Campbell Biology Chapter 6

light microscopy

magnification of cellular structures up to 1000 X

scanning electron microscopy (SEM)

image of 3D surface coated with heavy metal like gold (100,000 X)

transmission electron microscopy (TEM)

image of ultra thin slice to view intracellular components (500,000 x)

cell fractionation

technique that breaks cells and separates their components

cytosol

aqueous part of cytoplasm within which particles and organelles are suspended

nucleoid

densly staining DNA region in a prokaryotic cell

chromatin

uncondensed DNA wrapped around histones (used during transcription)

chromosome

condensed chromatin (used during cell division)

nucleus

organelle that contains DNA and controls processes of cell

nucleolus

organelle where ribosomes are synthesized and partially assembled (within nucleus)

nuclear envelope

perforated double membrane that controls flow of materials (around nucleus)

ribosomes

organelles made of protein and rRNA that direct protein synthesis (in cytoplasm or tethered to rough ER)

nuclear lamina

netlike array of intermediate filaments that maintains shape of nucleus

endoplasmic reticulum (ER)

internal membrane system in which components of cell membrane and some proteins are constructed

rough ER

organelle continuoues with nuclear membrane, to which ribosomes are tethered and proteins are synthesized for export

smooth ER

organelle where lipids are synthesized

vesicles

small sacs surrounded by phospholipid bilayer that specialize in moving products into, out of, and within a cell

golgi apparatus

stack of membranes that modifies, sorts, and packages proteins for transport

lysosome

organelle filled with enzymes that break down chemicals

phagocytosis

when extensions of cytoplasm surround and engulf LARGE food particles

contractile vacuole

saclike organelles that expand to collect excess water and contract to squeeze it out of cell

central vacuole

membranous sac in plant cells with roles in reproduction, growth, and storage

mitochondria

organelle in all eukaryotic cells where chemical energy in glucose and fats is transformed into ATP (cellular respiration SITE)

chloroplast

organelle in plants where sunlight energy is used to synthesize glucose (photosynthesis SITE)

endosymbiont theory

states that mitochondria and chloroplasts originated as prokaryotic cells engulfed by ancestral eukaryotic cell

mitochondrial matrix

(D) internal compartment of mitochondria (Krebs cycle SITE)

cristae

(E) inner membrane infoldinfgs of mitochondria that increase surface area (Electron Transport Chain and ATP synthase SITE)

thylakoids

(C) flattened membrane sacs in chloroplast (Light Reactions SITE)

grana

(B) stacked thylakoid membranes in chloroplast

stroma

(A) innermost compartment of chloroplast (Calvin cycle SITE)

plastids

plant organelles surrounded by double membrane with their own DNA, that make and store food and pigments

peroxisomes

animal orgnalles that contain enzymes that detoxify alcohols, hydrogen peroxide, and other harmful chemicals

cytoskeleton

microscopic network of protein fibers within cytoplasm that gives shape to cell

microtubules

(bottom) thickest, hollow tubes of tubulin proteins that make up cilia, flagella, and mitotic spindle and help move organelles around cell

microfilaments

(top) thinnest, intertwined fibers of actin proteins that allow cytoplasmic streaming, ameboid movement and keep cell extensions rigid (microvilli, axons)

intermediate filaments

(middle) medium, coiled fibers of keratin that help maintain cell shape, stabilize positions of organelles

keratin

protein found in epidermis, hair, and nails

centrioles

organelles in animal cells from which mitotic spindle forms during cell division (resemble basal bodies)

mitotic spindle

microtubules that attach to centromeres through kinetochore proteins of chromosomes and pull sister chromatids apart during cell divisions

cilia

(A) short, many extensions of membrane-covered microtubules that move cell or materials past cell (ex. paramecium, trachea)

flagella

(E) long, few, whiplike tails of membrane-covered microtubules that move cells

9+2 structure

cylinder of 9 microtubule doublets around a 1 doublet (make up cilia, flagella, mitotic spindle)

basal body

star of 9 microtubules triplets that anchors cilia and flagella in membrane (resembles centrioles)

dyneins

proteins that connect microtubules in the 9+2 structure AND attach organelles to microtubules; when they contract, flagella/cilia move AND organelles "walk"

cytoplasmic streaming

circular flow of cytosol using myosin and actin filaments that speeds up distribution of materials within cells

cell wall

strong supporting layer of cellulose, chitin, or peptidoglycans around cell membrane in plants, fungi, or bacteria

middle lamina

(A) thin layer of adhesive extracellular material (pectins) between primary walls of adjacent young plant cells

primary cell wall

(B) thin, flexible and furthest out because it is secreted first

secondary cell wall

(C) strong, durable matrix added between plasma membrane and outermost structure for structure and support

extracellular matrix (ECM)

substance in which animal cells are embedded, consisting of proteins and polysaccharides

peptido/proteo-glycans

small core proteins with EXTENSIVE carbohydrate chains found in bacterial cell walls and animal ECM

glycoproteins

transmembrane proteins with SHORT carbohydrate chains that identify the cell

fibronectin

a glycoprotein that helps cells attach to extracellular matrix

integrins

transmembrane proteins that connect both to outside extracellular matrix and inside cytoskeleton of animal cells.

plasmodesmata

(2) openings in plant cell walls through which strands of ER and cytosol connect adjacent cells

gap junctions

(C) cytoplasmic channels between adjacent animal cells that allow movement of materials

tight junctions

(A) membrane fusions of neighboring cells that prevent leakage of fluid between them

desmosomes

(B) anchoring junctions that prevents cells subjected to mechanical stress from being pulled apart

microvilli

finger-like extensions of cells that increase surface area to increase absorption (ex. small intestine)

prokaryote

unicellular organism without nucleus and membrane bound organelles (archea and bacteria)

eukaryote

cells with nucleus and membrane bound organelles

psuedopodia

temporary projections of eukaryotic cell membranes or unicellular protists in direction of movement

collagen

fibrous protein found in connective tissues and ECM