Lecture 3

48問 • 2年前

問題一覧

Basic shape

spherical, cubical, cylindrical

Characteristics of Cells _____ : animals, plants, fungi, and protists – Contain membrane-bound organelles that compartmentalize the cytoplasm and perform specific functions – Contain double-membrane bound nucleus with DNA chromosomes _______: bacteria and archaea – No nucleus or other membrane-bound organelles

Eukaryotic cells, Prokaryotic cells

– genome composed of DNA packed in chromosomes; produce offspring sexually or asexually

Reproduction and heredity

– chemical and physical life processes

Metabolism

– respond to internal/external stimuli; self-propulsion of many organisms

Movement and/or irritability

External Structures Bacterial Cell

Appendages, Glycocalyx

– surface coating

Glycocalyx

- Rotates 360o • Functions in motility of cell through environment

Flagella

(Flagella) – single flagellum at one en

Monotrichous

Flagella – small bunches emerging from the same site

Lophotrichous

Flagella – flagella at both ends of cell

Amphitrichous

– flagella dispersed over surface of cell

Peritrichous

Fine, proteinaceous, hairlike bristles emerging from the cell surface

Fimbriae

• Rigid tubular structure made of pilin protein • Found only in gram-negative cells • Function to join bacterial cells for partial DNA transfer called conjugation

Pili

Coating of molecules external to the cell wall, made of sugars and/or proteins • Two types: 1. Slime layer- loosely organized and attached 2. Capsule- highly organized, tightly attached

Glycocalyx

External covering outside the cytoplasm

Cell Envelope

- thick cell wall composed primarily of peptidoglycan and cell membrane

Gram-positive bacteria

outer cell membrane, thin peptidoglycan layer, and cell membrane

Gram-negative bacteria

Differential stain that distinguishes cells with a gram-positive cell wall from those with a gram- negative cell wall

Gram Stain

- retain crystal violet and stain purple

Gram positive

- lose crystal violet and stain red from safranin counterstain

Gram negative

Phospholipid bilayer with embedded proteins – fluid mosaic model

Cell Membrane Structure

– Dense gelatinous solution of sugars, amino acids, and salts – 70-80% water • Serves as solvent for materials used in all cell functions

Cell cytoplasm

– Single, circular, double- stranded DNA molecule that contains all the genetic information required by a cell

Chromosome

– Free small circular, double- stranded DNA – Not essential to bacterial growth and metabolism – Used in genetic engineering - readily manipulated and transferred from cell to cell

Plasmids

Made of 60% ribosomal RNA and 40% protein – Consist of two subunits: large and small – Prokaryotic differ from eukaryotic ribosomes in size and number of proteins – Site of protein synthesis – Found in all cells

Ribosomes

– Intracellular storage bodies – Vary in size, number, and content – Bacterial cell can use them when environmental sources are depleted

Inclusions and granules

– Many bacteria possess an internal network of protein polymers that is closely associated with the cell wall

Cytoskeleton

– Inert, resting, cells produced by some G+ genera: Clostridium, Bacillus, and Sporosarcina

Endospores

- formation of endospores • Hardiest of all life forms • Withstands extremes in heat, drying, freezing, radiation, and chemicals • Not a means of reproduction

Sporulation

- return to vegetative growth

Germination

– spherical

Coccus

– rod

Bacillus

– helical, comma, twisted rod,

Spirillum

- Variation in cell shape and size within a single species • Some species are noted for their pleomorphism

Pleomorphism

Arrangement of cells is dependent on pattern of division and how cells remain attached after

Bacterial Arrangements

– primitive, adapted to extreme habitats and modes of nutritio

Domain Archaea

– Phylum Proteobacteria– Gram-negative cell walls – Phylum Firmicutes– mainly Gram-positive with low G + C content – Phylum Actinobacteria– Gram-positive with high G + C content

Domain Bacteria

– a collection of bacterial cells which share an overall similar pattern of traits in contrast to other bacteria whose pattern differs significantly

Species

– a culture derived from a single parent that differs in structure or metabolism from other cultures of that species (biovars, morphovars)

Strain

– a subspecies that can show differences in antigenic makeup (serotype or serovar), susceptibility to bacterial viruses (phage type) and in pathogenicity (pathotype)

Type

Free-living nonpathogenic bacteria

Prokaryotes with UC

– Gram-negative cell walls – Extensive thylakoids with photosynthetic chlorophyll pigments and gas inclusions

Cyanobacteria (blue-green algae)

• Photosynthetic • Contain photosynthetic pigment bacteriochlorophyll • Do not give off oxygen as a product of photosynthesis

Green and Purple Sulfur Bacteria

Gliding and Fruiting Bacteria • Gram-negative • Glide over moist surfaces

Gliding and Fruiting Bacteria

– Rickettsias • Very tiny, gram-negative bacteria • Most are pathogens • Obligate intracellular pathogens • Cannot survive or multiply outside of a host cell • Rickettsia rickettisii– Rocky Mountain spotted fever

Obligate intracellular parasites

• Tiny • Obligate intracellular parasites • Not transmitted by arthropods

Chlamydias

• Live in the most extreme habitats in nature, extremophiles • Adapted to heat, salt, acid pH, pressure, and atmosphere • Includes: methane producers, hyperthermophiles, extreme halophiles, and sulfur reducers

Archaea

Latin Abbreviations

JULLIANNE DANDAN · 43問 · 2年前

Latin Abbreviations