by Sam Cooke in C

chord progression

Chord Progression:
{: C Dm7 Am7
C Dm F7 E7 Am7 C :}

Part A

Chord Mode (in C major) Notes
C I C E G
Dm7 ii D F A C
Am7 vi A C E G
F7 IV F A C Eb
E7 V7/vi E G# B D

F7: borrows Eb for a bluesy feel.

E7: E is the iii (minor) chord in C’s diatonic scale, so it doesn’t really fit here.
But if we look at A, the relative minor of C, then we see that E is the V of A.

Resulting to a C major key.
There are mostly natural notes from C, which is occasionally escaped to other notes to create feel, e.g. bluesiness (F7) and a resolution (E7)

Part B

Chord Progression:
{: Dm7 C Dm7 Am
Dm7 Am E7 Dm9 G7 :}

Chord Mode (in C major) Notes
C I C E G
Dm7 ii7 D F A C
Dm9 ii9 D E F A
Am vi A C E
E7 V7/vi E G# B D
G7 V7 G B D F

E is the iii (minor) chord in C’s diatonic scale, so E7 doesn’t belong naturally in C major.
But if we look at A, the relative minor of C, we see that E is the V of A. So in C major, E7 functions as a secondary dominant (V7/vi) leading to Am.

Resulting to a C major key again.