Biology 101 - Modules 4, 5, and 6 Study Flashcards

Flashcards covering key vocabulary terms for Units 4, 5, and 6, including cell biology, bioenergetics, and cell division.

Cell Theory

A fundamental theory in biology stating that all organisms are composed of one or more cells, cells are the basic units of organization, and all cells come from pre-existing cells.

Plasma Membrane

A biological membrane composed of a phospholipid bilayer that regulates the passage of materials into and out of the cell.

Cell Surface Proteins

Proteins located on the surface of the cell membrane that facilitate identification and interaction with the environment.

Transmembrane Proteins

Proteins that span across the lipid bilayer of the cell membrane, often acting as channels or transporters.

Cytoskeleton

A network of protein fibers, including microtubules and microfilaments, that maintains cell shape and assists in movement.

Microtubules

Thick protein fibers that make up part of the cytoskeleton and are also the primary components of centrioles.

Endosymbiosis

A theory suggesting that eukaryotic cells evolved through a symbiotic relationship where one prokaryote lived inside another, eventually leading to organelles like mitochondria.

Chromatin

The relaxed, thread-like form of DNA and proteins found in the nucleus when the cell is not dividing.

Chromosomes

Condensed structures of DNA and protein that form when chromatin coils up tightly for cell division.

Nucleolus

A structure within the nucleus where ribosomal components are synthesized.

Endomembrane System

A group of organelles, including the endoplasmic reticulum and Golgi body, that work together to produce, package, and transport lipids and proteins.

Rough ER

A region of the endoplasmic reticulum studded with ribosomes that is involved in protein synthesis.

Smooth ER

A region of the endoplasmic reticulum that lacks ribosomes and is involved in lipid synthesis.

Golgi Body

An organelle composed of flattened stacks that processes, sorts, and packages proteins into vesicles.

Lysosome

A membrane-bound sac containing digestive enzymes used to break down macromolecules and cell debris.

Mitochondria

The organelle responsible for generating the majority of the cell's energy in the form of ATP.

Centrioles

Cylindrical structures composed of microtubules that help organize microtubule assembly during animal cell division.

Potential Energy

Energy that is stored and not currently being used to do work.

Kinetic Energy

The energy of motion, or energy that is currently performing work.

Thermodynamics

The study of energy and the laws governing its transformation.

Entropy

A measure of the disorder or randomness in a system; it increases as energy is wasted as heat during transformations.

Activation Energy

The minimum amount of energy required to initiate a chemical reaction.

Catalysis

The process of speeding up a chemical reaction by lowering the activation energy.

Enzyme

An organic molecule, usually a protein, that serves as a biological catalyst.

Enzyme-Substrate Complex

The temporary physical association formed when an enzyme binds to its specific reactant molecules.

Competitive Inhibition

A process where a molecule other than the substrate binds to the active site, preventing the enzyme from functioning.

Somatic Cells

Regular body cells that are typically diploid and undergo mitosis.

Germ Cells

Reproductive body cells that undergo meiosis to produce haploid gametes.

Mitosis

A type of cell division that results in two daughter cells with the same number of chromosomes as the parent cell.

Meiosis

A specialized type of cell division that reduces the chromosome number by half, creating haploid cells for reproduction.

Haploid

A cell containing only one member of each homologous pair of chromosomes.

Diploid

A cell containing both members of every homologous pair of chromosomes.

Interphase

The longest part of the cell cycle consisting of $G_1$, $S$, and $G_2$ phases where the cell grows and replicates its DNA.

Mitotic Spindle

A network of microtubules that forms during mitosis to direct the movement of chromosomes.

Metaphase

The stage of mitosis where chromosomes line up in the middle of the cell.

Anaphase

The stage of mitosis where sister chromatids separate and move toward opposite poles.

Telophase

The final stage of mitosis where the nuclear membrane reforms and chromosomes relax.

Cleavage Furrow

The indentation that forms in animal cells to divide the cytoplasm during cytokinesis.

Metastasis

The spread of cancer cells from their original site to other parts of the body.

Proto-oncogene

A normal gene that promotes cell division in a healthy cell but can become an oncogene when mutated.

Tumor Suppressor Gene

A gene that normally suppresses cell division to prevent uncontrolled growth; its mutation can lead to cancer.