Bio 130 Exam 1

What determines the properties of a compound?

A compound's properties depends on its atoms and how they are bonded together

What is a compound?

Two or more atoms of different elements joined by bonds

What determines an atom's identity?

The number of protons an atom has

What determines an atom's ability to form bonds?

The atoms electron distribution(number of valence electrons)

Element

A substance that cannot be broken down to other substances by chemical reactions

Essential Elements

Elements an organism needs to survive

Trace elements

Elements needed by organisms but only in minute quantities

Atom

The smallest unit of matter

Subatomic particles

Neutrons, protons, and electrons make up atoms

What are the charges of subatomic particles?

Proton-Positively charged, Neutron-no charge/neutral, Electrons-Negatively charged

Atomic Nucleus

The center of an atom where the protons and neutrons are stored

Why do electrons move around the nucleus?

The attraction between opposite charges keep the electrons in the vicinity of the nucleus

Atomic Number

The number of protons in an element

Atomic Mass

The total number of protons and neutrons in an atom

How do you find the number of neutrons?

Atomic Mass-Atomic Number=# of Protons

Isotope

Atoms of the same elements that have a different number of neutrons

Radioactive Isotope

An isotope where the nucleus decays spontaneously, giving off particles and energy

Energy

The capacity to cause change

Potential Energy

The energy that matter possesses because of its location or structure

Electron Shells

Where the electrons are stored in an atom, surrounding the nucleus. The farther an electron is from the nucleus the more energy it has

What determines the chemical behavior of an atom?

The distribution of electrons in the atom's electron shells

Valence Electrons

The electrons in the outermost shell

Valence shell

The outermost electron shell

Orbital

The 3-D shape where an electron is found 90% of the time

Chemical Bonds

Attractions that hold atoms together

Covalent Bonds

The sharing of a pair of valence electrons by two atoms

Molecule

Two or more atoms of the same/different element that are bonded

Electronegativity

The attraction of a particular atom for the electrons of a covalent bond

Nonpolar Covalent Bond

The electrons in a bond are shared equally between the two atoms

Polar Covalent Bond

An atom is bonded to a more electronegative atom and the electrons of the bond are not shared equally

Ion

A charged atom

Cation

A positively charged ion

Anion

A negatively charged ion

Ionic Bond

The attraction of cations and anions. Not specifically the transfer of electrons, but the attraction between charged atoms

Hydrogen Bond

Noncovalent attraction between a hydrogen and an electronegative atom

van der Waals interactions

Ever-changing regions of positive/negative charge that enable molecules to stick together

When do van der Waals interactions occur?

When atoms/molecules are very close together

Why are weak bonds important?

They form parts of large molecules like proteins and nucleic acids

How does ice's structure allow it to float in water?

The hydrogen bonds form a stable lattice shape, causing it to be less dense than liquid water

Cohesion

Hydrogen bonds allow water to stick to other water molecules

Adhesion

Hydrogen bonds allow water molecules to stick to different molecules

Specific heat

the amount of heat that must be absorbed/lost for 1g of the substance to change temp by 1*C

What are the 4 unique properties of water?

Expansion upon freezing, moderation of temp, solvent capabilities, and cohesive behavior

Solvent

a liquid substance capable of dissolving other substances

Solute

the dissolved matter in a solution

Hydrophillic substance

Likes water

Hydrophobic

affraid of water

Organic molecules

Formed when carbon atoms are covalently bound to other carbon and hydrogen atoms

Inorganic molecule

Carbon atoms bound to non-carbon atoms, cannot form long chained polymers

What are the 4 classes of biological molecules?

Carbohydrates, Proteins, Nucleic Acids, and Lipids

Macromolecules

Large biological molecules that are essential to life: carbs, proteins, nucleic acids

Monomers

Subunits that link to form polymers

Polymers

Chain of monomers

Carbohydrates

includes sugars and polymers of sugar

Monosaccharides

simple sugar

Disaccharide

consists of two monosaccharides joined by a glycosidic linkage

Glycosidic Linkage

A covalent bond that links two monosaccharides together to form a dissacharide

Polysaccharides

polymers with many monosaccharides

Starch

Storage polymer for plants

glycogen

Storage polymer for animals

What subatomic particle causes chem. reactions?

Valence electrons

How do electron shields work?

Shells closest to the nucleus have the least energy

What's the difference between a molecule and a compound?

Molecule: 2+ atoms(same/different)
Compound: 2+ atoms(different)

Nonpolar covalent bonds

Covalent bond b/n two atoms of the same element that equally share the electrons

Polar covalent bond

Covalent bond with unequal sharing of electrons

What happens in an ionic bond?

The opposite charges of cations and anions are attracted to each, causing a bond to form

What is the purpose of weak bonds?

They form and break apart easily

Van der Waals interactions

electrons are not evenly distributed, they may accumulate by chance

What type of bonding occurs in a water molecule?

1. Polar covalent bonding within the compound
2. Hydrogen bonds to other molecules

Water Property: Expansion upon freezing

-When frozen, forms lattice structure
-Ice less dense than water allowing it to float

What are the three classes of macromolecules?

Carbs, proteins, and nucleic acids

Lipids

Fats, phospholipids, and steroids

Why are lipids not considered macromolecules?

Because they're not polymers

Triglycerides

Fats and oils, categorized as saturated/unsaturated/trans fats

Saturated fats

-no double bonds b/n the carbons
-solid at room temp
-typically animal fats
-lead to heart disease

Unsaturated fats

-1+ double bonds b/n carbons
-liquid at room temp
-plant and fish fats

Trans fats

When hydrogen is added to unsaturated to create saturated. More unhealthy than normal saturated fats

Phospholipids

-Major component of cell membranes
-hydrophillic head and hydrophobic tail

kink

double bond in a fatty acid tail

Steroids

-lipids w/ a carbon skeleton consisting of 4 fused rings

Cholesterol

type of steroid, precursor from which other steroids are synthesized

Proteins

-Made of polymers that are made of amino acids

What is the functions of protein?

Defense, storage, transport, cell communication, movement, & structural support

Enzymes

Proteins that speed up chemical reactions(catalyst)

Polypeptides

unbranched polymers built from amino acids

Peptide bond

bond between amino acids

What is different in each amino acid?

The R group changes, the Nitrogen and side groups stay the same

Primary protein structure

Sequence of amino acids to form polypeptide chain

Secondary protein structure

Peptide chain w/ coil/fold, helix or pleated sheet shape

Tertiary protein structure

Helix and pleated sheet-shaped polypeptide chains bonded by disulfide to make one chain

Quaternary protein structure

2+ polypeptide chains bonded together

Nucleic Acids

DNA/RNA-store, transmit, and express hereditary info

Nucleic acid

monomer(Adanine, Guanine)

Nucleotides

polymer made of sugar, phosphate, and nitrogen base

Complimentary base pairing

Nucleic acids that pair in a DNA/RNA strand
-A=T
-C=G
-In RNA, A=U

What are the 4 most important biological molecules

carbs, lipids, proteins, nucleic acids

What is hydrolysis?

When polymers are broken into monomers

Which type of carbohydrate is a monomer

monosaccharides

What connects two monosaccharides?

glycosidic linkage

What are polysaccharides used for?

\-Storage units that provide a cell w/ monosaccharides

\-material to protect the cell