TLS Online TPP Program

#Question id: 457


Which are membrane associated pathways?

A) electron transport chain in eukaryotes

B) citric acid cycle in bacteria

C) photosynthesis

D) glycolysis

#Unit 1. Molecules and their Interaction Relevant to Biology
  1. A & D Only   

  2. A & B Only

  3. A & C only  

  4. B & C Only

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TLS Online TPP Program

#Question id: 2974

#Unit 2. Cellular Organization

Following statements are regarding to control of the G1–S phase transition in budding yeast.

A. G1 cyclin-CDK complexes stimulate the formation of G1/S phase cyclin-CDKs, which then initiate bud formation, centrosome duplication, and DNA replication. In yeast, the G1 cyclin gene is called CLN3.

B. Once sufficient Cln3 is synthesized from its mRNA, Cln3-CDK complexes phosphorylate and activate the transcriptional repressor Whi5.

C. Phosphorylation of Whi5 promotes its export out of the nucleus, allowing the transcription factor complex SBF to induce transcription of the G1/S phase cyclin genes CLN1 and CLN2 as well as other genes important for DNA replication.

D. Once produced, Cln1/2-CDKs contribute to further Whi5 phosphorylation. This positive feedback loop ensures the rapid accumulation of G1/S phase cyclin-CDKs.

Which of the following statements are correct?

TLS Online TPP Program

#Question id: 2975

#Unit 2. Cellular Organization

Following statements are regarding to the Surveillance mechanisms in cell cycle regulation.

A. Surveillance mechanisms known as checkpoint pathways establish dependencies among cell cycle events and ensure that the next cell cycle event does not occur prior to the completion of a preceding event.

B. In response to DNA damage, two related protein kinases, ATM and ATR, are recruited to the site of the damage, where they activate signaling pathways that lead to cell cycle arrest, repair, and under some circumstances, apoptosis.

C. The spindle assembly checkpoint pathway, which causes initiation of anaphase, utilizes Mad2 and other proteins to regulate APC/CCdc20, which targets securing and mitotic cyclins for ubiquitinylation.

D. The spindle position checkpoint pathway prevents mitotic CDK inactivation when the spindle is mispositioned. In this pathway, localized activators and inhibitors and a sensor that shuttles between them allow cells to sense spindle position.

Which of the following statement is incorrect?

TLS Online TPP Program

#Question id: 2976

#Unit 2. Cellular Organization

Match the following Regulators with its functions.

Column I

Column II

A.  Wee1 kinase

i. Degradation of phosphorylated Sic1 or p27KIP1

B. Cdc25A phosphatase

ii. Induces degradation of B-type cyclins

C. APC/CCdc20

iii. Activates vertebrate S phase CDKs

D. SCF

iv. Inhibits CDKs

Which of the following is correct?

TLS Online TPP Program

#Question id: 2977

#Unit 2. Cellular Organization

The mitotic exit network that localizes to spindle pole bodies and whose activity is regulated by spindle position belongs to the family of signaling pathways known as the Hippo pathway in metazoans. Following statements are-

A. The conserved core of the Hippo signaling pathways consists of the Hippo protein kinase, which activates the Lats-Mob1 kinase.

B. The kinases are organized by a scaffolding molecule that, at least in budding and fission yeasts, targets the kinase cascade to centrosomes.

C. As in many kinase signaling cascades, a GTPase controls the activity of the mitotic exit network and the septation initiation network.

D. In metazoans, activation of the Hippo pathway leads to tissue overgrowth because the transcriptional activator TAZ (known as YAP in the mouse) constitutively promotes the expression of growth- and proliferation-promoting genes.

Which of the following statements are incorrect?

TLS Online TPP Program

#Question id: 2978

#Unit 2. Cellular Organization

The most important regulatory control that restricts cyclins to the appropriate cell cycle stage is ubiquitin mediated, proteasome-dependent protein degradation. Which of the following statement is incorrect regarding to the degradation of protein?

TLS Online TPP Program

#Question id: 2979

#Unit 2. Cellular Organization

Use the data in the accompanying table to answer the question. Minutes Spent in Cell Cycle Phases-

Cell type

G1

S

G2

M

Beta

18

24

12

16

Delta

100

1

0

0

Gamma

18

48

14

20

The data in the table were obtained from a study of the length of time spent in each phase of the cell cycle by cells of three eukaryotic organisms designated beta, delta, and gamma. What is the best explanation for the data associated with delta cells?