An experiment of Anfinsen on ribonuclease A (RNase A) showed that proteins can be denatured reversibly by 2-mercaptoethanol and 8 M urea. The protein must therefore renature spontaneously;

a) Remove mercaptoethanol and then removal of the urea

b) Removal of the mercaptoethanol allows the protein to re-form disulfide bonds in the presence of oxygen and then removal of the urea

c) Removal of the denaturant (urea) and reductant (mercaptoethanol) allows the protein to renature and re-form disulfide bonds in the absence of oxygen

d) Adding a small amount of mercaptoethanol to the scrambled protein in the absence of O2 catalyzes its conversion to the active enzyme

Which one of the following steps will leads to regaining of the full activity of ribonuclease A (RNase A)

#Question id: 11806

#Unit 6. System Physiology – Plant

sap is translocated from areas of supply, called sources, to areas of metabolism or storage, called sinks. Which of the following statements about source and sink are TRUE?

a.) Sinks include any nonphotosynthetic organs of the plant and organs that do not produce enough photosynthetic products to support their own growth or storage needs

b.) Sources include exporting organs that are capable of producing photosynthate in excess of their own needs

c.) During the growing season of the first year, storage root is a sink, when it accumulates sugars received from the source leaves. During the second growing season the same root becomes a source

d.) Roots, tubers, developing fruits, and immature leaves, which must import carbohydrate for normal development, are all examples of sources tissues

Find the correct combination of the source and sink pattern of translocation.

#Question id: 10553

#Unit 6. System Physiology – Plant

Cell walls allow plant cells to build up large internal hydrostatic pressures called

#Question id: 10554

#Unit 6. System Physiology – Plant

Transpiration is an important means of dissipating the heat input from sunlight, Heat dissipates because the water molecules that escape into the atmosphere

#Question id: 10555

#Unit 6. System Physiology – Plant

The water molecule, hydrogen–oxygen bonds form an angle of 105°, The opposite partial charges (δ– and δ+) on the water molecule lead to the formation of which bond with other water molecules,

#Question id: 10557

#Unit 6. System Physiology – Plant

The attraction of water to a solid phase such as a cell wall or glass surface known as

#Question id: 10559

#Unit 6. System Physiology – Plant

which gives water a high tensile strength,