Answer:
a. The directionality of the complementary strand is antiparallel. The double-stranded DNA is antiparallel comprising two strands, which run alongside each other, however, point in reverse directions. In a double-stranded molecule of DNA, the 5 prime ends of one strand align with the 3 prime ends of the other strand, and vice versa.
b. The mediation of base pairing is done by non-covalent hydrogen bonds. It is reversible, that is, the strands can separate and can come combined again without any chemical modification.
The specificity of base pairing is illustrated by hydrogen bonds that is, the first strand produces hydrogen bonds only with a particular base in the second strand, and these two bases produce a base-pair.
c. The interaction or association of non-covalent type, that is, hydrophobic interaction and hydrogen bonding. Collectively, they both are strong. In the process, one base associate with the other base on the complementary strand.
d. The phosphate backbone possesses the tendency to associate with water on the outside of the molecule, and this is favorable chemically as both the strands are held together by hydrogen bond and hydrophobic interaction.
The polar molecules of sugar can produce hydrogen bonds with the surrounding molecules of water. The negatively charged phosphate group associate with the positively charged ions. The nonpolar nitrogen bases are found within the molecule and associate favorably through stacking interactions.
Answer:
The endosymbiotic theory
Explanation:
Protists are the multicellular organisms which possess characteristics of both the prokaryotes and eukaryotes.
The protist can derive nutrition by either heterotrophic mode or photoautotrophic mode. This variation could exist within the same genus and same species.
This variation could be explained with the endosymbiotic origin of the organisms as some species could engulf the photosynthetic bacteria whereas some could have engulfed the chemosynthetic bacteria.
This can be observed in the green and red algae which depend on a different mode of nutrition belonging to the same group.
Thus, the endosymbiotic theory is correct.
Answer:
A) The striations are due to the orderly arrangement of actin and myosin
Explanation:
Smooth muscles are non-striated involuntary muscles which are found in the walls of stomach, urinary bladder, blood vessels...Smooth muscle tissue is composed of spindle-shaped muscle cells with single central nucleus. Like the other two type of muscles (cardiac and skeletal), smooth muscles also have four main functions:
- Contractility-ability to contract. In the case of skeletal muscles it is voluntary, while in cardiac and smooth muscles it is unconscious.
- Excitability-ability to change membrane potential usually by the influence of nervous impulse.
- Extensibility-the capacity to lengthen
- Elasticity-ability to change its length and then return to previous.
It's A, because it's always important to drink water. If you think about it, all the other answers seem invalid.
If your cells got filled up with water, the cells would expand and then explode. You would eventually die.
