Life Cycles And Viruses

Question 1

what are the six common parasite groups

Answer 1

protists, platyhelminthes, bacteria, anthropods, viruses and Nematoda

Question 2

describe a protist and give an example of one

Answer 2

small unicellular organism, plasmodium

Question 3

give an example of a platyhelminthes

Answer 3

schistosoma, tape worms

Question 4

what is tb

Answer 4

a bacteria

Question 5

in what host does the parasite reach sexual maturity

Answer 5

definitive host

Question 6

describe the life cycle of a plasmodium

Answer 6

protist that causes malaria, definitive host is mosquito, intermediate host is human, vector is mosquito

Question 7

describe the life cycle of schistosomiasis

Answer 7

cause by platyhelminthes, definitive host is human, intermediate host is water snail, transmitted by water borne stages

Question 8

how are ectoparasites usually transmitted

Answer 8

direct contact

Question 9

how are body cavities endoparasites usually transmitted

Answer 9

direct contact or consumption of intermediate host

Question 10

how are endoparasites of body tissues usually transmitted

Answer 10

vectors

Question 11

what is a virus

Answer 11

an infectious agent that can only replicate inside a host cell

Question 12

describe the structure

Answer 12

envelope, antigens, nucleic acid, protective protein code

Question 13

what are antigens

Answer 13

proteins coded by viral genes detected by immune system

Question 14

give an example of a virus that contains DNA

Answer 14

chickenpox

Question 15

give an example of a virus that contains rna

Answer 15

influenza

Question 16

describe the four stages of DNA viral replication

Answer 16

1. virus antigens attach to cell surface, 2. virus DNA inserted into the host cell, 3. virus DNA is replicated using host enzymes, 4. viruses genes are transcribed to rna which is translated to make viral proteins coded

Question 17

what is a retrovirus

Answer 17

contains rna, uses a different reproduction method to form a DNA copy of its genome

Question 18

describe the steps in retrovirus reproduction

Answer 18

virus antigens attach to host cell surface, virus RNA inserted into host cell, viral enzyme called reverse transcriptase reads viral RNA to form DNA, new virus particles are assembled and burst out of host cell

Question 19

what is retrotransposons

Answer 19

virus derived mobile DNA elements with ability to copy and paste themselves into hosts genome long after initial attack