Chapter 1

Question 1

What is biochemistry?

Answer 1

The study of life at the molecular level
The application of principles of chemistry to explain biology
The study of the molecular logic of life

Question 2

What do all organisms use in common?

Answer 2

A common repertoire of building blocks to create common nucleic acids, proteins, polysaccharides, and lipids
A common core of essential biomedical processes

Question 3

What are the 6 distinguishing features of living organisms?

Answer 3

1. High degree of chemical complexity and organization
2. Systems for extracting and using energy from environment
3. Defined functions for each the organisms components and interactions
4. Mechanism for sensing and responding to alterations in their surrounding
5. A capacity for self replication and assembly
6. A capacity to change over time by evolution

Question 4

What is he chemical foundation of life?

Answer 4

Carbon oxygen and hydrogen account for 98% of most organisms
Humans big four are hydrogen then oxygen then carbon then nitrogen
Water accounts for much of the oxygen and hydrogen

Question 5

Was is silicon the second best candidate to carbon for the chemical foundation of life?

Answer 5

It can also form four covalent bonds

It is highly abundant in the earths crust

Question 6

Why are humans based in carbon rather than silicon?

Answer 6

Carbon-to-carbon bonds are stronger
More energy is released by combustion of carbon carbon bonds
Combustion products of carbon (CO2) are soluble and remain active in biosphere

Question 7

What determines the structure, function, and properties of a biomolecule?

Answer 7

The collective properties of the functional groups within that biomolecule

Structure dictates function

Question 8

Once we understand the structure function relationship, what can we do?

Answer 8

Can predict function, for diseases can develop molecular treatments

Question 9

What is conformation?

Answer 9

Flexible spatial arrangement of atoms within a molecule

Can be changed without breaking bonds

Question 10

What is configuration?

Answer 10

Fixed spatial arrangement of atoms within a molecule
Cannot he changed without breaking bonds
Ex: double bonds or chiral centres

Question 11

What are geometric isomers?

Answer 11

They have the same chemical formula but differ in the arrangement of groups
“Cis-trans”
Cis: groups on the same side as the double bond
Trans: groups on opposite sides of the double bonds

Question 12

What is a chiral carbon?

How can you find the amount of stereoisomers in a molecule with chiral carbons?

Answer 12

A carbon atoms that has four DIFFERENT chemical groups attached

A molecule with n chiral carbons will have 2^n stereoisomers

Question 13

What are stereoisomers?

What are the sub levels enantiomers and diastereomers?

Answer 13

Stereoisomers- non superimposable molecules that differ in configurations at a chiral centre (hands are stereoisomers of eachother)
Enantiomers- mirror images (rotate a plane of polarized light in opposite directions (hands are enantiomers)
Diastereomers- not mirror images

Question 14

What are the three advantages of polymers for biomolecules?

Answer 14

1. Simplicity of chemistry (one reaction for polymerization, one for degradation)
2. Recycling (they can be digested back into building blocks)
3. Incredible diversity of polymer length and sequence

Question 15

What are the four classes of biomolecules?

Answer 15

Proteins- linear polymers of amino acids
Nucleic acids- linear polymers of nucleotides (genetic information)
Polysaccharides- linear or branched polymers or sugars (cellular recognition roles)
Lipids- fats and aggregates of fats that store energy

Question 16

What three fundamental features do all cells share?

Answer 16

Plasma membrane
Cytoplasm
Nucleic acid

Question 17

What are the two basic classes of living organisms?

Answer 17

Prokaryotes- small single cell rapid growth and division

Eukaryotes- large multicell contains organelles

Question 18

What do humans have more of, Eukaryotes or prokaryotes?

Answer 18

30 trillion eukaryotic cells
But it’s home to 10-100 trillion prokaryotic cells
Prokaryotes are critical for our health (help us digest food, our second brain)

Question 19

What are the two experimental approaches to studying molecules in isolation?

Answer 19

In vitro (in glass) studies behaviour of molecules outside the context of the cell and organism
In Vivi (in the living) studies occur within the context and complexity of the cell or organism

Experiments that succeed in vitro often fail in Vivo

Question 20

What is the first law of thermodynamics?

Answer 20

In any physical or chemical change, the total amount of energy in the universe remains constant, although the form of the energy may change

Cells are highly affective transducers of energy

Question 21

What is the second law of thermodynamics?

Answer 21

The tendency in nature is toward ever greater disorder: the total entropy (disorder) of the universe is continually increasing

Question 22

What is the definition of free energy? (Equation)

Answer 22

G= H - TS
ΔG= ΔH - TΔS

G- Gibbs free energy
H- enthalpy- number and kinds of bonds
T- temperature in kelvins
S- entropy- the degree of randomness

Question 23

How do you know if an equation is endergonic or exergonic?

Answer 23

Endergonic- ΔG>0
Non spontaneous process that needs input of energy

Exergonic - ΔG<0
Spontaneous process releases free energy

Question 24

What does energy coupling do?

Answer 24

Couples energy requiring endergonic reactions to reactions that liberate free energy (exergonic) which causes cells to drive thermodynamically unfavourable reactions

Question 25

What links anabolic and catabolic reactions?

Answer 25

ATP

Question 26

What dictates the sequence of amino acids incorporated into the corresponding protein?

Answer 26

The nucleotide sequence within Genes

The amino acid sequence then in turn dictates the structure of the protein
The structure of the protein then in turn dictates the biological activity of the protein