Lecture 1

Question 1

The cell as a living system, obeys the same laws of chemistry and physics that influence nonliving systems and reactions. Give examples of the type of principles.

Answer 1

-chemical bonding

• thermodynamics
• ph

Question 2

What limits the size of the cell?

Answer 2

Rate of diffusion

Question 3

Evolutionarily diverse organisms have similar characteristics how?

Answer 3

• biological macromolecules, DNA, proteins

- use the same metabolite-same metabolic pathways

Question 4

What are the three domains of life? what are the differences between the two?

Answer 4

Bacteria, Archea, Eukarya-Prokaryotic cells: lack a nucleus. It consists of bacteria and archaea (lack peptidoglycan).
-eukaryotic cells contain a membrane bound nucleus.

Question 5

What is the key characteristics of Archea?

Answer 5

microbes are prokaryotic

-lack peptidoglycan

Question 6

What are the four kingdoms of Eukarya?

Answer 6

protists,fungi, plantae, animalia

Question 7

What is the characteristic of kingdom protista?

Answer 7

-single cellular with a few multicellular

Question 8

What are the characteristics of kingdom fungi?

Answer 8

• cell wall contains chitin
• heterotrophic by absorption
• nonmotile
• Haplontic life cycle: adult (n), zygote is diploid (2n)
• energy storage is glycogen

Question 9

Kingdom plantae

Answer 9

• cell wall containing cellulose
• autotrophic
• nonmotile
• life cycle: alternation of generations
• energy storage: starch

Question 10

Kingdom Animalia

Answer 10

• cell lacking cell wall
• nutrition: heterotrophic
• motile
• life cycle: diploid adults 2n that produce haploid gametes (n).
• energy storage:glycogen

Question 11

Energy required to raise the temperature of 1 gram of water 1 degree celcius

Answer 11

Specific Heat

Question 12

What type of energy are covalent bonds? What about the energy?

Answer 12

The interaction is sharing a pair of electrons. The energy is 355kj/mol

Question 13

What about Hydrogen bonds? Where are they found

Answer 13

chemical bonds of hydrogen bonds that occur between 2 other electronegative atoms.

4-20 kj/mol

• complementary DNA
• alpha and beta sheets of protein

Question 14

What about ionic (electrostatic) interaction?

Answer 14

Attraction of opposite charges.
~ 5.8 kj/mol
at active sites of enzymes

Question 15

Vanderwaals

Answer 15

Interaction: electron clouds. Weak forces due to transient electrostatic interactions
2-4 kj/mol
found on substrate specificity

Question 16

Hydrophobic interactions

Answer 16

Interaction of nonpolar substances. very weak.

Question 17

What about covalent bonding?

Answer 17

chemical bond formed between two atoms due to the sharing of pair of electrons. overlapping electron shells.-strong interaction: don’t break spontaneously under physiological conditions

Question 18

Hydrogen bond

Answer 18

-hydrogen atom is shared between 2 other electronegative atoms.-In DNA H holds bonds together complemetary strands.in proteins, h bonds stabilize alpha helixes and beta sheets.

Question 19

Know the electronegativity trend.

Answer 19

j

Question 20

Ionic Bond

Answer 20

chemical bond that occurs between two opposite charges (either full + or - or partial charges)-important interactions at active sites of enzymes

Question 21

Van der Waals interaction

Answer 21

Weak forces between neutral atoms due to transient electrostatic interactions.-substrate specificity may come from large numbers of van der Waals bonds resulting from matching surfaces.

Question 22

Hydrophobic Interaction

Answer 22

-nonpolar molecules-water forms cage.-interaction is more energetically favorable-an active cleft may be strongly nonpolar-an active site cleft may be strongly nonpolar, therefore attract nonpolar substrates. Use low free energy, enthalpy but gain in entropy

Question 23

What is the most important compound? and what are its characteristics?

Answer 23

water:-high specific heat-high heat enthalpy of vaporization-universal solvent-high surface tension-density of solid water is less than water-water ionizes

Question 24

Specific Heat

Answer 24

-the measure of the amount of heat required to raise 1g of 1 celcius of water.

Question 25

What is surface tension?

Answer 25

The measure of how difficult it is to break the surface of the liquid
Ex: insects walking on water

Question 26

Why is water so important for life?

Answer 26

1. )water is a liquid at physiological temperatures
2. )water has an unusually high boiling point for its mw
3. ) water is a good thermal regulator. Large amount of heat is required to change its temperature.
4. ) water provides very effective heat dissipation (involves phase change)

Question 27

Why does water have such unusual properties?

Answer 27

• shape of molecule

- hydrogen bond (requires energy to break)

Question 28

Know the 4 formulas of pH and OH

Answer 28

1 x 10-14 = [H+][OH]
14 = pH + pOH
pOH = -log [OH-]
pH = -log [H+]

Question 29

What is the first law of thermodynamics?

Answer 29

The total energy of a system and surrounding is constant; energy can’t be created or destroyed.

Question 30

What is the second law of thermodynamics?

Answer 30

The total energy of the system plus the surrounding always increases.

Question 31

Heat (enthalpy) of Vaporization

Answer 31

amount of heat required to convert liquid into gas