Chapter 4 Biology

Front 1

Cell biology

Back 1

the study of individual cells and their interactions with each other

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Cell theory

Back 2

a theory that states that all organisms are made of cells, cells are the smallest units of living organisms, and new cells come from pre-existing cells by cell division

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microscope

Back 3

a magnification tool that enables researchers to study very small structures such as cells

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micrograph

Back 4

an image taken with the aid of a microscope

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resolution

Back 5

in microscopy, the ability to observe two adjacent objects as distinct from one another; a measure of the clarity of an image

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contrast

Back 6

in microscopy, relative differences in the lightness, darkness, or color between adjacent regions in a sample

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magnification

Back 7

the ratio between the size of an image produced by a microscope and a sample's actual size

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light microscope

Back 8

a microscope that utilizes light for illumination

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electron microscope

Back 9

a microscope that uses an electron beam for illumination

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transmission electron microscope (TEM)

Back 10

a type of microscopy in which a beam of electrons is transmitted through a biological sample to form an image on a photographic plate or screen

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scanning electron microscopy (SEM)

Back 11

a type of microscopy that utilizes an electron beam to produce an image of the three-dimensional surface of biological samples

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protein-protein interactions

Back 12

the specific interactions between proteins that occur during many critical cellular processes

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genome

Back 13

the compete genetic composition of a cell or a species

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genes

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a unit of heredity that contributes to the characteristics or traits of an organism. At the molecular level, a gene is composed of organized sequences of DNA

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Prokaryotic cells

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refers to organisms having cells lacking a membrane-enclosed nucleus and cell compartmentalization; includes all members of the domains Bacteria and Archaea

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bacteria

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when not capitalized, refers to a cell or species within the domain Bacteria

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arachaea

Back 17

when not capitalized, refers to a cell or species within the domain Arachaea

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plasma membrane

Back 18

the biomembrane that separates the internal contents of a cell from its external environment

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cytoplasm

Back 19

the region of the cell that is contained within the plasma membrane

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nucleoid region

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a site in a bacterial cell where the genetic material (DNA) is located

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ribosomes

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a structure composed of proteins and rRNA that provides the site where polypeptide synthesis occurs

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Glycocalyx

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1. an outer viscous covering surrounding a bacterium that traps water and helps protect bacteria from drying out

2. A carbohydrate-rich zone on the surface of animal cells; also called a cell coat

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pili

Back 23

threadlike surface appendages that allow bacteria to attach to each other during conjugation or to move across surfaces

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basal body

Back 24

a site at the base of flagella or cilia from which microtubules grow. Basal bodies are anchored on the cytosolic side of the plasma membrane

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nucleus

Back 25

1. In cell biology an organelle found in eukaryotic cells that contains most of the cell's genetic material.

2. In chemistry, the region of an atom that contains protons and neutrons.

3. In neurobiology, a group of neuronal cell bodies in the brain that are devoted to a particular function

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endomembrane system

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a network of membranes that includes the nuclear envelope, the endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, and plasma membrane

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vesicle

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a small membrane-enclosed sac within a cell

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nuclear envelope

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a double-membrane structure that encloses the cell's nucleus

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nuclear pores

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a passageway for the movement of molecules and macromolecules into and out of the nucleus; formed where the inner and outer nuclear membranes make contact with each other

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chromosomes

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a discrete unit of genetic material composed of DNA and associated proteins. Eukaryotes have chromosomes in their cell nuclei and in plastids and mitochondria

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chromatin

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refers to the biochemical composition of chromosomes, which contain DNA and many types of proteins

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nuclear matrix

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a filamentous network of proteins that is found inside the nucleus and lines the inner nuclear membrane. The nuclear matrix serves to organize the chromosomes

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chromosome territory

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a distinct, nonoverlapping area where each chromosome is located within the cell nucleus of eukaryotic cells

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nucleolus

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a prominent region in the nucleus of nondividing cells where ribosome assembly occurs

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Endoplasmic reticulum ER

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a convoluted network of membranes in a cell's cytoplasm that forms flattened, fluid-filled tubules or cisternae

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cisternae

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flattened, fluid-filled tubules of the endoplasmic reticulum

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lumen

Back 37

the internal space or hollow cavity of an organelle or an organ, such as the stomach or a blood vessel

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ER lumen

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a single compartment enclosed by the ER membrane

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Rough Endoplasmic Reticulum (rough ER)

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the part of the ER that is studded with ribosomes; this region plays a key role in the initial synthesis and sorting of proteins that are destined for the ER, Golgi apparatus, lysosomes, vacuoles, plasma membrane or outside of the cell

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Glycosylation

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the attachment of carbohydrate to a protein or lipid, producing a glycoprotein or glycolipid

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Smooth Endoplasmic Reticulum (smooth ER)

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the part of the ER that is not studded with ribosomes. This region is continuou s with the rough ER and functions in diverse metabolic processes such as detoxification, carbohydrate metabolism, accumulation of calcium ions (Ca2+) and synthesis and modification of lipids

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golgi apparatus

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a stack of flattened, membrane- bound compartments that performs three overlapping functions; secretion, processing, and protein sorting

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proteolysis

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a processing event within a cell in which enzymes called proteases cut proteins into smaller polypeptides