The Structure of DNA

Bell Ringer: What does DNA have to do with cell division (mitosis & meiosis)?
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Slide 1: Open question

This lesson contains 11 slides, with interactive quizzes, text slides and 1 video.

Items in this lesson

Bell Ringer: What does DNA have to do with cell division (mitosis & meiosis)?

Slide 1 - Open question

Before cell division (like mitosis above) can occur, a cell must first make an identical copy of its DNA during interphase.

Slide 2 - Slide

Which monomer makes up nucleic acids, such as DNA?
Amino acids
Fatty acids

Slide 3 - Quiz

Recall from yesterday...
A nucleotide is the monomer for nucleic acids.

They are made up of 3 main parts: 
1) Nitrogenous base
2) Sugar
3) Phosphate group

Slide 4 - Slide

Sugar & Phosphate
The sugar and the phosphate make up the backbone of DNA.

The sugar found in DNA's backbone is deoxyribose (which is where DNA gets its name: deoxyribonucleic acid)

Slide 5 - Slide

Nitrogenous Bases
There are four different nitrogenous bases that make up the nucleotides of DNA.
1) Adenine     2) Thymine
3)Cytosine     4) Guanine
Adenine always pairs with thymine.  Cytosine always pairs with guanine. 
The base pairs are held together by hydrogen bonds.

Slide 6 - Slide

Base Pairing Rules
If A always pairs with T and C always pairs with G, you can use one side of the DNA strand to figure out what the opposing side would look like.  That's why they say DNA has complementary strands.

Slide 7 - Slide

What would be the complementary strand to ACTGATTG?

Slide 8 - Open question

Double Helix
DNA's shape is known as a double helix.  A double helix looks like a ladder with its two sides twisted around each other.

The center is held together by weak hydrogen bonds between the nitrogenous bases.

Slide 9 - Slide

Draw and label a DNA molecule in your notes. Be sure to include the sugar phosphate backbone & bases. Upload your picture here.

Slide 10 - Open question

Slide 11 - Video