduction of carbon dioxide occurs, creating monosacchardies. this process is unfavourable. then oxidation occurs, converting the monosaccharide back to carbon dioxide. this process released free energy into the surroundings and is favourable

Question 19

amino acids

Answer 19

contain amino group (-NH2) and carboxylic acid group (-COOH). under physiological conditions, they are present as NH3+ and COO-

Question 20

nucleotides

Answer 20

• contains 5-carbon sugar, nitrogen-containing ring, and 1 or more phosphate groups
• nitrogenous ring compounds/bases: adenine (A), cytosine (C), guanine (G), thymine (T), uracil (U)

Question 21

proteins

Answer 21

• polymer of amino acids
• peptide bonds link amino acids residues
• 20 different amino acids
• this biological polymer class is the most structurally variable and therefore the most functionally versatile

Question 22

nucleic acids

Answer 22

• polymer of nucleotides
• phosphodiester bonds
• RNA: A, C, G, U
• DNA: A, C, G, T
• sequence is important rather than structure. it determines genetic information

Question 23

order of oxidation states from least reduced to most reduced

Answer 23

carbon dioxide, acetic acid, carbon monoxide, formic acid, acetone, acetaldehyde, formaldehyde, acetylene, ethanol, ethene, ethane, methane