Biology Review: Cell Structure, Macromolecules, and Cell Cycle

Vocabulary flashcards covering cellular organelles, plasma membrane structure, biological macromolecules, enzymes, and the cell cycle based on biology review notes.

Metabolism

The sum of all the biochemical processes in the body.

Cell

The most basic structural and functional unit of life, representing the smallest part of an organism capable of all life processes.

Organelles

Specialized structures within a cell that work together to help the cell function.

Cytoplasm

A jelly-like fluid inside cells, mainly made up of water, that holds organelles in place.

Cell (Plasma) Membrane

A selectively permeable barrier made of a phospholipid bilayer that controls what enters and exits the cell.

Phospholipid Bilayer

A two-layer membrane structure composed of phospholipids with hydrophilic polar heads facing outward and hydrophobic nonpolar tails facing inward.

Cytoskeleton

A network of threadlike protein fibers—microtubules, intermediate filaments, and microfilaments—that supports cell shape, provides motility, and regulates biochemical activities.

Centrioles

Structures made of microtubules that appear during cell division to pull chromosomes apart during Anaphase; two centrioles together form a centrosome.

Cilia

Shorter, numerous projections on the cell surface that move fluid across the cell's surface.

Flagella

Longer, fewer projections (typically 1 to 3) that move the entire cell through extracellular fluid.

Microvilli

Short, numerous projections on the surface of human body cells that are similar to cilia but do not move.

Nucleus

The organelle surrounded by a nuclear membrane with pores that contains genetic material (DNA) and protects the cell's genetic instructions.

Chromatin

The uncondensed, threadlike form of DNA present in the nucleus.

Chromosomes

Condensed, rodlike structures of DNA containing genes; human body cells contain 46 chromosomes while sex cells contain 23.

Genes

Sections of chromosomes that code for specific proteins.

Nucleolus

The structure located in the center of the nucleus where ribosomes are formed.

Ribosomes

Organelles made of proteins and rRNA that synthesize proteins, either on the Rough ER (for export) or floating in the cytoplasm (for intracellular use).

Rough ER (Endoplasmic Reticulum)

A network of membranes studded with ribosomes that hugs the nucleus, makes proteins, and packages them for secretion into transport vesicles.

Smooth ER (Endoplasmic Reticulum)

A membrane network attached to the Rough ER lacking ribosomes that synthesizes lipids, modifies small molecules, degrades glycogen, and stores $Ca^{2+}$.

Golgi Apparatus

Folded and flattened membrane sacs that receive, process, modify, package, and sort proteins from vesicles for transport.

Lysosomes

Organelles containing hydrolytic enzymes that break down waste, food, bacteria, and old cell parts, and can induce apoptosis.

Apoptosis

Programmed cell death mediated by cellular machinery such as lysosomes.

Vacuoles

Cellular structures used for the storage of water, nutrients, and waste products.

Mitochondria

Organelles consisting of an inner folded membrane (cristae) and fluid matrix where cellular respiration breaks down chemical energy into usable ATP.

Macromolecules

Large polymers made of smaller monomer subunits linked by covalent bonds, comprising around 26% of living tissue.

Nucleic Acids

Informational macromolecules made of nucleotide monomers (such as DNA and RNA) that store, transmit, and express genetic information.

Carbohydrates

Energy storage macromolecules made of monosaccharides (e.g., glucose, fructose, glycogen) also used for structural support and cell signaling.

Lipids

Energy storage macromolecules composed of fatty acids and glycerol (e.g., fats, oils, steroids, phospholipids) that provide structure, insulation, and protection.

Proteins

Molecules made of amino acid monomers that perform structural, enzymatic, regulatory, transport, and contractile functions in the cell.

Enzymes

Biological catalysts, mainly proteins, that speed up biochemical reactions by binding to specific substrates and lowering activation energy.

Substrate

The specific reactant molecule that binds to an enzyme's active site.

Interphase

The primary phase of the somatic cell cycle where the cell grows and doubles its DNA into sister chromatids prior to division.

Mitosis

The phase of division in somatic cells consisting of Prophase, Metaphase, Anaphase, and Telophase.

Cytokinesis

The stage of cell division in which the cytoplasm splits, generating two identical daughter cells.

Differentiation

The process by which undifferentiated stem cells become specialized in structure and function through selective gene expression.