The rate of movement of materials in the sieve elements can be expressed in two ways: as velocity, or as mass transfer rate. In early publications reporting on rates of transport in the phloem, what is the velocity and the mass transfer rate?

i) velocity-centimeters per hour (cm h^-1) and mass transfer- grams per hour per square centimeter (g h^-1 cm^-2)

ii) velocity-the linear distance traveled per unit time and mass transfer rate-the quantity of material passing through a given cross section of phloem or sieve elements per unit time.

iii) velocity- the quantity of material passing through a given cross section of phloem or sieve elements per unit time and mass transfer rate- the linear distance traveled per unit time

iv) velocity- per hour per square centimeter (h^-1 cm^-2) and mass transfer- kg centimeters per hour (cm h^-1)

#Question id: 390

#Unit 1. Molecules and their Interaction Relevant to Biology

What are the properties arising due to varying concentrations of solute in a given solvent, irrespective of the nature of solute with respect to the solvent?

#Question id: 391

#Unit 1. Molecules and their Interaction Relevant to Biology

In a hospital laboratory, a 10.0 mL sample of gastric juice, obtained several hours after a meal, was titrated with 0.1 M NaOH to neutrality; 7.2 mL of NaOH was required. The patient’s stomach contained no ingested food or drink, thus assume that no buffers were present. What was the pH of the gastric juice?

#Question id: 392

#Unit 1. Molecules and their Interaction Relevant to Biology

When an ionic compound such as sodium chloride (NaCl) is placed in water, the component atoms of the NaCl crystal dissociate into individual sodium ions (Na+) and chloride ions (Cl-). In contrast, the atoms of covalently bonded molecules (e.g., glucose, sucrose, glycerol) do not generally dissociate when placed in aqueous solution. Which of the following solutions would be expected to contain the greatest number of solute particles (molecules or ions)?

#Question id: 393

#Unit 1. Molecules and their Interaction Relevant to Biology

Carbon dioxide (CO2) is readily soluble in water, according to the equation CO2 + H2O ↔ H2CO3. Carbonic acid (H2CO3) is a weak acid. If CO2 is bubbled into a beaker containing pure, freshly distilled water, which of the following graphs correctly describes the results?

#Question id: 394

#Unit 1. Molecules and their Interaction Relevant to Biology

What will be the H+ ion concentration in a solution prepared by mixing 50.0 mL of 0.20 M NaCl, 25 mL of 0.10M NaOH and 25.0 mL of 0.30M HCl?

#Question id: 395

#Unit 1. Molecules and their Interaction Relevant to Biology

How would acidification of seawater affect marine organisms? Acidification of seawater would ________.