definitions B1

Question 1

Antigenic shift

Answer 1

minor change in the amino acid sequence due to point mutation in the antigenic sites.
* Results in outbreak, minor periodic epidemics, occurs every 2-3 years

Question 2

Antigenic drift

Answer 2

abrupt, major variation in the amino acid sequence due to genetic reassortment in the genome
* Results in pandemics and major epidemics, occur every 10-20 years

Question 3

transformation

Answer 3

a process of random uptake of free /naked DNA fragments fr the surrounding environment by bacterial cell n incorporation of this DNA frag into its chromosome in a heritable form

Question 4

transduction

Answer 4

transmission of a portion of DNA fr 1 bacterium to another by a bacteriophage

Question 5

conjugation

Answer 5

transfer of DNA fr the donor to the recipientby direct physical contact btw cells

Question 6

IMMUNITY

Answer 6

resistance offered by host toward injury caused by microorganism and their products

Question 7

sterilization

Answer 7

method by which an article,medium or surface is freed of all viable microorganism including their spores