Anatomy and Physiology Marieb Chapter 3 - Cells

Cisternae

Any cavity or enclosed space serving as a reserviour

Cyclic AMP

Intracellular second messenger that mediates the effects of the first (extracellular) messenger (hormone or neurotransmitter); formed from ATP by the plasma membrane enzyme (adenylate cyclase).

Mitosis

Process during which the chromosomes are redistributed to two daughter nuclei; nuclear division. Consists of prophase, metaphase, anaphase, and telophase.

Aquaporins

Transmembrane proteins that form water channels.

Microvilli

Tiny projections on the free surface of some epithelial cells; increase surface area for absorption.

Hypertonic

Excessive, above normal, tone or tension\nContains higher concentration of solutes than are present inside the cell\nThe cells lose water by osmosis and shrink

Transfer RNA (tRNA)

Short-chain RNA molecules that transfer amino acids to the ribosome.

Organelles

Small cellular structures (ribosomes, mitochondria, and others) that perform specific metabolic functions for the cell as a whole.

Apoptosis

A process of controlled cellular suicide; eliminates cells that unneeded, stressed or aged.

Phagocytosis

Engulfing of foreign solids by (phagocytic) cells.

Receptor mediated endocytosis

One of three types of endocytosis in which engulfed particles attach to receptors before endocytosis occurs

Pinocytosis

Engulfing of extracellular fluid by cells

Mitotic (M) phase

One of two major periods in the cell life cycle; involves the division of the nucleus (mitosis) and the division of the cytoplasm (cytokinesis)

Cytokinesis

The division of cytoplasm that occurs after the cell nucleus has divided

Hypotonic solution

A solution that is more dilute (containing fewer nonpenetrating solutes) than the reference cell. Cells plump up rapidly as water rushes into them. And can burst

Translation

One of the two major steps in the transfer of genetic code information, in which the information carried by mRNA is decoded and used to assemble polypeptides

Concentration gradient

The difference in the concentration of a particular substance between two different areas

DNA replication

Process that occurs before the cell division; ensures that all daughter cells have identical genes

Facilitated diffusion

Passive transport process used by certain large or charged molecules (eg glucose, Sodium) that are unable to pass through the plasma membrane unaided. Involves movement through channels or movement facilitated by a membrane carrier

Multinucleate cell

Cell with more that one nucleous eg skeletal muscle cells, osteoclasts

Interphase

One of two major periods in the cell life cycle; includes the period from cell formation to cell division

Telophase

The final phase of mitosis; begins when migration of chromosomes to the poles of the cell has been completed and ends with the formation of two daughter cells

Gene

One of the biological units of heredity located in chromatin; transmits hereditary information

Vesicular transport

Transport of large particles and macromolecules into or out of a cell or between its compartments in membrane-bound sacs

G Protein

Protein that relays signals between extracellular first messengers (hormones or neurotransmitters) and intracellular second messengers (such as cyclic AMP) via and effector enzyme

Metaphase

Second stage of mitosis

Flagellum

Long, whiplike cellular extension containing microtubules; propels sperm and some single celled eukaryotes

Cytosol

Vicous, semitransparent fluid substance of the cytoplasm in which other elements are suspended

Glycocalyz (cell coat)

A layer of externally facing glycoproteins on a cell's plasma membrane; its components determine bloodtype and are involved in the cellular interactions of fertilization, embryonic development, and immunity, and acts as an adhesive between cells

Carrier

A transmembrane protein that changes shape to envelop and transport a polar substance across the cell membrane

Hypertrophy

Increase in size of tissue or organ independent of the body's general growth

Tight Junction

Area where plasma membranes of adjacent cells are tightly bound together forming an impermeable barrier.

Second messenger

Intracellular molecule generated by the binding of a chemical (hormone or neurotransmitter) to a receptor protein; mediates intracellular responses to the chemical messengar

Exons

Amino acid specifying informational sequences (separated by introns) in the genes of higher organisms

Peristalsis

Progressive, wavelike contractions that move foodstuffs through the alimentary tube organs (or that move other substances through other hollow body organs)

Intron

Noncoding segment or portion of DNA that ranges from 60 to 100,000 nucleotides long

Messenger RNA m(RNA)

Long nucleotide strands that reflect the exact nucleotide sequences of the genetically active DNA and carry the DNA's message

Polarized

State of plasma membrane of an unstimulated neuron or muscle cell in which the inside of the cell is relatively negative in comparison to the outside; the resting state

S (synthetic) phase

The part of the interphase period of the cell life cycle in which DNA replicates itself, ensuring that the two future cells will receive identical copies of genetic material

Electrochemical gradient

The combined difference in concentration and charge; influences the distribution and direction of diffusion of ions

Nuclear envelope

The double membrane barrier of a cell nucleus

Endocytosis

Mean by which fairly large extracellular molecules or particles enter cells eg phagocytosis, pinocytosis, receptor mediated endocytosis

Hydrophobic

Fear of water. Refers to molecules, or portions of molecules, that interact only with nonpolar molecules

Membrane potential

Voltage across the plasma membrane

Glycolipid

A lipid with one or more covalently attached sugars

Golgi apparatus

Membranous system close to the cell nucleous that packages protein secretions for export, packages enzymes into lysosomes for cellular use, and modifies proteins destines to become part of the cellular membranes

Ribosomal RNA (rRNA)

A constituent of ribosome; exists within the ribosomes of cytoplasm and assists in protein synthesis

Interstitial fluid (IF)

Fluid between cells

Ribosomes

Cytoplasmic organelles at which proteins are synthesized

Isotonic solution

A solution with a concentration of nonpenetrating solutes equal to that found in the reference cell.

Cell life cycle

Series of changes a cell goes through from the time it is formed until it reporduces itself

Autolysis (aw-tol-i-sis)

Process of autodigestion (self-digestion) of cells, espically dead or degenerate cells

Anaphase

Third stage of mitosis in which a full set of daughter chromosomes move toward each pole of the cell

Cell

Structural unit of all living things

Vesicle

A small liquid filled sac or bladder

Fluid mosaic model

A pepiction of the structure of the membranes of a cell as phospholipid layers in which proteins are dispersed

Anucleate cell

A cell without a nucleus

Diffusion

The spreading of particles in a gas or solution with a movement toward uniform distribution of particles

Osmotic pressure

A measure of the tendancy of water to move into more concentrated solution

Free radicals

Highly reactive chemicals with unpaired electrons that can scramble the structure of proteins, lipids and nucleic acids

Ligands

Signaling chemicals that bind specifically to membrane receptors

Vesicular transport

The movement of large particles and macromolecules across a plasma membrane

Dialysis

Diffusion of solute(s) through a semipermeable membrane

Endoplasmic reticulum (ER)

Membranous network of tubular or saclike channels in the cytoplasm of a cell

Nucleus

Control centre of a cell; contains genetic material; clusters of nerve cell bodies in the CNS (central nervous system)

Active Transport

Membrane transport processes of which ATP is provided eg solute pumping and endocytosis

Genetic code

Refers to the rules by which the base sequence of a DNA gene is translated into protein structures (amino acid sequences)

Codon

The three base sequence on a messenger RNA molecule that provides genetic information used in protein synthesis

Nucleosome

Fundamental unit of chromatin; consists of a strand of DNA wound around a cluster of eight histone proteins

Hypertonic solution

A solution that has a higher concentration of nonpenetrating solutes than the reference cell; having greater osmotic pressure than the reference solution (blodd plasma or interstitial fluid)

Channel

A transmembrane protein that helps form aqueous channels that transport substances from one side of the membrane to the other

Mitochondria

Cytoplasmic organelles responsible for ATP generation for cellular activities

Microtubles

One of three types of rods in the cytoskeleton of a cell; hollow tubes made of shperical protein that determine the cell shape as well as the distribution of cellular organelles

Peroxisomes

Membranous sacs in cytoplasm containing powerful oxidase enzymes that use molecular oxygen to detoxify harmful or toxic substances, such as free radicals

Plasma membrane

Membrane, composed of phospholipids, cholesterol, and proteins, that enclosed cell contents; outer limiting cell membrane

Solute pump

Enzyme like protein carrier that mediates active transport of solutes such as amino acids and ions uphill against their concentration gradients

Cytoplasm

The cellular material surrounding the nucleous and enclosed by the plasma membrane

Pressure gradient

Difference in hydrostatic pressure that drives filtration

Translation

One of two major steps in the transfer of genetic code information, in which the information carried by mRNA is decoded and used to assemble polypeptides

Gap junction

A passageway between two adjacent cells; formed by transmembrane proteins called connexons

Membrane receptors

A large, diverse group of integral proteins and glycoproteins that server as binding sites

Phagosome

Vesicle formed as a result of phagocytosis

Intron

Noncoding segment or portion of DNA that ranges from 60 to 100,000 nucleotides long

Lysosomes

Orgnaelles that orginate from the Golgi apparatus and contain strong digestive enzymes

Prophase

The first stage of mitosis, consisting of coiling of the chromosomes accompanied by migration of the tow daugher centrioles toward poles of the cell, and nuclear membrand breakdown

Selectively permeable membrane

A membrane that allows certain substances to pass while restricting the movement of others; also called differentially permeable membrane

Passive transport process

Membrane transport processes that do not require cellular energy (ATP) eg diffusion, which is driven by kinetic energy

Centriol

Minute body found near the nucleus of the cell; active in cell division

Exocytosis

Mechanism by which substances are moved from the cell interior to the extracellular space as a secretory vesicle fuses with the plasma membrane

Chromosomes

Barlike bodies of tightly coiled chromatin; visible during cell division

Tonicity

A measure of the ability of a solution to cause a change in cell shape or tone by promoting osmotic flows of water

Simple diffusion

The unassisted transport across a plasma membrane of a lipid-soluble or very small particle

Necrosis

Death or disintegration of a cell or tissues caused by disease or injury

Cytoskeleton

Literally, cell skeleton. An elaborate series of rods running through the cystol, supporting cellular structures and providing the machinery to generate varous cell movements

Flagellum

Long, whiplike extension of the plasma membrane of some bacteria and of sperm; propels the cell

Secretory vesicles (granules)

Vesicles containing proteins that migrate to the plasma membrane of a cell and discharge their contents from the cell by exocytosis