Unit 2 Learning Guide - Cell Structure and Membranes (Vocabulary Flashcards)

A comprehensive set of vocabulary-style flashcards covering cell structure, organelles, membranes, and transport mechanisms based on the lecture notes.

Cell theory

The idea that the cell is the building block of all organisms and that cells come from pre-existing cells.

Prokaryotic cell

A cell that lacks a nucleus and internal membranes; generally has few organelles (Monera are prokaryotes).

Eukaryotic cell

A cell that contains a nucleus and many membrane-bound organelles (examples: plants, animals, protists, fungi).

Monera

The kingdom consisting of prokaryotic cells.

Nucleus

Largest organelle with a double membrane (nuclear envelope); contains DNA, chromatin, nucleolus; regulates cell activities.

Nuclear envelope

Double membrane surrounding the nucleus; contains nuclear pores for material exchange.

Nuclear pores

Protein-lined openings in the nuclear envelope that regulate passage of large molecules between the nucleus and cytoplasm.

Chromatin

DNA-protein complex in the nucleus; hereditary material that condenses to form chromosomes during cell division.

Chromosomes

Rod-shaped bodies in the nucleus that contain hereditary information; visible as they condense during cell division.

Nucleolus

Dark region in the nucleus where ribosomal RNA (rRNA) is produced for ribosome assembly.

Ribosome

RNA-protein particles that synthesize proteins; can be free in cytosol or bound to rough ER; can form polyribosomes.

Endoplasmic reticulum (ER)

A network of membranes; Rough ER has ribosomes for protein synthesis; Smooth ER lacks ribosomes and builds lipids.

Rough ER

ER with attached ribosomes; synthesizes proteins destined for export or membranes.

Smooth ER

ER lacking ribosomes; synthesizes lipids and detoxifies chemicals; abundant in liver cells.

Golgi apparatus

Stack of flattened sacs (cisternae) that receives, modifies, sorts, and packages proteins in vesicles for transport.

Lysosome

Membrane-bound organelle with hydrolytic enzymes for digestion; involved in autophagy and digestion of unwanted substances.

Vacuole

Large membrane-bound storage organelle (often central in plants) storing water, nutrients, and waste.

Mitochondrion

Powerhouse of the cell; performs cellular respiration to produce ATP; has a double membrane and cristae.

Chloroplast

Site of photosynthesis in plants; contains chlorophyll; double membrane; converts light energy to chemical energy.

Cell wall

Rigid layer outside the cell membrane in plants (made of cellulose) that provides support and protection.

Cytoskeleton

Network of protein filaments (microfilaments, intermediate filaments, microtubules) that supports shape and enables movement.

Cilia

Short, numerous projections on cells used for locomotion or sensing the environment.

Flagella

Long, whip-like projections used for locomotion in certain cells (e.g., sperm).

Cell membrane (plasma membrane)

Phospholipid bilayer that forms a selective barrier; regulates movement of substances in and out.

Fluid mosaic model

Membrane structure where the phospholipid bilayer is fluid and proteins float within it; carbohydrates attach to proteins/lipids for identification.

Glycoprotein

Protein with carbohydrate chains attached; often functions as cell identification markers.

Glycolipid

Lipid with carbohydrate chains attached; contributes to cell identification markers.

Diffusion

Movement of solutes from high to low concentration; no energy or membrane required.

Osmosis

Diffusion of water across a semipermeable membrane from high to low water concentration; no energy required.

Facilitated diffusion

Diffusion that requires a carrier protein; still down a concentration gradient and without ATP.

Active transport

Movement of substances against their concentration gradient; requires energy (ATP) and a carrier protein.

Endocytosis

Process of taking in external material via vesicle formation; includes phagocytosis (solids) and pinocytosis (liquids).

Phagocytosis

Type of endocytosis where the cell engulfs large particles or cells (cell eating).

Pinocytosis

Type of endocytosis where the cell ingests liquids in small vesicles (cell drinking).

Exocytosis

Vesicles fuse with the plasma membrane to release contents outside the cell.

Endomembrane system

Interconnected membranes (ER, Golgi, lysosomes, vesicles) that synthesize, modify, and transport cellular products.

Vesicle

Small membrane-bound sac that transports materials between organelles or to/from the cell membrane.

Autophagy

Lysosomes digest damaged organelles and cellular components within the cell.

Isotonic

Solution with the same solute concentration as the cell; no net water movement; cell size remains the same.

Hypertonic

Solution with higher solute concentration than the cell; water moves out; cell shrinks.

Hypotonic

Solution with lower solute concentration than the cell; water moves in; cell swells.

Surface area to volume ratio (SA:V)

Relation that affects diffusion and nutrient/waste exchange; small cells have high SA:V, large cells have low SA:V, limiting cell size.