Intro to Cell Biology and Biochemistry

Flashcards covering foundational cell biology concepts including the properties of life, cell theory, prokaryotic and eukaryotic structures, domains of life, scientific method and variables, chemical bonding, and carbohydrate macromolecules.

Order

A fundamental characteristic of life characterized by an ordered structure on all scales.

Energy Processing

A characteristic of life involving metabolic processes to obtain and utilize energy (e.g., eating).

Irritability

An organism's ability to respond to stimuli or changes in its environment.

Regulation

The maintenance of internal homeostasis within an organism.

Evolutionary Adaptation

Changes occurring in organisms over long periods through natural selection.

Biogenesis

The principle stating that all cells arise only from pre-existing cells.

Mycoplasma gallisepticum

The smallest known type of cell.

Cell Theory

The unifying biological theory stating that all living things are composed of one or more cells, the cell is the fundamental unit of structure and function, and all living cells arise from pre-existing cells by division.

Glycolysis

The universal metabolic pathway utilized by cells to break down glucose.

Eukaryote

A cell measuring $10\text{--}100\,\mu\text{m}$ that possesses a membrane-bound nucleus (karyon) filled with DNA, membrane-bound organelles, a cytoskeleton, and larger ribosomes (e.g., plants, fungi, and animals).

Prokaryote

A cell measuring $1\text{--}10\,\mu\text{m}$ that contains circular, naked DNA, smaller ribosomes, lacks a cytoskeleton, and has no separate internal membranes such as a nucleus or mitochondria (e.g., Bacteria, Archaea).

Domain Bacteria

An ancient prokaryotic lineage characterized by diverse metabolic evolution, essential roles in decomposition, lack of internal cell organelles, and cell walls typically containing peptidoglycan.

Cocci

Round or berry-shaped bacteria that usually stick together.

Bacilli

Rod-shaped bacteria.

Spirilla

Corkscrew-shaped bacteria.

Domain Archaea

A domain of prokaryotes lacking internal organelles and peptidoglycan, found widely in oceans and in extreme environments (including methanogens, extreme thermophiles, and halophiles).

Domain Eukarya

A domain of organisms found widely across the planet characterized by cells with a membrane-bound nucleus, organelles providing compartmentalization, and cell walls lacking peptidoglycan.

Scientific Method

A cyclical process of investigation involving observation, generating questions, formulating hypotheses, developing testable predictions, gathering data, refining or rejecting hypotheses, developing theories, and undergoing peer review.

Research Hypothesis

A logical, precise, testable, and falsifiable statement explaining the focus and direction of an experiment by identifying a mechanism and variables, which can be eliminated or confirmed but not proven.

Variable

Any factor, trait, or condition that can exist in differing amounts or types.

Independent Variable

The single factor intentionally altered by the researcher in a well-designed experiment at a given time.

Dependent Variable

The factor that is observed and measured in response to changes in the independent variable (e.g., resting heart rate).

Mechanism

The primary underlying reason or causal explanation behind a hypothesized outcome.

Chemical Bond

An attraction between atoms that holds them together due to the sharing or exchanging of electrons.

Covalent Bond

A chemical bond formed by the sharing of electrons between two atoms to complete their valence shells.

Molecule

A group of atoms held together by covalent bonds.

Non-polar Covalent Bond

A covalent bond in which electrons are shared equally between atoms.

Electronegativity ($\chi$)

The attraction of an atom for electrons in a covalent bond, where a higher $\chi$ results in a greater pull toward its nucleus.

Polar Covalent Bond

A bond occurring between atoms of differing electronegativity ($\chi$) in which electrons are shared unequally, pulling electrons toward the more electronegative atom and resulting in a separation of charge (e.g., $\text{H}_2\text{O}$).

Ionic Bond

A chemical bond formed when an atom with high electronegativity takes the lone valence electron from an atom with low electronegativity to produce oppositely charged ions that strongly attract each other.

Hydrogen Bond

An attraction between opposite partial charges involving a partially positive $\delta^{+}$ hydrogen atom covalently bonded to an electronegative atom and a partially negative $\delta^{-}$ atom (usually $\text{O}$ or $\text{N}$) of a second polar covalent bond; electrons are not shared, and each $\text{H}$ atom forms only one such bond.

Macromolecule

Large, complex, carbon-rich molecules found in cells belonging to four major classes: carbohydrates, lipids, nucleic acids, and proteins.

Polymer

A large molecule consisting of many similar or identical building blocks linked together by covalent bonds.

Monomer

A small molecule used as a repeating building block in the synthesis of a polymer.

Dehydration Reaction

A chemical reaction that synthesizes polymers by forming covalent bonds between monomers, requiring energy and enzymes while releasing a water molecule ($\text{H}_2\text{O}$).

Hydrolysis Reaction

A chemical reaction that degrades polymers by breaking covalent bonds between monomers through the addition of a water molecule ($\text{H}_2\text{O}$), releasing energy and requiring enzymes.

Carbohydrates

Sugars and sugar polymers that function as a source of energy, a source of carbon to build other molecules, and structural components of the cell.

Monosaccharide

A simple sugar monomer consisting of one carbonyl group and many hydroxyl groups (one per carbon), which spontaneously forms ring structures in solution when containing 5 or more carbons.

Alpha ((\alpha)) Glucose

A glucose ring isomer in which the hydroxyl group ($-\text{OH}$) on carbon 1 ($\text{C}_1$) points downward.

Beta ((\beta)) Glucose

A glucose ring isomer in which the hydroxyl group ($-\text{OH}$) on carbon 1 ($\text{C}_1$) points upward.

Glycosidic Linkage

A covalent bond formed by a dehydration reaction that links $\text{C}_1$ and $\text{C}_4$ between different monosaccharide monomers.

Polysaccharide

A carbohydrate polymer consisting of more than two monosaccharides joined by glycosidic linkages, functioning in energy storage or structural support.

Starch

A plant storage polysaccharide with a helical structure composed of glucose monomers joined by $\alpha\text{-1,4-glycosidic}$ bonds.

Amylose

An unbranched, helical glucose polymer found as a component of plant starch.

Glycogen

A branched, helical storage polysaccharide composed of glucose monomers joined by $\alpha\text{-1,4-glycosidic}$ bonds, stored in animal liver and muscle cells, as well as in bacteria.

Cellulose

An unbranched, linear (non-helical) structural polysaccharide found in plant cell walls made of glucose monomers linked by $\beta\text{-1,4-glycosidic}$ linkages that forms strong bundles.