Biological Chemistry

Question 1

how do cells vary?

Answer 1

appearance and function

Question 2

how did living cells evolve?

Answer 2

from the same ancestral cell

Question 3

what do genes do?

Answer 3

Provide instructions for the form, function, and behavior of cells and organisms

Question 4

what makes a cell eukaryotic

Answer 4

nucleus with genome, membrane bound compartments, and cytoskeleton

Question 5

how do cells vary enormously in appearance and function?

Answer 5

structure = function, so for their specific function, they have to be a certain shape (ie: a neuron is shaped like a tree with long branches to enable dendrites and axons to work well)

Question 6

how do the domains of life form?

Answer 6

1. prokaryotes - bacteria & archaea
2. eukaryotes - eukaryotic cells

Question 7

how do eukaryotes differ from prokaryotes

Answer 7

1. euk cells are bigger and more complex
2. they have a nucleus and a cytoskeleton
3. they have extensive internal membranes
4. bacterial cells have circular DNA

Question 8

what are archaea?

Answer 8

they are found in extreme conditions, such as the bottom of the ocean floor

Question 9

what is the endosymbiotic theory?

Answer 9

eukaryotic cells evolved by a primordial cell capturing other free-lving cells through phagocytosis

Question 10

what are the five principles for the chemistry of biological systems?

Answer 10

1. carbon
2. water
3. selectively permeble membranes
4. polymerization of small molecules
5. self-assembly

Question 11

what is an element? atom? molecule?

Answer 11

1. it cannot be broken down into other substances by chemical methods
2. smallest unit with the properties of the element
3. atoms held together by chemical bonds

Question 12

why are CHONSP reactive?

Answer 12

1. they have open electron spaces to fill and bonds to make

Question 13

what is a covalent bond?

Answer 13

atoms that share electrons

Question 14

why are covalent bonds not always equal?

Answer 14

due to electrongativity (oxygen is the most electronegative atom)

Question 15

what is a polar covalent bond? nonpolar covalent bond?

Answer 15

1. electrons are not shared equally
2. electrons are equally shared

Question 16

what is an ionic bond?

Answer 16

a bond between two atoms that results in either a gain or loss of electrons and it typically gneerates an ion

Question 17

what are bond characteristics?

Answer 17

bond angle, bond length, bond strength

Question 18

what are noncovalent bonds?

Answer 18

• they do not involve sharing eletrons and are relatively waker, transient (they can come together and apart quickly) and do not require enzymes
• examples include hydrogen bonds, hydrophobic interactions and van der Waals interactions

Question 19

why is water important

Answer 19

1. it is a universal solvent
2. it forms polar, covalent bonds
3. surface tension
4. high boiling point
5. high specific heat
6. high heat of vaporization

Question 20

what is an acid? base?

Answer 20

1. any molecule, ion, or chemical group that donates H+
2. any molecule, ion, or chemical group that combines with H+

Question 21

what is ionic equilibria?

Answer 21

the measurable equilibrium between the weak acid and its conjugate base

Question 22

what is the henderson hasselbach equation?

Answer 22

Question 23

what does a larger Ka value mean?

Answer 23

the more the acid or base will likely be dissociated

pKa = -log(Ka)

Question 24

How do acids and bases exist in conguates?

Answer 24

• HCl can donate a H+, and Cl- can accept that H+, hence Cl- is the conjugate base
• HA (acid/protonated) → H+ + A- (conjugate base, deprotonated, ionized)

Question 25

what is a pKa value?

Answer 25

pKa is the pH at which the dissociation of an ionizable group is in complete equilibrium

Question 26

In a solution that is 1 pH unit higher than the pKa value, a group will be found predominantly in what state?

Answer 26

A- state (91%)

Question 27

In a solution that is 1 pH unit lower than the pKa value, a group will be found predominantly in what state?

Answer 27

HA state (91%)