Combined all questions

What is the stable form of guanine? And what bond does it form?

Keto form, hydrogen bonding with cytosine

What is the unstable form of guanine? And what bond does it form?

Enol form, and it forms a hydrogen bond with thymine

What is the stable form of cytosine? And what bond does it form?

Amino and a hydrogen bond with guanine

What is the unstable form of cytosine? And what bond does it form?

Imino and a hydrogen bond with adenine

What two nucleic acids are purines?

guanine and Adenine (two rings)

What two nucleic acids are pyrimidines?

Thymine and cytosine (one ring)

Consider this normal sequence of DNA:

5' ACT 3'
3' TGA 5'

Determine the mutated sequence that would result from a tautomerization of a C in the template at the moment of DNA replication?

5’ ATT 3’

3’ TAA 5’

What is the unstable form of Thymine? And what bond does it form?

Enol and it forms a hydrogen bond with guanine

What is the stable form of Thymine? And what bond does it form?

Keto and it forms a hydrogen bond with adenine

What letter is the ‘5 end

B, the 5’ end is shown by the phosphate group

What letter is the 3’ end

A, the 3’ side has the free oh group

What letter represents the phosphodiester bond?

C, its a bond between the phosphate and the sugar group

What letter represents the glycosidic bond?

D, bond between the sugar and the base

Do mutants 3 and 4 complement each other?

undefined

What would be the result of a complementation test between 5 and 6?

No growth, they are in the same group

Do mutants one and two complement each other?

Undefined

What does the letter A represent?

control elements, binding sites for the regulatory proteins

What does the letter B represent?

+1 region, where the rna polymerase makes the rna

What does the letter C represent?

3’ Untranslated region

What does the letter D represent?

Coding region, codes for the amino acids

What does the letter E represent?

5’ untranslated region, its the region after the 5’ cap

What does the letter F represent?

F is the promotor, initiates transcription

Which underlined region is the -10 region?

TATAAT

Which underlined region is the -35 region?

TTGACA

Which of the two underlined sequences is the complementary sequence for the -35 sequence?

AACTGT

What direction will it transcribe?

Right, because it goes from 35 end to the 10 region

where are the two 5’ ends?

Top left and bottom right

What strand is the template for the model rna?

The bottom strand

Assuming that the first nucleotide transcribed from this sequence is at the end of one of the strands (marked in bold), what will be the first nucleotide incorporated into RNA?

It starts from the 5’ end of the bottom strand since that is the template, so it would be U since the nucleotide A is the template.

nucleoside or nucleotide?

nucleoside

nucleoside or nucleotide?

nucleoside, adenosine

nucleoside or nucleotide?

nucleoside, cytidine

nucleoside or nucleotide?

nucleoside, Guanosine

nucleoside or nucleotide?

nucleoside, uridine

nucleoside or nucleotide?

nucleotide

nucleoside or nucleotide?

nucleotide

nucleoside or nucleotide?

Nucleotide

Is this the green the major or minor groove?

The green is the major groove as its larger

Is the blue the major or minor groove?

Minor groove, the sugars are closer together

What does the major groove do?

Its the wider of the two grooves, because its wider its easier for proteins to access, so that is where most of the transcripton factors and the repressors and activators bind

What does the minor groove do?

The smaller of the two grooves, cant hold as much information

is G1 the major or minor groove and why?

G1 is the minor groove, because the two black dots (sugars) are closer together on the g1 side then the g3 side

are glucose and lactose levels high or unavailable in this scenario?

Glucose is unavailable, Lactose is high

are glucose and lactose levels high or unavailable in this scenario?

Glucose is high, Lactose is unavailable

are glucose and lactose levels high or unavailable in this scenario?

glucose is unavailable, lactose is unavailable

are glucose and lactose levels high or unavailable in this scenario?

Glucose is high, lactose is high

For ecoli transcription the wild type is given glucose how does that effect the ara operon and the lac operon transcription

Glucose decreases AC which decreases cAMP which in turn means that the ara and lac operon will not transcribed

For ecoli transcription the wild type is given glucose and cAMP; how does that effect the ara operon and the lac operon transcription

cAMP activates both the lac and ara operon

For ecoli transcription the cya- phenotype is given cAMP how does that effect the ara operon and the lac operon transcription

cya- doesnt have AC so glycose is down and the lac and ara operon are trascribed

In a LacI⁺ / LacI⁻ merodiploid strain (one chromosome has LacI⁺, the other LacI⁻), lactose is absent — will the lac structural genes be repressed or constitutively expressed?

The structural genes will be repressed, because its a transacting gene so the lacI+ works for both strains and the gene will be repressed

In E. coli, if glucose is low and lactose is high, what happens to cAMP levels and how does that affect lac operon expression? What enzyme would you expect to be produced in high quantities?

cAMP will be high which will cause the lac operon to be on and create beta galactosidase

An E. coli cell is given both glucose and lactose. A researcher then adds exogenous cAMP to the culture. How does beta-galactosidase production change compared to the cell without added cAMP, and why?

The cAMP would could for the CAP protein and cause the lac operon to be on and create beta galactosidase

A mutation results in a LacI⁻ genotype. How does this affect lac operon transcription when lactose is absent, and is this mutation cis-acting or trans-acting?

LacI- means that the lac operon will be on nomatter what, so a lack of lactose doesnt effect the lac operon transcription and it is Transacting

Compare the roles of LacZ, LacY, and LacA in lactose metabolism. Which two are considered the primary structural genes?

LacY and Lac Z are the primary structural genes because they incode for beta galactosidase in lac z and in lac y they incode for lactose permease which is the primary structure of the gene, Lac A incodes for an enzyme that gets rid of the waste which isnt apart of the primary structure of the gene.

A LacOᶜ mutation is introduced into an E. coli cell. How does this affect transcription of the structural genes regardless of lactose levels, and why can't a second wild-type operator on another DNA strand rescue this phenotype?

LacOᶜ mutation means that the operator cant bind to the resistor, which means that lac operon is constantly expressed, the mutation is also cis so it cannot change strands

What is the difference between a constitutive and inducible mutation in the context of the lac operon?

constitutive mutations means that the lac operon is always on, inducible means that the lac operon can be turned on or off depending on the amount of lactose in the system

A wild-type E. coli cell has glucose present and lactose absent. Predict the level of beta-galactosidase produced?

very little to no beta galactosidase produced

On e coli mutants which result in uniducible phenotype for beta galactosidase

Lac Z-: cant produce beta galactosidase so the amount of beta galactosidase doesnt change with the amount of lactose, LacY-: same thing as before it stops lactose from entering the cell so it cannot be induced, LacI^S the reducer is always on so its not inducible

In ecoli the genotype of the chromosome is lacZ- and lacI- and the genotype of the F’ plasmid is LacZ+ LacI+ is beta galactosidase inducible, uninducible or constitutive?

Inducible: LacZ and lacI are transacting so they will lead to a wildtype phenotype and thus make it inducible

In ecoli the genotype of the chromosome is lacZ- and lacI- and the genotype of the F’ plasmid is LacZ+ LacI^S is beta galactosidase inducible, uninducible or constitutive?

Uninducible: The LacI^S means that the reducer is always on

In ecoli the genotype of the chromosome is lacZ- and lacI- and the genotype of the F’ plasmid is LacZ+ LacI- is beta galactosidase inducible, uninducible or constitutive?

Constitutive: The lac I which codes for the repressor is always off, so it is constitutive

In ecoli the genotype of the chromosome is lacZ- and lacI- and the genotype of the F’ plasmid is O^C LacZ+ LacI+ is beta galactosidase inducible, uninducible or constitutive?

constitutive: O^C means that the repressor cant bind to operator, which means that the gene is always being transcribed for

In ecoli the genotype of the chromosome is lacZ+ and lacI+ and the genotype of the F’ plasmid is none, is beta galactosidase inducible, uninducible or constitutive?

Inducible: This is the wildtype phenotype

In ecoli the genotype of the chromosome is lacZ+ and lacI+ and the genotype of the F’ plasmid is LacZ+ LacI+ is beta galactosidase inducible, uninducible or constitutive?

Inducible: wildtype phenotype

In ecoli the genotype of the chromosome is lacZ+ and lacI+ and the genotype of the F’ plasmid is LacZ+ LacI^S is beta galactosidase inducible, uninducible or constitutive?

Uninducible: The LacI^S means that the reducer is always on

In ecoli the genotype of the chromosome is lacZ+ and lacI+ and the genotype of the F’ plasmid is LacZ+ LacI- is beta galactosidase inducible, uninducible or constitutive?

inducible: lacI+ is transacting so they will lead to a wildtype phenotype and thus make it inducible

In ecoli the genotype of the chromosome is lacZ+ and lacI+ and the genotype of the F’ plasmid is LacZ+ LacI+,O^c is beta galactosidase inducible, uninducible or constitutive?

constitutive: O^C means that the repressor cant bind to operator, which means that the gene is always being transcribed for