Exam (elaborations)

Microbiology Exam 3 Material 2024/2025 With 100% Correct Answers

0 purchase

Course
Microbiology E3 Material 2024/2025 With 100% C

Institution
Microbiology E3 Material 2024/2025 With 100% C

Coupled transcription and translation - correct answers Ribosomes bind mRNA while mRNA is still being created, so that translation begins while transcription is still occurring - Advantage of lacking a nucleus Translation initiation - correct answers - Initiation factors bind ribosome to the ri...

[Show more]

Preview 3 out of 19 pages

View example

Uploaded on December 9, 2024
Number of pages 19
Written in 2024/2025
Type Exam (elaborations)
Contains Questions & answers

microbiology exam 3 material with 100 c

Institution Microbiology E3 Material 2024/2025 With 100% C
Course Microbiology E3 Material 2024/2025 With 100% C

QUILLSKY Member since 2 year 398 documents sold

$16.49

Add to cart

Save

100% satisfaction guarantee
Immediately available after payment
Both online and in PDF
No strings attached

Microbiology Exam 3 Material 2024/2025
With 100% Correct Answers

Coupled transcription and translation - correct answers ✔✔Ribosomes bind mRNA while mRNA is still
being created, so that translation begins while transcription is still occurring

- Advantage of lacking a nucleus

Translation initiation - correct answers ✔✔- Initiation factors bind ribosome to the ribosome binding site
known as the Shine Delgarno sequence (AGGAGG)

- Begins at start codon

1. 30s subunit binds mRNA

2. IF2 interacts with initiator tRNA

3. fMet-tRNA binds to start codon

4. Association of initiator tRNA with 30s mRNA releases IF3 and allows IF1 to bind

5. 50s subunit binds to 30s complex and GTP hydrolysis occurs

Translation elongation - correct answers ✔✔- A site: charged tRNA entry site

- P site: peptidyl site

- E site: uncharged tRNA exit site

- tRNA binds at A site and peptide bond between amino acid in P and A site

Translation termination - correct answers ✔✔- Uncharged tRNA leaves ribosome

- Stop codon enters the A site and protein release factor enters site

- Binding of release factor releases completed protein from tRNA in P site and causes complex to
dissociate

Protein folding - correct answers ✔✔- Primary structure: sequence of amino acids as dictated by gene;
ribosome generates primary structure

,- Secondary structure: coils and folds in the polypeptide chain; hydrogen bonding of the polypeptide
backbone between amine groups

- Tertiary structure: determined by interactions among various side chains (R groups); 3D shape due to R
group interactions

- Quaternary structure: results when a protein consists of multiple polypeptide chains

Operon - correct answers ✔✔Unit of genetic material that functions in a coordinated manner by means
of an operator, promoter, and one or more structural genes

Promoter - correct answers ✔✔Specific region of a gene that binds RNA polymerase and indicates where
to start transcribing RNA

Regulon - correct answers ✔✔System of genes, formed by one or more operons, that have a common
regulatory element

Reasons why cells do not express every gene at maximum level functioning - correct answers ✔✔-
Physical space limitations

- Energy and resource conservation

- Contradicting functions

Constitutive proteins - correct answers ✔✔Proteins made all the time at a constant rate and are needed
at the same level all the time

Post-transcriptional regulation - correct answers ✔✔Control of activity of preexisting enzymes; protein is
modified to change its activity

Homodimeric - correct answers ✔✔Protein composed of two identical polypeptides

Negative regulator/repressor - correct answers ✔✔Binds to regulatory sequences in the DNA and
prevents transcription of target genes

- Often they block sigma factors of RNA polymerase from binding promoter

- Bind DNA at sequence called operator sequence

, - Repressors can require co-factors to repress or be released from binding site

Positive regulator/activator - correct answers ✔✔Binds to regulatory sequences in the DNA and
promotes transcription of target genes

- Often acts to recruit or stabilize sigma factor interaction with a promoter

- Binding site is generally upstream of -35, -10 sequence (activator binding site)

- Interacts with alpha subunit RNA polymerase.

- Can also alter DNA structure to allow binding of sigma factor

- Activators can require co-factors to bind DNA

Organization of lac operon - correct answers ✔✔- lacZ: B-Galactosidase; converts lactose to glucose and
galactose, can also convert lactose to allolactose (an inducer)

- lacY: Lactose permease; membrane protein that imports lactose from the extracellular environment

- lacI: Lac repressor; protein blocks transcription of the lac operon

- lacO: lac operator; DNA sequence that binds LacI

In the absence of lactose - correct answers ✔✔LacI binds to the operator region and represses the lac
operon by preventing open complex formation by RNA polymerase

In the presence of lactose - correct answers ✔✔- B-galactosidase (LacZ) cleaves and rearranges lactose
to make the inducer allolactose

- Allolactose binds to LacI, reducing its affinity to the operator and thus allowing induction of the operon

Catabolite repression - correct answers ✔✔- Presence of glucose affects signal inside the cell called cyclic
adenosine monophosphate (cAMP)

- Concentrations of cAMP are assessed via cAMP Receptor Proteins (CRP)

- CRP responds to the presence of cAMP

Cyclic adenosine monophosphate (cAMP) - correct answers ✔✔Intracellular second messenger in the
signaling cascade synthesized from ATP by adenylate cyclase

- Nutrient sensor

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller QUILLSKY. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $16.49. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

64232 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 15 years now

Start selling

Exam (elaborations)

Microbiology Exam 3 Material 2024/2025 With 100% Correct Answers

Document information

Subjects

Written for

Seller

Reviews received

Content preview