Exam 1 Lecture Cards

Topics: Water & Life

what substance do all living organisms require the most?

water

what are cells surrounded by?

water

How many percent of a cell is water?

70-95%

How long can a human survive without water?

1 week

How much of earth’s surface is submerged in water?

3/4

What makes earth habitable?

the abundance of water

Life begins in what type of environment?

a watery environment

How many covalent bonds do water molecules contain?

2

What allows water molecules to form hydrogen bonds with one another?

the partial charges

Does water have emergent properties?

yes

what are the four emergent properties of water?

cohesion/adhesion, temperature moderation, density of ice, good solvent

What is cohesion?

the binding together of like molecules, often by hydrogen bonding (a substance being attracted to itself)

does water have a strong or weak cohesion?

a very strong cohesion

what is adhesion?

the attraction between different kinds of molecules

is water adhesive, cohesive, or both?

both

what is transpiration?

the evaporative loss of water from a plant

what is surface tension?

how difficult it is to stretch or break the surface of a liquid

why does water have an unusually high surface tension?

because of hydrogen bonds

which emergent property of water explains surface tension?

cohesion

how does water moderate air temperature?

by absorbing heat from air that is warmer than water, and releasing stored heat to air that is cooler than water

why is water able to absolve or release a large amount of heat but only slightly change its own temperature?

because it has a high specific heat

what is specific heat?

the amount of heat that must be absorbed or lost for 1 g of a substance to change its temperature by 1 degree C

define “heat of vaporization”

the quantity of heat a liquid must absorb for 1 gram of it to be converted from liquid to gas

does water have a high or low heat of vaporization?

high

define “evaporative cooling”

the process in which the surface of an object becomes cooler during evaporation

what is an example of humans doing evaporative cooling?

sweating

why can’t water molecules break their hydrogen bonds when frozen?

because it loses energy and the molecules aren’t moving fast enough

why does ice float?

because the density of frozen water is less than the density of liquid water

what would happen if ice sank?

If ice didn't float it would form at the bottom of a body of cold water rather than the top. The water would continue radiating heat away from its surface and so would get colder and colder until the water and everything in it had frozen solid from the bottom up.

what is a solvent

the dissolving agent

what does it mean to dissolve something

to make or become liquid

what is a solution?

a liquid that is a homogenous mixture of two or more substances

what is a solute?

the substance being dissolved

what is an aqueous solution?

solution where water is the solvent

what is a hydration shell?

a more or less continuous cluster of water molecules surrounding some other substance that the water molecules are attracted to

what happens when water forms a hydration shell around a molecule?

the molecule dissolves

water can dissolve what type of molecules?

polar molecuels

what does hydrophilic mean

having an affinity for water (water loving)

define hydrophobic

having an aversion to water

are molecules with non-polar covalent bonds more likely to be hydrophobic or hydrophilic?

hydrophobic

what is a colloid?

a mixture made up of a liquid and particles that remain suspended rather than dissolved in that liquid

How many bonds can carbon form?

4 bonds

Why is carbon the perfect backbone for biomolecules?

because it can form 4 STRONG covalent bonds

what is the oversimplified definition of organic chemistry?

the studying of carbon-containing molecules usually found in living things

Can organic molecules come from non-living things?

yes, some non-living things contain carbon

do all organic molecules contain carbon?

yes

are all things containing carbon organic?

no, some are inorganic

If carbon is bound to N,O, or H it’s ____ except for CO2

organic

What is vitalism?

the belief that life in living organisms was caused and sustained by a vital force that is distinct form all physical and chemical forces

can organic molecules be synthesized from inorganic molecules?

yes, we discovered this in a lab

How did Wohler create an organic compound from inorganic molecules? did he continue to believe in vitalism after?

he mixed ammonium ions and cyanate ions which made urea (urea is organic); no

How did Kolbe create an organic compound from inorganic molecules? did he continue to believe in vitalism after?

he synthesized acetic acid from inorganic molecules not sourced from living material; no

what is spontaneous generation

the hypothetical process by which living organisms develop from nonliving matter

what was the miller experiment intending to replicate?

the conditions of earth when it was first created to see if we can get some of these orgional organic molecules

how many amino acids were discovered in the Miller Experiment?

over 20, which is more than the amount that naturally occurs in the genetic code

which of the types of models (molecular formula, structural formula, ball and stick model, and space filling model) is the most accurate?

the space filling model (is less used because its kinda hard to see stuff)

where on the skeletal structure would you find the carbons? where are the hydrogens?

the carbons would be at the ends and at every corner; the hydrogens would fill the remaining spots

How many carbons would this molecule have?

6

can double bonds rotate?

no

can single bonds rotate?

yes

what are the different ways hydrocarbons can vary?

length, branching, single or double bonds, rings

what is an isomer?

molecules with the same molecular formula, but different physical structures

what is a structural isomer?

isomer with different arrangement of bonds (note: molecules are 3D so flipping something upside or the other way would not count as an isomer!)

what are cis-trans isomers?

isomers that have different arrangements around the double bond

what type of isomer is this?

cis isomer

what type of isomer is this?

trans isomer

what are enantiomers? Practice identifying them!

mirror images which are not superimposable

what are hydrocarbons?

a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon

carbon skeletons serve as a backbone for _____ to attach and branch off

functional groups

what are functional groups? practice identifying them

small molecules which are directly involved in chemical reactions

which functional groups do we need to know?

-OH (hydroxyl)

>C=O (carbonyl)

-COOH (carboxyl)

-NH2 (amine)

-SH (sulfhydryl)

-OPO3 (phosphate)

-CH3 (methyl)

compounds with hydroxyl groups are called ______

alcohols

what do the names of compounds with hydroxyl groups end with

“ol”

why do hydroxyl groups mix well with water?

because they tend to be polar compounds

what are the two names for compounds with carbon groups?

aldehydes and ketones

where is the carbonyl group for aldehydes?

the end

where is the carbonyl group for ketones?

the middle

what are the names of compounds that have carboxyl groups?

carboxylic acids or organic acids (has both an CO group and OH group)

compounds with amine groups are called ____?

amines

amines act as a _____

base

sulfhydryl functional groups are called?

thiols

sulfhydryl functional groups form _____ in hair proteins

cross links

compounds with phosphate functional groups are called

organic phosphates

what do phosphate functional groups do?

make up the backbone of DNA and stores energy in ATP

what are compounds with methyl functional groups called?

methylated compounds

what do methylated compounds do?

change the expression of genes

what are the four types of macromolecules?

carbohydrates, proteins, lipids, and nucleic acids

which of the four macromolecules is heavily debated to be classified as a macromolecule?

lipids

what do carbohydrates do?

give cells fuel (like sugar) and gives cells simple structures (like cellulose)

what do proteins do?

make up most of the complex structures in cells

are lipids hydrophobic or hydrophillic?

hydrophobic

lipids make up (3 things)

fats, cell membranes (phospholipids), and hormones (steroids)

what are the two types of nucleic acids?

DNA and RNA

what do nucleic acids do?

stores, moves, and processes genetic information

are these monomers or polymers?

monomers

are these monomers or a polymer?

polymer

when monomers or polymers fuse together, it is called a ______

dehydration synthesis

during a dehydration synthesis, is water removed or created?

removed

when monomers or polymers split apart, it is called a _______

hydrolysis reaction

during a hydrolysis reaction, is water removed or added?

added