Exam 1 Practice Questions Review

Vocabulary flashcards covering key concepts from Exam 1 practice questions related to chemistry, water properties, organic molecules, and cell biology.

Atomic Number

The number of protons in an atom, which also determines the number of electrons in a neutral atom.

Mass Number

The sum of protons and neutrons in an atom's nucleus.

Balancing Chemical Reactions

Ensuring the conservation of matter by placing coefficients in front of chemical formulas.

Electrons

Subatomic particles that determine the bonds an atom can form, especially valence electrons.

Valence Electrons

Electrons in the outermost shell of an atom that participate in chemical bonding.

Nonpolar Covalent Bond

A type of bond where electrons are shared equally between atoms, common in lipids and contributing to their hydrophobic properties.

Hydrophobic

Describes substances that repel or do not mix with water, often due to nonpolar covalent bonds.

Surface Tension

A property of a liquid's surface that results from the cohesive forces between its molecules, influencing droplet formation and the ability of objects to float.

Water Expansion on Freezing

The phenomenon where water increases in volume when it turns into ice, capable of exerting significant force.

Specific Heat

The amount of heat required to raise the temperature of one gram of a substance by one degree Celsius; water has an unusually high specific heat.

pH Scale

A logarithmic scale used to specify the acidity or basicity of an aqueous solution, indicating the concentration of hydrogen ions.

Buffer

A chemical system that resists changes in pH by absorbing excess hydrogen or hydroxide ions, such as carbonic acid and bicarbonate ion in blood.

Double Bond (in molecules)

A covalent bond formed by sharing two pairs of electrons between two atoms, contributing to a planar molecular geometry.

Triple Bond (in molecules)

A covalent bond formed by sharing three pairs of electrons between two atoms, also contributing to a planar molecular geometry.

Structural Isomers

Molecules that have the same molecular formula but differ in the covalent arrangement of their atoms.

Amino Group (-NH2)

A functional group in organic molecules that behaves as a base by accepting hydrogen ions.

Carboxyl Group (-COOH)

A functional group in organic molecules that behaves as an acid by donating hydrogen ions.

Covalent Bond (Functional Group)

The type of chemical bond that typically joins a functional group to the carbon skeleton of a large organic molecule.

Sulfhydryl Group (-SH)

A functional group crucial for stabilizing protein shape, particularly through the formation of disulfide bridges.

Dehydration Reaction (Condensation Reaction)

A chemical reaction that links monomers together to form polymers, typically by removing a molecule of water.

Hydrocarbon

An organic molecule composed solely of carbon and hydrogen atoms.

Quaternary Protein Structure

The most complex level of protein organization, involving the aggregation of multiple polypeptide chains.

Phosphodiester Bonds

Covalent bonds that link 5-carbon sugars in the backbone of nucleic acids.

Double Helix

The characteristic spiral structure of DNA, consisting of two strands.

Hydrogen Bonds (DNA)

Weak bonds that hold together complementary nitrogenous bases from the two polymer chains in a DNA molecule.

Saturated Fat

A type of fat where hydrocarbon chains contain only single bonds, meaning they are 'saturated' with hydrogen atoms and typically solid at room temperature.

Thymine

A nitrogenous base found exclusively in DNA, replaced by Uracil in RNA.

N-terminus

The end of a polypeptide chain that has a free amino group (H2N-).

C-terminus

The end of a polypeptide chain that has a free carboxyl group (-COOH).

Cellulose

A polysaccharide composed of unbranched β-glucose molecules that cannot be digested by humans.

Complementary DNA Strand

A DNA strand that binds to another DNA strand through specific base pairing (Adenine with Thymine, Guanine with Cytosine).

Phospholipid

A lipid molecule with a hydrophilic head (glycerol + phosphate) and two hydrophobic fatty acid tails, forming the basis of cell membranes.

Unsaturated Lipids

Lipids containing one or more double bonds in their fatty acid chains, causing kinks that result in looser packing and liquid state at room temperature.

Phospholipid Bilayer Cell Membrane

A fundamental structure common to all living cells, forming a barrier that separates the cell interior from its external environment.

Peroxisome

An organelle that contains enzymes to carry out metabolic reactions, including the breakdown of fatty acids and detoxification of harmful substances like alcohol.

Chromosomes

Structures found inside the nucleus of eukaryotic cells, consisting of DNA tightly coiled around histone proteins.

Nucleolus

A dense structure within the nucleus where ribosomal RNA (rRNA) is synthesized and ribosomes are assembled.

Ribosomes

Cellular organelles composed of ribosomal RNA (rRNA) and proteins, responsible for protein synthesis.

Cristae

The infoldings of the inner mitochondrial membrane, which increase the surface area for cellular respiration.

Mitochondrion

An organelle found in most eukaryotic cells, responsible for generating energy (ATP) through cellular respiration; common to both plant and animal cells.

Chloroplasts

Organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis; they possess their own DNA.

Glyoxysomes

Specialized peroxisomes in plants that can convert fatty acids into sugar, aiding in seed germination.

Plasma Membrane Composition

Primarily composed of phospholipids, with embedded and associated proteins and carbohydrates, forming the outer boundary of animal cells.

Eukaryotic DNA Location

Located within the membrane-bound nucleus of eukaryotic cells.

Prokaryotic DNA Location

Located in a region called the nucleoid, which is not membrane-bound, within the cytoplasm of prokaryotic cells.