The heart cells must be able to continue aerobic metabolism when skeletal muscle cannot. Aerobic metabolism is a part of cellular respiration and involves body cells making energy through glycolysis, the citric acid cycle, and the electron transport/oxidative. It is done in the heart at a rate below 85% of maximum heart rate and does not use vigorous muscle contraction. fatty acids , ketone bodies and carbohydrates are the primary substrates of the heart metabolized to generate ATP. The metabolic demands of the heart are the largest than any other organ in the body, and normal cardiac metabolism is required to fuel contractile function and viability.
Explanation:
A single nucleotide-pair substitution missense mutation causes a change of a single amino acid into another. Aa a result, the produced protein will have an almost normal sequence except for one amino acid.
On the other hand, a frameshift mutation changes the Open Reading Frame (ORF) of the ribosome. The ribosome moves along the mRNA every three nucleotides (codons) and translates them into amino acids that will form the nascent protein. If there is a frameshift mutation (an insertion or deletion of a number of nucleotides not multiple of three) the ribosome will "read" the mRNA differently and will identify different codons than the wild-type sequence, so a large number of amino acids will be different in the mutated protein.
B seasonal variations in climate tend to increase with distance from the equator
This is obvious but the correct answer is B. Earth
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