ddt 13

Question 1

total biomass of earth is

Answer 1

35x greater than the total biomass of all animals

Question 2

bacterias size range is

Answer 2

1-10 um length and 0.2-2 in diameter

Question 3

the three types of bacteria shapes

Answer 3

1- rods aka bacillus as: salmonella
2- spherical aka ovoid aka coccus as: micrococcus
3- spiral/ wavy aka spirillus as: spiroplasma

Question 4

bacteria lack

Answer 4

membrane bounded organelle bc they r prokaryotes as: er, mitochondria , nucleas, lysosome, chloroplast

Question 5

main components of the bacteria

Answer 5

• cytoplasm
• nucleoid contains the dna
• plasma membrane
• ribosome

Question 6

the function of cytoplasm

Answer 6

• dense and contains ribomes
  -storage granules as glycogen, lipids, phosphate
• metabolic enzymes
• ribosomes have 2 subunits large and small contains proteins and rna

Question 7

function of the nucliod

Answer 7

• instead of the nucleas
• contains 3000-6000 genes from cytoplasm
• contains single circular double helix dna
• histone don’t need to be utilised bc the dna is supercoiled

Question 8

a small circular double stranded dna molecule w selective benefits genes which increases the virulence

Answer 8

plasmid

Question 9

capsule is a

Answer 9

thick gelatinouse structure composed of polysacrides that extend 10 micrometers and they increase the virulence.
- defines against hosts immune system
- prevent binding of antibodies to antigens
- prevents phagocytosis of bacteria

Question 10

allows motility for the bacteria and acts as propeller

Answer 10

flagella and is composed of: hook, filament, basal granuel anchored in the cell wall and cell membrane

Question 11

pilli is

Answer 11

• hair like structure
• increases virulence by enhancing the ability to bind to body tissues
• allows clumping of bacteria
• used to transfer dna in conjunction
• 2 types: ordinary which is adherence of bacteria to the host cells and sex pills which is attachment of donor an recipient in bacterial conjunction

Question 12

true or false: gram negative is more pathogenic and resist antibiotic

Answer 12

true bc the outer membrane is more antigenic and contributes to its pathogenicity.

Question 13

the gaps between the outer ( periplasmic spaces ) and inner membrane are filled with

Answer 13

enzymes and transport protein for biochemical reactions

Question 14

staining

Answer 14

+ve: purple also stained by pink but only purple will be visible
-ve: stains pink

Question 15

endospores

Answer 15

• bacteria enters high resistant dormant stage
• unfavored conditions as lack of nutrients
• after dna replication, the spore septum will form around the newly synthesis dna and section of the cytoplasm
• layer of plasma membrane will cover it with peptiglycan in between
• tough spore coat will form around it causing dehydration
• now the bacteria can resist extreme conditions such as: radiation, antibiotics, dehydration.
• favorable conditions will reactive it and they will grow and multiply,

Question 16

bacteria reproduce by

Answer 16

-binary fission asexual reproduction
- origin of replication will open allowing dna replication to start, cells elongate more towards end as the dna will be copied, septum will form down the middle, two cells will be produced.
- the multiply every 20 minutes
- bacteria can produce 250,000 individuals every 6 hours

Question 17

true or false: fusion of gametes don’t occur in bacteria

Answer 17

true, they undergo bacterias exchange of dna instead in three methods:
- transformation: fragments of dna are taken after disruption of other cell.
- conjucntion: two cells exchange dna but sex pills
- transduction: genes carried from one cell to another by virus aka bacteriophage. Also known as: horizontal gene transfer ( sideways to unrelated organisms ) while vertical is direct gene transfer

Question 18

the process of transformation can be done

Answer 18

• naturally by changing their genome rapidly to adapt to new environment
  -artifically by placing plasmids inside so they can produce useful products as insulin

Question 19

the process of conduction is when

Answer 19

• direct contact is needed
  1- donor cells produce conjunctions pillus and attaches it to recipient cell
  2- donor plasmid is nick and single strand of dna will be attached to recipient cell
  3- both cells will synthesise a complementary strand to produce double strand circular plasmid

Question 20

transduction

Answer 20

• viral transfer of genetic material
• some viruses can infect the bacteria : bacteriphage
• viruse will utilise the bacteria replicative proteins and produce copies of itself
• new viruses will be produced, fragments of bacterial dna can be incorporate.
• when phage infects new bacteria, dna from the first bacteria can integrate into the new bacterias chornosme.