BIO 231 - CHP 2

basic chemistry, functional groups, polymers/macromolecules

All living things are composed of ____.

matter

___ is defined as any substance that has mass and occupies space

matter

___ = amount of substance

mass

____ = the force that gravity exerts on a substance

weight

All matter is composed of ___

atoms

___ are the smallest portion of a chemical element that retains its chemical properties

atoms

a _____ is any substance that cannot be broken down by normal means

chemical element

T/F: Hydrogen has 1 neutron.

False. It has none

1 dalton =

1 amu = 1 proton = 1 neutron

1 electron = ____ amu

1/1800

___ are charged atoms

ions

____ atoms of the same element that have different atomic mass numbers due to different number of neutrons.

isotopes

how many electrons can each orbital contain that surrounds the nucleus?

2

Electrons possess what type of energy?

potential

T/F: Electrons far from the nucleus have the least amount of energy.

False.

Electrons far from the nucleus have the MOST energy.

An element’s chemical properties depend on

interactions between valence electrons of different atoms

Octet rule: (what three numbers?)

2, 8, 8

T/F: Atoms with full energy levels are less reactive than atoms with unfilled energy levels.

True

96% of all matter is what four elements?

CHON

What bond forms when atoms share 2 or more valence electrons?

covalent bonds

What are three characteristics of covalent bonds?

1. no net charge
2. valence shells of both atoms are filled
3. no free electrons - no lose or gain of electrons

T/F: Covalent bonds have low energy bond strength.

False.

Covalent bonds have HIGH energy bond strength

List the number of covalent bonds in increasing bond strength.

single bond, double bond, triple bond

____ is an atom’s ability to attract electrons towards itself

electronegativity

Differences in _____ dictate how electrons are distributed in covalent bonds.

electronegativity

What type of bond is formed by the attraction of oppositely charged ions?

ionic bonds

What bond forms weak attractive forces between H and other molecules?

hydrogen bond

__% of a cell by weight is water

75-85%

Why is water a polar molecule?

\-has unequal distribution of charge makes it polar

\-water is excellent at forming hydrogen bonds

The ability for hydrogen bonds to attract water molecules to each other is called?

cohesion

The ability for water to be attracted to other substances is called?

adhesion

How many hydrogen bonds can a water molecule form?

4

\*\*but, there is constant transiency(change) in these hydrogen bonds

The combined effect of many hydrogen bonds accounts for water’s high:

\-surface tension

\-specific heat

\-boiling point

\-heat of vaporization

Water is an excellent solvent because of its ____.

polarity

Molecules that readily dissolve in water are called?

hydrophilic molecules

\-includes: polar molecules and ions

What makes a molecule a polar molecule?

molecules that contain a polar covalent bond (unequal sharing of electrons)

List common polar bonds.

C-O

C=O

N-H

O-H

S-H

Water molecules form ____ bonds with polar molecules

hydrogen

Molecules that don’t dissolve in water are called?

hydrophobic molecules

\-includes: nonpolar molecules like hydrocarbons, fats and oils

Hydrophobic interactions are often considered a ____ bond.

noncovalent

Hydrophobic groups are usually held together due to “hydrophobic bonds” but really due to?

repulsion from the water

Water forces hydrophobic groups together in order to

minimize their disruptive effects on the hydrogen-bonded water network

Water is cohesive and adhesive due to?

its polarity

What is the term for: water molecules stick to other water molecules by hydrogen bonding

cohesion

(role in surface tension)

What is the term for: water molecules stick to other polar molecules by hydrogen bonding

adhesion

What are the 6 properties of water?

1. water has high specific heat

\-a large amount of energy is required to change the temp. of water
2. water has high heat of vaporization
3. solid water is less dense than liquid water
4. water is a good solvent
5. water organizes nonpolar molecules
6. water can form ions

\-ex: H2O → OH(-1) + H(+) : hydroxide ion + hydrogen ion

The evaporation of water from a surface causes ___ of that surface.

cooling

T/F: Bodies of water freeze from the down top.

False

Bodies of water freeze from the TOP DOWN

T/F: Water dissolves polar molecules and ions.

True

How does water organize nonpolar molecules?

water causes hydrophobic molecules to aggregate or assume specific shapes

How many identified organic compounds are there?

\~9 million

Why are organic compounds larger and more complex?

Carbon!

\-4 valence e-’s

\-3-D stx.

\-cantenation

What is catenation?

the ability of a chemical element to form a long chain-like structure via a series of covalent bonds

T/F: Organic compounds can be rings or chians.

True

T/F: Organic compounds can be simple hydrocarbons or more complex.

True

What elements do organic compounds contain?

C, H, often O &/or N

What are functional groups?

cluster of atoms replacing 1 or more hydrogens along the carbon skeleton

Are functional groups hydrophilic or hydrophobic?

most are hydrophilic

What are the six functional groups?

amino: NH2 or NH3+

carboxyl: COOH or COO-

carbonyl: COH or CO

hydroxyl: OH

phosphate: PO4-

sulfhydryl: SH

Name the family of molecules for: amino

amines

Name the family of molecules for: carboxyl

carboxylic acids

Name the family of molecules for: carbonyl

aldehydes (if COH is at the end)

ketones (if CO is in the middle)

Name the family of molecules for: sulfhydryl

thiols

What functional group: acts as a base - tends to attract a proton?

amino group

What functional group: acts as an acid - tends to lose a proton in solution?

carboxyl

What functional group: reacts with certain compounds to produce larger molecules?

carbonyl

What functional group: are highly polar, so makes compounds more soluble through hydrogen bonding with water?

hydroxyl

What functional group: may also act as a weak acid and drop a proton (other than carbonyls)

hydroxyl

What functional group: stores large amounts of chemical energy?

phosphate

What functional group: when present in proteins, can form disulfide bonds that contribute to protein structure?

sulfhydryl

What are macromolecules?

large molecules made of smaller molecular subunits (monomers) joined together

Monomers are covalently linked together through?

condensation reactions or dehydration synthesis

\-removes water

Macromolecules can be broken down to monomers by?

hydrolysis reactions

\-adds water

Are hydrolysis or condensation reactions more energetically favorable?

hydrolysis

Name the four macromolecules(polymers).

carbohydrates or polysaccharides

proteins

nucleic acids

lipids

What is the monomer for: carbohydrates or polysaccharides?

simple sugars or monosaccharides

What is the monomer for: proteins?

amino acids

What is the monomer for: nucleic acids?

nucleotides

What is the monomer for: lipids

fatty acids are most common but also glycerol, isoprene units, and other small molecules

What is the covalent linkage for: carbohydrates or polysaccharides?

glycosidic linkage

What is the covalent linkage for: proteins

peptide bonds

What is the covalent linkage for: nucleic acids

phosphodiester bonds

What is the covalent linkage for: lipids

ester linkages are most common

What is the empirical formula for carbohydrates?

(CH2O)n

What are some examples of carbohydrates?

sugars, starch, glucose

All carbohydrates have -OH, except for one with C=O. What do you call those type of sugars?

Aldose (if C=O is on the end) or Ketose (if C=O is in the middle)

How do you number the carbons in carbohydrates?

numbering begins with C at or nearest the carbonyl

T/F: C-H covalent bonds hold much energy.

True

T/F: Carbohydrates are good energy storage molecules.

True

What are the three general characteristics of monosaccharides or simple sugars?

\-(CH2O)n where n=3-6 most typically

\-contains an aldehyde or a ketone

\-presence of two or more -OH groups

What do you call a monosaccharide if it has an aldehyde?

aldose monosaccharide

What do you call a monosaccharide if it has a ketone?

ketose monosaccharide

Glucose is a monomer for what type of polymer/macromolecule?

carbohydrates

Glucose contains how many carbons?

6

What is the empirical formula for glucose?

C6H12O6

Glucose is very important in?

energy storage

T/F: Fructose, glucose, mannose, galactose are all isomers.

True

-they all have the chemical formula: C6H12O6

What are isomers?

molecules that differ only in the spatial arrangement of atoms

What are optical isomers?

isomers that are mirror images of one another

Optical isomers have L and D forms. What does that mean?

L means levo or left orientation

D means dextro or right orientation