Cells and Mitosis

© 2004 Wadsworth – Thomson Learning

Prokaryotic and Eukaryotic Prokaryotic and Eukaryotic CellsCells


PROKARYOTIC VS. EUKARYOTIC

Prokaryotic No nucleus No membrane-

bound organelles Cell wall contains

peptidoglycan Size: less than

several micrometers

Eukaryotic Nucleus Membrane-bound

organelles No peptidoglycan if

cell wall even present Size: may be 10 times

larger


PROKARYOTES--CELL STRUCTURE

Appendages on outside Capsule and envelope

outer membrane (some) periplasmic space

between two membranes cell wall (most) cytoplasmic membrane

Cytoplasm nucleoid ribosomes storage granules Figure 4.3


PROKARYOTES: OUTER MEMBRANE

Lipid bilayer phospholipid lipopolysaccharide (LPS)

endotoxin lipid A porins lipoprotein

anchors to cell wall unique to bacteria

Figure 4.5


PROKARYOTES: CELL WALL Provide shape Withstand turgor pressure

(osmotic pressure) Composition

peptidoglycan: murein part protein (peptido-) part polysaccharide (-glycan) chains of alternating

polysaccharide N-acetylglucosamine (NAG) N-acetylmuramic acid (NAM)

cross-linked with peptidesFigure 4.6


SPHERICAL BACTERIA

Cocci (Coccus) single pair

diplococcus group of four

tetrads chain

streptococcus clusters

staphylococcus

Figure 4.7


ROD-SHAPED BACTERIA

Bacilli (Bacillus) Arrangement

single pair

diplobacillus chain

streptobacillus

Figure 4.7


SPIRAL AND OTHER SHAPED

Spiral shaped spirilla (spirillum)

Comma shaped vibrio

Other Square Star-shaped

Figure 4.7


CYTOPLASMIC MEMBRANE Contain the cytoplasm Both Eucaryotic and Procaryotic regulate passage into and out of cell Components

phospholipid bilayer proteins

transmembrane cytoplasmic peripheral

Fluidity of membrane

Figure 4.8


PROKARYOTES: APPENDAGES

Pili (Pilus) or fimbriae attachment

Flagella (flagellum) locomotion

propeller-like motion structure

helical-shaped filament hook

attached to anchor basal body

anchors in membrane Figure 4.10


PROKARYOTES: MOVEMENT

Chemotaxis sense chemicals

Phototaxis sense light intensity

Aerotaxis favorable oxygen

concentrations Magnetotaxis

move along magnetic lines


PROKARYOTES: CHEMOTAXIS Run: swimming motion

propelled by flagella working in unison Tumble: senses the chemical concentration

flagella loosen apart repeat actions changing direction slightly

Figure 4.12


PROKAYROTES: OUTERMOST LAYER

Capsule, slime layer, glycocalyx Slimy or gummy substance Composition varies Most made of polysaccharides

Function Protection

Against drying out Against phagocytosis

Adhere to surface pathogenesis


PROKARYOTES: CYTOPLASM Primarily water Site of metabolism Nucleoid

region contains DNA Ribosomes

site of protein synthesis Inclusion bodies

storage granules Gas vacuoles Chlorosomes magnetosomes


PROKARYOTES: ENDOSPORES

Resting structures formed inside cell Conditions unfavorable for growth

extreme heat dehydration toxic chemicals radiation

Long-term survival hundreds of years


SPORULATON

Unequal cell division begins

Cytoplasm divides vegetative cell forespore

DNA in both parts

Figure 4.15


SPORULATION Thick protective wall forms

peptidoglycan--different than vegetative cell keratinlike

Spore body contains all essential cell components

Vegetative cell lyses--releases endospore Germinates when conditions become favorable

Figure 4.15


STRUCTURE OF ARCHAEA

Cell walls archaea have protein or

pseudomurein Plasma membrane

fatty acids attached to glycerol differently bacteria--ester bond archaea-ether bond

stronger bond withstand harsh

conditions

Figure 4.16


EUKARYOTES: APPENDAGES

Flagella Purpose

motility wave-like motion (not propeller-like)

Composition microtubules

9 pair surrounding 2 central

Cilia shorter more numerous


EUKARYOTES: CELL WALL AND CYTOPLASMIC MEMBRANE

Cell wall great diversity many cells don’t have (animal cells) composition varies

Cytoplasmic membrane similar to prokaryotes


EUKARYOTES: CYTOSKELETON Function

structure movement

cytoplasmic streaming transport of molecules

cell division Fibrous protein

structures three types

Microtubules Microfilaments Intermediate filaments

Figure 4.17a


EUKARYOTES: NUCLEUS

Function contain the DNA

Nuclear membrane lipid bilayer surrounding nucleus nuclear pores

passage of material Nucleoplasm

gelatinous matrix of nucleus Nucleoli

dense masses of RNA and protein


EUKARYOTES:CYTOMEMBRANE SYSTEM

Function sorting and transport

of synthesized molecules

Components Endoplasmic reticulum

(ER) rough ER

ribosomes attached smooth ER

no ribosomes Figure 4.21


EUKARYOTES:CYTOMEMBRANE SYSTEM

Golgi apparatus stacks of flattened

membrane sacs molecules are

modified

Vessicles transport from ER to Golgi from Golgi to final

destination inside the cell outside the cell

Figure 4.22


EUKARYOTES:MITOCHONDRIA AND CHLOROPLASTS

Energy production Double membrane system

outer membrane--separate from rest of cell inner membrane--highly folded

Mitochondria respiration

Chloroplasts photosynthesis


CELL DIVISION: MITOSIS

Cell division ending in two identical cells Stages:

Interphase DNA decondenses DNA replicated

Mitosis Prophase Metaphase Anaphase Telophase

Figure 4.19



Early prophase double number of

chromosomes chromosomes condense

Late prophase spindle forms chromosomes condensed

Figure 4.19



Metaphase chromosomes attach to

spindle fibers chromosomes line up

middle of cell

Anaphase chromosomes moved to

opposite ends of cell

Figure 4.19



Telophase chromosomes

decondense nuclear membrane

reforms cell separation occurs

Interphase identical daughter cells

Figure 4.19

Cells and Mitosis

Documents