Human Anatomy, Chapter 2: Foundations The Cell

The cell theory concepts

1) Cells are the building blocks of all plants and animals. 2) Cells are produced by the division of preexisting cells. 3) Cells are the smallest units that preform all vital functions.

Concentration gradient

A difference in the concentration of a substance across a distance.

Phospholipid bilayer

A double layer of phospholipids that makes up plasma and organelle membranes.

Nuclear envelope

A double membrane that surrounds the nucleus in the cell

Cytoplasm

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

Flagellum

A long, hairlike structure that grows out of a cell and enables the cell to move.

Cytoskeleton

A network of fibers that holds the cell together, helps the cell to keep its shape, and aids in movement

Rough ER

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

Gated channels

A protein channel in a cell membrane that opens or closes in response to a particular stimulus.

Golgi Apparatus

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

Organelles

A tiny cell structure that carries out a specific function within the cell

Phagocytosis

A type of endocytosis in which a cell engulfs large particles or whole cells

Pinocytosis

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

Endoplasmic Reticulum (ER)

An extensive membranous network in eukaryotic cells, continuous with the outer nuclear membrane and composed of ribosome-studded (rough) and ribosome-free (smooth) regions.

Lysosomes

An organelle containing digestive enzymes

Desmosomes

Anchoring junctions that prevent cells from being pulled apart

Centrioles

Cell organelle that aids in cell division in animal cells only

Peroxisomes

Contain oxidase enzymes that detoxify alcohol, hydrogen peroxide, and other harmful chemicals

Nucleus

Control center of the cell. Contains DNA.

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

Plasma membrane (Plasmalemma)

Envelops the entire cells and provides a selective barrier that regulates transport of substances into and out of the cell and contains receptors which bind with various substances that can regulate cell activity

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

Cytosol

Fluid portion of cytoplasm

Cilia

Hairlike projections that extend from the plasma membrane and are used for locomotion

Microfilaments

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

Tight Junctions

Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

Diffusion

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

Mitochondria

Powerhouse of the cell

Cell Division

Process by which a cell divides into two new daughter cells

Exocytosis

Process by which a cell releases large amounts of material

Microtubules

Spiral strands of protein molecules that form a tubelike structure that make of cilia

Smooth ER

That portion of the endoplasmic reticulum that is free of ribosomes. Makes lipids

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.

Peripheral proteins

The proteins of a membrane that are not embedded in the lipid bilayer; they are appendages loosely bound to the surface of the membrane.

Intermediate filaments

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

Carrier proteins

a protein that transports substances across a cell membrane

Somatic cells

all cells in the body, not including sex cells.

Hemidesmosomes

attach epithelial cells to the basement membrane

Fixed Ribosomes

attached to the endoplasmic reticulum

Exchange pumps

carrier proteins that move one solute in one direction and another solute in the opposite direction

Cell Junctions

contact points between the plasma membranes of tissue cells

Non-membraneous organelles

cytoskeleton, centrioles, ribosomes

Ion pumps

enzymes that use the energy released by the breakdown of ATP to transport certain ions across the membrane

Prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

Extracellular fluid

fluid outside the cell

Sex cells

germ cells or reproductive cells

Nuclear pores

holes in the nuclear envelope that allow materials to pass in and out of the nucleus

Membraneous organelles

mitochondria, nucleus, endoplasmic reticulum, golgi apparatus, lysosomes, peroxisomes

Thick filaments

myosin

Basal body

organelle that develops from a centriole

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

Integral proteins

penetrate the hydrophobic interior of the lipid bilayer (embedded in the membrane)

Interphase

period of the cell cycle between cell divisions

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

Apoptosis

programmed cell death

Selectively permeable

property of biological membranes that allows some substances to pass across it while others cannot; also called semipermeable membrane

Ribosomes

protein synthesis

Cell Adhesion Molecules (CAMs)

proteins found on the surface of most cells that aid in the binding of the cell to the extracellular matrix or other cells; integral membrane proteins; three major families: cadherins, integrins, selectins

Gap Junctions

provide cytoplasmic channels between adjacent animal cells

Mitotic rate

rate of cell division

Channels

regulate water flow and solutes through membrane

Metaphase

second phase of mitosis, during which the chromosomes line up across the center of the cell

Secretory vesicles

secrete substances outside the cell by exocytosis

Free Ribosomes

suspended in the cytosol

Membrane flow

the continuous movement and exchange of membrane segments

Telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.

Anaphase

the third phase of mitosis, during which the chromosome pairs separate and move toward opposite poles

Facilitated diffusion

the transport of substances through a cell membrane along a concentration gradient with the aid of carrier proteins through protein channels

Intercellular Attachments

there are three different types of cell junctions, by which cells attach to each other or to extracellular protein fibers

Chromosomes

threadlike structures made of DNA molecules that contain the genes

Spot Desmosomes

tie cells together allow bending and twisting

Stem cells

unspecialized cells that are able to renew themselves for long periods of time by cell division