BIO 107 - EXAM #1 - CSUN
mass number =
(# of protons) + (# of neutrons)
What do carbohydrates do?
-Store chemical energy -Contribute building blocks -form fibrous structural material -indicate identity
ionic bonds have three key features:
-exert an attractive force -force extends in all directions -vary in strength
the formula for pH is:
-log10[H+]
The pH scale ranges from:
1 to 14
a pH change of 1.0 is a ______ change in [H+]
10x
5' ATTGCA 3' pair strand =
5' TGCAAT 3'
the pH of pure water is:
7 or neutral
Acidic solutions have a pH:
<7
Basic solutions have a pH:
>7
Hydrocarbons
Are molecules consisting of only carbons and hydrogen
Atoms of reactive elements tend to combine into molecules by forming:
Chemical bonds
The five most important chemical interactions in biological molecules are:
Covalent bonds, Ionic bonds, Hydrogen bonds, Hydrophobic interactions, and Van Der Walls Forces
animals store sugars as:
Glycogen
Water dissociates into positively charged:
Hydrogen ions (H+ or protons) and negative Hydroxide Ions (OH-)
The most common functional groups on biological molecules are:
Hydroxyl, Carbonyl, Carboxyl, Amino, Phosphate, and Sulfhydryl
Each atom consists of an atomic __________ surrounded by negatively-charged electrons
Nucleus
Protons are:
Positively charged particles located in the nucleus
Functional groups are:
Small, polar, reactive groups of atoms that give larger molecules specific chemical properties
DNA
Stores genetic information
DNA strans form complementary pairs where A goes to ____ and G goes to ____
T , C
Cohesion is:
The tendency of water molecules to stick to each other due to hydrogen-bonding
Adhesion is:
The tendency of water molecules to stick to the walls of tubes or other surfaces by forming hydrogen bonds
Unlike DNA which is synthesized with thymine, RNA uses:
Uracil
Surface tension is:
a consequence of H-bonding of water molecules with their neighbors.
A Calorie is (C):
a kilocalorie or 1,000 calories
a nucleotide is:
a nucleoside phosphate
An Element is:
a pure substance that cant be broken down into simpler components by ordinary chemical or physical techniques.
The concentration of H+ in water solution determines the:
acidity of the solution
Hydrogen Bonds
are attractions between partially positive H atoms and partially negative atoms
Van der Waals Forces
are weak forces that develop over very short distances between nonpolar molecules
The number of protons in a nuclei are called the:
atomic number
All Matter including living organisms, are composed of:
atoms and combinations of atoms
RNA
carries genetic information, protein synthesis, rna processing, gene expression
Organic molecules:
collectively what most carbon containing molecules are known as.
buffers are:
combinations of molecules that compensate for pH changes by absorbing or releasing H+
Chatin is:
composed of N-Acetylglucosamine monoers - in cell walls
nucleotides are:
composed of one or more phosphate groups bonded to a 5-carbon sugar
DNA contains
deoxyribose
Deoxyribonucleic acids contain:
deoxyribose
Isotopes are:
distinct forms of atoms of an element with the same number of protons but different numbers of neutrons.
RNA is single stranded where DNA is:
double stranded
An atom with a high _________ will hold the electrons more tightly and have partial negativity
electronegativity
In a nonpolar covalent bond:
electrons are shared equally
In a polar covalent bond:
electrons are shared unequally
Two stereoisomers that are mirror images of each other are called:
enantiomers
Orbitals make up:
energy levels or electron shells
in water, an oxygen atom:
forms polar covalent bonds with two hydrogen atoms
in Ionic bonds atoms have:
full charge
Stereoisomers
have the same atoms attached to each other, but the arrangement of atoms differs.
A calorie is (c):
heat energy required to raise 1 g of water 1 degree celcius
Water also has a high:
heat of vaporization
Polar molecules associate readily with water, this is called:
hydrophilic
Nonpolar substances that are excluded by water, this is called:
hydrophobic
Hydrophobic Interactions
involve the exclusion of non-polar molecules from the hydrogen-bonding lattice of water molecules
Two different molecules with the same molecular formula are called:
isomers
specific heat means that:
it can absorb or release relatively large quantities of heat energy without undergoing extreme changes in temperature
Atoms combine chemically in fixed numbers and rations to form the:
molecules
Polysaccharides form from:
monosaccharides through dehydration reactions
In a polar covalent bond the atom that attracts the electrons:
more strongly carries a partial negative charge.
an anion carries a:
negative charge
Electrons are:
negatively charged particles found in orbitals surrounding the nucleus
The nuclei of all atoms also contain uncharged:
neutrons
In nonpolar covalent bonds atoms have:
no charge
nitrogen base + 5-carbon sugar =
nucleoside
The region of space where an electron is found most frequently is its:
orbital
as [H+] goes up:
pH goes down
in Polar covalent bonds atoms have:
partial charge
Bacteria cell walls are made of:
peptidglycan
A cation carries a:
positive charge
ATP is
primary energy currency in the cell
Bases are:
proton acceptors that reduce that H+ concentration of a solution.
Acids are:
proton donors that release H+ when they dissolved in water, increasing H+ concentration
Nuclei of some isotopes are unstable and break down giving off particles of matter and energy, this is:
radioactivity
RNA contains
ribose
ribonucleic acids contain:
ribose
for covalent bonds, stronger bonds are:
shorter than longer bonds
Water has a relatively high:
specific heat
plants store sugars as:
starches
Carbohydrates have:
the generalized chemical formula (CH2O)
The heat of vaporization is:
the heat of vaporization is the amount of heat energy required for a liquid to transition to a gas
Acidity is measured using:
the pH scale
Cellulose is:
the primary component of the plant cell wall
The most important applications of radioisotopes are as labels or:
tracers
Neutrons are:
uncharged particles located in the nucleus
Covalent bonds form when atoms share pairs of:
valence electrons
electrons in an atoms outermost energy level are its:
valence electrons
monosaccharides
vary in the placement of the carbonyl group
