Biochemistry

Question 1

Biochemistry

Answer 1

Branch of science that studies chemical processes, substances (and the atoms/molecules that comprise them) in living things.
Chemistry of living organisms and the MOLECULAR BASIS for the CHANGES occurring in living CELLS.
Life Science + Chemical Science
- proteins, nucleic acids, lipids, vitamins, and hormones

Question 2

Metabolism

Answer 2

The sum total of all the reactions that occur throughout the body in each cell.
The cell’s TOTAL CHEMICAL ACTIVITY.

Question 3

Metabolic Pathway

Answer 3

Complex sequence (series) of controlled biochemical reactions
EX: cellular respiration, protein synthesis, transport, cell division, excretion

Question 4

Most abundant chemicals in the human body

Answer 4

Oxygen - 65%
Carbon - 18.5%
Hydrogen - 9.5%
Nitrogen - 3.2%
Calcium - 1.5% (neuron signals, muscle contractions)
Phosphorus - 1%
Potassium - 0.4%
Sulfur - 0.3%

Question 5

Elements of Life

Answer 5

CHNOPS - 98% of life
Carbon - backbone
Hydrogen - water, acid-base reactions
Nitrogen - DNA, amine groups
Oxygen - water, breathing
Phosphorus - DNA, ATP, (de)phosphorylation
Sulfur - amino acids

Question 6

Why are they called “carbon-based” life forms?

Answer 6

Carbon backbone

Question 7

The Atom

Answer 7

Smallest part of an element
Composed of subatomic particles: protons, neutrons and electrons

Question 8

Ion

Answer 8

Charged atom
Cation - positive (loss of e-)
Anion - negative (gain of e-)

Question 9

Isotopes

Answer 9

Atoms of the same element with the same number of protons, but a different number of neutrons
~400 stable isotopes

Question 10

Isotopes of Hydrogen

Answer 10

1/1 - Protium
2/1 - Deuterium
3/1 - Tritium

Question 11

Radioisotopes

Answer 11

Unstable, radioactive isotopes that decay to release radiation

Question 12

Applications of Radioisotopes

Answer 12

Carbon dating with C-14

Question 13

Radioactive Tagging (Tracer/Label)

Answer 13

A chemical compound in which one or more atoms have been replace by a radionuclide, so by its radioactive decay, it can be used to explore the mechanism of chemical reactions by tracing its path from reactants to products

Question 14

Valence electrons

Answer 14

Electrons in the outer most shell

Question 15

Chemical Bonds

Answer 15

Attractive forces that hold atoms/ions together in a compound

Question 16

Electronegativity

Answer 16

The measure of an atoms ability to attract electrons.
Determines the type of bond atoms form

Question 17

Ionic Bonds

Answer 17

Bonds formed between cations and anions, involving electrostatic attraction between them

Question 18

Covalent Bonds

Answer 18

Bonds between non-metal atoms, where electrons are shared
Polar - unequal sharing (0.4<EN diff<1.7)
Nonpolar - equal sharing (EN<0.4)

Question 19

Intermolecular bonds

Answer 19

van de waals/London
dipole-dipole
hydrogen bond
DETERMINE PHYSICAL PROPERTIES

Question 20

Applications of Water

Answer 20

• primary inorganic molecule of life (90% of a cell)
• carrier for dissolved molecules in/out of cell
• raw material essential for cell reactions (added to make/break bonds)
• lubricant between organs, tissues, and individual cells

Question 21

Unique Properties of Water

Answer 21

1. Remains a liquid over wide temp range
2. Changes temp gradually when heated/cooled
3. Only pure substance that expands when becomes solid (H-bonding)
4. Dissolves most substances involved in living processes - Universal Solvent

Question 22

Polarity of Water

Answer 22

Permanent dipole
O - negative
H - positive

Question 23

Hydrogen Bonding

Answer 23

Hydrogen atom with Nitrogen, Oxigen, or Fluorine

Question 24

Hydrophobic

Answer 24

Molecules that do not interact well with water
- nonpolar (can’t h-bond)
- insoluble in water
EX: fats (lipids), hydrocarbons

Question 25

Hydrophilic

Answer 25

Molecules that interact with water
- polar (h-bond)
- soluble in water
EX: alcohols, salts, acids, bases

Question 26

Amphiphilic (Amphipathic)

Answer 26

Compunds that contain two distinct covalently bonded components with DIFFERENT AFFINITY for the solvent in the same molecule
- one has high affinity for polar solvents
- other for nonpolar solvents
Have both polar (hydrophilic) and nonpolar (hydrophobic) parts