Quiz 1 Chap 2&3 Flashcards
Atoms, Bonds, and Water, and Biological Molecules
1
Q
primordial soup
A
water in oceans many years ago, where life originated
2
Q
matter
A
made up of elements, containing mass
3
Q
elements
A
substance that cannot be broken down to other substances by chemical reactions
4
Q
compounds
A
substance consisting of 2 or more elements in a fixed ratio
- different from the individual elements in its characteristics
5
Q
how many elements are essential to life? which elements are essential to life?
A
25 elements total, although some are trace elements (minute quantities)
- 96% of human body. weight is oxygen, carbon, hydrogen, and nitrogen
- then calcium, phosphorus, potassium, and sulfur
6
Q
atom
A
smallest unit of an element
composed of subatomic particles (protons, neutrons, electrons)
electrons move around nucleus in orbitals
7
Q
what does the chemical behavior of an element depend on?
A
the number of UNPAIRED valence elections in the valence shell
8
Q
molecule
A
atoms that stay close together by chemical bonds (can be 2 of the same atom)
9
Q
intramolecular forces
A
bonds that hold molecules together (ionic bonds, covalent bonds, polar covalent bonds)
10
Q
intermolecular forces
A
bonds that hold different molecules together (hydrogen bonds, Van der Waal bonds)
11
Q
bonding capacity of an element
A
of covalent bonds that each element can form (# of unpaired electrons in the valence shell)
12
Q
ionic bonds
A
- give away or steal an electron
- formed by attraction of two oppositely-charged ions
- strong in dry environment
- weak in aqueous environment (water is polar, it splits apart ions)
- formed by a metal and a non-metal
13
Q
salts
A
compounds formed by ionic bonds, typically crystals containing huge numbers of cations and anions
14
Q
covalent bonds
A
- share valence electrons so that both atoms can fill their valence shells
- can from between atoms of the same or different elements
- very strong bonds
- bonds made and broken from chemical reactions
15
Q
nonpolar covalent bonds
A
no charges on molecule, atoms share electron(s) equally
16
Q
polar covalent bonds
A
partial positive and negative charges on each molecule due to the electron not being shared equally (one atom is more electronegative)
17
Q
hydrogen bonds
A
result of attraction between a partially positive hydrogen (covalently bonded to a more electronegative atom like oxygen) and another electronegative atom
- what causes water to adhere to itself
- hydrogen typically bonded to oxygen or nitrogen in living cells
- weak individually, but many can be strong
18
Q
role of hydrogen bonds in biological systems
A
- bonds between nitrogenous bases in DNA, able to be unzipped
- factor in protein structure
19
Q
why do substances dissolve in water??
A
water is the universal solvent because of its polarity (oxygen has partial negative, hydrogens have partial positive)
- ionic bonds broken as ions are attracted to these partial charges
- large proteins have polar regions on their surfaces which attract water molecules
20
Q
hydration
A
ionic bonds break and ions attach/come close to polar water molecules
21
Q
Van der Waals bond
A
- intermolecular force
- electrons accumulate randomly in nonpolar molecules (temporary and by chance)
- individually weak, powerful if occurring simultaneously
22
Q
which type of bond is strongest?
A
covalent bonds
23
Q
role of weak bonds (ionic, hydrogen)
A
- reinforce shape of large molecules
- help molecules adhere to each other
24
Q
what determines molecular shape?
A
the position of valence orbitals
- orbitals may hybridize in covalent bonds
25
what is the importance of molecular shape?
biological molecules recognize and interact with each other based on shape, so molecules with similar shape can have similar biological effects
- i.e. morphine and endorphins
26
significance of water in organisms
most cells surrounded by water and are made up of 70-95% water
27
what 4 properties of water facilitate life processes
1. cohesive behavior
2. ability to moderate temperature
3. expansion upon freezing
4. versatility as a solvent
28
cohesion
hydrogen bonds hold water molecules together
- causes surface tension
- helps transport of water against gravity in plants
29
adhesion
attraction between water and other substances
| - notably, plant cell walls (again allows for transport up plants)
30
what is the significance of water's high specific heat capacity?
- can absorb/release large amounts of heat without changing its own temperature much, which helps maintain HOMEOSTASIS
* **heat is absorbed when hydrogen bonds break (ice crystals breaking) and released when bonds form
31
why does water expand when it freezes?
hydrogen bonds are more ordered, causing molecules to be farther apart (less dense)
32
at what temp is water the most dense?
4 celsius
33
why is water a versatile solvent?
- polarity (hydrogen bonds) allow for even large molecules (e.g. proteins) to be dissolved if they have ionic/polar regions
34
hydration shell
when each ion in an ionic compound is dissolved in water
35
primary molecules that make up cells
carbon-based (organic) compounds
36
why is carbon so important in organic chemistry?
it's tetravalent (4 unpaired valence electrons)
37
hydrocarbons and example of a hydrocarbon
organic molecules made up of carbon and hydrogen only (e.g. fats)
38
macromolecule and the 4 classes
large organic molecules made up of thousands of covalently connected atoms
- carbohydrates, lipids, proteins, nucleic acids
39
monomer
small organic molecule, "building block" of polymers
40
polymer and 3 types of polymers
long molecule made up of many similar, smaller units (monomers)
- carbohydrates, proteins, nucleic acids
41
isomers
compounds with the same numbers of each atom, but a different configuration
***different structure means different function!!
42
dehydration reaction
2 monomers bond together through the loss of a H2O molecule
43
hydrolysis reaction
polymer disassembled into monomers, reverse of a dehydration reaction (requires water)
44
main functions of carbohydrates
fuel, building material
45
what are monosaccharides and how are they classified?
simple sugars--molecular formulas in multiples of CH2O
- glucose is most common
- classified by location of carbonyl group (C=O) and # of carbons in skeleton
46
aldoses vs ketoses
aldoses have double bonded O on end of carbon chain
| ketoses have double bonded O on a middle carbon
47
examples and roles of storage polysaccharides
starch
- plants: granules in chloroplasts and plastids
- beneficial form of storage compared to lipids because it doesn't go bad
glycogen
- animals: stored in liver and muscle cells of vertebrates
48
examples and roles of structural polysaccharaides
cellulose
- component of tough cell wall in plants, allow them to grow tall
chitin
- found in insect exoskeletons and fungi cell walls
49
difference between cellulose and starch in digestion
***both are glucose polymers with different linkages
- humans can digest alpha linkages of starch, but don't have enzymes to digest beta linkages of cellulose
- cellulose passes through digestive tract as insoluble fiber
- microbes in some herbivores digest cellulose
50
characteristics of lipids and the 3 types
- do not form polymers
- mostly hydrocarbons that form nonpolar covalent bonds --> hydrophobic
- generally lighter than water
- fats, phospholipids, and steroids
51
fats
made up of glycerol (3 carbon alcohol with 3 hydroxyl groups) and fatty acids (carboxyl group attached to long carbon skeleton) attached with ester linkage
52
triglyceride
3 fatty acids joined to a glycerol by an ester linkage
53
where is fat stored in animals, and what is its role?
stored in adipose cells
- energy storage
- cushions organs
- insulates body (warmth)
54
saturated vs unsaturated fatty acids
saturated (most animals)
- max # of hydrogen atoms possible on each carbon
- no double bonds
- solid at room temp (with exceptions)
unsaturated (fish, plants)
- double bonds
- liquid at room temp
55
what is the danger of excess saturated fats?
it can form plaques blocking things like arteries
56
hydrogenation
unsaturated fats turned into saturated fats by adding hydrogen to create trans fats
- hydrogen atoms on opposite sides before/after double bonded carbon
- even more unhealthy than saturated fats
57
phospholipid structure and purpose
2 fatty acids and a phosphate group attached to glycerol
- fatty acids are hydrophobic, phosphate forms a hydrophilic head
- major component of all cell membranes
58
what happens when phospholipids are added to water?
they self-assemble into a bilayer, with hydrophobic heads pointing interior and phosphate group on the outside
(both interior and exterior of cells are aqueous)
59
structure and function of steroids
carbon skeleton consisting of 4 fused rings
- hormones, metabolism, inflammation, immune functions, salt & water balance, development of sexual characteristics
60
danger of steroids
important component of animal cell membranes, but high levels in blood can cause cardiovascular disease
61
protein
one or more polypeptides
62
function and importance of proteins
- more than 50% of dry mass of cells
- structurally diverse (structure determines function)
- structural support, storage, transport, movement, cellular communications, defense against foreign substances
63
enzymes
protein that acts as a catalyst (speeds up chemical reactions)
- perform functions repeatedly
64
polypeptide
polymers built from the same set of 20 amino acids
65
amino acid
organic molecules with a central carbon, a hydrogen, an amino group, a carboxyl group, and a variable group
66
peptide bonds
bonds that link amino acids to form polypeptides
- formed by a dehydration reaction to connect the carboxyl group of one amino acid with the amino group of another
67
primary protein structure
unique sequence of amino acids
68
secondary protein structure
(in most proteins) by inherited genetic info, coils and folds in the chain as a result of hydrogen bonds between animo acids
*alpha helices and beta pleated sheets
69
alpha helices vs beta pleated sheets
alpha helices are coils, beta pleated sheets have folded structure
70
tertiary protein structure
determined by interactions among various side chains (R groups)
- hydrogen bonds, van de waals bonds, ionic bonds, hydrophobic interactions, disulfide bridges (covalent)
71
quaternary protein structure
protein consisting of multiple polypeptide chains (i.e. collagen, hemoglobin)
72
what causes sickle cell anemia?
a single amino acid substitution (passed on genetically) completely changes the shape
73
other factors determining protein structure
alterations in pH, salt concentration, temperature, and environmental factors
74
denaturation
protein unravels, losing its native structure
| - becomes biologically inactive!
75
how do we determine protein structure (historically and now)?
- x-ray crystallography
- nuclear magnetic resonance spectroscopy
- now: bioinformatics (computer programs)
76
what were the two types of bacteria in lab and what were their features?
micrococcus luteus - round, gram positive (violet)
| E. coli - rod shaped, gram negative (pink)
77
If an antibiotic is effective, the bacteria is _______ to the antibiotic.
If an antibiotic is ineffective, the bacteria is _______ to the antibiotic.
susceptible, resistant
78
two types of antibiotics used
- classes
- mode of action
- effective on
penicillin
- B lactam
- inhibits peptidoglycan layer
- effective on gram + (micrococcus luteus)
streptomyosin
- aminoglycocide
- inhibits protein formation on ribosomal level
- effective on gram - (E. coli)
79
what techniques did we use in lab?
zone of inhibition bioassay and a gram stain
80
why were antibiotics effective/not effective on Gram +/- bacteria?
Penicillin targets peptidoglycan layer, so it's only effective on the gram + cells with a thick peptidoglycan layer.
Streptomyosin targets ribosomal functions but is large in size, so it's only effective on gram - cells with thinner peptidoglycan layers that it can pass through.
