Characteristics of Life, Quantitative Biology, and Biological Macromolecules

Vocabulary practice flashcards generated from introductory biology lecture material covering the properties of life, cellular classification, introductory chemical quantitative calculations, and biological macromolecules.

Homeostasis

The biological process of maintaining a stable internal balance, such as regulating temperature, pH, and blood sugar levels.

Prokaryote

A simpler, single-celled type of organism, such as bacteria, that lacks a membrane-bound nucleus.

Eukaryote

A more complex type of cell that makes up organisms like animals, plants, and fungi.

Mutation

A change in DNA that provides genetic variation, which can lead to evolution.

Virus

A protein-covered compartment containing genetic material that cannot reproduce on its own and requires a host cell's machinery.

Concentration

A measure of the amount of a substance present per unit volume.

Molarity ($M$)

A unit of concentration defined as moles of solute per liter of solution ($M = \text{moles}/L$).

Dalton ($Da$)

A unit of atomic mass where one proton or one neutron weighs approximately $1\,Da$.

Mole

A scientific unit representing $6.02 \times 10^{23}$ atoms or molecules.

Dimensional Analysis

A step-by-step mathematical approach used for conversions and word problems by choosing conversion factors to cancel unwanted units.

Phospholipid

A key cell membrane molecule featuring a hydrophilic head and hydrophobic tails, which forms a bilayer in water.

Steroid

A lipid molecule characterized by a carbon skeleton consisting of four interconnected rings.

Cholesterol

A steroid lipid with attached functional groups used by the body to synthesize other steroids, including sex hormones.

Amino Acid

The monomer building block of proteins, composed of an amino group, a carboxyl group, a hydrogen atom, and a variable $R$ group.

$R$ Group

The variable side chain attached to an amino acid that determines its unique identity and properties as nonpolar, polar, or charged.

Polypeptide

A continuous chain of amino acids joined together by peptide bonds formed through dehydration reactions.

Primary Structure

The unique, linear sequence of amino acids in a polypeptide chain determined by genetic information.

Secondary Structure

Localized structural patterns in a protein, such as $\alpha$-helices and $\beta$-pleated sheets, formed by hydrogen bonds along the backbone.

Tertiary Structure

The overall three-dimensional shape of a single polypeptide chain driven by interactions between $R$ groups.

Quaternary Structure

The overall protein structure resulting from the combination of two or more individual polypeptide chains.

Disulfide Bridge

A strong covalent bond formed between the sulfur atoms of cysteine amino acids that stabilizes tertiary protein structure.

Denaturation

The process in which a protein loses its normal shape and biological function due to extreme environmental conditions like pH or temperature.

Nucleotide

The monomer of nucleic acids, consisting of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Purines

A class of nitrogenous bases featuring a double-ring structure, consisting of adenine ($A$) and guanine ($G$).

Pyrimidines

A class of nitrogenous bases featuring a single-ring structure, consisting of cytosine ($C$), thymine ($T$), and uracil ($U$).

Phosphodiester Linkage

The covalent bond that joins adjacent nucleotides via condensation reactions to build a nucleic acid backbone in a $5' \rightarrow 3'$ direction.

Complementary Base Pairing

The specific pairing of nitrogenous bases in DNA where adenine ($A$) hydrogen-bonds with thymine ($T$), and cytosine ($C$) pairs with guanine ($G$).

Gene

A sequence of DNA bases that contains the specific instructions required to synthesize a functional product like a protein.