BNC 1005 Ch 3 cell Structure and Function

Vocabulary flashcards covering key terms from the lecture notes.

Cell Theory

All living things are made of cells; new cells arise only from preexisting cells; first observed by Robert Hooke in 1665.

Cell

The smallest unit of life that can function independently; basic unit of structure and function in organisms.

Light Microscope

A microscope that uses visible light to illuminate thin tissue, allowing viewing of the entire cell at lower magnification.

Electron Microscope

A microscope that uses beams of electrons for much higher magnification to reveal finer cell ultrastructure.

Prokaryote

A cell that lacks membrane-bound organelles and a true nucleus; DNA is in the cytoplasm (nucleoid).

Eukaryote

A cell with a nucleus and membrane-bound organelles; found in protists and all multicellular organisms.

Nucleus

Large, membrane-bound organelle containing the cell’s DNA; central control of cellular activities.

Nucleoid

Region in prokaryotes where DNA is concentrated; lacks a surrounding membrane.

Cytoplasm

The interior of the cell excluding the nucleus; contains cytosol and organelles.

Plasma Membrane (Cell Membrane)

Phospholipid bilayer that surrounds the cell; forms a barrier and regulates substance passage.

Phospholipid

Molecule with glycerol, a phosphate group, and two fatty acids; amphipathic nature helps form membranes.

Amphipathic

Having both polar (hydrophilic) and nonpolar (hydrophobic) regions within the same molecule.

Phospholipid Bilayer

Two-layered arrangement of phospholipids forming the core structure of cellular membranes.

Fluid Mosaic Model

Description of the cell membrane as a dynamic, fluid phospholipid bilayer with embedded proteins.

Membrane Proteins

Proteins in the cell membrane that perform recognition, receptor, and transport functions.

Cytoskeleton

Network of protein filaments that provides support, aids movement, and organizes organelles.

Microfilaments

Smallest cytoskeletal filaments (~7 nm) made of actin; contribute to shape and movement.

Intermediate Filaments

Cytoskeletal filaments (~8–10 nm) that provide mechanical support.

Microtubules

Largest cytoskeletal filaments (~25 nm), hollow tubes of tubulin; form structures like cilia/flagella and aid transport.

Cilia

Short, hairlike structures moved by microtubules to move substances across cell surfaces.

Flagella

Long, whip-like structures used for cell propulsion (e.g., sperm).

Plant Cell

Eukaryotic cell with cell wall, chloroplasts, and a large central vacuole; performs photosynthesis.

Animal Cell

Eukaryotic cell lacking a cell wall; contains a variety of organelles for diverse functions.

Chloroplast

Organelle in plants and some protists where photosynthesis occurs; contains chlorophyll.

Mitochondrion

Organelle where cellular respiration occurs; generates ATP; numerous in many eukaryotic cells.

Nucleolus

Region inside the nucleus that synthesizes ribosomal RNA and assembles ribosomal subunits.

Rough Endoplasmic Reticulum (rER)

ER studded with ribosomes; synthesizes and folds proteins destined for secretion or membranes.

Smooth Endoplasmic Reticulum (sER)

ER lacking ribosomes; synthesizes lipids and detoxifies certain substances.

Golgi Apparatus

Processing center that modifies, sorts, and packages proteins into transport vesicles.

Lysosome

Organelle containing hydrolytic enzymes that digest macromolecules and cellular waste.

Peroxisome

Organelle that breaks down toxic substances and aids in digestion; originates from the ER.

Vacuole

Membrane-bound storage organelle; in plants, a large central vacuole maintains turgor pressure.

Cell Wall

Rigid layer outside the plant cell membrane providing structure and protection (also in some bacteria).

Amyloplast

Plastid that stores starch in plant cells.

Centrosome

Microtubule organizing center in many animal cells; helps organize the spindle during cell division.

Ribosome

Small organelles where protein synthesis occurs; can be free in the cytosol or attached to the rough ER.

RNA

Ribonucleic acid; carries genetic instructions from DNA for protein synthesis (mRNA, tRNA, rRNA).

mRNA

Messenger RNA; copy of a DNA sequence used as a template for protein synthesis.

DNA

Deoxyribonucleic acid; genetic material stored in the nucleus; double helix.

Endomembrane System

Interconnected membranes (ER, Golgi, lysosomes, vesicles) that modify, package, and transport proteins.

Cellular Respiration

Process in mitochondria that converts glucose energy into ATP (includes glycolysis, Krebs cycle, and electron transport).

Photosynthesis

Process in chloroplasts that converts light energy into chemical energy stored as sugars.