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Flashcards in ch 1 Deck (37):
1

Cells, the basic structural units of living organisms are:

highly organized and constant source of energy is required to maintain their ordered state

2

what types of molecules are used by all organisms

carbohydrates, proteins, lipids and nucleic acids

3

what elements are the most abundant and essential for all organisms

C, N, O, P, S, H

4

what elements are less abundant and essential for all organisms

Na, Mg, K, Ca, Cl

5

what elements abundant at trace levels are essential for all organisms?

Mn, Fe, Co, Cu, Zn

6

what elements abundant at trace levels are essential for some organisms?

V, Cr, Mo, B, Al, Ga, Sn, Si, As, Se, I

7

what is the geometry of a water molecule? what is the covalent bond angle?

tetrahedra, 104.5

8

how do dipoles of water and ammonia differ from that of CO2

water and ammonia have a perament dipole, while CO2 does not

9

how many hydrogen bonds can water form?

4

10

compared to in ice, how much less (percent) of hydrogen bonds does liquid water have?

25% of hydrogen bonds in ice are broken in liquid

11

what are the 4 types of noncovalent interactions? What is another name for these reactions?

reversible molecular interactions:

electrostatic
hydrogen bonding
van der waals bonds
hydrophobic interactions

12

what is the rnage of electrostatic bond energy?
hydrogen bond?
van der waals bonds?

40-200 kJ/mol
2-20 kJ/mol
.4-4 kJ/mol

13

which is the hydrogen bond donor and which is the hydrogen bond acceptor?
which one has the partial negative charge?

hydrogen donor: atom to which H is more tightly associated
hydrogen acceptor: atom to which H is less tightly associated with.
acceptor has partial negative charge

14

how many nanometers is an angstrom?

.1 nm = 1 angstrom

15

when are van der waals bonds most important?

when numerous atoms in one molecule come close to atoms inanother molecule

16

the distribution of electric charge around an atomc hanges with time. Therefore:

charge distribution is asymmetric, which encourages similar asymmetry around the neigboring atoms leading to attraction

17

what is attration of van der waals bonds dependent on?

distance dependent. strongly reuplsive at short internuclear distances, and very weak at long internuclear distances. attraction is maximal when 2 atoms are separated by their van der waals radii

18

what is the van der waals contact distance?

it is the distance between centers: 2.4-4.0 angstroms

19

what is the van der waals contact radius?

distance between outside of molecule and center: 1.2-2.0 angstoms

20

what are hydrophobic interactions?

interactions between nonpolar molecules due to the tendency of water to bond strongly to itself

21

acids are proton ______
bases are proton ______

donor, acceptor

22

what is Kw = ?

keq of [H2O] = [H+][OH-] = 1.0 x 10 ^ -14

23

equation for pH?

-log[H+]

24

what is the henderson hasselbach equation?

pH= pKa + log ([A-]/[HA])

25

what does pKa measure?

pH at which an acid is half dissociated

26

what is the pH of blood? an how is it regulated?

7.4, CO2 carbonic acid - bicarbonate buffer system

27

what else contibutes to intracellular buffering?

proteins (hemoglobin) and phosphate

28

what is the bicarbonate buffer system equlibrium reaction?

HCO3 H2CO3 (aq) CO2 (g)

29

which bases are purines, how many rings do they have?

A, G: have 2 ring structure

30

which bases are pyrimidines, how many rings do they have?

U, T, C: 1 ring structure

31

how does ribose differ from deoxyribose

deoxyribose lacks 2' hydroxyl

32

who one nobel prize for double helix structure of DNA?

watson and crick 1962

33

what did erwin chargaff discover?

compositionally, A = T and G = C in all domains of life

34

what form of DNA is most common in vivo?

B form

35

what for of RNA is most common in vivo?

A state

36

what is unique about RNA? and why is it unique?

the 2' hydroxyl allows it to form a multitude of un ique folds and tertiary interactions, form different base pairs, and form base triples and base quartets

37

who won the nobel prize for discovering that rnas can be catalytic?

Tom Cech (group I interon) and Sid Altman ( Rnase P)