Cell and Molecular Biology BIO 2210: Midterm 1

**Have only created flashcards for the first 2 lectures until this point**

Cells

Made of organic chemicals, filled with ion-containing water, typically surrounded by water

Carbon

Most important atom in biological molecules

Water

Indispensable role as the universal solvent

Aqueous

Water-containing

Polarity

Accounts for water’s cohesiveness, temperature-stabilizing capacity, and solvent properties

Polar

Results from unequal distribution of electrons (some atoms electronegative, others with a partial positive charge)

Cohesive

Water molecules are attracted to each other (opposite charges attract)

Solvent

A fluid in which the solute can be dissolved

Hydrophilic

Solutes with a high affinity for water and dissolve in it easily

Hydrophobic

Molecules that are not easily soluble in water

Hydrophobicity

Determines chemical structure and interactions of biological molecules

Spheres of hydration

Formed around water molecules, decreases their chances of reassociation

Electrostatic interactions

How anions and cations separate when dissolved in water

Extracellular

Outside of cell

Intracellular

Inside of cell

Membrane

Separates extracellular and intracellular environments, form semi-permeable barriers

Lipid bilayer

Principle component of membranes

Polysaccharides

used for cell energy, structure, and signalling

Nucleic acids

Store, transmit, and express genetic information. Are the instructions for life. Are linear polymers of nucleotides

Proteins

Have many functions in the cell

DNA

The molecule of heredity. Stores and transmits biological information

Genes

Are written in DNA

Genome

All of the genes in an organism. Provide all of the instructions for making that organism

RNA

Used to “express” genetic information

Ribose

The 5 carbon sugar of RNA

Deoxyribose

The 5 carbon sugar of DNA

Nucleotides

Consist of a phosphate group, a 5 carbon sugar, and a nitrogen-containing aromatic base

Purines

The larger of the bases. Adenine and Guanine

Pyrimidines

The small of the bases. Thymine (DNA), uracil (RNA), cytosine

Adenine

Pairs with thymine/uracil

Guanine

Pairs with cytosine

Thymine

Pairs with Adenine in DNA

Uracil

Pairs with Adenine in RNA

Cytosine

Pairs with Guanine

5’ to 3’

Direction of nucleotide synthesis

Phosphodiester bonds

Hold together nucleotides in polymers

Hydrogen bonds

Form between bases

Phosphate

At the 5’ end of a nucleotide polymer

Hydroxyl

At the 3’ end of a nucleotide polymer

DNA structure

Complementary, antiparallel, strands act as templates, double-stranded helix

RNA structure

Normally single stranded, base pairing happens between bases in different areas of the same molecule

Proteins

Are polymers of amino acids

L

The enantiomer that is used in proteins (L or D?)

R-group

unique side chains of amino aicds

Polypeptide

Product of amino acid polymerization

Protein synthesis

Process of elongating a chain of amino acids

Requirements to be a protein

Stable, 3D shape, is biologically active

9

How many hydrophobic/nonpolar amino acids?

6

How many hydrophilic/polar, uncharged amino acids?

5

How many hydrophilic/polar, charged amino acids?

Acidic

Amino acids with a negative charge

Basic

Amino acids with positive charges

Hydrophilic amino acids

Found on water-facing surfaces

Hydrophobic

Found on interior surfaces

Peptide bonds

Link amino acids in a polypeptide

N-terminus

end of the polypeptide with the amino group. Is considered to be the beginning of the protein

C-terminus

end of the polypeptide with the carboxyl group. Is considered to be the end of the protein.

Covalent bonds (disulfide bonds)

Very stable, formed between sulfur atoms in cystein residues

Primary Structure

structure that corresponds to the amino acid sequence. results from covalent peptide bonds

Secondary structure

structure that corresponds to (local) folding (mainly alpha helix and beta sheet). results from hydrogen bonding

alpha helix

spiral in shape, R groups jut out from the spiral

beta sheet

formed by multiple polypeptide strands, hydrogen bonding between backbones, R groups jut out on alternating sides

Tertiary structure

structure that corresponds to 3D folding of a single polypeptide chain. many different bonds involved. depends upon interactions between R groups

Quaternary structure

structure that corresponds to associations of multiple polypeptides to form a multimeric protein. many different bonds involved