Cell Structure and Function – Lecture Review

50 vocabulary flashcards covering key scientists, cell theory, cell types, organelles, and essential cellular processes from the lecture notes.

Cell

The smallest unit capable of carrying out all life processes; all living things are made of one or more cells.

Cell Theory

States that all living things are made of cells, cells are the basic units of structure and function, and new cells arise only from existing cells.

Heterotroph

Organism that obtains energy by consuming other organisms; consumer (e.g., animals, fungi).

Autotroph

Organism that produces its own food, typically via photosynthesis; producer (e.g., green plants).

Homeostasis

The maintenance of a stable internal environment within an organism or cell.

Cytoplasm

The fluid portion of the cell inside the membrane that surrounds organelles (excluding the nucleus).

Cell Membrane (Plasma Membrane)

Phospholipid-protein boundary regulating the passage of substances into and out of the cell.

Prokaryotic Cell

Cell lacking a true nucleus and membrane-bound organelles; DNA is free in cytoplasm (e.g., bacteria).

Eukaryotic Cell

Cell with a true nucleus and membrane-bound organelles; generally larger and more complex.

Organelle

Specialized sub-cellular structure that performs a specific function within a eukaryotic cell.

Nucleus

Membrane-bound control center housing DNA and coordinating cellular activities such as protein synthesis and reproduction.

Chromatin

Threadlike DNA-protein material present when the cell is not dividing.

Chromosome

Condensed form of chromatin visible during cell division, carrying genetic information.

Nucleolus

Dense region in the nucleus that assembles ribosomal subunits.

Ribosome

Organelle made of rRNA and protein where protein synthesis occurs; may be free or bound to ER.

Rough Endoplasmic Reticulum

ER studded with ribosomes; modifies and transports proteins.

Smooth Endoplasmic Reticulum

ER without ribosomes; synthesizes lipids and detoxifies substances.

Golgi Apparatus

Stack of membranes that modifies, sorts, and packages proteins and lipids for transport.

Vesicle

Small membrane-bound sac that transports or stores substances within a cell.

Lysosome

Vesicle containing hydrolytic enzymes that digest macromolecules, debris, and worn-out organelles.

Peroxisome

Organelle that breaks down fatty acids and toxins, converting harmful hydrogen peroxide to water and oxygen.

Vacuole

Membrane-bound storage sac for water, salts, proteins, or carbohydrates.

Central Vacuole

Large, water-filled vacuole in mature plant cells that maintains turgor pressure and stores compounds.

Mitochondrion

Double-membraned “powerhouse” of the cell where cellular respiration generates ATP; contains its own DNA.

Cellular Respiration

Process in mitochondria that converts glucose into usable energy (ATP) for the cell.

Cytoskeleton

Network of protein fibers (microfilaments and microtubules) providing shape, support, and movement.

Microfilament

Thin actin filament that supports cell shape and aids in movement and muscle contraction.

Microtubule

Hollow tubulin rod involved in maintaining cell shape, chromosome separation, and formation of cilia/flagella.

Centriole

Paired cylindrical structures in animal cells that organize microtubules during cell division.

Cell Wall

Rigid cellulose layer outside the plasma membrane of plant cells providing support and protection.

Plastid

Double-membraned organelle in plant cells with its own DNA; includes chloroplasts, chromoplasts, and leucoplasts.

Chloroplast

Green plastid containing chlorophyll; site of photosynthesis converting solar energy to glucose.

Chromoplast

Plastid containing pigments other than green, giving color to fruits and flowers.

Leucoplast (Amyloplast)

Colorless plastid that stores starch in plant cells.

Turgor Pressure

Pressure of water inside the central vacuole against the cell wall, providing plant rigidity.

Surface Area–to–Volume Ratio

Relationship that limits cell size; volume grows faster than surface area, restricting material exchange.

Photosynthesis

Process in chloroplasts where light energy is converted into chemical energy stored in glucose.

Cyclosis

Cytoplasmic streaming—the movement of materials within a cell.

Biosynthesis

Cellular process of using food energy to build new cell parts for growth and repair.

Ingestion (cellular)

The uptake of food and water by a cell.

Excretion (cell)

Removal of liquid metabolic waste products from a cell.

Egestion

Removal of solid, undigested waste from a cell.

Irritability

A cell’s ability to respond to stimuli.

Secretions

Substances produced in one part of a cell and used in another part or outside the cell.

Thylakoid

Flattened membrane sac inside chloroplasts containing chlorophyll; site of the light reactions of photosynthesis.