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