If the culture is kept in stationary phase for a prolonged period, the cells may die. Why?

a) due to the time taken for doubling of cell number

b) duration of a cell generation is too large, depending mainly on the plant species.

c) stationary phase is forced on the culture by a depletion of the nutrients

d) due to an accumulation of cellular wastes

#Question id: 11548

#SCPH28 | Zoology

If a portion of the pancreas is surgically removed from a rat and the rat subsequently loses its appetite, one explanation is that the removed portion contains cells that secrete a chemical signal that somehow stimulates appetite. Given this scenario, what type of chemical signaling is occurring?

#Question id: 11549

#I Life Science/ Life Sciences Group – I-V

If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone?

I) The molecule is lipid soluble.

II) The molecule is derived from a series of steps beginning with cholesterol.

III) The molecule acts at a target tissue some distance from where it is produced.

IV) The molecule uses a transport protein when in an aqueous solution such as blood.

#Question id: 11549

#SCPH28 | Zoology

If a biochemist discovers a new molecule, which of the following pieces of data would allow her to draw the conclusion that the molecule is a steroid hormone?

I) The molecule is lipid soluble.

II) The molecule is derived from a series of steps beginning with cholesterol.

III) The molecule acts at a target tissue some distance from where it is produced.

IV) The molecule uses a transport protein when in an aqueous solution such as blood.

#Question id: 11550

#I Life Science/ Life Sciences Group – I-V

Which of the following are similar in structure to cholesterol?

I) estradiol

II) insulin

III) glucocorticoids

IV) testosterone

V) antidiuretic hormone

#Question id: 11550

#SCPH28 | Zoology

Which of the following are similar in structure to cholesterol?

I) estradiol

II) insulin

III) glucocorticoids

IV) testosterone

V) antidiuretic hormone

#Question id: 11551

#I Life Science/ Life Sciences Group – I-V

Polypeptides can have which of the following types of effects?

I) autocrine

II) paracrine

III) endocrine