Cell Transport & Cell Theory - Vocabulary

Vocabulary flashcards covering key terms from the lecture notes on cell transport, cell theory, organelles, cell division (mitosis and meiosis), prokaryotic/eukaryotic cells, and levels of organization.

Cell transport

The movement of materials into and out of the cell across the cell membrane.

Selective permeability

Property of the cell membrane that allows some substances to pass while blocking others.

Passive transport

Transport that does not require energy (ATP) and moves substances down their concentration gradient (high to low).

Diffusion

Movement of small molecules across the cell membrane from high to low concentration until equilibrium is reached.

Facilitated diffusion

Diffusion aided by transport proteins in the membrane; still follows a high-to-low concentration gradient.

Osmosis

Diffusion of water across a semipermeable membrane from high water concentration to low water concentration.

Hypotonic

A solution with lower solute concentration than the cell, causing water to enter and the cell to swell.

Hypertonic

A solution with higher solute concentration than the cell, causing water to leave and the cell to shrink.

Isotonic

A solution with equal solute concentration inside and outside the cell; water moves in and out equally with no size change.

Active transport

Transport that requires energy (ATP) and moves substances against the concentration gradient (low to high).

Protein pump transport

Active transport using membrane proteins to move ions (e.g., Na+ and K+) across membranes.

Endocytosis

Process by which the cell engulfs large particles or fluids by wrapping the membrane around them.

Phagocytosis

Endocytosis of solids; 'cell eating'.

Pinocytosis

Endocytosis of liquids; 'cell drinking'.

Exocytosis

Vesicle-mediated export of large substances from the cell.

Mitosis

Nuclear division producing two genetically identical diploid nuclei, followed by cytokinesis.

Prophase

Chromatin condenses into visible chromosomes; nuclear envelope breaks down; spindle forms.

Metaphase

Chromosomes line up at the cell's equator; spindle fibers attach to centromeres.

Anaphase

Sister chromatids separate and are pulled to opposite poles; each chromatid becomes a chromosome.

Telophase

Chromosomes arrive at poles; nuclear membranes reform and chromosomes de-condense.

Cytokinesis

Division of the cytoplasm; completes cell division (cleavage furrow in animals; cell plate in plants).

Cell cycle

Series of phases (Interphase and Mitosis) that prepare for and execute cell division.

Interphase

Longest phase; cell grows (G1), replicates DNA (S), and prepares for division (G2).

G1 phase

Growth phase: cell grows and carries out normal activities.

S phase

DNA replication occurs, doubling the genetic material.

G2 phase

Second growth phase: cell prepares organelles for division.

Meiosis

Special cell division that produces gametes; reduces chromosome number by half and increases genetic variation.

Gamete

Haploid reproductive cell (sperm or egg).

Diploid

Cells containing two complete sets of chromosomes (2n).

Haploid

Cells containing one set of chromosomes (n).

Crossing-over

Exchange of genetic material between homologous chromosomes during Prophase I of meiosis.

Independent assortment

Random orientation of homologous chromosomes at Metaphase I, generating variation.

Random fertilization

Any sperm can fertilize any egg, increasing genetic diversity.

Somatic cell

Body cell; typically diploid; not a gamete.

Prokaryotic cell

Cell lacking a nucleus; simple structure, usually smaller (e.g., bacteria).

Eukaryotic cell

Cell with a true nucleus and membrane-bound organelles; usually larger and more complex.

Capsule

Sticky outer layer of some bacteria that aids in adhesion.

Cell wall

Rigid protective layer outside the plasma membrane; in plants made of cellulose; provides support and prevents excessive water uptake.

Peptidoglycan

Polymer forming the bacterial cell wall; provides rigidity.

Plasmid

Small circular DNA molecule in bacteria that can carry genes.

Nucleoid region

Region in prokaryotes where DNA is located; not enclosed by a membrane.

Pili

Hair-like appendages on some bacteria used for adhesion and transfer of material.

Flagellum

Whip-like structure that enables bacterial movement (locomotion).

Golgi apparatus

Modifies, sorts, and packages proteins; forms lysosomes.

Lysosome

Organelle containing hydrolytic enzymes that digest waste, old organelles, and invaders.

Vacuole

Membrane-bound storage organelle; plants have a large central vacuole; stores water and nutrients.

Chloroplast

Organelle containing chlorophyll; site of photosynthesis.

Chlorophyll

Green pigment that captures light energy for photosynthesis.

Plastids

Plastid family involved in storage and synthesis; includes chloroplasts, chromoplasts, leucoplasts.

Chromoplast

Plastid that stores pigments other than chlorophyll.

Leucoplast

Colorless plastid involved in storage, e.g., amyloplasts store starch.

Amyloplast

Leucoplast that stores starch.

Centrioles

Tube-like structures that organize microtubules during animal cell division.

Cytoplasm

Jelly-like interior of the cell; site of many metabolic processes and cushions organelles.

Nucleus

Organelle that houses DNA in eukaryotic cells; controls activities of the cell.

Mitochondrion

Powerhouse of the cell; site of cellular respiration; produces ATP.

Ribosome

RNA-protein complexes that synthesize proteins; found in all cell types.

Endoplasmic reticulum

Network of membranes; Rough ER has ribosomes and makes proteins; Smooth ER makes lipids and detoxifies.

Cytoskeleton

Network of protein filaments that provides structure, aids movement, and organizes cell components.