Cell Theory and Cellular Biology - Vocabulary Flashcards

Vocabulary-style flashcards covering key terms and definitions from the lecture notes on cell theory, cell structure, cell cycle, meiosis, and transport mechanisms.

Compound microscope

A microscope with two lenses used by Zacharias Janssen.

Cell

Basic unit of life; term named by Robert Hooke after viewing cork tissue.

Micrographia

Hooke’s book describing his microscopic observations.

Animacules

Leeuwenhoek’s term for microorganisms observed with his microscope.

Anton van Leeuwenhoek

Father of microbiology; first to observe animacules.

Schleiden

German botanist who concluded that plants are made of cells.

Schwann

Said that all animals have cells.

Virchow

Omnis cellula e cellular; every cell stems from another cell.

Postulate 1 (Cell Theory)

All living things are composed of one or more cells.

Postulate 2 (Cell Theory)

The cell is the basic unit of structure and organization in organisms.

Postulate 3 (Cell Theory)

Cells arise from pre-existing cells.

Prokaryotic cell

Single-celled; no nucleus or membrane-bound organelles.

Eukaryotic cell

Has a true nucleus and membrane-bound organelles.

Plant cell

Has a cell wall, large central vacuole, chloroplasts; lacks centrosomes and lysosomes.

Animal cell

Lacks cell wall; contains centrioles/centrosomes and lysosomes; small vacuoles.

Plasma membrane

Outer covering that separates the cell’s interior from its environment.

Cytoplasm

Jelly-like cytosol containing the cell’s organelles.

Ribosomes

Molecular machines that synthesize proteins.

DNA

Polynucleotide that forms a double helix; carries genetic information.

Endomembrane system

Group of membranes that modify, package, and transport lipids and proteins.

Nucleus

Holds the cell’s DNA and directs cell activities; contains nuclear envelope and nucleolus.

Nuclear envelope

Double membrane surrounding the nucleus; controls entry/exit.

Nucleolus

Site of ribosome synthesis.

Mitochondria

Powerhouses of the cell; generate most ATP.

Peroxisomes

Small organelles carrying out oxidation reactions to break down fats and amino acids.

Lysosomes

Digestive organelles that break down waste; cell’s waste disposal.

Endoplasmic reticulum (ER)

Network of membranous sacs; modifies proteins and synthesizes lipids.

Rough ER

ER with ribosomes on its surface; site of protein synthesis.

Smooth ER

ER lacking ribosomes; synthesizes carbohydrates, lipids, and steroids.

Golgi apparatus

Processing and packaging center for proteins and lipids.

Vesicles

Small membrane-bound sacs used for transport.

Vacuoles

Membrane-bound sacs; larger than vesicles; storage and regulation.

Cytoskeleton

Protein filaments that give the cell its shape and support.

Microfilaments

Actin filaments (~7 nm) involved in movement and shape.

Intermediate filaments

Filaments that bear tension and provide mechanical support.

Microtubules

Hollow tubes that are the widest cytoskeletal components.

Flagella

Tail-like structures used for locomotion.

Cilia

Hair-like projections used to move the cell or fluids past it.

Centrosome

Microtubule-organizing center in animal cells.

Centrioles

Part of the centrosome; involved in organizing spindle fibers.

Chloroplasts

Plant cell organelles that perform photosynthesis.

Chlorophyll

Green pigment in chloroplasts that captures light energy.

Central vacuole

Large vacuole in plant cells regulating water balance.

Cell wall

Rigid layer that protects and supports the cell; made of cellulose in plants.

Cellulose

Glucose polymer that builds plant cell walls.

Capsule

Sticky outer layer in bacteria that helps cling and prevents drying.

Pili

Hair-like appendages used for genetic exchange during conjugation.

Fimbriae

Shorter pili that help bacteria attach to surfaces.

Nucleoid

Region in prokaryotes where DNA is located; not a true nucleus.

Plasmid

Small, circular, extrachromosomal DNA carrying advantageous genes.

Conjugation

Process of DNA exchange between bacteria via pili.

Prokaryote

Simple, mostly unicellular organism lacking a nucleus.

Meiosis

Cell division producing gametes with half the chromosome number.

Mitosis

Nuclear division (karyokinesis) yielding two diploid daughter nuclei.

Cell cycle

Ordered series of events for cell growth and division.

Interphase

Phase where the cell grows and DNA is replicated.

G1 phase

First gap; cell grows and builds energy reserves.

S phase

DNA replication occurs; sister chromatids form; centrosome duplicates.

G2 phase

Second gap; energy reserves and proteins for division are prepared.

Prophase

Chromosomes condense; spindle forms; nuclear envelope breaks down.

Prometaphase

Nuclear envelope breaks down; spindle attaches to kinetochores.

Metaphase

Chromosomes align at the metaphase plate; spindle is fully formed.

Anaphase

Sister chromatids separate and move to opposite poles.

Telophase

Chromosomes arrive at poles; nuclei form; chromosomes decondense.

Cytokinesis

Cytoplasm divides to form two daughter cells.

Prophase I

Homologous chromosomes condense; tetrads form; crossing over occurs.

Crossing over

Exchange of genetic material between homologous chromosomes.

Chiasmata

Sites where crossing over occurs between non-sister chromatids.

Meiosis II

Second division separating sister chromatids into four haploid cells.

Prophase II

Chromosomes condense; new spindle begins to form.

Metaphase II

Sister chromatids align at the metaphase plate.

Anaphase II

Sister chromatids separate and move to opposite poles.

Telophase II

Chromosomes arrive at poles; nuclei form; four haploid cells result.

Isotonic

Solution with the same osmolarity as the cell; no net water movement.

Hypotonic

Solution with lower solute concentration; water enters the cell.

Hypertonic

Solution with higher solute concentration; water exits the cell.

Osmolarity

Total solute concentration of a solution.

Osmosis

Movement of water across a semipermeable membrane along water gradient.

Diffusion

Net movement of molecules from high to low concentration.

Facilitated diffusion

Diffusion aided by membrane proteins (channels and carriers).

Channel proteins

Proteins forming hydrophilic channels for substances to pass.

Aquaporins

Channel proteins that specifically transport water.

Carrier proteins

Proteins that change shape to move a substance across the membrane.

Osmotic gradient

Difference in solute concentration driving osmosis.

Endocytosis

Active transport that brings materials into the cell via vesicles.

Phagocytosis

Endocytosis of large particles (cell eating).

Pinocytosis

Endocytosis of liquids (cell drinking).

Receptor-mediated endocytosis

Targeted uptake of substances via receptor binding.

Exocytosis

Expulsion of material from the cell by vesicle fusion with the membrane.