Download presentation
Published byHector Long Modified over 9 years ago
1
CHAPTER 4 Functional Anatomy of Prokaryotic and Eukaryotic Cells
Stem Cells
2
DNA found in multiple chromosomes Histones with DNA
PROKARYOTES Greek “prenucleus” DNA not enclosed within a membrane DNA is usually a singular circularly chromosome DNA not associated with histones Lack membrane bound organelles Cell walls contain polysaccharide peptidoglycan Divide by binary fission EUKARYOTES “true nucleus” DNA in a nucleus DNA found in multiple chromosomes Histones with DNA Membrane bound organelles Cell walls chemically simple mitosis
3
Prokaryote Characteristics
0.2 to 2.0 μm in diameter and 2 to 8 μm in length Shapes: coccus, bacillus, spiral
4
ARRANGEMENTS OF COCCI Diplococci (remain in pairs)
Streptococci (remain in chain) Tetra (divide in 2 planes, remain in groups of four) Sarcinae (divide in 3 planes, remain in cube) Staphylococci (divide in multiple planes, remain in grapelike clusters)
5
ARRANGEMENT OF BACILLI
Diplobacilli: appear in pairs Streptobacilli: appear in chains Coccobacilli: oval, look like cocci Palisades: picket fence
6
ARRANGEMENT OF SPIRILIUM
Vibrios: curved rods Spirilla: helical shape, rigid bodies Spirochetes: helical and fexible
7
External Structures GLYCOCALYX (sugar coat):
sticky, gelatinous polymer outside the cell wall Composed of polysaccharide, polypeptide or both If attached to cell wall, considered a capsule If unorganized and loosely attached, considered a slime layer Contributes to bacterial virulence Important component of biofims Help attach to various surfaces, protects, facilitates communication (Extracellular polymeric substance EPS) Cyanobacterium Capsule in olive green
8
FLAGELLA Atichous: cell without flagella
Monotrichous: a single flagellum at one pole Lophotrichous: tuft of flagella from one or both poles Amphitrichous: single flagella at both boles Peritrichous: distributed over the entire cell
9
FLAGELLA MOVEMENT file:///E:/Chapter_04/A_PowerPoint/a_Lecture_Outline/flagella_arrange.html
10
Fimbriae and Pili Short, straight, thin hair-like appendages FIMBRIAE
occur at poles or evenly distributed Few to several hundred / cell Adhere to surfaces forming biofilms PILI Usually longer Only one or two /cell Involved in motility (twitching and gliding motility) and DNA transfer (conjugation) Electron Micrograph of E. coli Geobacter sulfurreducens
11
CELL WALL FUNCTION Responsible for shape
Prevents cell from rupturing from too much water Contributes to ability of some to cause disease STRUCTURE Peptidoglycan: repeating disaccharide attached by polypeptides forming a lattice Disaccharides: N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)
12
Peptidoglycan in Gram-Positive Bacteria
Linked by polypeptides Figure 4.13a
13
Gram-Positive Bacterial Cell Wall
Figure 4.13b
14
Gram-Negative Bacterial Cell Wall
Figure 4.13c
15
Gram-positive Cell Wall
Thin peptidoglycan Outer membrane Periplasmic space Thick peptidoglycan Teichoic acids Figure 4.13b–c
16
Internal Structures: Plasma (cytoplasmic) Membrane
Phospholipid bilayer Polar head: phosphate group and glycerol that is hydrophilic Nonpolar tails: hydrophobic fatty acids Proteins Peripheral proteins: lie at inner or outer surface Integral proteins: inside membrane Glycoproteins: proteins attached to carbohydrates Glycolipids: lipids attached to carbohydrates Help protect/lubricate cell
17
Selective permeability Breakdown of nutrients and production of energy
FUNCTION Selective permeability Breakdown of nutrients and production of energy Some have pigments and enzymes involved in photosynthesis in foldings Chromatophores or thylakoids file:///E:/Chapter_04/A_PowerPoint/a_Lecture_Outline/membrane_permeability.html
19
80% water, proteins, carbos, lipids, inorganic ions
NUCLEOID Single long, continuous circular thread of double-stranded DNA Attached to plasma membrane PLASMID Circular, double-stranded DNA Replicate independently 5 to 100 genes RIBOSOMES Site of protein synthesis CYTOPLASM 80% water, proteins, carbos, lipids, inorganic ions Thick, aqueous, semitransparent, elastic
20
Inclusions (reserve deposits)
Metachromatic granules Volutin: reserve of inorganic phosphate used in the synthesis of ATP Corynebacterium diphtheriae (agent of diphtheria) ID: stain red with blue dyes Polysaccharide Granules Glycogen (reddish brown) and starch (blue) ID: iodine Sulfur Granules Lipid Inclusions ID: fat-soluable dyes Carboxysomes Enzyme ribulose 1,5-diphosphate carboxylase Use as sole source of carbon Gas Vacuoles Maintain buoyancy Magnetosomes Iron oxide, act as magnets
21
Endospores Cells formed when essential nutrients are depleted
Very resistant to heat, chemicals, hard to kill Can be dormant for thousands of years Gram positive bacteria Bacillus: anthrax, food poisoning Clostridium: gangrene, tetanus, botulism Core: DNA and protein Cortex: peptidoglycan (rigid protective) Spore Coat: protein Exosporium: protective layer Endospore formation in Bacillus subtilis.
22
http://student. ccbcmd
Similar presentations
© 2025 SlidePlayer.com. Inc.
All rights reserved.