Answer:
Nitrogenous bases contain the genetic information, their amount is variable among different species, and the arrangement of these bases is also variable among different species
Explanation:
Both Watson-Crick and Pauling's DNA models considered that DNA nitrogenous bases (i.e., Adenine, Cytosine, Thymine and Guanine) contain the genetic information that determines the characteristics of living organisms. Moreover, both DNA models also considered that nitrogenous base composition varies between species, as well as the arrangement of these bases in the DNA chain also varies between species. Based on these features, Linus Pauling considered that a model where nitrogenous bases would be arranged on the outside of the DNA molecule would be easier for the DNA molecule to be replicated, transcribed, or repaired. Although incorrect, Pauling's DNA triple helix model was fundamental to develop the helical (double-stranded) structure of DNA, which was finally discovered by Watson and Crick in 1953.
Xylem are tubes in the stem that transport water and minerals upward, from the roots to the leaves. Phloem are tubes in the stem that move food made in the leaves to other parts of the plant. ... Chlorophyll is a pigment that helps plants use energy from the sun to produce sugars.
A place where 2 geologic units meet is called contact .
Answer:
The correct answer is - tight junctions.
Explanation:
Tight junctions are one of the cell-cell junctions that make a barrier to the passage of material which is a present in epithelia. This barrier is impermeable to most of the materials with soluble molecules. This barrier is made up of the occludin and claudin proteins.
Tight epithelia have tight junctions and examples of such junctions are the distal convoluted tubule or DCT, and the collecting duct of the nephron in the kidney.
Thus, the correct answer is - tight junctions.
