UNIT II A- BAFPAVH Flashcards
Proposed by Carl Woese
Phylogenetic relationship
Phylogenetic relationship
Provides information on shared ancestry but
not necessarily on how organisms are similar
or different
evolutionary history and relationship of an
organism or group of an organisms
phylogeny
phylogeny
another such as which organisms thought to
have evolved from which species it is closely
related to
bacteria
single-celled organisms
- lack organelles, such as chloroplast and
mitochondria
- do not have true nucleus found in eukaryotic
cells
- a double stranded DNA that is continuous
and circular is located in a nucleoid
an irregular-shaped region that
does not have a nuclear membrane
Nucleoid
Bacterial cell membrane and cell wall is made
of
peptidoglycan
cell membrane+ cell wall
cell envelope
Binary fission
-bacterial reproduction
splitting of a bacterial cell after
reaching a certain size
bacterial reproduction. sexual/ asexual?
reproduce asexually hence the two
daughter cells, result from the binary fission,
have the same DNA as the parent cell
horizontal gene transfer or
transformation, conjugation and
transduction
bacterial exchange of genetic
material among one another
bacterial shape: Coccus: define and examples.
- spherical/ovoid in shape
- some remain attached after binary fission
even forming separate cells
examples: Streptococci – cocci in chains - Staphylococci – clusters of multiple
cocci - Tetrads – square arrangements of
four cocci - Sarcinae – cubes of eight cocci
bacterial shape: bacillus: define and examples.
-Rod-shaped bacteria
- Can be solitary or arranged together
Example:
o Diplobacilli – 2 bacilli arranged next
to each other
o Streptobacilli – chains of bacilli
bacterial shape: spiral: define and examples.
Spiral in shape Example: o Spirillum - thick, tough spirals o Spirochetes – thin, flexible spirals o Vibrious – comma-shaped rods with a small twist
State other bacterial shape.
- Filamentous – long and thin
- Square
- Star
- Stalk
what makes gram staining of bacteria possible?
cell wall
define gram staining
- A method of staining bacteria involving
crystal violet dye, iodine, and the
counterstain safranine - Used for general identification of bacteria or
detect the presence of certain bacteria - Cannot be used to identify bacteria in the
species level - Can be used for grouping bacteria, gram-positive or gram-negative
Appearance of gram-positive bacteria and why?
Violet – due to the thick
cell wall that trapped the crystal violet iodine
complex
Appearance of gram-negative bacteria and why?
appear red due to the thin cell wall not holding the violet iodine complex but can hold safranine
Selectively permeable barrier, mechanical boundary of cell, nutrient and waste transport, location of many metabolic processes (respiration, photosynthesis), detection of environmental cues for chemotaxis
Plasma
membrane
Gas
vacuole
An inclusion that provides
buoyancy for floating in aquatic
environments
Ribosomes
Protein synthesis
Storage of carbon, phosphate,
and other substances
Inclusions
Localization of genetic material
DNA
Nucleoid
In typical gram-negative bacteria, contains hydrolytic enzymes and binding proteins for nutrient processing and uptake In typical gram-positive bacteria, may be smaller or absent
Periplasmic
space
Cell wall
Protection from osmotic stress,
helps maintain cell shape
Capsules
and slime
layers
Resistance to phagocytosis,
adherence to surfaces