Cytology and Cell Biology Flashcards

A comprehensive set of vocabulary flashcards covering cell structure, organelles, membrane transport, and cell division based on cytology lecture notes.

Cytology

The study of the general characteristics, components, and functions of cells.

Eukaryotic Cells

A type of cell containing a nucleus and main components like the plasma membrane and cytoplasm with various organelles.

Prokaryotic Cells

One of the two main cell types, distinguished from eukaryotic cells by the absence of a nucleus.

Plasma Membrane

Also called the plasmalemma, it is a phospholipid bilayer with proteins that provides a physical barrier and selective permeability for the cell.

Amphipathic

A descriptor for phospholipids which have both a hydrophilic (polar) head and a hydrophobic (nonpolar) fatty acid tail.

Trilaminar Appearance

The distinct three-layered look of the plasma membrane when viewed under high magnification.

Integral Proteins

Also known as intrinsic proteins, these are embedded within the phospholipid bilayer; some are transmembrane proteins that act as channels or pumps.

Peripheral Proteins

Also known as extrinsic proteins, these are attached to the inner or outer faces of the cell membrane.

Glycocalyx

An external cell coating formed by oligosaccharides linked to either phospholipids or proteins.

Selective Permeability

A function of the plasma membrane that regulates the entry and exit of ions, nutrients, and waste molecules.

Simple Diffusion

A passive process involving the unassisted net movement of small, nonpolar substances down their concentration gradient.

Facilitated Diffusion

Movement of ions and small polar molecules down their concentration gradient assisted by transport proteins (channels or carriers).

Osmosis

The diffusion of water across a selectively permeable membrane determined by relative solute concentrations.

Active Transport

The movement of substances up their concentration gradient required the expenditure of cellular energy ($ATP$).

Symport

A type of secondary active transport where two substances move in the same direction across the membrane.

Antiport

A type of secondary active transport where two substances move in opposite directions across the membrane.

Exocytosis

Vesicular transport that involves the bulk movement of substances out of the cell by fusion of secretory vesicles with the plasma membrane.

Phagocytosis

A form of endocytosis meaning "cell eating," where large particulate materials are engulfed by pseudopodia.

Pinocytosis

A form of endocytosis meaning "cell drinking," where the cell takes up interstitial fluid into small vesicles.

Receptor-Mediated Endocytosis

A selective process where plasma membrane receptors first bind specific substances before they are taken up by the cell.

Signal Transduction

Communication between cells via extracellular molecules (endocrine, paracrine, autocrine, or synaptic) binding to membrane protein receptors.

Cytosol

The fluid portion of the cytoplasm containing organelles, nutrients, ions, enzymes, and waste products.

Ribosomes

Sites of protein synthesis composed of rRNA and proteins, found either attached to the rER or free in the cytosol.

Rough Endoplasmic Reticulum (rER)

A membranous network with attached ribosomes that accepts proteins for glycosylation and other post-translational modifications.

Smooth Endoplasmic Reticulum (sER)

A membranous network involved in the synthesis of phospholipids and steroids, detoxification, and calcium storage and release.

Golgi Apparatus

A complex of flattened membranous sacs that completes protein modifications, packages them, and forms lysosomes.

Lysosomes

Membranous vesicles containing about 40 hydrolytic enzymes used for intracellular digestion, autophagy, and turnover of cellular components.

Proteasomes

Structures that degrade denatured or nonfunctional proteins and remove proteins no longer needed by the cell.

Mitochondria

The cell's powerhouse containing enzymes for aerobic cellular respiration and $ATP$ production; they possess their own DNA, ribosomes, and RNA.

Peroxisomes

Membrane-bound vesicles containing oxidative enzymes that produce and degrade $H_2O_2$ and assist in the formation of bile acids and cholesterol.

Centrioles

A pair of structures composed of 9 triplets of microtubules located near the nucleus, critical for mitotic spindle formation.

Cilia

Hair-like processes composed of a "9 + 2" array (9 peripheral doublets and 2 central singlets) used to move substances like mucus or the ovum.

Flagellum

A long cellular process with a "9 + 2" microtubular arrangement, found in the tail of sperm to provide motility.

Microfilaments

Components of the cytoskeleton composed of actin; they interact with myosin for muscle contraction and form the cleavage furrow during cell division.

Microvilli

Surface specializations composed of actin microfilaments that increase the surface area of the cell.

Intermediate Filaments

Various fibers like keratins, vimentin, neurofilaments, and lamins that maintain cell shape and anchor organelles.

Cytoplasmic Inclusions

Temporary structures of metabolites or pigments, such as lipid droplets, glycogen granules, melanin, lipofuscin, and hemosiderin.

Nucleolus

An aggregate of RNA and proteins within the nucleus that functions in the synthesis of ribosomes and rRNA.

Nuclear Envelope

A double membrane bridged by nuclear pore complexes that regulates the movement of macromolecules into and out of the nucleus.

Chromatin

Double-stranded DNA helix complexed with histone proteins; it condenses into chromosomes during cell division.

Euchromatin

A more open structure of chromatin that is actively being transcribed.

Heterochromatin

A more compacted form of chromatin where little to no transcription is occurring.

Diploid

Refers to somatic cells containing 23 pairs (46 total) of chromosomes.

Haploid

Refers to germ cells (sperm and ova) containing only 23 total chromosomes.

Karyotype

A microscopic analysis of chromosomes used for screening genetic diseases.

Interphase

The sequence of the cell cycle including $G_1$ (duplicating contents), S (duplicating chromosomes), and $G_2$ (double-checking for errors).

Quiescent (G0)

A phase of cell cycle arrest where terminally differentiated cells like cardiac muscle or nerve cells remain.

Mitosis

Division of somatic cells where a diploid parent cell produces two identical diploid daughter cells.

Meiosis

Division of germ cells (reduction division) where a diploid parent cell produces four haploid daughter cells.

Prophase

The first stage of mitosis where chromatin condenses into chromosomes, the nucleolus and nuclear envelope disappear, and centrioles form the spindle.

Metaphase

The stage of mitosis where paired chromosomes line up at the equatorial or metaphasal plate.

Anaphase

The stage of mitosis where sister chromatids are separated toward opposite poles and the cleavage furrow begins to develop.

Telophase

The final stage of mitosis where the mitotic spindle disappears, chromosomes revert to chromatin, and the nuclear envelope and nucleolus reform.

Cytokinesis

The physical separation of the cytoplasm into two daughter cells via the deepening of the cleavage furrow.

Apoptosis

Programmed "cell suicide" characterized by cell shrinkage, chromatin condensation, and membrane blebbing without inflammation.

Parenchyma

The functional tissue of an organ.

Stroma

The supporting tissue of an organ.