Following statements are regarding to the mechanism of migration of pollen tube.

A. The embryo sac is the product of three mitotic divisions of the diploid megaspore; it comprises seven cells and eight haploid nuclei.

B. The two polar nuclei in the central cell will fuse with the second sperm nucleus and produce the endosperm that will nourish the egg. The other six cells, including the egg, contain one haploid nucleus each.

C. After compatible pollen germinates, the pollen tube grows toward the micropyle.

D. The three cells from the pollen are connected to one another at the tip of the tube, and waves of sodium ions play a key role in the growth of the tube.

Which of the following combinations are correct?

TLS Online TPP Program

#Question id: 4577

#Unit 11. Evolution and Behavior

Which of these is a statement that Darwin would have rejected?

TLS Online TPP Program

#Question id: 3047

#Unit 2. Cellular Organization

A rapidly growing bacterial species such as E. coli exhibits a typical phase of growth cycle in liquid nutrient broth. If a bacterial culture has starting density 1000 cells/ml in log phase and after four hours cell density is 4000 cells/ml.  What is specific growth rate per hour? 

TLS Online TPP Program

#Question id: 28255

#Unit 5. Developmental Biology

Which of the following structure of egg homologous to the acrosomal vesicle of the sperm?

TLS Online TPP Program

#Question id: 16120

#Unit 7. System Physiology – Animal

Following statements are regarding to the regulation of body temperature.

A. The temperature-regulating center is located in the anterior hypothalamus. This center receives information about environmental temperature from thermoreceptors in the skin and about core temperature from thermoreceptors in the anterior hypothalamus itself.

B. The temperature-regulating center is located in the posterior hypothalamus. This center receives information about environmental temperature from thermoreceptors in the posterior hypothalamus itself and about core temperature from thermoreceptors in the skin.

C. If core temperature is below the set-point temperature, then heat-generating and heat-retaining mechanisms are activated.

D. If core temperature is above the set-point temperature, then heat-dissipating mechanisms are activated.

E. If core temperature is below the set-point temperature, then heat-dissipating mechanisms are activated.

F. If core temperature is above the set-point temperature, then heat-generating and heat-retaining mechanisms are activated.

Which of the following combination is correct?

TLS Online TPP Program

#Question id: 89

#Unit 1. Molecules and their Interaction Relevant to Biology

In solution α-D-glucopyranose and β-D-glucopyranose ________.