Ch. 3 Cells and Tissues

secretory vesicles

"Cargo Trucks" of the cell. Small membrane-bound structures that function to move molecules from place to place in cell.

hydrophilic

"Water loving", Attracted to water

hydrophobic

"water hating", Having an aversion to water; tending to coalesce and form droplets in water.

nucleus

(1) a dense central body in most cells containing the genetic material of the cell; (2) cluster of neuronal cell bodies in the brain or spinal cord.

Cell theory

(biology) the theory that cells form the fundamental structural and functional units of all living organisms

Simple diffusion

- net movement of dissolved particles down their concentration gradient

peroxisomes

A cell organelle containing enzymes that catalyze the production and breakdown of hydrogen peroxide.

endoplasmic reticulum (ER)

A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.

concentration gradient

A difference in the concentration of a substance across a distance

nuclear envelope

A double membrane that surrounds the nucleus in the cell.

Gap junctions

A gap junction or nexus is a specialized intercellular connection between a multitude of animal cell-types. It directly connects the cytoplasm of two cells, which allows various molecules and ions to pass freely between cells.

nuclear membrane

A highly-porous membrane that separates the nucleus from the cytoplasm

solution

A homogeneous mixture of two or more substances.

cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended.

flagella

A long, whip-like filament that helps in cell motility. Many bacteria are flagellated, and sperm are flagellated.

Vesicle

A membrane bound sac that contains materials involved in transport of the cell.

organelles

A membrane-enclosed structure with a specialized function within a cell.

rough ER

A network of interconnected membranous sacs in a eukaryotic cell's cytoplasm; covered with ribosomes that make membrane proteins and secretory proteins.

cytoskeleton

A network of long protein strands in the cytosol that helps support the cell

Mitosis

A process of nuclear division in eukaryotic cells conventionally divided into five stages: prophase, prometaphase, metaphase, anaphase, and telophase. Mitosis conserves chromosome number by equally allocating replicated chromosomes to each of the daughter nuclei.

filtration

A process that separates materials based on the size of their particles.

selective permeability

A property of biological membranes that allows some substances to cross more easily than others.

plasma membrane

A selectively-permeable phospholipid bilayer forming the boundary of the cells

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

transport vesicles

A tiny membranous sac in a cell's cytoplasm carrying molecules produced by the cell.

pinocytosis

A type of endocytosis in which the cell ingests extracellular fluid and its dissolved solutes., Cell drinking

Endocytosis

Active transport process where a cell engulfs materials with a portion of the cell's plasma membrane and releases the contents inside of the cell.

Lysosomes

An organelle containing digestive enzymes

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

Desmosomes

Anchoring junctions scattered like rivets alone the sides of abutting cells. They prevent cells subjected to mechanical stress from being pulled apart.

interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

Mitochondrion

Cell organelle that converts the chemical energy stored in food into compounds that are more convenient for the cell to use.

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates., - Membrane-bound sacs for storage, digestion, and waste removal.

Inclusions

Chemical substances such as stored nutrients or cell products. May or may not be present depending on cell type.

free radicals

Chemicals that harm the bodies tissues by starting destructive chain reactions in the molecules of the bodies cells, such reactions are believed to trigger or worsen some diseases

solutes

Components in smaller quantities within a solution.

osmosis

Diffusion of water through a selectively permeable membrane.

cytokinesis

Division of the cytoplasm during cell division

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

Microvilli

Fingerlike extensions of plasma membrane of apical epithelial cells, increase surface area, aid in absorbtion, exist on every moist epithelia, but most dense in small intestine and kidney

Tight junctions

Impermeable, bind cells together into leak-proof sheets that prevent substances from passing through the extracellular space between cells.

solvent

In a solution, the substance in which the solute dissolves.

smooth ER

Is ER that does not have ribosomes attached. It is a major site of lipid synthesis.

Microfilaments

Long, thin fibers that function in the movement and support of the cell

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

facilitated diffusion

Movement of specific molecules across cell membranes through protein channels

Exocytosis

Moving of molecules out of the cell using active transport

pressure gradient

Pressure difference between two points

cell division

Process by which a cell divides into two new daughter cells

cytosol

The aqueous part of the cytoplasm within which various particles and organelles are suspended

Fibroblast

The elongated shape of this cell lies along the cable-like fibers that it secretes. It has an abundant rough ER and a large Golgi apparatus to make and secrete the protein building blocks of these fibers.

Epithelial cell

The hexagonal shape of the cell is exactly like a "cell" in a honeycomb of a beehive. This shape allows epithelial cells to pack together in sheets. An epithelial cell has abundant intermediate filaments that resist tearing when the epithelium is rubbed or pulled.

Fat cell

The huge spherical shape of a fat cell is produced by a large lipid droplet in its cytoplasm.

Oocyte (female)

The largest cell in the body, this egg cell contains several copies of all organelles, for distribution to the daughter cells that arise when the fertilized egg divides to become an embryo.

Receptor-mediated endocytosis

The movement of specific molecules into a cell by the inward budding of membranous vesicles containing proteins with receptor sites specific to the molecules being taken in; enables a cell to acquire bulk quantities of specific substances.

Skeletal muscle and smooth muscle cells

These cells are elongated and filled with abundant contractile filaments, so they can shorten forcefully and move the bones or change the size of internal organs.

Erythrocyte (red blood cell)

This cell carries oxygen in the bloodstream. Its concave disc shape provides extra surface area for the uptake of oxygen and streamlines the cell so it flows easily through the bloodstream. So much oxygen-carrying pigment is packed in erythrocytes that all other organelles have been shed to make room.

Macrophage (a phagocytic cell)

This cell extends long pseudopods ("false feet") to crawl through tissue to reach infection sites. The many lysosomes within the cell digest the infectious microorganisms it takes up.

Nerve cell (neuron)

This cell has long processes (extensions) for receiving messages and transmitting them to other structures in the body. The processes are covered with an extensive plasma membrane, and a plentiful rough ER synthesizes membrane components.

Sperm (male)

This cell is long and streamlined, built for swimming to the egg for fertilization. Its flagellum acts as a motile whip to propel the sperm.

intermediate filaments

Threadlike proteins in the cell's cytoskeleton that are roughly twice as thick as microfilaments

generalized cell

a cell used for diagram purposes, with general organelles and shape.

solute pumps

are protein carriers energized by ATP

Cells

are the basic biological unit of living organisms, enclosed by a limiting membrane; cells in more complex organisms contain a nucleus and variety of organelles.

Ribosomes

are tiny, bilobed, dark bodies made of proteins and one variety of RNA called ribosomal RNA.

Cilia

are whiplike cellular extensions that move substances along the cell surface., Hairlike projections that extend from the plasma membrane and are used for locomotion

chromosomes

barlike body of tightly coiled chromatin; visible during cell division.

nucleoli

dense masses of RNA and protein that manufacture ribosomes, several of these are located in the nucleus.

connexons

hold tissues/membranes together; hollow cylinders composed of proteins that span the entire width of the abutting membranes

vesicular transport

involves help from ATP, moves substances into or out of cells without their actually crossing the plasma membrane.

Intracellular fluid

is a solution containing small amounts of gasses (oxygen and carbon dioxide), nutrients, and salts, dissolved in water.

centrioles

lie close to the nucleus. They are rod-shaped bodies that lie at right angles to each other; internally they are made up of pinwheel array of fine microtubules.

interstitial fluid

liquid found between the cells of the body that provides much of the liquid environment of the body.

microtubles

long strands such a spindle fibers that move chromosomes, - Hollow tubes of a protein called tubulin that support the cell.

phagocytosis

process in which phagocytes engulf and digest microorganisms and cellular debris, "Cell eating"

Cell life cycle

series of changes a cell goes through from the time it is formed until it divides

sodium-potassium pump

simultaneously carries sodium ions (Na+) out of and potassium ions (K+) into the cell is absolutely necessary for normal transmission of impulses by nerve cells.

Nuclear pores

structures in the nuclear envelope that allow passage of certain materials between the cell nucleus and the cytoplasm

chromatin

the structures in the nucleus that carry the hereditary factors (genes).