Introduction to Cell and Molecular Biology Exam 1

Protons

Positively charged particles that are found in the nucleus

Neutrons

Neutrally charged particles that are found in the nucleus

Electrons

Negatively charged atoms that orbit around the nucleus

Mass Number

The number of protons and neutrons

Atomic Number

Number of protons

Isotope

Forms of elements with different amounts of neutrons

Covalent Bond

Forms when unpaired valence electrons are shared by two atoms

Molecule

Substances held together by covalent bonds

Compounds

Molecules in which atoms of different elements are held together

Electronegativity

The strength in which an element pulls electrons towards itself. If an element is not sharing well, it has a high electronegativity.

Nonpolar Covalent Bonds

Electrons are shared evenly

Polar Covalent Bond

Electrons are shared unevenly

Ionic Bonds

Electrons are transferred from one atom to another to give both atoms full valence shells

Ion

Atom or molecule that carries a charge

Cation

An atom that loses an electron and becomes positively charged

Anion

An atom that gains an electron and becomes negatively charged

Why is water polar?

Oxygen pulls the electrons from hydrogen which means it is very electronegative

Polar likes

Polar

Nonpolar likes

Nonpolar

Hydrophilic

Water loving atoms and molecules

Hydrophobic

Water fearing molecules

Cohesion

Ability for water to stick to itself

Adhesion

Ability for water to adhere to other surfaces

Amino groups

Attract a proton and act as a base

Carboxyl groups

Drop a proton and act as acids

Carbonyl groups

Have sites that link molecules into more complex compounds

Hydroxyl groups

Act as weak acids

Phosphate groups

Have two negative charges

Sulfhydryl groups

Link together via disulfide bonds

Proteins are

Macromolecules

Monomer

One lego

Polymer

Many legos

Amino group

has hydrogen

Side chain

the r group (nametag)

Carboxyl group

has oxygen

Condensation Reaction / Dehydration Reaction

Monomer in, water out

Hydrolysis

Water in, monomer out

Peptide Bond

Forms when one amino group reacts with another

Peptide Chain

A chain of fewer than 50 amino acids

Polypeptide Chain

A chain of more than 50 amino acids

Primary structure of a protein

Sequence of amino acids (Polypeptide Chain)

Secondary structure of a protein

Formed by hydrogen bonds between the carbonyl group of one amino acid to the amino group of another

Tertiary structure of a protein

Interactions between R-groups or between the R-groups and the peptide background

R Group Interactions

Hydrogen bonds, Hydrophobic interactions, Van der Waals Interactions, Covalent disulfide bonds, and Ionic bonds

Hydrogen Bonds

Formed between polar side chains and opposite partial charges

Hydrophobic Interactions

Water forces hydrophobic side chains together

Van der Waals Interactions

Weak electrical interactions between hydrophobic side chains

Covalent disulfide bonds

Form bridges between two sulfhydryl groups

Ionic bonds

The form between the groups with full and opposing charges

Quaternary structure of a protein

The bonding of two or more distinct polypeptide subunits

Denaturation

The loss of the protein’s native structure

Molecular Chaperones

Help proteins fold correctly in cells

Prions

Improperly folded forms of normal proteins

Catalysis

Speeds up chemical reactions and is the most important part of protein function

Enzyme

A protein that functions as a catalyst

Substrates

The reactants in enzyme-catalyzed reactions

Nucleic acids

Stored information

Nucleotide

Building block of nucleic acids (monomer)

DNA

2 way street

RNA

1 way street

Pyrimidines

Thymine, Uracil, and Cytosine

Purines

Adenine and Guanine

Phosphodiester Linkage

The bond that connects the sugar molecules in the backbone of DNA and RNA. It links one nucleotide to another using a phosphate group.

Erwin Chargaff

Established that the # of purines = the # of pyrimidines

Rosalind Franklin and Maurice Wilkins

Used x-ray to measure distances between atoms in DNA

James Watson and Francis Crick

Determined that two strands are held together by hydrogen bonds between pyrimidines and purines

One turn in DNA occurs

Every 10 base pairs

Monosaccharide

one sugar (monomer)

Disaccharide

two sugars (small polymers)

Oligosaccharide

few sugars (small polymers)

Polysaccharide

many sugars (large polymers)

Hydroxyl points up

Beta (glucose)

Hydroxyl points down

Alpha (galactose)

Carbonyl group

where C and O are

Chitin

Structural polymer found in cell walls of fungi and exoskeletons of insects/crustaceans

Peptidoglycan

Structural polymer found in bacterial cell walls

Phosphorylase

Breaks down glycogen (hydrolyzed)

Amylase

Breaks down starch (hydrolyzed)

What is the monomer of a protein?

Amino Acid

What is the polymer of a protein?

Polypeptide chain

What is the bond of a protein?

Peptide

What is the monomer of a carbohydrate?

Monosaccharide

What is the polymer of a carbohydrate?

Polysaccharide

What is the bond of a carbohydrate?

Glycosidic Linkage

What is the monomer of a lipid?

glycerol and fatty acids

What is the bond of a lipid?

Ester bonds

What is the monomer of a nucleic acid?

Nucleotide

What is the polymer of a nucleic acid?

Polynucleotide

What is the bond of a nucleic acid?

Phosphodiester Linkage

Plasma Membrane (cell membrane)

Separates the cell’s interior from the external environment

Lipids

Carbon containing compounds (do not mix with water)

Hydrocarbons

molecules that contain only carbon and hydrogen

Phospholipids

a lipid-containing a phosphate group in its molecule

Saturated Fats

Hydrocarbon chains consist of only single bonds and are solid at room temperature

Unsaturated Fats

Hydrocarbon chains have one or more bonds (forms a kink)

3 main types of lipids

Steroids, fats, and phospholipids

Diffusion

the movement of molecules from an area of higher concentration to an area of lower concentration

Concentration Gradient

created by the difference in solute concentrations from more to less

Passive Transport

a type of membrane transport that does not require energy to move substances across cell membranes

Active Transport

a process that involves the movement of molecules from a region of lower concentration to a region of higher concentration against a gradient or an obstacle with the use of external energy