In heart muscle, activation series of the muscarinic acetylcholine receptor its effector K+ channel via the Gβγ subunit of a Gi protein.

a. Binding of acetylcholine triggers activation of the Gαi subunit and its dissociation from the Gβγ subunit in the usual way. 

b. The released Gβγ subunit (rather than Gαi∙GTP) binds to and opens the associated effector protein, a K+ channel. 

b. The increase in K+ permeability hyperpolarizes the membrane, which reduces the frequency of heart muscle contraction. 

d. Activation is terminated when the GTP bound to Gαi is hydrolyzed (by a GAP enzyme that is an intrinsic part of the Gαi subunit) to GDP and Gαi∙GDP recombines with Gβγ.

#Question id: 5437

#Unit 8. Inheritance Biology

A pure line dominant plant has height of 100 cm while pure line of recessive plant has 20 cm. If one dominant gene contribution is 8 cm, what is number of QTL control plant height?

#Question id: 9283

#Unit 6. System Physiology – Plant

Organization of the protein complexes the photosystems I and II Are spatially separated in the thylakoid membrane, choose the correct arrangement of PSI and PSII on the membrane ;

a.) The PSI reaction centre and its associated antenna pigments and electron transfer proteins, as well as the coupling-factor enzyme that catalyzes the formation of ATP, are found almost exclusively in the stroma lamellae and at the edges of the grana lamellae

b.) The PSI reaction centre, along with its antenna chlorophylls and associated electron transport proteins, is located predominantly in the stromal lamellae

c.) The PSII reaction centre and its associated antenna pigments and electron transfer proteins, as well as the coupling-factor enzyme that catalyzes the formation of ATP, are found almost exclusively in the stroma lamellae and at the edges of the grana lamellae

d.) The PSII reaction centre, along with its antenna chlorophylls and associated electron transport proteins, is located predominantly in the grana lamellae

Which of the following given combination correct?

#Question id: 11037

#Unit 7. System Physiology – Animal

A 22-year-old man has a muscle blood flow of 250 ml/min and a hematocrit of 50. He has a mean arterial pressure of 130 mm Hg, a muscle venous pressure of 5 mm Hg, and a heart rate of 80 beats/min. Which of the following is the approximate vascular resistance in the muscle of this man?

#Question id: 5214

#Unit 11. Evolution and Behavior

What is the most probable explanation for the continued presence of pseudogenes in a genome such as our own?

#Question id: 12229

#Unit 10. Ecological Principles