In response to a stimulus a brain cell called a neuron will send a signal to the brain using
a). electrical signals and chemical neurotransmitters
b). myosin and actin
c). contraction and relaxation
d). respiration and absorption

This is the amino acid cysteine. circle the amine group, put a box aroundthe carboxylic acid group and use a different colored pencil/pen to circle the sidechain (r group). h o | ||nh2— c- c-oh | ch2 | sh

Amino acids contain the elements carbon, hydrogen, oxygen, nitrogen, and sometimes sulfur. of the 20 amino acids found in humans, 11 are called "nonessential" because they can be manufactured by the body when needed. which elements in these 11 amino acids are commonly obtained from the metabolism of sugar molecules?

Some substances but not other can cross the (blank) membrane of a cell