Unit 3: Anatomy and Physiology - How Cells Work

Vocabulary practice flashcards defining key cell components, organelles, membrane structures, and principles of cell theory from Unit 3.

Cell Theory

The fundamental biological theory stating three principles: 1) All organisms are composed of one or more cells; 2) Cells are the most basic structure of all organisms; 3) All cells are created by pre-existing cells.

Light Microscope

An optical microscope commonly used in school and hospital labs that is effective for viewing tissues and organs, but limited in viewing cell detail.

Electron Microscope

A high-power microscope required to view cell ultrastructure, which is the fine internal detail of a cell.

Photomicrograph

A photograph taken through a microscope.

Cell Membrane

A thin, flexible, selectively permeable outer boundary surrounding the cell that protects it and controls what enters and exits.

Cytoplasm

A gel-like substance filling the cell that provides structural support, keeps organelles in place, and facilitates the movement and storage of nutrients, enzymes, and molecules.

Nucleus

The control centre of the cell that directs its activities and contains most of its genetic material in the form of multiple linear DNA molecules organized into chromosomes.

Nuclear Membrane

The double membrane surrounding the nucleus containing pores through which proteins and nucleic acids pass.

Nucleolus

A sub-structure housed inside the nucleus that acts as the site for RNA production.

Chromatin

The tangled mass of DNA found in non-dividing cells.

Chromosomes

Condensed chromatin structures visible during cell division that carry genes determining inherited traits; humans have 23 pairs.

Deoxyribonucleic Acid (DNA)

The double helix molecule containing genetic instructions, with roughly two meters contained in each human cell.

Fluid Mosaic Model

A model describing the cell membrane as a flexible phospholipid bilayer embedded with proteins that function as channels, receptors, and markers.

Phospholipid Bilayer

The structural core of the cell membrane consisting of two layers of lipids with hydrophilic heads facing outward and hydrophobic tails facing inward.

Selectively Permeable

A characteristic of the cell membrane that allows it to regulate entry and exit by permitting only specific substances to cross.

Mitochondria

Organelles known as the powerhouse of the cell that serve as the site of aerobic respiration, converting oxygen and glucose into ATP.

Aerobic Respiration Equation

The biochemical reaction represented by $\text{Glucose} + \text{Oxygen} \rightarrow \text{Carbon dioxide} + \text{Water} + \text{ATP}$ ($C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + \text{ATP}$).

Adenosine Triphosphate (ATP)

The usable energy molecule of the cell produced by mitochondria through aerobic respiration.

Ribosome

The organelle where protein synthesis occurs by reading messenger RNA (mRNA) and translating genetic code into chains of amino acids.

Rough Endoplasmic Reticulum (Rough ER)

A network of membranes studded with ribosomes that folds and transports proteins to the Golgi apparatus for modification.

Smooth Endoplasmic Reticulum (Smooth ER)

A membrane network lacking ribosomes that synthesises lipids and helps detoxify drugs and toxins in liver cells.

Golgi Apparatus

A series of stacked, fluid-filled membranes located near the nucleus that modifies and packages lipids and proteins for export out of the cell.

Lysosomes

Organelles that act as the cell's waste disposal and recycling centre by digesting nutrients, old cell parts, foreign pathogens, and repairing membrane injuries.

Centrioles

Organelles composed of microtubule protein strands arranged at right angles near the nucleus that help separate chromosomes during cell division.

Cytokinesis

The final process of the cell cycle resulting in the physical division of a single cell into two daughter cells.