Bio 2 1St Exam Review Chapter 27/28

Front 1

Virus structure (smaller than bacteria)

Back 1

capsid: outer layer composed of protein subunits; protein on surface can interact with a protein on the surface of the host cell
nucleic acid core: inner most portion is made of DNA or RNA

envelope: possessed by some viruses; are lipid bilayers surrounding virus capsid

spike: glycoproteins that project from some enveloped viruses allowing for attachment of the virus to the targeted host cell

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good to know about Virus structure (smaller than bacteria)

Back 2

Consider: Viruses are obligate acellular parasites that do not themselves possess a cell. They are, essentially, chemical complexes of RNA or DNA protected by protein. A virus particle can also be referred to as a virion.

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Viral Reproduction

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entry into hose because portions of capsid adhere to specific receptor on host Cell's outer surface...viral nucleic acid enter hose cell and codes for protein units inside capsid...takes over metabolic machinery of host cell

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good to know about Viral Reproduction

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Consider: Reproduction occurs through the following stages: attachment, penetration, biosynthesis (assembly), maturation, and release.

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Host Range

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suitable organisms a virus is capable of infecting

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Tissue Tropism

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targeting of specific range of cells within suitable organism

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Transformation

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genetic alteration of a cell's genome by the introduction of foreign DNA

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Prions

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a class of infectious proteins with no associated nucleic acid; causes Mad-cow disease

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Latent Virus

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a virus that after being integrated into the host cell chromosomes, it does not begin replicating immediately; HIV virus is an example of such

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HIV Infection

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each HIV particle has a glycoprotein on its surface, called gp120, that fits a cell-surface marker protein called CD4 on the surfaces of the immune system cells called macrophages and T cells; this virus is closely related a chimpanzee virus

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Phages

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virus that can infect bacteria

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Envelope

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a layer of liporpotien and glycoprotein that covers the oiter surface of some viruses

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Virulent Virus

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causes lysis of thier hosts (lytic)

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good to know about Virulent Virus.

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Consider: (Refer to illustration below) A virulent virus is one that infects the host cell and enters into the lytic stage causing replication of virus and lysis of the host cell to release these produced viruses. A temperate virus is one that con incorporate its genome into the host cell's genome and remain dormant, only reproducing as the host cell reproduces itself (lysogenic stage). But the virus genome can become activated and it can enter a lytic stage. NEW INFO added 5/14/2012

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Temperate Virus

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becomes establoshed as stable psrts of the host cell genome (lysogenic)
refer to picture in review

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Emerging Virus

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virus in a new host with a lethality rate in excess of 50%; example is Ebola virus; these viruses are able to jump from one species to another; hantavirus originates in deer mice and causes hemorrhagic-type fever; SARS is completely new form of corona virus

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Viroids

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they are tiny, naked molecules of RNA a few hundred nucleotides long whose sequence resembles intron sequences in rRNA genes; they are causative agents of plant diseases

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Lysogenic Cycle

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integration and stabilizing of viral genes into the host cell's genome

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Lytic Cycle

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host cell lyses, releasing many viral particles

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Induction

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the switch from a lysogenic prophage to a lytic cycle

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Cancer

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may be caused by triggering the expression of cancer-causing genes present in the genome.

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Coronaviruses

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fall into 3 groups based on thier surface protiens

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Prophage

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parasitic viral DNA that has been intergrated into the chromosome of its bacterial host.

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Influenza Virus

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3 major types of flu virus (A< B< and C), only Type A can occur in human, other mammals, and birds; the flue subtype is determined by the kinds of proteins representing the H and N protein spikes making up the capsid of the virus; different strains of the virus requires different vaccines; genetic recombination is primarily responsible for the high diversity in strains; genetic recombination between flu strains from different species is common

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Latent Viral Infection

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virus is able to hide from host's immune system by integrating itself into the host cell's genome and not producing new viruses...e.g., chickenpox may be followed, years later, with shingles with both the result of the same viral infection

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Elipse Period

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spans from the point of phage adsorption to the point at which the first phage progeny have matured with an infected cell

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Prion

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misshapen protein agents that may convert other proteins in the cell to also become these agents

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Prokaryote Classification

Back 28

Based on sequencing of proteins, DNA ad RNA

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Prokaryote Facts

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1) oldest organisms on Earth with fossils ~3.5 billion years old
2) structurally simplest organisms
3) most abundant life forms on earth
4) lack a discrete nucleus and other organelles or cell inclusions

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consider: Prokaryote Facts

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Consider: Archaea and Eukarya share nucleic acid similarities so Eukarya split off from Archaea

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Cynobacteria

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group of bacteria that produced oxygen and changed the Earth's atmosphere from an anoxic one to one rich in oxygen

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Prokaryotes Differing from Eukaryotes

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cell size, multicellularity, Chromosomes, organelles, reproduction

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Consider: Prokaryotes Differing from Eukaryotes

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Note: Eukaryotes and Prokaryotes do both have ribosomes.

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Bacteria differing from Achaea

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1. cell wall composition
2. plasma membrane make-up
3. DNA replication
4. gene expression

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Consider: Bacteria differing from Archaea

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Consider: Archaea are able to live in the most extreme environments.

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Prokaryote structure (bacteria)

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have cell walls consisting of a network of polysaccharides connected by cross links of polypeptides (peptidoglycan)

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Prokaryote structure (bacteria)

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pili - hairlike structures that occur on the cells of some gram-negative prokaryotes...important in adhesion; specific form has role in conjugation

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Prokaryote structure (bacteria)

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flagella - used for movement

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Prokaryote structure (bacteria)

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have enzymes used for cellular respiration attached to cell membrane

have 3 shapes (due to cell walls): bacillus, coccus, and spirillum

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Exchange of Genetics Material via Horizontal Transfer

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occurs through conjugation (depends on presence of conjugative plasmids when genes are transferred through rigid, tubular sex pili),
transduction (occurs when viruses (bacteriophage) package host DNA and transfer it upon subsequent infection),
transformation (bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria), and Exchange of R plasmids (plasmids are different from bacterial chromosomes in that plasmids have few genes, bacterial chromosome have many)

increases genetic diversity; helps infer phylogeny; common occurrence in bacteria; can produce large genetic change

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Gram-postive

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positive bacteria have a thicker peptidoglycan wall with small amounts of teichoic and lipoteichoic acid and will stain a purple color...

Front 42

Gram-negative

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gram-negative contain lipopolysaccharides, less peptidoglycan and no acids and do not retain the purple-colored dye; differences in cell's wall determines outcome of the Gram stain

lipopolysaccharides in the outer membrane of certain bacteria make them more resistant to penicillin

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E. Coli

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found in the lower intestine of warm blooded animals;

5000 genes, help host by produce vitamin K2

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Endospores

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thick-walled structures that contain chromosome and small amount of cytoplasm...these are formed in response to environmental stress (e.g., low nutrients)

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Rhizobium

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example of a diazotrophs (nitrogen fixing bacteria)...only organisms (bacteria group) capable of taking gaseous nitrogen and combining it with hydrogen to make ammonia

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Nitrogen fixation and use

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this pathway begins with atmospheric nitrogen ( Dinitrogen; unusable by plants in this form because of strength of N-N triple bond), bacterial nitrogenase(enzyme that catalyzes the reactions); ammonia; conversion by plants or algae; synthesis of proteins

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Binary Fission

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reproductive process that produces indentical cells by simple splitting

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Nucleoid Region

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area where prokaryotic DNA is found (no membrane)

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Obligate Aerobes

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requires oxygen

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Facultative Aerobes

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can use oxygen or not

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Obligate Anaerobe

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organisms poisoned by oxygen

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Aerotolerent Anaerobes

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do not use oxygen but can survive exposure to it

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Mutualism

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2 kinds of organisms living together in ways benefical to both

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Prokaryotic metabolism

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1. photoautotrophs carry out photosynthesis (cyanobacteria use chlorophyll a)
2. chemolithoautotrophs - energy through oxidizing inorganic substances (nitrifiers oxidize ammonia or nitrite to obtain energy, producing nitrate that is taken up by plants)

3. photoheterotrophs - purple and green nonsulfur bacteria use light as energy source and carbon from organic molecules

4. chemoheterotrophs - obtain both carbon atoms and energy from organic molecules (humans)

Front 55

Is a virus structure bigger or smaller than bacteria?

Back 55

a virus structure is smaller than bacteria

Front 56

Part of Virus structure
Capsid components (2)-

Back 56

Outer layer composed of protiens subunits

the protien on surface can interact with a protien on the surface of the host cell

Front 57

Part of Virus structure
Nucleic acid core-

Back 57

inner most portion os made of DNA or RNA

Front 58

Part of Virus structure
Envelope (possessed by some viruses) -

Back 58

are lipid bilayers surrounding virus capsid

Front 59

Part of Virus structure
Spike-

Back 59

glycoprotiens that project from some enveloped viruses allowing for attachment of the virus to the targeted host cell

Front 60

Viruses can also be referred to as

Back 60

Virion

Front 61

what steps occur through viral reproduction? (5)

Back 61

attachment
penetration
biosynthesis (assembly)
maturation
release

Front 62

prions

Back 62

class of infectious protiens
no associated nucleic acid
causes Mad Cow Disease

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an example of a emerging virus

Back 63

ebola virus
(able to jump from one species to another)

hantavirus
(origin; deer and mice and causes hemorrhagic fever)

SARS
(completely new form of corona virus)

Front 64

which influenza virus can occur in humans and mammals and birds?

Back 64

type A
(A<B<C)
subtype is determined by kinds of protiens representing the H and N spikes making up the capsid of the virus.

Front 65

The three shapes of bacteria are
A. haplontic, diplontic, and alternations.
B. anaerobic, aerobic, and facultative.
C. heterotrophic, autotrophic, and chemosynthetic.
D. bacillus, coccus, and spirillum.
E. helical, spiral, and streptococci.

Back 65

D. bacillus, coccus, and spirillum.

Front 66

The response of bacteria that allows them to be identified as Gram-positive or negative is due to
A. the type of DNA or RNA they contain.
B. their ability or lack of ability to fix nitrogen.
C. whether they are aerobic or anaerobic.
D. whether their cell walls have a thin or thick layer of peptidoglycan.
E. the rRNA sequences they demonstrate.

Back 66

D. whether their cell walls have a thin or thick layer of peptidoglycan.

Front 67

Which type of organism will form endospores when faced with unfavorable environmental conditions?
A. viruses
B. bacteria
C. algae
D. protozoans
E. fungi

Back 67

B. bacteria

Front 68

Bacterial cells pick up free pieces of DNA from the medium-pieces that were released from dead bacteria-in a process called
A. transformation.
B. transduction.
C. conjugation.
D. infection.
E. replication.

Back 68

A. transformation.

Front 69

What is the evolutionary relationship among Archaea, Bacteria, and Eukarya?
A. Since Archaea are the most primitive, Archaean ancestors gave rise to bacteria that in turn gave rise to eukaryotes.
B. All three domains are equally distant from the most primitive common ancestor, a protocell.
C. Archaea and Eukarya share nucleic acid similarities so Eukarya split off from Archaea.
D. Bacterial ancestors gave rise to both Archaea and to eukaryotes as two separate side branches.
E. Archaea ancestors gave rise to both bacteria and to eukaryotes as two separate side branches.

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C. Archaea and Eukarya share nucleic acid similarities so Eukarya split off from Archaea.

Front 70

Which of the following is considered to be noncellular?
A. bacteria
B. fungi
C. algae
D. protozoans
E. viruses

Back 70

E. viruses

Front 71

Which of these is the most accurate description of a virus?
A. a noncellular living organism
B. one of the smallest bacteria known
C. a member of the kingdom Virusae
D. a cell at the boundary between living and nonliving things
E. chemical complexes of RNA or DNA protected by protein

Back 71

E. chemical complexes of RNA or DNA protected by protein

Front 72

In order to infect a cell, a virus must
A. inject its protein into the cell while the nucleic acid remains attached to the host cell surface.
B. have a special protein on its surface capsid that can interact with a protein on the surface of the host cell.
C. actively burrow through the cell wall or cell membrane of the host cell to reach the cell's nucleus.
D. produce a special extension of its cytoplasm when it comes into contact with the appropriate host cell.
E. have enzymes to break down the cell wall or cell membrane of the host cell.

Back 72

B. have a special protein on its surface capsid that can interact with a protein on the surface of the host cell.

Front 73

If a virus is latent, it
A. cannot be a retrovirus.
B. has integrated itself into the host cell genome.
C. must be a retrovirus.
D. is gaining a new envelope via "budding."
E. is easy to develop immunity against.

Back 73

B. has integrated itself into the host cell genome.

Front 74

Some human diseases appear to be due to protein agents that may convert other proteins in the cell to also become these agents; this new disease protein agent is called a(n)
A. archeon.
B. prion.
C. cyanobacterium.
D. phage.
E. retrovirus.

Back 74

B. prion.