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?

#Question id: 381

#Unit 1. Molecules and their Interaction Relevant to Biology

Consider an acetate buffer, initially at the same pH as its pKa (4.76). When sodium hydroxide (NaOH) is mixed with this buffer, the:

#Question id: 382

#Unit 1. Molecules and their Interaction Relevant to Biology

The molar ratio of sodium acetate to acetic acid in a buffer solution with a pH OF 5.76 is 10:1. Assuming the total buffer concentration is 2.2 X 10^-2 mol/L, how many grams of sodium acetate (m.w. 82) and how many grams of acetic acid (m.w. 60) should be used in preparing a litre of the solution?

#Question id: 383

#Unit 1. Molecules and their Interaction Relevant to Biology

Three buffers are made by combining a 1 M solution of acetic acid with a 1 M solution of sodium acetate in the ratios shown below

 Which of these statements is true of the resulting buffers?

#Question id: 384

#Unit 1. Molecules and their Interaction Relevant to Biology

A solution was prepared by dissolving 0.02 moles of acetic acid (HOAc; pKa = 4.8) in water to give 1 liter of solution. What is the pH? To this solution was then added 0.008 moles of concentrated sodium hydroxide (NaOH). What is the new pH? (In this problem, you may ignore changes in volume due to the addition of NaOH).

#Question id: 385

#Unit 1. Molecules and their Interaction Relevant to Biology

In which reaction below does water not participate as a reactant (rather than as a product)?

#Question id: 386

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following properties of water does not contribute to the fitness of the aqueous environment for living organisms?