General Biology 1 – Midterms Review (Cell History, Structure & Cycle)

A comprehensive set of 120 vocabulary flashcards covering historical figures, foundational theories, cell structures, membrane concepts, organelles, prokaryote–eukaryote distinctions, and key stages of the cell cycle to aid midterm exam preparation.

Hans & Zacharias Janssen (1590)

Dutch father-son eyeglass makers who built the first primitive microscope.

Primitive Microscope

Early telescope-like instrument ~2.5 ft long with one concave and one convex lens, magnifying 3-10×.

William Barell

Dutch diplomat who informed the French king about the Janssens’ microscope.

Marcello Malpighi (1660)

Italian biologist who first described blood capillaries in fish tails and is viewed as a precursor of embryology.

Robert Hooke (1665)

English scientist who coined the word “cell” after observing cork slices and published Micrographia.

Francesco Redi (1668)

Italian physician whose maggot-and-meat experiment challenged spontaneous generation.

Anton van Leeuwenhoek (1683)

Dutch lens-grinder who created practical single-lens microscopes (up to 270×) and first observed living cells (‘animalcules’).

Robert Brown (1831)

Botanist who discovered the plant nucleus during orchid epidermis studies.

Matthias Jakob Schleiden (1838)

Proposed all plants are composed of cells and recognized the nucleus’ role in cell division.

Theodor Schwann (1839)

Zoologist who stated all animals are made of cells; co-formulated first two tenets of Cell Theory.

Rudolf Virchow (1855)

Pathologist who added the third cell theory tenet "Omnis cellula e cellula"—cells arise from pre-existing cells.

Gregor Johann Mendel (1865)

Augustinian monk who proposed the Laws of Inheritance: Segregation, Independent Assortment, Dominance.

Walter Flemming (1882)

Cytogenetics pioneer who named and described mitosis while studying chromosomes.

Thomas Hunt Morgan (1915)

Geneticist who confirmed Mendelian laws by Drosophila breeding; genes reside on chromosomes.

Watson & Crick (1953)

With data from Rosalind Franklin and Maurice Wilkins, elucidated the double-helix DNA structure.

Rosalind Franklin

X-ray crystallographer who produced Photograph 51, critical for DNA structure discovery.

Basic Cell Theory – Tenet 1

All living organisms are composed of one or more cells.

Basic Cell Theory – Tenet 2

The cell is the basic structural and functional unit of life.

Basic Cell Theory – Tenet 3

All cells come from pre-existing cells.

Modern Cell Theory – Tenet 1

Cells contain hereditary information (DNA) passed during cell division.

Modern Cell Theory – Tenet 2

All cells share similar chemical composition and metabolic activities.

Modern Cell Theory – Tenet 3

All basic chemical & physiological functions occur within cells.

Modern Cell Theory – Tenet 4

Cell activity depends on subcellular structures such as organelles and membranes.

Exception – Virus

Has life-like features but lacks cellular structure; challenges cell theory.

Exception – First Cell

The original cell did not derive from a pre-existing cell, an exception to tenet 3.

Exception – Mitochondria & Chloroplasts

Organelles with their own DNA that replicate independently, supporting endosymbiotic theory.

Endosymbiotic Theory

Hypothesis that mitochondria and chloroplasts originated as engulfed prokaryotes living symbiotically inside ancestral eukaryotes.

Domain Bacteria

Prokaryotic domain consisting of typical bacteria.

Domain Archaea

Prokaryotic domain of extremophiles distinct from bacteria.

Domain Eukarya

Domain containing all eukaryotic organisms—protists, fungi, plants, animals.

Prokaryote Size

Generally 0.2–10 µm; smaller than eukaryotes.

Eukaryote Size

Typically 10–100 µm; larger than prokaryotes.

Nucleoid

Region in prokaryotes where circular DNA chromosome resides; no membrane.

Membrane-Bound Organelles

Structures such as nucleus, ER, Golgi, mitochondria found only in eukaryotes.

70S Ribosome

Smaller ribosome type found in prokaryotes and inside mitochondria/chloroplasts.

80S Ribosome

Larger ribosome type free in eukaryotic cytoplasm.

Peptidoglycan (Murein)

Polymer composing bacterial cell walls.

Cellulose

Polysaccharide forming plant cell walls.

Chitin

Nitrogen-containing polysaccharide forming fungal cell walls.

Flagellin

Protein building prokaryotic flagella.

Microtubule-based Flagella

Eukaryotic flagella composed of 9+2 microtubule arrangement.

Glycocalyx

Carbohydrate-rich protective outer layer present on some eukaryotic cells lacking a wall.

Binary Fission

Asexual prokaryotic cell division.

Mitosis

Eukaryotic nuclear division producing two identical diploid cells.

Meiosis

Eukaryotic division that halves chromosome number to create gametes.

Cell Wall (Plants)

Rigid structure of cellulose providing support and protection.

Cell Wall (Fungi)

Rigid chitinous layer surrounding fungal cells.

Plasma Membrane

Phospholipid bilayer controlling substance movement in and out of the cell.

Selective Permeability

Property allowing some molecules to cross membranes more easily than others.

Phospholipid Bilayer

Two-layer structure with hydrophilic heads outward and hydrophobic tails inward.

Fluid Mosaic Model

Describes membranes as fluid lipid bilayers with embedded, mobile proteins and carbohydrates.

Nucleus

Membrane-bound repository of DNA directing cellular activities.

Nucleolus

Dense nuclear region where rRNA synthesis and ribosome assembly occur.

Smooth Endoplasmic Reticulum (SER)

Organelle for lipid synthesis, detoxification, carbohydrate metabolism, Ca²⁺ storage.

Rough Endoplasmic Reticulum (RER)

Ribosome-studded membrane network synthesizing membrane and secretory proteins.

Golgi Apparatus

‘Packaging’ organelle that modifies, sorts, and ships proteins; forms lysosomes & vesicles.

Lysosome

Digestive vesicle containing hydrolytic enzymes; nicknamed ‘suicide bag.’

Peroxisome

Organelle that breaks down fatty acids and detoxifies harmful compounds via hydrogen peroxide.

Mitochondrion

Double-membrane ‘powerhouse’ that converts food energy to ATP; contains its own DNA (mtDNA).

Chloroplast

Plant/algal organelle where photosynthesis converts light energy to sugar; contains grana & stroma.

Grana

Stacks of thylakoid membranes inside chloroplasts housing light-capturing pigments.

Thylakoid

Disk-shaped membrane sac within chloroplast grana where light reactions occur.

Stroma

Fluid matrix surrounding grana inside chloroplasts, site of Calvin cycle.

Central Vacuole

Large plant organelle for storage, digestion, and turgor maintenance.

Centrioles

Cylindrical microtubule pairs inside centrosomes of animal cells; help organize spindle.

Microtubule

Cytoskeletal filament of tubulin providing support and forming cilia, flagella, spindle.

9+2 Arrangement

Pattern of nine microtubule doublets around two singlets in eukaryotic cilia/flagella.

Cytoplasm

Cell contents between plasma membrane and nucleus, including cytosol and organelles.

Cytosol

Semi-fluid component of cytoplasm excluding organelles.

Plasmodesmata

Channels connecting plant cells for transport and communication.

Somatic Cell

Diploid body cell produced via mitosis (e.g., skin, liver).

Gamete

Haploid sex cell (sperm or egg) produced via meiosis.

Homologous Chromosomes

Pair of chromosomes with same genes but possibly different alleles; one from each parent.

Sister Chromatids

Identical copies of a chromosome joined at the centromere post-replication.

Cell Cycle

Ordered sequence of events from cell formation to division into daughter cells.

Interphase

Growth phase (G₁, S, G₂) occupying ~90 % of cell cycle; DNA replication occurs.

G₁ Phase

First gap where cell grows, synthesizes proteins & organelles.

G₁ Checkpoint

Point verifying cell size, nutrients, and DNA integrity before S phase.

S Phase

Synthesis phase where DNA replication produces sister chromatids.

G₂ Phase

Second gap where proteins for mitosis are produced; DNA checked for damage.

G₂ Checkpoint

Ensures DNA replication success and cyclin-MPF levels adequate for mitosis.

G₀ Phase

Non-dividing quiescent state; typical of neurons, cardiac cells, some stem cells.

Cyclin

Regulatory protein whose concentration oscillates to activate CDKs.

Cyclin-Dependent Kinase (CDK)

Enzyme phosphorylating target proteins when bound to cyclin, driving cell cycle transitions.

Mitotic Promoting Factor (MPF)

CDK-cyclin complex that triggers entry into mitosis by phosphorylation cascade.

Apoptosis

Programmed cell death eliminating damaged or unnecessary cells.

Prophase

Mitosis stage where chromatin condenses, nucleoli disappear, spindle begins forming.

Prometaphase

Nuclear envelope breaks; spindle microtubules attach to kinetochores on chromosomes.

Metaphase

Chromosomes align at metaphase plate; spindle fully formed.

Metaphase Checkpoint

Verifies all chromosomes attached to spindle before anaphase.

Anaphase

Sister chromatids separate and move to opposite poles; cell elongates.

Telophase

Chromosomes decondense; nuclear envelopes reform; spindle disassembles.

Cytokinesis

Division of cytoplasm producing two daughter cells.

Cleavage Furrow

Contractile ring of actin in animal cells that pinches cell during cytokinesis.

Cell Plate

Structure formed by fused vesicles in plant cells that becomes new cell wall during cytokinesis.

Cancer

Disease arising from unregulated cell cycle and mutations in cell-cycle genes.

Kinetochore

Protein complex at chromosome centromere where spindle microtubules attach.

Centrosome

Microtubule-organizing center containing a pair of centrioles in animal cells.

Aster

Radial array of microtubules extending from centrosome during mitosis.

Basal Body

Organelle structurally identical to centriole anchoring cilia/flagella.