part 2

Question 1

name the two infectious agents of diseases that are non cellular organisms:

Answer 1

virus
viroids

Question 2

name the two infectious agents of diseases that are prokaryotic organisms:

Answer 2

bacteria and mollicutes (phytoplasma)

Question 3

name the three infectious agents of diseases that are eukaryotic organisms

Answer 3

fungi, oomycetes, protozoa

Question 4

true or false: viruses are obligate parasites

Answer 4

true

Question 5

describe the plant virus cycle

Answer 5

1. virus to host cell
   2.Dna
2. replication
   4assembly
   5.release
   6transmission

Question 6

Many viruses are transmitted by
arthropods,. These examples of insects
and mites are referred to as …. of the viruses

Answer 6

vectors

Question 7

T-f: virus can only be transmitted by insects, nematodes, fungi.

Answer 7

false:virus can be transmitted by insects, nematodes, fungi, mites and others plants (vegetative propagation)

Question 8

T-F:Any plant that is vegetatively
propagated from a virus-infected
mother plant will also be infected.

Answer 8

True

Question 9

T-F: virus infections of plants are currable

Answer 9

false, they are incurable

Question 10

what means : infections of plants are systemic?

Answer 10

that they occurs throughout the plant

Question 11

what are some control methods for viruses:

Answer 11

• Quarantine and surveillance
• Control of vectors
• Use of plant resistant varieties
• Use of clean certified seeds and plant
  materials for propagation
• Use of In vitro tissue culture for
  propagation

Question 12

wich of these symptoms is not a symptom of viral infections:Green and yellow mottling or mosaic,ringspots, color break on flowers,vein clearing(lighter than normal), veins banding (darker green areas follow the veins), mildew, stunting, leaf malformation or shoot proliferation

Answer 12

mildew is not a symptom

Question 13

T-F witches broom is a symptom of viral infection

Answer 13

True

Question 14

name some of viral infections symptoms:

Answer 14

Green and yellow mottling or mosaic,ringspots, color break on flowers,vein clearing(lighter than normal), veins banding (darker green areas follow the veins), stunting, leaf malformation or shoot proliferation

Question 15

what are the smallest known agents

Answer 15

viroids

Question 16

what are the general symptoms of viroids:

Answer 16

dwarf, epinasty deformation and creased (wrinkled) leaves

Question 17

characteristic of prokaryotic organisms

Answer 17

their DNA is not coated by nuclear
membrane

Question 18

t-f bacteria are multicellular
organisms with no organized nucleus

Answer 18

false: their are single-celled organisms

Question 19

do bacteria have cell walls?

Answer 19

yes

Question 20

imagine a bacterial cell, animal and plant cell

Answer 20

voir image (cell wall)

Question 21

t-f:Gram-positive organisms have a thicker cell wall compared with gram-negative bacteria

Answer 21

true

Question 22

t-f: bacteria can penetrate plant tissues.

Answer 22

false

Question 23

how bacteria enter in plant tissues?

Answer 23

they enter through wounds-blessures- (either caused by human activity
or by insect feeding) or through natural openings

Question 24

how bacteria transmit and survive?

Answer 24

Bacteria can be spread from plant to plant by way of soil, insects, splashing water (rain splashes and run-off), infected seeds, or pruning tools. The bacterium that causes fire blight can be spread by bees.

Question 25

Leaf spots caused by - tend to be angular because they are initially limited by the veins on leaves.

Answer 25

bacterium

Question 26

Gram positive bacteria vs gram neg. bacteria

Answer 26

positive ex.:potato ring , leaf canker, potato scab negative: blights

Question 27

t-f fungus digests food externally and absorbs nutrients directly through its cell walls.

Answer 27

true

Question 28

t-f: fungi are heterotrophs

Answer 28

yes

Question 29

biotrophs; saprotrophs (saprophytes). necrotrophs. expliquez

Answer 29

biotrophs: feeding from within living host cells throughout its lifecycle. saprotrophs: extract nutrient from dead and decomposing tissues necrotrophs: kill a plants before feeding on it

Question 30

t-f, yeast and molds are the only unicellular fungi the others types are multicellular

Answer 30

true

Question 31

Ascomycota : Basidiomycota: are typically filamentous fungi composed of hyphae. Most species reproduce sexually with a club-shaped spore-bearing organism that usually produces four sexual spores

Question 32

what do fungi do?

Answer 32

involve in a wide range of activities: most of them are decomposers some are parasites or pathogens of other organisms

Question 33

t-f: some fungi are so effective at killing insects that they are used as biological control

Answer 33

true

Question 34

t-f: fungi cant be beneficial because they kill other organisms

Answer 34

false:s some are beneficial partners in symbiosis with animals, plants or algae

Question 35

There are thousands of species of plant pathogenic fungi that collectively are responsible for ---% of all known plant disease

Answer 35

70% of all known plants diseases

Question 36

* Biotrophic fungal pathogens obtain nutrients from living host tissues, how are named the specialized cells that form inside host cells.? They form specialized structures called ---- at the end of germ tubes

Answer 36

haustoria appressoria

Question 37

difference between generalist and specialized nectrophic fungi

Answer 37

Necrotrophic fungi can be either generalists, growing on a wide range of host species, or specialized on a restricted range of hosts.

Question 38

what are the group of organisms that include some of the most devastating plant pathogens.

Answer 38

oomycetes

Question 39

oomycetes that reproduce sexually (A) are named and those who reproduce asexually are named (B)

Answer 39

A oospores B zoospores

Question 40

The diseases they cause include seedling blights, damping-off, root rots, foliar blights and downy mildews.

Answer 40

oomycetes

Question 41

t-f: mildew are only caused by oomycetes

Answer 41

true

Question 42

wich type of plant pathogens occurs mainly in South America on crops such as coffee

Answer 42

protozoa

Question 43

flagellates single celled eukaryotes are:

Answer 43

protozoa