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TLS Online TPP Program

#Question id: 12186

In 2001, the Nobel Prize in Physiology or Medicine was awarded to three cell cycle scientists. Paul Nurse was recognized for his studies with the fission yeast S. pombe, in particular for the discovery and characterization of the wee1+ gene. What did the characterization of the wee1+ gene tell us about cell cycle control?

#Unit 2. Cellular Organization
  1. The dual-specificity protein kinase Wee1 phosphorylates CDKs on the activatory tyrosine 15.
  2. Yeast cells with a defective wee1+ gene activate S phase CDKs prematurely and hence experience premature entry into DNA replication. 
  3. Fission yeast cells carrying a CDK1 mutation in which the tyrosine 15 residue is replaced by phenylalanine (which is structurally similar to tyrosine but cannot be phosphorylated) show the premature mitotic CDK activation and entry into mitosis.
  4. The dual-specificity protein phosphatase Wee1 dephosphorylates CDKs on the inhibitory tyrosine 15.

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TLS Online TPP Program

#Question id: 16113

#Unit 7. System Physiology – Animal

Which of the behavioural components may not contribute by reducing the exposure of skin to the cold?
TLS Online TPP Program

#Question id: 16114

#Unit 7. System Physiology – Animal

Which of the following hormones are thermogenic?
TLS Online TPP Program

#Question id: 16115

#Unit 7. System Physiology – Animal

Cold environmental temperatures:
TLS Online TPP Program

#Question id: 16116

#Unit 7. System Physiology – Animal

Which of the following hormones acts synergistically with sympathetic nervous system?
TLS Online TPP Program

#Question id: 16118

#Unit 7. System Physiology – Animal

Following statements are regarding to the heat production by the activation of sympathetic nervous system.
A. Activation is stimulation of β receptors in brown fat, which increases metabolic rate and heat production.
B. Activation is stimulation of α2 receptors in brown fat, which increases metabolic rate and heat production.
C. Stimulation of α1 receptors in vascular smooth muscle of skin blood vessels, producing vasoconstriction. Vasoconstriction reduces blood flow to the surface of the skin.
D. Stimulation of α1 receptors in vascular smooth muscle of skin blood vessels, producing vasodilation. Vasodilation reduces blood flow to the surface of the skin.
Which of the following combination is correct?
TLS Online TPP Program

#Question id: 16310

#Unit 7. System Physiology – Animal

The temperature of the body is regulated almost entirely by nervous feedback mechanisms, and almost all these mechanisms operate through temperature regulating centers located in the hypothalamus. Following statements are as follows:
A. The anterior hypothalamic-preoptic area contains large numbers of heat-sensitive neurons, as well as about one third as many cold-sensitive neurons. These neurons are believed to function as temperature sensors for controlling body temperature.
B. The heat-sensitive neurons increase their firing rate 2- to 10-fold in response to a 10°C increase in body temperature. 
C. The cold-sensitive neurons, by contrast, increase their firing rate when the body temperature increases.
D. Anterior hypothalamus integrates the central and peripheral temperature sensory signals.
Which of the following combination is correct?