Biology - Exam 1

What are the characteristics of life?

Cellular structure, reproduction, heredity, metabolism, and evolution.

Where is hereditary information stored in cells?

In genes.

What is the atomic number?

The number of protons in an atom.

What is atomic mass?

The number of protons plus neutrons in an atom.

What is an ion?

An atom or molecule with a net electric charge due to the loss or gain of electrons.

What is a cation?

A positively charged ion.

What is an anion?

A negatively charged ion.

Where are electrons located in an atom?

In orbitals surrounding the nucleus.

What determines the number of bonds an atom can make?

The number of electrons in its valence shell.

Why are noble gases non-reactive?

They have full valence shells.

What is a covalent bond?

A chemical bond formed by sharing electrons.

What is a polar covalent bond?

A bond where electrons are shared unequally.

What is an ionic bond?

A bond formed when one atom gives up an electron to another.

What is a hydrogen bond?

A weak bond between a hydrogen atom and a more electronegative atom.

What is adhesion?

Attraction between unlike molecules.

What is cohesion?

Attraction between like molecules.

What does pH measure?

The concentration of hydrogen ions (H⁺) in a solution.

What is a buffer?

A substance that minimizes changes in pH.

What makes water a good solvent?

Its polarity and ability to form hydrogen bonds.

What are the four biological macromolecules?

Proteins, carbs, lipids, nucleic acids

What is the monomer of proteins?

Amino acids.

What is the monomer of nucleic acids?

Nucleotides.

What is the monomer of carbohydrates?

Monosaccharides.

What is the monomer of lipids?

Fatty acids (not true polymers).

What is the difference between condensation and hydrolysis?

"Condensation forms bonds, hydrolysis breaks

What is a peptide bond?

A covalent bond between amino acids.

What determines protein primary structure?

The sequence of amino acids.

What stabilizes protein secondary structure?

Hydrogen bonds.

What interactions form tertiary protein structure?

"Hydrogen bonds ionic bonds, disulfide bridges, and hydrophobic interactions."

What is protein quaternary structure?

The association of multiple polypeptide subunits.

What are the three parts of a nucleotide?

"Phosphate group 5-carbon sugar, and nitrogenous base."

What type of bond links nucleotides?

Phosphodiester bond.

What is complementary base pairing in DNA?

A pairs with T, and G pairs with C

What are the purines?

Adenine and guanine.

What are the pyrimidines?

Cytosine, thymine (DNA), and uracil (RNA).

What is the structure of DNA?

Double helix with antiparallel strands.

How is DNA replicated?

"By strand separation, base pairing, and polymerization."

What sugar is found in RNA?

Ribose.

What base is found in RNA instead of thymine?

Uracil.

What is RNA’s secondary structure?

Hairpin formed by folding and base pairing.

What is the central dogma of biology?

DNA → RNA → Protein.

What is the general formula of carbohydrates?

CnH2nOn.

What is a glycosidic bond?

A bond between two monosaccharides.

What is cellulose?

A structural polysaccharide in plants.

What are the three types of lipids?

Fats oils waxes steriods

What is a triglyceride?

A lipid made of one glycerol and three fatty acids.

What is the structure of a phospholipid?

Hydrophilic head and two hydrophobic tails.