Biology Answers

Which of the following statements from A to D about water transport in plants is/are correct?

1- Transpiration happens as a consequence of the need for gas exchange.

2- There are cohesive forces between water molecules because they from hydrogen bonds with one another.

3- Water is drawn up from the stem due to adhesive forces between water molecules.

A) 1, 2 and 3

B) only 1 and 2

C) only 2 and 3

D) only 1

Which of the following statements A to D describes the movement of water across plant roots?

A) The Casparian strip blocks movement by the symplast pathway.

B) The symplast pathway requires water to cross partially permeable membranes.

C) Water moves from the soil to the root hair cells up a water potential gradient.

D) Water moves through the leaves only by the symplast pathway and across the roots only by the apoplast pathway.

Which of the following statements A to D does not correctly describe the structure or formation of plant vascular tissues?

A) Companion cells are linked to xylem vessels by plasmodesmata.

B) Mature sieve tube elements do not contain nuclei.

C) Phloem and xylem are formed by differentiation of vascular meristems.

D) Xylem vessels have non-lignified pits to allow movement in and out.

Which of the following statements A to D about microscopes is correct?

A) A light microscope with an eyepiece lens magnification of x10 and an objective lens magnification of x50 will have an overall magnification of x60.

B) Scanning electron microscopes and laser scanning confocal microscopes can both produce three dimensional images.

C) The maximum resolution of a scanning electron microscope is lower than that of a light microscope.

D) Transmission electron microscopes and laser scanning confocal microscopes can both produce three dimensional images

Which of the following statements A to D about differential staining is not true?

A) Differential staining can distinguish between different organelles.

B) Differential staining can distinguish between types of cell.

C) Differential staining can distinguish between types of organism.

D) Differential staining is a common feature of electron microscopy

Subject: This year’s Nobel Prize announcement will take place from 4-11 October. According to you, which subject (regarding Molecular Biology and Genetics, such as cell biology, genetics, epigenetics, microbiology, biochemistry, biophysics, etc.) will be awarded the Nobel prize in 2021? Please specify the topic and briefly explain your reasons.

MAIN TEXT: Briefly introduce/explain the rationale for the subject and your major objectives. Provide background information on the research subject, summarize a concise literature review to orient the reader, and bring the reader up to date on what has already been done. Interpret the literature with emphasis on the problem, question, or hypothesis you put forward in the introduction. Review and summarize the main point of your essay. Give your final opinion on the matter.

A black guinea pig crossed with an albino guinea pig produced 12 black offspring. When albino was crossed with a second black one, 7 blacks ang 5 albinos were obtained. What is the best explanation for this genetic situation?

I know that animals become extinct. Are "new" animals coming into being? Any examples? Thanks!

There are two alleles in the population of 7500 individuals: the wild-type allele A and the mutation allele a with frequencies of 0.98 and 0.02.

If  population is in Hardy-Weinberg equilibrium, how many individuals would you see with the disease if it was fully recessive?

If chlorophyll is extracted from plant cells and exposed to light, it absorbs light energy momentarily and this energy is almost immediately reradiated as light. Thus chlorophyll molecules can not cause photosynthesis by themselves. Why? What is required for photosynthesis to occur?