Answer:
Natural selection
Explanation:
Natural populations have variations. Organisms of a population have various genetic traits. Some of these genetic variations make the organisms better suited to the prevailing environmental conditions. These organisms are more likely to produce more progeny. Over generations, the frequency of the beneficial genetic traits increases in the population due to the higher reproductive success of the organisms with these genetic traits.
This process of differential fitness of organisms of a population where the organisms with adaptive genetic traits have survival and reproductive benefits is called natural selection.
Meiosis differs from mitosis in the number of chromosomes in each ending cell. In addition, one of the purposes of meiosis is to reduce the chromosome number in each cell by half and meiosis contains two rounds of division which is meiosis I and meiosis II and ends with four gametes that are not the same genetically.
<span>In the skeletal muscle cells of vertebrates, as many as 38 molecules of ATP are produced from one molecule of glucose. This is less than might be expected, because electrons from NADH produced during glycolysis must be shuttled through the inner mitochondrial membrane at a cost.
</span>The energy of the electrons can be used to make ATP and in eukaryotes, glycolysis occurs in the <span>cytosol, outside mitochondria. </span>
Answer:
The correct answer is 3: "<em>High levels of Ca2+ are expected to be found </em><em>within the sarcoplasmic reticulum</em>".
Explanation:
Muscular contraction is a highly regulated process that depends on free calcium concentration in the cytoplasm. Amounts of cytoplasmic calcium are regulated by <u>sarcoplasmic reticulum</u> that functions as a storage of the ion.
When a nerve impulse reaches the membrane of a muscle fiber, through acetylcholine release, the membrane depolarizes producing the entrance of calcium from <u>extracellular space</u>. The impulse is transmitted along the membrane to the sarcoplasmic reticulum, from where calcium is released. At this point, <em>tropomyosin is obstructing binding sites for myosin on the thin filament</em>. The calcium channel in the sarcoplasmic reticulum controls the ion release, that activates and regulates muscle contraction, by increasing its cytoplasmic levels. When <em>calcium binds to the troponin C</em>, <em>the troponin T alters the tropomyosin by moving it and then unblocks the binding sites,</em> making possible the formation of <em>cross-bridges between actin and myosin filaments.</em> When myosin binds to the uncovered actin-binding sites, ATP is transformed into ADP and inorganic phosphate.
Z-bands are then pulled toward each other, thus shortening the sarcomere and the I-band, and producing muscle fiber contraction.
Because it makes accessing them easier for the cell, it is assumed that the bases will be on the outside of the DNA molecule.
<h3>
What is DNA molecule?</h3>
- Because the two DNA strands are made up of simpler monomeric units termed nucleotides, they are referred to as polynucleotides.
- Each nucleotide is made up of a phosphate group, a deoxyribose sugar, and one of the four nitrogen-containing nucleobases (cytosine [C], guanine [G], adenine [A], or thymine [T]).
- An alternating sugar-phosphate backbone is created when the nucleotides are linked together in a chain by covalent connections (also referred to as the phospho-diester linkage) between the sugar of one nucleotide and the phosphate of the next.
- To create double-stranded DNA, the nitrogenous bases of the two distinct polynucleotide strands are joined by hydrogen bonds in accordance with the base pairing principles (A with T and C with G). Pyrimidines and purines make up the two families of complimentary nitrogenous bases.
To learn more about DNA molecule with the given link
brainly.com/question/22499464
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