Cells and Tissues Ver 2

Vocabulary-style flashcards covering key terms, definitions, and concepts from the Cells and Tissues lecture notes.

Cell theory

All living things are composed of cells; cells are the basic unit of life; new cells come from preexisting cells.

Cell

The basic structural and functional unit of living organisms.

Nucleus

Control center of the cell that contains the DNA.

DNA

Deoxyribonucleic acid; genetic material used to build proteins and for cell reproduction.

Nuclear envelope

Double membrane surrounding the nucleus with nuclear pores for exchange with the cytoplasm.

Nucleolus

Site of ribosome subunit synthesis inside the nucleus.

Chromatin

DNA wound around histone proteins; condenses into chromosomes when the cell divides.

Chromosome

Condensed chromatin visible during cell division that carries genetic information.

Nuclear pores

Channels in the nuclear envelope that allow exchange of materials with the rest of the cell.

Nucleoplasm

Fluid inside the nucleus.

Cytoplasm

All cellular material outside the nucleus and inside the plasma membrane; site of most cellular activities.

Plasma membrane

Transparent barrier surrounding the cell; separates cell contents from the environment and regulates entry/exit.

Phospholipid bilayer

Two layers of phospholipids forming the core structure of the plasma membrane.

Hydrophilic (heads)

Water-loving polar region of phospholipids facing the surrounding aqueous environments.

Hydrophobic (tails)

Water-fearing nonpolar region of phospholipids forming the membrane interior.

Cholesterol (in membrane)

Sterol molecule that helps regulate membrane fluidity and stability.

Glycoprotein

Proteins with attached sugars; help with cell recognition and signaling.

Glycocalyx

Sugar-rich area on the cell surface formed by glycoproteins and glycolipids.

Integral protein

Membrane proteins that span the phospholipid bilayer and perform transport or signaling roles.

Channel protein

Proteins that form pores allowing specific ions or molecules to pass through the membrane.

Carrier protein

Proteins that bind substances and actively or passively transport them across the membrane.

Receptor

Membrane protein that binds signaling molecules to trigger a cellular response.

Tight junction

Impermeable junction that binds cells into a leakproof sheet.

Desmosome

Anchoring junction that prevents tearing by linking cells under mechanical stress.

Gap junction

Communicating junctions allowing direct chemical/electrical communication between cells.

Microvilli

Fingerlike extensions that increase surface area for absorption.

Cilia

Hairlike projections that move substances across the cell surface.

Flagellum

Long, whip-like structure that propels a cell; sperm are flagellated.

Mitochondrion

Powerhouse of the cell; site of ATP production via aerobic respiration.

Ribosome

Site of protein synthesis; can be free or attached to rough endoplasmic reticulum.

Rough endoplasmic reticulum (RER)

ER studded with ribosomes; synthesizes proteins destined for export or membranes.

Smooth endoplasmic reticulum (SER)

ER lacking ribosomes; lipid metabolism and detoxification.

Golgi apparatus

Packages, modifies, and ships proteins; forms secretory, membrane, and lysosome vesicles.

Lysosome

Membranous sacs with digestive enzymes; digest worn-out cell parts and bacteria.

Peroxisome

Detoxifies harmful substances and breaks down reactive oxygen species.

Cytoskeleton

Internal framework of the cell providing shape, support, and transport pathways.

Microfilaments

Thickest cytoskeletal elements involved in cell movement and shape.

Intermediate filaments

Cytoskeletal elements providing mechanical strength.

Microtubules

Cytoskeletal tubes that organize cell structure and transport.

Centrioles

Rod-shaped bodies that organize the mitotic spindle during cell division.

DNA replication

Process by which DNA is duplicated in preparation for cell division.

RNA

Ribonucleic acid; single-stranded; uses ribose sugar and uracil instead of thymine.

mRNA

Messenger RNA; carries genetic instructions from DNA to ribosomes for protein synthesis.

tRNA

Transfer RNA; delivers specific amino acids to the ribosome during translation.

rRNA

Ribosomal RNA; component of ribosomes that catalyzes protein synthesis.

Transcription

Process of copying DNA’s base sequence into a complementary mRNA sequence.

Translation

Process by which the sequence of mRNA codons is decoded into an amino acid sequence.

Codon

A sequence of three mRNA bases that codes for a specific amino acid.

Gene

DNA segment that carries the blueprint for building a protein.

Triplet

DNA sequence of three bases that codes for an amino acid; corresponds to a codon in mRNA.

Interphase

Longest phase of the cell cycle when the cell grows and DNA is replicated.

Mitosis

Nuclear division producing two daughter nuclei; followed by cytokinesis."

Prophase

First phase of mitosis; chromosomes condense, spindle forms, nuclear envelope breaks down.

Metaphase

Chromosomes align along the metaphase plate at the cell’s center.

Anaphase

Sister chromatids separate and move to opposite ends of the cell.

Telophase

Nuclei reform and chromosomes de-condense; nuclear envelope re-forms.

Cytokinesis

Division of the cytoplasm resulting in two separate daughter cells; completes cell division.

Chromatid

One copy of a replicated chromosome held together at the centromere.

DNA replication (sister chromatids)

Duplication of DNA, producing two identical sister chromatids held at the centromere.

Protein synthesis

Process of building proteins from amino acids via transcription and translation.

Glandular epithelium

Epithelium that forms secretory glands producing sweat, oil, etc.

Epithelial tissue

Tissue that covers body surfaces, lines cavities, and forms glands; avascular and regenerative.

Simple epithelium

Epithelium with a single cell layer.

Stratified epithelium

Epithelium with two or more cell layers; provides protection.

Squamous

Flattened cell shape; found in diffusion regions and membranes.

Cuboidal

Cube-shaped cell shape; commonly forms glands and kidney tubules.

Columnar

Tall, column-like cells; often seen in absorptive/secretory surfaces.

Simple squamous epithelium

One layer of flat cells; lines air sacs and blood vessels; involved in diffusion.

Simple cuboidal epithelium

One layer of cube-shaped cells; involved in secretion and absorption.

Simple columnar epithelium

One layer of tall cells; contains goblet cells that secrete mucus.

Pseudostratified columnar epithelium

One layer that appears stratified due to varying cell heights; often ciliated.

Stratified squamous epithelium

Many cell layers; provides protection against abrasion.

Stratified cuboidal epithelium

Two layers of cuboidal cells; rare; found in ducts of large glands.

Stratified columnar epithelium

Surface cells are columnar; rare; protective function.

Transitional epithelium

Stratified tissue that stretches and recoils; lines urinary organs.

Areolar connective tissue

Widely distributed loose connective tissue acting as a packing tissue.

Areolar tissue functions

Universal packing tissue; holds organs in place and can absorb fluids.

Adipose connective tissue

Loose connective tissue dominated by fat cells; stores fat and provides insulation.

Reticular connective tissue

Delicate network forming the stroma of organs like lymph nodes and spleen.

Bone (osseous tissue)

Rigid connective tissue with osteocytes in lacunae; mineralized matrix and collagen fibers.

Cartilage

Flexible connective tissue; major cell is the chondrocyte; types include hyaline, elastic, fibrocartilage.

Hyaline cartilage

Most widespread cartilage; glassy matrix; found in trachea, ends of long bones, fetal skeleton.

Elastic cartilage

Cartilage with elastic fibers; provides flexible support (ear).

Fibrocartilage

Cartilage with thick collagen fibers; cushions intervertebral discs.

Dense connective tissue

Tissue with densely packed collagen fibers; includes tendons and ligaments.

Loose connective tissue

Tissues with more cells and fewer fibers (areolar, adipose, reticular).

Blood (vascular tissue)

Liquid connective tissue; transports nutrients, wastes, gases via plasma.

Muscle tissue

Tissue that contracts to produce movement; three types: skeletal, cardiac, smooth.

Skeletal muscle

Voluntary, striated, multi-nucleated muscle attached to bones.

Cardiac muscle

Involuntary muscle of the heart with striations and intercalated discs.

Smooth (visceral) muscle

Involuntary muscle in walls of hollow organs; non-striated and spindle-shaped.

Nervous tissue

Tissue that receives and conducts electrochemical impulses; includes neurons and neuroglia.

Tissue repair (wound healing)

Regeneration or fibrosis (scar formation) to restore tissue integrity.

Regeneration

Replacement of damaged tissue with the same kind of cells.

Fibrosis

Repair by dense connective tissue (scar formation).

Inflammation

Initial response to injury; capillaries become permeable and clot forms.

Granulation tissue

New connective tissue and microscopic blood vessels forming during healing.

Hyperplasia

Increase in tissue size due to excessive cell production.

Atrophy

Decrease in tissue or organ size due to reduced stimulation.

Neoplasms

Abnormal masses of tissue from uncontrolled cell growth; benign or malignant.