In most organisms, the start of translation is signaled by an AUG codon. What is the first amino acid in most proteins? Question 20 options:

proline

leucine

isoleucine

methionine

This is an active transport mechanism by which cells pump sodium and potassium ions against the concentration gradient

Which muscle cell structure stores calcium ions that are used to trigger the contraction?

An adult inhales about 6.0×10−4 m3 of fresh air during a breath. only 20% of fresh air is oxygen. assume the pressure in the lungs is 1.0×105 paand the air is at a temperature of 300 k. how many oxygen molecules are in each breath? a. 1.4x10^23 b. 2.9x10^21 c. 4.9x10^-4 d. 2.9 x10^25