Unit 2 - The Cell Episode 3 Flashcards
Long outermost region
constant in diameter and contains
the globular (roughly spherical) protein
flagellin arranged in several chains that
intertwine and form a helix around a
hollow core
Filament
Arrangement of the Flagella
Atrichous
Monotrichous/
Polar
Amphitricous
Lopotrichous
Peritrichous
without flagellum
Atrichous
single flagellum at
one end
Monotrichous/
Polar
single flagellum at
both ends
Amphitricous
tuff or group of
flagella on one
end or both ends
Lopotrichous
entire cell surface
covered with
flagella
Peritrichous
Ways of Determining Motility in the Lab:
Hanging Drop Method
Sulfide Indole Motility (SIM)
Flagellar Staining
Serologic Test
Fluorescent Antibody Technique
(FAT)
Swarming Phenomenon
Darkfield Microscopy
True motility and Brownian Movement are best observed here
Hanging Drop Method
bundles of fibrils that arise at the end of the
cell beneath an outer sheath and spiral around
the cell
AXIAL FILAMENTS
anchored at one end of the spirochete
AXIAL FILAMENTS
→ have a structure similar to that of flagella
AXIAL FILAMENTS
rotation of the filaments produces a
movement of the outer sheath that propels the
spirochetes in a spiral motion
AXIAL FILAMENTS
movement is similar to the way a corkscrew
move through a cork
AXIAL FILAMENTS
group of bacteria that have unique structure
and motility
Spirochetes
move by means of axial filaments or
endoflagella
Spirochetes
Syphilis
Treponema pallidum
Lyme disease
Borrelia burgdorferi
motility and DNA transfer
PILI
hairlike, proteinaceous structures that extend
from the cell membrane into the external
environment; some may be up to 2 μm long
PILI
hair-like microfibrils usually produced by
flagellated gram-negative bacteria observable
by electron microscopy
PILI
serves as adhesins that help bacteria attach
to animal host cell surfaces, often as the first
step in establishing infection
PILI
pili is composed of structural subunits: ____
Pilins
Adhesins: _______
attachment | tips of pili
a pilus extends by the addition of subunits of
pilin, makes contact with a surface or another
cell, and then retracts (power stroke) as the pilin
subunits are disassembled- grappling hook
model
Twitching Motility
results in short, jerky, intermittent movements
Twitching Motility
results in short, jerky, intermittent movements
3 examples
1.
2.
3.
Pseudomonas aeruginosa
Neisseria gonorrhea
Some strains of Escherichia coli
Pili (fimbriae) → Pili is ______ than fimbriae
longer
play a role in bacterial adherence to surfaces
thus contributing to virulence
Common Pili or Ordinary Pili
serves as the conduit for the passage of
DNA from donor to recipient during conjugation
Sex Pilus
present only in cells that produce a protein
referred to as the F facto
Sex Pilus
F-positive cells initiate conjugation on with F-negative cells, thereby limiting the conjugative
process to cells capable of transporting genetic
material through the hollow _______
Sex Pilus
because of ______, DNA is transferred to
another cell (exchanged DNA can add in new
function to the recipient cell)
Sex Pilus
Somatic cells
Sex cells
EUKARYOTES
Somatic cells: ___ copies of genome | ______
Sex cells: ___ copy of genome | _____
2: Diploid
1: Haploid
Macromolecules present:
Carbohydrates
Lipid
Proteins
Nucleic Acids
information center
contains most of genes in the cell
NUCLEUS
Genes can also be seen in:
Animals:
Plants:
Mitochondria
Chloroplast
nucleus is ____ in diameter
5 μm
double membrane that encloses the nucleus,
separating its contents from the cytoplasm
each membrane is a lipid bilayer
separated by a space 20-40 cm
Nuclear Envelope
intricate protein that lines each pore (nuclear
pore): allows nucleus to communicate with the
cytoplasm
Pore Complex
regulates the entry and exit of proteins and
RNAs, as well as large complexes of
macromolecules
Pore Complex
protein structure + nuclear pore = _______
Pore Complex
netlike array of protein filaments that
maintains the shape of the nucleus by
mechanically supporting the nuclear envelope
Nuclear Lamina
lines the nuclear side of the envelope
maintain structure of nucleus
Nuclear Lamina
discrete units of organized DNA that carry
the genetic information
Chromosomes