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72 Cards in this Set
- Front
- Back
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Is the regulatory gene of an operon constantly transcribed and translated? |
Yes |
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What is the product of an Operon's regulatory gene? |
Repressor protein |
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Is the Repressor gene in Lac Operon's active or inactive? |
Active |
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Is the Repressor gene in Tryp Operon's active or inactive? |
Inactive |
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Is the Lac Operon a repressive or inducible Operon? |
Inducible operon (off to on) |
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Is the repressor protein inactive or active when lactose is present? |
Active |
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Are the structural genes turned on or off when lactose is not present in the environment? |
On |
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When lactose is not present in the environment, the ___________ binds to the _______ and blocks transcription and translation of the structural genes. |
Repressor; Operator |
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When lactose is present in the environment, ________ inactivates the _________ so the structural genes can be transcribed and translated. |
Lactose; Repressor |
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When lactose is present in the environment, ________ inactivates the _________ so the structural genes can be transcribed and translated. |
Lactose; Repressor |
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Is the tryp operon an inducible or repressible operon? |
Repressible (on to off) |
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When tryptophan is present in the environment, is the repressor protein active or inactive? |
Inactive |
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Are the structural genes on or off when tryptophan is present in the environment? |
On |
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When tryptophan is present in the environment, the _________ binds to the __________ |
Repressor; Operator |
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Define mutation |
A permanent change in an organisms DNA |
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Define Point Mutation |
Mutation that affects just one base pair (most common mutations) |
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Define Genetic Recombination |
When a donor bacterium donates DNA to a recipient bacterium and then the recipient bacterium adds donor bacterium to existing DNA. A new strain is created with the combination. |
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List the three methods of genetic recombination |
1. Transformation 2. Transduction 3. Conjugation |
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Define transformation |
Transfer and integration of DNA fragments from dead, lysed bacterium to a recipient bacterium |
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In the Griffith experiment, did the rough or smooth bacteria cause pneumonia? |
Smooth bacteria |
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What is the limitation of transformation? |
Recipient bacterium must be competent or able to take up DNA from its environment |
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Define virus |
Small obligate intracellular parasites |
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Can a virus be viewed with a light microscope? |
No. Needs and electron microscope |
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Explain why viruses are obligate intracellular parasites |
They are specific about the host cell they use and infect a wide range of hosts |
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How do viruses determine which cells to use as their host cell? |
Bind to receptor to specific host cell |
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List the two viral components that ALL viruses contain |
1. Nucleic acid 2. Protein coat or capsid |
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Can the nucleic acid of a virus contain DNA and RNA? |
No. Either/Or |
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Could a virus contain single stranded DNA as its nucleic acid? |
Yes |
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Do ALL viruses have a viral envelope? |
No |
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Do ALL viruses have a viral envelope? |
No |
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What is a viral envelope composed of? |
Host cell membrane that surrounds the capsid and can have spikes to help virus attach to host cell |
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List Viral morphologies |
1. Helical- spiral 2. Polyhedral- spherical 3. Complex- not Helical or polyhedral |
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Why is lytic viral replication called LYTIC viral replication? |
Because it ends in lysis or bursting of the host cell to release progeny viruses |
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List Lytic replication steps |
1. Attachment 2. Entry 3. Synthesis 4. Assembly 5. Release |
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List Lysogenic viral replication |
1. Attachment 2. Entry 3. Insertation 4. Replication 5. Induction 6. Synthesis 7. Assembly 8. Release |
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Are both Gram+ and Gram- bacteria capable of bacteria genetic recombination? |
Yes |
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What is the purpose if an Ames test? |
Test to determine if a chemical is a mutagen of salmonella and screens a chemical to see if it can reverse point mitation |
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What are the components are an operon? |
1 or more structural genes + regulatory gene that controls transcription and translation |
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What are the components are an operon? |
1 or more structural genes + regulatory gene that controls transcription and translation |
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How do Operons control transcription and translation? |
Via a repressor protein that may be active or inactive |
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Define mutagen |
A chemical or physical agent that causes mutation |
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Define carcinogen |
Substance capable of causing cancer in living tissue |
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Define limitation of Transformation |
Recipient bacterium must be competent or able to take up DNA from its environment |
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What percent of bacteria are naturally competent? |
Less than 1% |
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Define transduction |
Transfer or integration of donor bacterium DNA to recipient bacterium via a bacteriophage |
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What is the limitation of Transduction |
Need a phage capable of infecting both donor and recipient bacteria which means that same species of bacteria. |
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Define Conjugation |
Transfer and integration of donor bacterium DNA to recipient bacterium via direct cell to cell contact |
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What is the limitation of conjugation? |
Requires 2 live bacteria |
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At the end of F+ X F- conjugation are the bacteria F+/F-/Hfr? |
F+ |
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At the end of Hfr X F- conjugation are the bacteria F+/F-/Hfr? |
F- |
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Define Capsid or coat |
Protects the viral nucleic acid |
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Define Nucleic acid |
Either DNA or RNA (can be double or single stranded) |
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Define Viral envelope |
Host cell membrane that surrounds the capsid (may have spikes to help virus attach to the host cell) |
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In Lytic Viral replication, what is the Bacteriophage? |
T4 |
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In Lysogenic viral replication, what is the bacteriophage? |
Lambda |
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What is the cancer hypothesis? |
Just because you get one viral strain infection, doesn't mean you will get cancer. It takes multiple hits. |
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Define Prions |
An infectious particle made of misfolded prion particles |
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What does everyone have in their DNA that encodes for for Prion protein? |
PRNP |
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In the AMES test, if the media doesn't have colonies growing, what does that mean? |
It means that the chemical did not reverse the mutation of Salmonella and couldn't produce Histadine. |
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How do viruses determine which cells to use as their host cell? |
Since viruses are specific about the host cell they use a receptor to bind to a suitable host cell |
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What are the 3 methods of entry in an animal virus |
1. Direct penetration 2. Membrane fusion 3. Endocytosis |
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What nucleic acid do retroviruses contain? |
RNA |
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What is reverse transcriptase? |
When RNA uses an enzyme to convert back to DNA so they can use the host cell machinery. |
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What step in viral replication utilizes reverse transcriptase? |
Step 3: synthesis |
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How does an enveloped animal virus acquire its enevelope? |
Enveloped viruses extrude from the host cell via exocytosis but they take a portion of the host cell membrane with them and it becomes their viral envelope |
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How do antiviral medications work? Name the 4 processes |
1. Block entry of virus into host cell 2. Block synthesis of viral components 3. Prevent assembly of progeny viruses 4. Prevent release of progeny viruses from the host cell |
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Define latent as it pertains to an animal virus |
Latent viruses can remain dormant for years but can reactivate via exposure to UV light, stress or infection |
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Are all animal viruses latent? |
No |
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Do some viruses contribute to human cancers? What percentage do? |
No only 15%-20% of viral infections contribute to human cancers |
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What are prions made of? |
An infectious particle made of misfolded prion proteins |
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How are prions inactivated? |
Must incinerate or autoclave (very high temperature and pressure) to inactivate prions |
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Is there a treatment or cure for prion disease? |
No |
