prokaryotic cell

Question 1

bacterial cell:
are —-
they lack —- but have —- and no —–

Answer 1

• prokaryotes
• no nucleas
• cell wall
• no organelles

Question 2

eukaryotic cells are —- and have —- with —- but lack —-

Answer 2

• eukaryotes
• nucleas
• cell organelles as mitochondria chloroplast and er
• cell wall

Question 3

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

Answer 3

• -ve exmaple: escherichia coli has an outer membrane
• red

Question 4

gram — cell envelope has low lipid content and is dehydrated by alcohol making it impermeable

Answer 4

+ve example: staphylococco , has thicker cell wall

Question 5

true or false:
crystal violete-iodine complex forms within the cell ( blue color )

Answer 5

true

Question 6

mycobacteria have high — content in their cell envelope and suspected mycobacteria are stained by the —–

Answer 6

• wax
• ziehl-neelsen stain

Question 7

mycoplasma are the —- known bacteria and have no cell wall to stain

Answer 7

smallest

Question 8

the shapes of bacteria are:
1- cocci which refers to —
2- bacilli which refers to —
3- curved or —

Answer 8

• spherical
• rod
• spiral

Question 9

the bacterial — or c/some have the bacterial genetic info and —- may be present

Answer 9

• genome
• plasmid

Question 10

—– surrounds the cytoplasm

Answer 10

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

Question 11

—- is a rigid layer surrounding the cytoplasmic membrane

Answer 11

cell wall

Question 12

outer layer of gram — bacteria covers the cell wall and acts as a molecular sieve

Answer 12

-ve
( check structure slide:12)

Question 13

—- principle component of the cell wall and is a unique polysacride which gives the cell characterstic shape and prevents osmotic lysis

Answer 13

peptiglycan

Question 14

in gram —- many peptidoglycan layers and 90% of cell emevelope material
in gram — one peptidoglycan layer from 2-20 of cell envelope

Answer 14

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

Question 15

— disrupts the peptiglycan sytheis , many —- are presented on the cell cycle surface

Answer 15

• penicillin
• antigens

Question 16

——– 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 —–

Answer 16

• pili and flagella
  -flagella
• pili
• capsules
• slime
• protection from phagocytosis and antibiotics and role in bacterial adherence

Question 17

spores are formed only by —- bacteria which provide protection from adverse condition

Answer 17

positive

Question 18

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:

Answer 18

1-
- binary fission
- 2 identical daughter cells
2-
- energy by catabolism
- building block for constructions
- appropriate environmental conditions ph temp 02 food

Question 19

emergence of antibiotic resistance pathogen is driven by —-

Answer 19

genetic variations processes and some antibiotic target genetic processes

Question 20

—- refers to the total collection of genes carried by bacterium both on its chromosomes and plasmid

Answer 20

bacterial genome

Question 21

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

Answer 21

dna gyrase , ligase , rna polymerase , ribosomes , trna

Question 22

the 4 steps of dna replication in bacteria involves:

Answer 22

• initation
• elongation
• proofradifn
• termination

Question 23

—- 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

Answer 23

plasmids , hospital bacteria
( plasmid genes include:
- antibiotic resistance genes which often multiple
- virulence genes as toxins
- metabolic genes )

Question 24

—- most common source of genetic variations and is spontaneous or induced and their rates are 10-3 - 1–9 per cell division

Answer 24

gene mutation their types are: insertion , deletion , substituiton

Question 25

— 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

Answer 25

• subsitiuion

Question 26

—- 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:

Answer 26

• deletion
• framshift

Question 27

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 —-

Answer 27

• frameshift
• non-functional

Question 28

different genera of bacteria can be differentiated by:

Answer 28

• shape
• how they r arranged in microscopy
• gram stain results