Cell Modifications, Cell Cycle, and Cell Types

Vocabulary flashcards reviewing key terms on cell modifications, the eukaryotic cell cycle, and differences between prokaryotic and eukaryotic cells.

Cell modifications

Structural changes or appendages that let a cell carry out specialized tasks more efficiently.

Cilia

Short, hair-like projections that beat rhythmically to move fluid or mucus across a surface or propel single-celled organisms.

Flagella

Long, whip-like appendages that generate propulsion, enabling cells such as sperm or some bacteria to swim through liquid.

Microvilli

Microscopic membrane folds that greatly increase surface area to enhance absorption, notably in intestinal cells.

Vacuoles

Membrane-bound sacs (large in plants) that store water or solutes and help maintain turgor pressure inside the cell.

Pseudopodia

Temporary, actin-driven cytoplasmic extensions used by amoeboid cells for movement and engulfing food or bacteria.

Cytoplasmic streaming

Directed flow of cytoplasm that circulates organelles and nutrients within large plant or animal cells.

Thickened cell wall

Reinforced plant-cell wall region that provides extra protection and structural support.

Leukocyte pseudopodia

Flexible extensions of white blood cells that capture and engulf invading bacteria.

Absorption

Uptake of nutrients or other molecules by a cell, often enhanced by structures like microvilli.

Motility structures

Collective name for cilia, flagella, and pseudopodia that enable cellular movement.

Cell cycle

Ordered sequence of growth (Interphase), nuclear division (Mitosis), and cytoplasmic division (Cytokinesis).

Interphase

Longest portion of the cell cycle in which the cell grows, performs normal functions, and prepares for division (G1, S, G2).

G1 phase

First gap phase; cell grows, synthesizes RNA/proteins, and builds enzymes required for DNA replication.

S phase

Synthesis phase; DNA is replicated so each chromosome now has two sister chromatids.

G2 phase

Second gap phase; cell continues growing, produces mitotic proteins, and checks replicated DNA for damage.

Checkpoints

Quality-control mechanisms that verify DNA integrity and cell readiness before allowing the cycle to proceed.

Apoptosis

Programmed cell death that eliminates cells unable to repair damage or pass checkpoints.

Mitosis

Process of nuclear division producing two genetically identical nuclei; subdivided into prophase, metaphase, anaphase, telophase.

Prophase

Stage of mitosis where chromatin condenses into visible chromosomes and the nuclear envelope breaks down.

Metaphase

Stage of mitosis in which chromosomes align along the cell's equatorial plate.

Anaphase

Stage of mitosis where sister chromatids separate and move toward opposite poles.

Telophase

Final stage of mitosis where nuclear membranes reform and chromosomes de-condense.

Cytokinesis

Division of the cytoplasm following mitosis, resulting in two separate daughter cells.

Contractile ring

Actin-myosin belt in eukaryotes that constricts the cell membrane during cytokinesis.

Binary fission

Asexual reproduction in prokaryotes where the cell copies its DNA and splits into two identical cells.

Prokaryote

Simple cell lacking a true nucleus and membrane-bound organelles; includes bacteria and archaea.

Eukaryote

Cell with a true nucleus and membrane-bound organelles; found in plants, animals, fungi, and protists.

Circular DNA

Closed, looped chromosome configuration typical of prokaryotes.

Linear DNA

Chromosomes arranged as linear molecules, typical of eukaryotic nuclei.

Nucleoid

Region of a prokaryotic cell where the circular chromosome is located without a surrounding membrane.

Membrane-bound organelles

Intracellular compartments enclosed by lipid bilayers (e.g., mitochondria, ER) found only in eukaryotes.

FtsZ

Tubulin-like protein that forms a ring guiding prokaryotic cytokinesis.

Actin

Cytoskeletal protein that forms filaments; with myosin, drives cell motility and the contractile ring.

Myosin

Motor protein that interacts with actin to generate force in muscle contraction and cytokinetic cleavage.

Origin of replication

Specific DNA sequence where replication begins; prokaryotes usually have a single origin.

Extreme temperature/pH

Environmental stress that can halt prokaryotic cell division by damaging proteins and DNA.

Antibiotic resistance

Ability of bacteria to survive antibiotics, often arising from rapid mutation and selection during fast division.

Surface area amplification

Strategy, such as forming microvilli, used to maximize membrane area for transport and absorption.

Turgor pressure

Internal pressure in plant cells maintained by water-filled vacuoles, keeping cells rigid.

DNA replication

Copying of genetic material during S phase to ensure each daughter cell receives a complete genome.

Mitotic order (PMAT)

Sequential stages of mitosis—Prophase, Metaphase, Anaphase, Telophase.