prokaryotic cell Flashcards
bacterial cell:
are —-
they lack —- but have —- and no —–
- prokaryotes
- no nucleas
- cell wall
- no organelles
eukaryotic cells are —- and have —- with —- but lack —-
- eukaryotes
- nucleas
- cell organelles as mitochondria chloroplast and er
- cell wall
gram — bacteria has a high lipid content which is extracted by alcohol to permeabilise the membrane , the crystal violet iodine complex defuses out and natural — color taken up
- -ve exmaple: escherichia coli has an outer membrane
- red
gram — cell envelope has low lipid content and is dehydrated by alcohol making it impermeable
+ve example: staphylococco , has thicker cell wall
true or false:
crystal violete-iodine complex forms within the cell ( blue color )
true
mycobacteria have high — content in their cell envelope and suspected mycobacteria are stained by the —–
- wax
- ziehl-neelsen stain
mycoplasma are the —- known bacteria and have no cell wall to stain
smallest
the shapes of bacteria are:
1- cocci which refers to —
2- bacilli which refers to —
3- curved or —
- spherical
- rod
- spiral
the bacterial — or c/some have the bacterial genetic info and —- may be present
- genome
- plasmid
—– surrounds the cytoplasm
cytoplasmic membrane which is composed of lipids and phosolipids acts as:
- osmotic barrier
- site for energy production
- transport of important molivles
- synthesise new cell wall
- anchors the c/come
—- is a rigid layer surrounding the cytoplasmic membrane
cell wall
outer layer of gram — bacteria covers the cell wall and acts as a molecular sieve
-ve
( check structure slide:12)
—- principle component of the cell wall and is a unique polysacride which gives the cell characterstic shape and prevents osmotic lysis
peptiglycan
in gram —- many peptidoglycan layers and 90% of cell emevelope material
in gram — one peptidoglycan layer from 2-20 of cell envelope
positive ( contains: tectonic and lipotechonic acid , extends into the environment for adherence and antigenic determinants )
, negative which contains an outermsmbrane , phospholipid-liposacride bilayer , used for bacterial cell adhesion , resistance to phagocytosis , molecular sieve and access of some molecules to cell wall and cytoplasm membrane
— disrupts the peptiglycan sytheis , many —- are presented on the cell cycle surface
- penicillin
- antigens
——– extends from the cell surface
—— rotates and are required for motility aka chemotaxis
—- for adherence
—- are tightly associated — loosely associated and are polysacrides or protein layers surrodnind many bacterial cells which provides —– and plays a role in —–
- pili and flagella
-flagella - pili
- capsules
- slime
- protection from phagocytosis and antibiotics and role in bacterial adherence
spores are formed only by —- bacteria which provide protection from adverse condition
positive
1-bacteria divide by — by which the c/somes divide into —- cells these growth in a hostile environment can create a selective —- for mutant cells which can presist , one mutant cell which can survive will rapidly grow and take over
2-growth requirments are:
1-
- binary fission
- 2 identical daughter cells
2-
- energy by catabolism
- building block for constructions
- appropriate environmental conditions ph temp 02 food
emergence of antibiotic resistance pathogen is driven by —-
genetic variations processes and some antibiotic target genetic processes
—- refers to the total collection of genes carried by bacterium both on its chromosomes and plasmid
bacterial genome
1.—- is a topoisomerase enzyme , type II topoisomerase and it catalyses the -ve supercoiling of dna which releases tension in structure , this activity accommodates replication and transcpriton
2.— links the Okazaki fragments
3.—- transcribes dna to rna
4.mrna is decoded by —- and —– specify the exact aa sequence of proteins
dna gyrase , ligase , rna polymerase , ribosomes , trna
the 4 steps of dna replication in bacteria involves:
- initation
- elongation
- proofradifn
- termination
—- are small cicurlar extrachromosomal dna molecule , replicates indepemdtly , can be copied and transferred between cells , can confer phenotypic advantages to the host cell .
when they have multiple antibiotic resistant gene predominates within —– which makes it resistant to wide ranges of antibiotics
plasmids , hospital bacteria
( plasmid genes include:
- antibiotic resistance genes which often multiple
- virulence genes as toxins
- metabolic genes )
—- most common source of genetic variations and is spontaneous or induced and their rates are 10-3 - 1–9 per cell division
gene mutation their types are: insertion , deletion , substituiton
— usually only affect the amino acid encoded by that triplet codon and no changes beyond that , affects fuction , maybe a silent mutation w no effcet on protein function
- subsitiuion
—- can affcet the amino acid sequence beyond the point of deletion and they cause misreading of the triplet codon beyond the deletion point and are often referred to as:
- deletion
- framshift
deletion and insertion aka —– often result in —- termination of translation as the stop codon can be generated by the frameshift ,
this termination resumers in truncated protein which maybe —-
- frameshift
- non-functional
different genera of bacteria can be differentiated by:
- shape
- how they r arranged in microscopy
- gram stain results
