TLS Online TPP Program

#Question id: 9248


Which of the following is a consequence of biological magnification?

#Unit 9. Diversity of Life Forms
  1. Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.
  2. Populations of top-level predators are generally smaller than populations of primary consumers.

  3. The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers.

  4. Only a small portion of the energy captured by producers is transferred to consumers.
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TLS Online TPP Program

#Question id: 2984

#Unit 2. Cellular Organization

Certain unicellular eukaryotes, including diatoms and some yeasts, have mechanisms of nuclear division that may resemble intermediate steps in the evolution of mitosis. Which of the following is a characteristic feature of nuclear division in these organisms?

TLS Online TPP Program

#Question id: 2983

#Unit 2. Cellular Organization

Cell cycle is regulated by master regulators (cyclin and CDKs). In vertebrates, G1 CDK activity rises during G1 and is stimulated by the presence of growth factors. When signaling from growth factors is sustained, the resulting cyclin D–CDK4/6 complexes begin phosphorylating Rb, releasing some E2F, which stimulates transcription of the genes encoding cyclin E, CDK2, and E2F itself. In a particular cell type there is a mutation in Rb such that it cannot be phosphorylated. What will be the correct expression pattern of cyclin E in these cells after mitotic stimulation?

TLS Online TPP Program

#Question id: 2982

#Unit 2. Cellular Organization

Match the following proteins (Column I) with their functions (Column II) during cell cycle.

Column I

Column II

A. Cdc25C phosphatase

i. Activates vertebrate S phase CDKs

B. INK4

ii. Activation of Mitotic CDKs

C. Cdc25A phosphatase

iii. Binds and inhibits G1 CDKs

D. APC/CCdc20

iv. Degradation of securin

TLS Online TPP Program

#Question id: 2981

#Unit 2. Cellular Organization

For the nuclear envelope to be broken down as cells go from prophase to prometaphase during mitosis, the nuclear lamina has to be disassembled. Which of the following statement is incorrect?

TLS Online TPP Program

#Question id: 2980

#Unit 2. Cellular Organization

Following statements are regarding to the protein phosphatase Cdc14 function in budding yeast.

A. In budding yeast, the protein phosphatase Cdc14 throws the switch between two mutually antagonistic states during anaphase.

B. Cdc14 is kept inactive during most of the cell cycle, but is activated during anaphase by a GTPase signaling pathway known as the mitotic exit network.

C. Mitotic exit network is unresponsive to spindle position and becomes active in anaphase.

D. Cdc14 phosphatase activated by the activation of protein kinase cascade.

E. Cdc14 dephosphorylates APC/CCdh1 and Sic1 to promote mitotic cyclin degradation

and mitotic CDK inactivation, respectively. This process leads to exit from mitosis.

Which of the following combination is incorrect?

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?