How do the concentrations of substrate and product change when reaction is at equilibrium?

a. product increases

b. substrate increases

c. neither change

There is another subtlety in cellular reaction control to recognize. how can a cell divide a nonspontaneous reaction forward WITHOUT upregulating expression of the enzyme associated with that reaction?

a. place a highly spontaneous reaction downstream of the nonspontaneous reaction

b. place a highly spontaneous reaction upstream of the nonspontaneous reaction

c. sandwich the nonspontaneous reaction in between 2 spontaneous reactions

Which of the following statements about differentiated cells is true?

a. cells of distinct types express nonoverlapping sets of transcription factors.

b. once a cell has differentiated, it can no longer change its gene expression.

c. once a cell has differentiated, it will no longer need to transcribe RNA.

d. some of the proteins found in differentiated cells are found in all cells of a multicellular organism.

Which of the following statements about transcription factors is false?

a. transcriptional regulators only interact with the sugar-phosphate backbone on the outside of the double helix to determine where to bind on the DNA helix.

b. transcriptional regulators will form hydrogen bonds, ionic bonds, and hydrophobic interactions with DNA.

c. the DNA-binding motifs of transcriptional regulators usually bind in the major groove of the DNA helix.

d. the binding of transcriptional regulators generally does not disrupt the hydrogen bonds that holds the double helix together.

Where in our concept map of gene expression do transcription factors fit in?

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Which of the following are false of the TATA Box promoter sequence?

a. it is a promoter sequence where transcription factors bind

b. the adaptor protein between the DNA and RNA Polymerase binds here

c. it is a sequence that lies upstream of a small number of genes involved in cell growth and differentiation

d. protein binding at the TATA box induces a 90-degree bend in the DNA

Imagine that an RNA polymerase is transcribing a segment of DNA that contains the following sequence:

5'-AGTCTAGGCACTGA-3'

3'-TCAGATCCGTGACT 5'

If the polymerase is transcribing from this segment of DNA from left to right, which strand (top or bottom) is the template?

a. top

b. bottom

Imagine that an RNA polymerase is transcribing a segment of DNA that contains the following sequence:

5'-AGTCTAGGCACTGA-3'

3'-TCAGATCCGTGACT 5'

What will be the sequence of that RNA?

A. 5'-AGUCUAGGCACUGA-3'

B. 3'-AGUCUAGGCACUGA-5'

C. 5'-AGTCTAGGCACTGA-3'

D. 3'-AGTCTAGGCACTGA-5'

Why is the dogma "one gene-one protein" not always true for eukaryotic genes?

a. there are multiple ways that a DNA sequence can be transcribed into RNA

b. introns are removed from the DNA transcript and some exons can be spliced differently

c. the primary RNA transcript can be alternatively spliced, producing distinct mRNAs that are translated into distinct proteins

d. the same mRNA can be translated into different amino acid polypeptide chains

[image]

The picture here depicts:

a. one gene yields one distinct protein

b. one gene yields one distinct mRNA

c. one gene yields alternatively spiced mRNAs, which will code for alternative proteins

d. one gene yields one polypeptide

How are most eukaryotic transcription regulators able to affect transcription when their binding sites are far from the promoter?

a. by binding to their binding site and sliding to the site of RNA polymerase assembly

b. by looping out the intervening DNA between their binding site and the promoter

c. by unwinding the DNA between their binding site and the promoter

d. by attracting RNA polymerase and modifying it before it can bind to the promoter

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What do the protein expression data in Panel C suggest?

a. when miR-145 is added OCT4 and Klf4 expression increase

b. when miR-145 is added, OCT4 and Klf4 expression decrease

c. cannot analyze protein expression because the loading control changes between treatment groups

[image]

In conjunction with the previous data, what do the protein expression data in Panel F suggest?

a.miR-145 decreases translation of Oct4, Sox2, and Klf4

b. miR-145 increases translation of Oct4, SOx2, and Kl4

How does miR-145 lead to reduced translation of these stem cell pluripotency maintenance factors?

a. factor transcription is reduced and thus protein expression in decreased.

b. factor transcription is increased and thus protein expression in increased.

c. translation of factor mRNA is inhibited and protein levels increased.

d. translation of factor mRNA is inhibited and thus protein levels decrease.

Which of the following pairs of cordons might you expect to be read by the same tRNA as a result of wobble?

a. CUU and UUU

b. UAG and UAA

c. CAC and CAU

d. AAU and AGU

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a. mutation in the DNA coding for the protein

b. a mutation in teh anticodon of the isoleucine tRNA

c. a mutation in the isoleucyl-tRNA sythetase that decreases its ability to distinguish between different amino acids

d. a mutation in the isoleucyl-tRNA synthetase that decreases its ability to distinguish between different tRNA molecules

The piece of RNA below includes the region that codes the binding site for the initiator tRNA needed in translation.

5′-GUUUCCCGUAUACAUGCGUGCCGGGGGC-3′ 

Which amino acid will be on the tRNA that is the first to bind to the A-site of the ribosome? 

a. Methionine

b. Arginine

c. Cystine

d. Valine

[image]

a. mutations in gene promoters

b. histone tail modification

c. the action of proteases

d. the action/abundance of transcription factors

How many reading frames could be used to 

translate the mRNA and what are is/are the 

polypeptide(s) that could be translated? 

A. 2; SCIENCE or LHRKLR 

B. 3; SCIENCE, PA, or LHRKLR 

C. 3; SCIENCE or LHRKLR 

D. 2; SCIENCE or PA 

[image]

A. Mutations in gene 

promoters 

B. Histone tail modification 

C. The action of proteases 

D. The action/abundance of 

transcription factors 

The amino acids glutamine and glutamic acid are shown below. They differ only in the structure of their side chains. In the ionization state shown, glutamic acid can participate in molecular interactions that are not 

possible for glutamine. What types of interactions are these? 

[image]

A. ionic bonds 

B. hydrogen bonds 

C. van der Waals 

interactions 

D. covalent bonds

Which of the following are true? 

A. A free protein in the cytosol must 

interrupt many H-bonds between water 

molecules in order to carry out its function. 

B. Most proteins will preferentially orient 

ionic side chain towards the cytosol. 

C. The H-bonding network between water 

molecules greatly reduces the 

electrostatic attraction between two 

proteins with complementary ionic charges. 

D. Large numbers of weak non-covalent 

bonds on the surfaces of large 

molecules can promote strong and specific binding. 

E. All of the above are true. 

Sickle cell disease is caused by a single amino acid substitution in the hemoglobin protein. The mutant amino acid is nonpolar. As such, the aqueous cytosol repels it 

and forces the mutant groups to aggregate together to escape the hydrophilic environment. The aggregates distort the biconcave RBC shape. Which amino acid 

(A or B) corresponds to the mutant amino acid in Sickle cell Disease?

[image]

a. A

b. B

[image]

a. alpha helix

b. beta pleated sheet

c. disulfide bridge

[image]

a. electrostatic forces

b. Van der Waals forces

c. hydrogen bonds

d. hydrophobic interactions

[image]

A. Random motion due to account for steric hindrance induced by oxygen binding. 

B. The positive charge of the oxygen induces electrostatic attraction from the heme iron group, inducing a conformational change of the entire globin protein. 

C. The electron cloud of molecular oxygen induces electrostatic attraction from the heme iron group, inducing a conformational change of the entire globin protein. 

D. When the amino acids in one globin are shifted by the oxygenation of one of the heme groups, the structure of the interfaces between the four subunits is altered. This 

causes the whole protein to change its shape. In the new shape, it is easier for the other three heme groups to become oxygenated.

The amino acid histidine is often found in enzymes. Depending on the pH of its environment, 

sometimes histidine is neutral and at other times it acquires a proton and becomes positively charged. 

Consider an enzyme with a histidine side chain that is known to have an important role in the function 

of the enzyme. It is not clear whether this histidine is required in its protonated or its unprotonated

state. To answer this question, you measure enzyme activity over a range of pH, with the results 

shown below. Which form of histidine is necessary for the active enzyme?

[image]

A. Protonated

B. Unprotonated

C. Ionized

D. Non-ionized

E. A and C

F. B and C

[image]

A. Random motion due to account for steric hindrance induced by oxygen binding.

B. The positive charge of the oxygen induces electrostatic attraction from the hemeiron group, inducing a conformational change of the entire globin protein.

C. The electron cloud of molecular oxygen induces electrostatic attraction from the heme iron group, inducing a conformational change of the entire globin protein.

D. When the amino acids in one globin are shifted by the oxygenation of one of the heme groups, the structure of the interfaces between the four subunits is altered. 

This causes the whole protein to change its shape. In the new shape, it is easier for the other three heme groups to become oxygenated.

[image]

a. 2

b. 3

c. 5

d. 6

e. 7

Signal sequences that direct proteins to the correct 

compartment are _________.

A. added to proteins through post-translational  modification. 

B. added to a protein by a protein translocator.

C. encoded in the amino acid sequence and sufficient 

for targeting a protein to its correct destination. 

D. always removed once a protein is at the correct 

destination.

[image]

A. 1--A, 2--C, 3--A, 4--C, 5--C

B. 1--A, 2--C, 3--A, 4--C, 5—B

C. 1--C, 2--C, 3--A, 4--A, 5—C

D. 1--C, 2--C, 3--A, 4--A, 5--C

[image]

A. in the cytoplasm

B. in the ER lumen

C. inserted into the ER membrane

D. degraded by signal peptidase

[image]

A. Hydrophobic start-transfer 

sequence

B. Hydrophobic stop-transfer 

sequence

C. Protein translocator

D. Signal peptidase

Place the following events in the best order:

1. Lysosomal dissociation of M6P receptor and hydrolase due to decreased pH.

2. Properly folded hydrolase exits Quality Control in ER.

3. Hydrolase docks to the lumenalside of the vesicular 

membrane.

4. A phosphate group is added to a mannose group on hydrolase in the Golgi.

5. M6P receptors are recycled.

6. Core oligosaccharide is added to hydrolase.

1. 6, 2, 4, 3, 1, 5

2. 2, 4, 3, 6, 1, 5

3. 2, 6, 4, 3, 1, 5

4. 6, 2, 3, 4, 1, 5

Patients with “I-disease” lack the mannose-6-phosphate signal that is present on protein-degrading enzymes. These patient have dysfunctional lysosome function and uneeded proteins can build up in their cells. Select the best possible medical treatment for this disease from the list below: 

1. Deliver a drug that increases vesicle 

transport of hydrolase from the Golgi.

2. Target an active form of hydrolase to the cell cytoplasm.

3. Deliver a drug that increase hydrolase synthesis in the ER.

4. Target an active form of hydrolase to the cell lysosome.

[image]

The adrenaline receptor…. (select incorrect statement) 

A. is a transmembrane or integral protein 

B. contains both polar and nonpolar stretches of amino 

acids 

C. can detach and move out of the lipid membrane freely 

D. has an active site on its extracellular face

[image]

The enzyme PKA…. (select incorrect statement) 

A. is a transmembrane or integral protein. 

B. contains both polar and nonpolar stretches of amino 

acids. 

C. is only active after undergoing a conformational change upon chemical interaction with cAMP. 

D. Adds a phosphate group to inactive phosphorylase kinase.

[image]

Is it likely that this is only the only signaling cascade 

initiated by adrenaline binding to its cell surface receptor. 

A. True 

B. false.

[image]

When adrenaline signaling is no longer needed (aka, you realize the red-washed snow was algae and NOT blood) what happens next? 

(which is/are least likely to occur) 

A. Adrenaline is released from the receptor and moves 

back into ECM and bloodstream. 

B. The adrenaline-receptor complex and surrounding 

lipid membrane is brought into the cell by endocytosis. 

C. In endocytic vesicles, chemical changes induce the 

release of adrenaline from the receptor and this 

molecule is recycled into other amino acid products. 

D. The embedded receptor is either stored in vesicles for 

repeated use or degraded and its amino acid components utilized for another process. 

E. Adrenaline remains bound to the receptor and the 

signaling cascade will dissipate. 

F. All of these may occur

Which of these events would you expect to go 

through more regulatory steps before beginning? 

1) DNA Synthesis 

2) moving hand away from hot stove 

A. 1 

B. 2