Building DNA (AP)

BUILDING DNA using Molecular Model Kits

AP BIO w/ Dr. Wiehl

Multiple Select

What composes a nucleotide? (choose all)

• a sugar

• a phosphate

• a nitrogenous base

• an amino acid

​Molecule building RULES

-​If you see a drawn structure, at every angle, there is an unlabled CARBON

-2 lines indicate a double bond

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-Carbon naturally forms 4 bonds

-Oxygen naturally forms 2 bonds

-Phosphorous naturally forms 5 bonds

-Nitrogen naturally forms 3 bond

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If nothing else is written, fill everything else in with Hydrogens (which form 1 bond)

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If there is a negative charge to it, it's missing a bond

​Now, let's try building a

Phosphate group!

​To create the "staircase"

we must combine the phosphate group with the deoxyribose sugars

TO PUT THESE TWO PIECES TOGETHER WE MUST REMOVE SOMETHING

Draw

What needs to be removed to form a bond to phosphate? (circle)

​To create the "staircase"

we must combine the phosphate group with the deoxyribose sugars

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Can you locate the 5' and 3' ends of your nucleotide?

(hint: think Phosphorous forms 5 bonds, to remember the phosphate group at the 5' end!)

​Last part! We need a NITROGENOUS BASE!

Draw

Which nitrogenous bases can be found in DNA? (circle all correct answers)

Lets build! (instructor's choice!)

​Btw:

<-----We call these PURINES

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And

<-----we call these pyramidines

BASED ON THEIR SHAPE!

Draw

What's the difference between the purines? (circle)

Draw

What's the difference between the pyramidines? (circle)

Time to create the Nucleotide!

Multiple Choice

If the deoxyribose removes an OH to attach and the N-base also loses an H to bond, then this reaction is called:

• hydrolysis reaction

• dehydration synthesis

​Adenine

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thymine

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Guanine

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Cytosine

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IF WE PUT THEM TOGETHER, WE
CREATE A SINGLE STRAND OF DNA!

​We know that DNA is double-stranded.

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The reason Adenine bonds to Thymine only

and Guanine bonds to cytosine only

has everything to do with their STRUCTURE

​Final Challenge:

Lets create mini molecule by putting it all together