Anatomy

Cell

Basic structural unit of all living organisms.

Nucleus

Control center containing genetic material (DNA).

DNA

Genetic material necessary for protein synthesis.

Cell Theory

Foundation stating cells are basic life units.

Nuclear Envelope

Double membrane surrounding the nucleus.

Nucleolus

Site of ribosome assembly within the nucleus.

Chromatin

DNA-protein complex present when the cell is not dividing.

Cytoplasm

Cellular material outside the nucleus.

Plasma Membrane

Barrier separating cell contents from the environment.

Fluid Mosaic Model

Describes plasma membrane structure with phospholipids and proteins.

Phospholipids

Molecules forming the bilayer of the plasma membrane.

Glycoproteins

Proteins with sugar chains on cell surface.

Glycocalyx

Fuzzy sugar-rich area on the cell surface.

Cell Junctions

Structures that connect adjacent cells.

Tight Junctions

Impermeable junctions forming leakproof sheets.

Desmosomes

Anchoring junctions preventing cell separation.

Gap Junctions

Channels allowing communication between adjacent cells.

Mitochondria

Powerhouses of the cell producing ATP.

Ribosomes

Sites of protein synthesis in the cell.

Endoplasmic Reticulum (ER)

Network of membranes for substance transport.

Rough ER

Studded with ribosomes; synthesizes proteins.

Smooth ER

Lacks ribosomes; involved in lipid metabolism.

Cytoskeleton

Network providing internal support and shape.

Golgi Apparatus

Modifies and packages proteins for transport.

Transport Vesicles

Carry proteins within the cell.

Free Radicals

Highly reactive chemicals needing detoxification.

Hydrogen Peroxide

Intermediate product in free radical detoxification.

Microfilaments

Smallest cytoskeleton elements providing structure.

Intermediate Filaments

Provide tensile strength to cells.

Organelles

Cellular structures performing specific functions.

Microtubules

Smallest cytoskeletal structures aiding in cell shape.

Lysosomes

Membranous bags containing digestive enzymes.

Centrioles

Rod-shaped bodies forming microtubule triplets.

Mitotic spindle

Structure that separates chromosomes during cell division.

Phagocytes

Cells that engulf and digest bacteria and debris.

Cilia

Surface extensions that move materials across cells.

Flagella

Long projections that propel cells, like sperm.

Peroxisomes

Sacs containing oxidase enzymes for detoxification.

Microvilli

Tiny extensions increasing surface area for absorption.

Erythrocyte

Red blood cell that carries oxygen in blood.

Oocyte

Largest human cell, involved in reproduction.

Fibroblast

Cell that secretes fibers connecting body parts.

Neuron

Cell that transmits messages throughout the body.

Skeletal muscle

Muscle cells responsible for voluntary movements.

Smooth muscle

Involuntary muscle cells moving organs and vessels.

Membrane Transport

Processes moving substances across cell membranes.

Diffusion

Movement of molecules from high to low concentration.

Osmosis

Diffusion of water across a selectively permeable membrane.

Isotonic solution

Equal solute concentration, no cell change.

Hypertonic solution

Higher solute concentration, causes cell shrinkage.

Hypotonic solution

Lower solute concentration, causes cell swelling.

Active transport

Movement of substances against concentration gradient using ATP.

Facilitated diffusion

Transport of substances via protein carriers without energy.

Sodium-potassium pump

Active transport mechanism maintaining ion balance in cells.

Exocytosis

Process of expelling substances from the cell.

Endocytosis

Process of engulfing substances into the cell.

Filtration

Movement of solutes through a membrane by pressure.

Intracellular fluid

Fluid within cells, includes cytosol and nucleoplasm.

Extracellular fluid

Fluid outside cells, includes interstitial fluid.

Phagocytosis

Cell engulfs large particles like bacteria.

Pinocytosis

Cell 'gulps' droplets of extracellular fluid.

Vesicle

Membranous sac transporting materials in cells.

Pseudopods

Cytoplasmic extensions for engulfing substances.

Receptor-mediated endocytosis

Selective uptake of specific target molecules.

Cytokinesis

Division of the cytoplasm during cell division.

Interphase

Metabolic phase before cell division starts.

Mitosis

Division of the nucleus into two nuclei.

Prophase

Chromatin condenses into visible chromosomes.

Metaphase

Chromosomes align at the metaphase plate.

Anaphase

Chromatids move apart to opposite cell ends.

Telophase

Chromosomes uncoil and nuclear envelope re-forms.

DNA Replication

Genetic material duplicates for cell division.

Triplet

Three bases coding for one amino acid.

RNA

Single-stranded nucleic acid for protein synthesis.

tRNA

Transfers amino acids to ribosomes.

rRNA

Forms ribosomes where proteins are synthesized.

mRNA

Carries instructions from DNA to ribosomes.

Transcription

DNA information transferred to mRNA sequence.

Translation

mRNA codons translated into amino acid sequence.

Amino Acids

Building blocks of proteins.

Chromatid

Identical strands of a chromosome.

Centromere

Region holding sister chromatids together.

Cleavage Furrow

Contractile ring forming during cytokinesis.

Gene

DNA segment coding for a protein.

Cell Cycle

Series of changes from formation to division.

Daughter Cells

Result of cell division, two identical cells.