Whereas superficial flexors in the anterior compartment of the forearm originate from the epicondyle of the humerus, the superficial extensors in the posterior compartment of the forearm originate from the epicondyle of the humerus.

Whereas superficial flexors in the anterior compartment of the forearm originate from the medial epicondyle of the humerus, the superficial extensors in the posterior compartment of the forearm originate from the lateral epicondyle of the humerus.

Explanation:

The forearm has 2 compartments: an anterior compartment responsible for the flexion of the wrist, and a posterior compartment with the function to extend the wrist.

The superficial muscles in the anterior compartment arise from the common flexor tendon that originates from the medial epicondyle of the humerus. This compartment is mostly innervated by the median nerve.

The superficial muscles in the posterior compartment originate from the lateral epicondyle of the humerus and are innervated by the radial nerve.

The ulnar nerve innervates the flexor carpi ulnaris and flexor digitorum profundus in the forearm.

step 1: initiation

initiation is the beginning of transcription. it occurs when the enzyme rna polymerase binds to a region of a gene called the promoter. this signals the dna to unwind so the enzyme can ‘‘read’’ the bases in one of the dna strands. the enzyme is now ready to make a strand of mrna with a complementary sequence of bases.

step 2: elongation

elongation is the addition of nucleotides to the mrna strand. rna polymerase reads the unwound dna strand and builds the mrna molecule, using complementary base pairs. there is a brief time during this process when the newly formed rna is bound to the unwound dna. during this process, an adenine (a) in the dna binds to an uracil (u) in the rna.

step 3: termination

termination is the ending of transcription, and occurs when rna polymerase crosses a stop (termination) sequence in the gene. the mrna strand is complete, and it detaches from dna.

a symbiotic relationship with the mitochondria