Chloroplast movement is widespread among algae, mosses, and leaves of higher plants, what will be the orientation of chloroplast in dark as well as in light?

a.) In dark, chloroplasts gather at the cell surfaces parallel to the plane of the leaf so that they are aligned perpendicularly to the incident light

b.) Under high light, , the chloroplasts move to the cell surfaces that are parallel to the incident light, thus avoiding excess absorption of light

c.) the orientation of the chloroplasts in the dark is such that maximizes absorption of light

d.) the orientation of the chloroplasts in the high light is such that maximizes absorption of light

Which of the following statements is correct?

#Question id: 365

#Unit 1. Molecules and their Interaction Relevant to Biology

Water is a polar molecule: the oxygen atom with its unshared electrons carries a partial negative charge (δ−) of ___________, and the hydrogen atoms each carry a partial positive charge (δ+) of __________, where e is the charge of the electron.

#Question id: 364

#Unit 1. Molecules and their Interaction Relevant to Biology

 A solution contains 0.0000001 (10-7) moles of hydrogen ions [H+] per liter. Which of the following best describes this solution?

#Question id: 363

#Unit 1. Molecules and their Interaction Relevant to Biology

What is the pH of a mixture of 0.042 M NaH2PO4 and 0.058 M Na2HPO4? If 1.0 mL of 10.0 M NaOH is added to a liter of the buffer prepared, how much will the pH change? (pKa = 6.86)

#Question id: 362

#Unit 1. Molecules and their Interaction Relevant to Biology

A 0.01 M solution of a substance has a pH of 2. What can you conclude about this substance?

#Question id: 361

#Unit 1. Molecules and their Interaction Relevant to Biology

Calculate the percentage of histidine that has its imidazole side chain protonated at pH 7.3. The pKa values for histidine are pK1 = 1.8, pK2 (imidazole) = 6.0, and pK3 = 9.2.

#Question id: 360

#Unit 1. Molecules and their Interaction Relevant to Biology

Which of the following is considered to be a strong base (alkali)?