Three dimensional space is often difficult for many to mentally visualize. Starting with what you know, then moving to what you don't, is always a good plan. [It also works well in doing genealogy.] So let's try to visualize the phosphate + sugar + nitrogen base using the dinning room picture shown to the right.
Get a good look. There is a dinning room table with chairs placed about. Pictures are on the walls, windows letting light invade the room. A floor and ceiling with the walls complete the picture. Now place yourself into this three dimensional space standing next to the table. It would come about waist high and you could sit yourself down. But no time to rest. Get a good feel for the space about you. Floor is down, ceiling is up, table is in the middle, and you are standing in this room.
Now imagine that the table beside you is a five sided table. It would be shaped like the Pentagon building. Place one point of this five sided table pointing toward the picture on the wall. Next, place a chair at each point along this table except for the point facing the picture. Chair one to the right of the point, chair two at the bottom right, chair three at the bottom left, and chair four at the the upper left. Then stand up in chair four with a fifth chair held about your head. It should just about reach the ceiling with your arms reaching upward. Looking down, you would see the top of the table with the first chair almost directly across from your position standing in chair number four. You can rest a little bit now, for I know holding up a chair to the ceiling would get old fast! Look around the room. Space above the table, under the table, to the right and to the left. Three dimensional space! You have it.
The five sided table is the ribose sugar of our DNA. Each chair is a carbon atom place equally about the points of the table. A oxygen atom is at the point facing the picture. You are holding the fifth carbon atom in your hands as you raise it to the ceiling. Now each chair has a number just as the carbon atoms are given numbers around the sugar table. Chair one (1) is where the nitrogen base attaches and reaches out to the window to the upper right. Chair three (3) is where the phosphate molecule attaches, but under the table, at the legs of carbon (3). Another phosphate molecule attaches to the chair you are holding above your head, but you have to push the chair through the ceiling to make this connection. In the same way, a person in the room below you is holding their chair (5) up to the ceiling, only you see it as the floor below chair (3). A person in the room above you would look down and see your ceiling as their floor! And so it goes. Floor, after floor, after floor, of phosphate + sugar + base streaches for hundreds of floors! The phosphate holds the chair (3) from the bottom, and you hold chair (5) to the top. A (3) chair to a (5) chair hook-up. The nitrogenous base connects at the (1) chair by its nitrogen atom extending its molecular structure out into the room toward the window much like one of those bucket trucks extending its arm into space. You are standing in a single nucleotide's 3-D space. Way to go!
Now go back to the previous blog that shows the drawing of the phosphate + sugar + base. Look at it through your 3-D eyes.