Week 5- Bacteria

Question 1

Prokaryotes

Answer 1

bacteria
archer

Question 2

Eukaryotes

Answer 2

protists
fungus
plants
animals

Question 3

bacteria

Answer 3

*prokaryotes: single celled
*forms chains and clusters
*diverse in shapes
*cell wall made of peptidoglycan (murein)
some have slime capsule surrounding walls (gram negative)
*reproduce asexually by binary fission

Question 4

shapes of bacteria (5)

Answer 4

sphere - cocci
rod - bacilli
spiral - spirilla
comma - vibrio
corkscrew - spirochaetes

Question 5

arrangements of bacteria (6)

Answer 5

single celled - coccus
pairs - diplococci
group of cocci - tetrad
cube - sarcina
chain-like - streptococci
grape shape - staphylococci

Question 6

structures of prokaryotes

Answer 6

*no nucleus
*no membrane-bound organelles
*nucleoid dna
*pilli
*flagellum
*70s ribosomes
*no ER, mitochondria, chloroplast, golgi apparatus or vacuoles

Question 7

gram positive

Answer 7

thich layer of peptidoglycan which stains due to retaining iodine complex within cells. when washed with alcohol, stains purples

Question 8

gram negative

Answer 8

when washed with alcohol the lipopolysaccharide capsule is removed from the gram negative cells. can be counterstained with safarin- stains pink

Question 9

stages of bacterial growth

Answer 9

lag phase
exponential phase
stationary phase
death phase

Question 10

how do bacteria grow

Answer 10

asexual reproduction, binary fission

Question 11

factors influencing growth

Answer 11

1. temp 25-45
2. oxygen (aerobes)
   no oxygen (anaerobes)
3. carbon and nitrogen
4. energy source (light/chemical)
5. water
6. minerals (sulphur, iron, etc.) and trace elements (zinc)

Question 12

pathogen definition

Answer 12

disease causing agents. bacteria grow while producing exotoxins

Question 13

what are exotoxins

Answer 13

chemicals that can
*damage host cells
*interfere with host cell metabolism
*cause inflammation/septic shock

Question 14

how is TB transmitted

Answer 14

airborne droplets

Question 15

what does TB attack

Answer 15

lungs and neck lymph nodes

Question 16

symptoms of TB

Answer 16

coughing
chest pain
coughing blood
fever
weight loss

Question 17

bacteria that causes TB

Answer 17

mycobacterium tubercolosum

Question 18

treatment for TB

Answer 18

4 antibiotics over the course of 6 months

Question 19

how does it damage a person

Answer 19

tubercles contain gas in damaged/dead cells

Question 20

bacteria tht causes cholera

Answer 20

vibrio cholerae

Question 21

how does vibrio cholerae affect body

Answer 21

produces toxin which affects channel proteins on the surface of the gut

this results in water, Cl- and Na+ being pumped out of cells and into the gut rather than beong absorbed in blood

leads to severe dehydration, low bp, eventually death

Question 22

types of antibiotics

Answer 22

bactericidal
bacteriostatic

Question 23

define bactericidal

Answer 23

kills the bacteria

Question 24

define bacteriostatic

Answer 24

prevents cell division

Question 25

how is bacterial cell wall strengthened

Answer 25

short chain polypeptides forming cross links between each other this prevents the cell from lysing cross links formed by enzyme called transpeptidase enzyme

Question 26

how does penicillin work

Answer 26

*blocks cell wall synthesis *contains B lactam ring which is an irreversible competitive inhibitor within the active site of transpeptidase

Question 27

what type of bacteria will penicillin not affect

Answer 27

gram negative bacteria because they have a thick lipopolysaccharide outer layer therefore B lactam cannot block enzyme

Question 28

what are some sites that bacteria target

Answer 28

cell wall DNA protein synthesis

Question 29

how does bacteria become resistant

Answer 29

*survival of fittest *some bacteria have allele which give resistance *resistant ones survive and pass on allele *antibiotic resistant genes can be found in plasmids and can be exchanged between bacteria