Module 3 MCB 2010 exam 3

Why are rRNA gene sequence an excellent tool for classifying bacteria?

Genes are present in all known bacteria.

Part of the gene sequences is highly conserved

part of the gene sequences varies from species

What is extremophile?

a microbe that requires extreme conditions.

ex. temperature ,PH and/or salinity to survive

An organism that requires an environment containing greater than 9% NaCI would be considered a...

Halophile

A______ is slightly curved rod

vibrio

which of the following is a unique characteristic of Mycoplasmas?

Lacks a cell wall and smallest free living cell

Autotrophic bacterium

Produces organic compounds from carbon dioxide.

Which of the following is NOT a taxonomic domain?

Protista

How would you classify a microbe that require temperatures over 80 C for growth?

Hyperthermophile

Scientists classify prokaryotes primarily based on similarities in ...

DNA

RNA

Protein sequences

What is nitrogen fixation?

The reduction of nitrogen gas to ammonia

Which statement regarding algal morphology is MOST accurate?

Algae can be unicellular ,colonial, or multicellular

Green algae are similar to plants in all except which of the following ways?

They have similar 16S rRNA sequences

which terms BEST describes a cell that contains only one single copy of each chromosome?

Haploid

What do you call the free-living motile feeding stage of protozoa?

trophozoite

How are insects different from arachnids?

insects have three body regions

What is the name given to the process of cytoplasmic division?

Cytokinesis

Plasmodium species reproduce asexually via a process called?

Schizogony

A virion is composed of a (n)

capsid and nucleic acid core

All prion disease result in what symptoms?

fatal neurological degeneration

Which statement MOST accurately describe lytic vital replication?

Viral replication usually results in the death and lysis of the host cell

What is the name of the proteinaceous subunit that makes up the viral capsid?

capsomere

How are viroid different from viruses?

viroids lack capsids

which of the following is NOT a way that viruses can cause human cancer?

Viruses can cause abnormalities in the host cytoplasmic membrane

What is the BEST method to use when attempting to culture bacteriophages?

Mix the phages with bacteria and liquid media and pour over a plate

How do disease-causing prions produce more disease-causing prions?

They change the shape of cellular PrP

All of the following are characteristic of life EXCEPT...

the ability to live in the presence of oxygen

What are viroids?

viroid lack capsids

What is a prion?

a proteinaceous infective particle

What is a capsid?

proteins coat (outer covering)

what is a envelope?

is portion of membrane system of host

Bacteriophage

A virus that infects bacteria

lytic replication

viral replication usually results in death and lysis of host cell( inserting its DNA and killing the host fast)

lysogenic replication

extended period of dormancy initiated by certain bacteriophages

(the virus's gets in to the cells and stays a while)

Retrovirus

virus that contains RNA as its genetic information.

dont use there own genomes mRNA

Latency

domains

Archaea, Bacteria, Eukarya

Prokaryote

unicellular organism that lacks a nucleus.

thrive in various habitats

exist in a variety of shapes

Endsopores

gram positive bacteria bacillus and clostridium

defensive strategy against unfavorable conditions

binary fission

A form of asexual reproduction in which one cell divides to form two identical cells.

snapping division

is a type of reproduction in prokaryotes that results in a palisade arrangement of cells

Budding

Asexual reproduction in which a part of the parent organism pinches off and forms a new organism

extremophiles

live in extreme environments

Thermophiles

temperature environment

(heat loving over 80c)

Halophiles

saline habitats (salt lover)

red or orange pigment protects from the sun

Methanogens

Convert carbon dioxide, hydrogen gas and organic acids to methane gas. (land field).

live in colons of animals

What is a pleomorphic prokaryote?

a prokaryote whose cell morphology varies in shape and size

bacteria reproduce asexually.Name the different processess they use?

Binary fission (most common).

Snapping division.

Budding

Prokaryotic morphologies

coccus-roughly spherical

Bacillus-rod shaped

vibrio- curved rods

coccobacillus-intermediate shape of cocci and bacilli

pleomorphic- many shapes

spiral-(two forms)

spirillum-stiff spiral(worm)

spirochetes-flexible spiral

binary fission steps

1.DNA replicate

2.cytoplasmic membrane elongates

3.cross wall forms when cytoplasmic membrane invaginates

4.daughter cell separates

_________lives in temperature above 45C

thermophiles

_______live in 9% or greater NaCI concentration

Halophiles

what does it mean that bacterium is low G +C?

Looks at organism to look at genomes that have less than 50%

what is the difference between spores and endospores ?

Spores are reproductive structure in plants; endospores are stable resting structure in bacteria

_________form when planes of cell division are random not at 90-degree angles.

Staphylococci

If organism X has a G +C content of 60% and organism Y has a G +C content of 35% ?

They are not closely related

What molecule is most used to determine phylogeny of a bacterium?

rRNA molecule

Meiosis

process in which the number of chromosomes per cell is cut in half through the separation of homologous chromosomes in a diploid cell

Budding

Asexual reproduction in which a part of the parent organism pinches off and forms a new organism

Schizogony

asexual reproduction by multiple fission

Chemoheterotrophic

an organism that uses organic molecules as a source of carbon and energy

Characteristics of a Protist

Unicellular

lack a cell wall

eukaryotic

lives in ponds ,lakes (moist places)

Mold

composed of long filaments called hyphae

Yeast

small, globular and composed of a single cell

Single-celled eukaryotes lacking a cell wall are_____

protozoa

The _______ have shells composed of calcium carbonate and thin pseudopods.

Foraminifera

plasmodium (protists) causes

Malaria

Trypanosoma (protist) causes

African sleeping skickness

Entamoeba(protist) causes

amoebic dysentery

Plasmodium species reproduce asexually via a process called

Schizogony

what do you call the free living ,motile feeding stage or protozoa?

Trophozite

Characteristic of the fungi

- chemoheterotrophic eukaryotes

- do not photosynthesize

- can be unicellular, filamentous, or multicellular

- have chitin in their cell walls

- classified by spores

-decomposed dead organism, absorpt nutrients

septate hyphae

there is a septum that forms in between into each single cell

aseptate hyphae

no septum its a continuous cell that contain multiple nuclei

Mycelium

entire interwoven mass of one multicellular fungal organism

unicellular fungus is called a

yeast

Fungal spores produced asexually within a sac-like chamber at the tip of a hypha are called

sporangiospores

sexual reproduction in Basidiomycota results in the production of

basidiospores

asexual reproduction in multicellular Ascomycota leads to the production of ____

asci

Hyphae are associated with which of the following?

molds

Fungi called Deuteromycetes are not known to reproduce sexually. Nonetheless, most of them are considered members of the ________ on the basis of genetic sequences.

ascomycota

what is a vector?

living organism that transmit an infectious agent from a infected animals to human

which of the following is transmitted by mosquitoes?

malaria

which statement regarding mosquitoes is TRUE?

Mosquitoes are a type of mite

mechanical vector

insects touch your food even though is been everywhere

biological vector

transmit pathogens and serve as hosts for the multiplication of a pathogen during stages of its life(penetrating your skin)