Intro to DNA

Monday

02/13

Goals for Today• Be able to name the scientists that helped

build our knowledge of DNA and be able to describe their contributions

• Be able to describe the structure of DNA & list the 3 major components of DNA and what type of bonds hold them together

• Be able to describe how DNA is replicated (how we make more DNA molecules)

Question of the Day

• What are the 3 major components of a nucleotide?

• Draw one if you can, and label the parts.

• Which piece is variable (changes from nucleotide to nucleotide?

Question of the Day

• What are the 3 major components of a nucleotide?

• Draw one if you can, and label the parts.

• Which piece is variable (changes from nucleotide to nucleotide?

DNA Nucleotide – a nucleotide is the three component parts together

PhosphateGroup

NNitrogenous base(A, G, C, or T)

Sugar(deoxyribose)

Lets Review Nitrogenous bases & pairing• Which are the larger of the bases? What is this

group called?

• Which are the smaller of the bases? What is this group called?

• Which bases pair together? How many bonds between each?

Ok…….So what is DNA good for?

• DNA has 2 major functions in our body:

1. Make more DNA

2. Make Protein

Making More DNA…

• DNA replication is the process we use to make more copies of DNA

• When would we need to make more DNA?

• DNA is copied in the “S” phase of interphase to prepare for cell division.

• DNA replication occurs so new daughter cells will have the same information and the same number of chromosomes as the parent cell.

What has to break for the DNA strand to come apart?

DNA Replication

DNA replication occurs in 3 basic steps:

1.The enzyme DNA helicase opens the double helix by breaking the hydrogen bonds that link the complementary nitrogen bases between the two strands.

*What two things can enzymes do?

DNA Replication

2. The Enzyme DNA polymerase move along each of the DNA strands. DNA polymerase adds nucleotides to the exposed nitrogen bases, according to the base-pairing rules.

3. Two DNA molecules form that are identical to the original DNA molecule.

*What do both of these enzymes end in?

DNA Replication

Lets see it in real time!

• http://www.youtube.com/watch?v=bee6PWUgPo8

Now its your turn!• Pyrimidines

• Purines

• Pairing Rules & Bonds

Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds

Now its your turn! • Pyrimidines

• Purines

• Pairing Rules & Bonds

Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds

Now its your turn! – Answer Key• Pyrimidines

• Purines

• Pairing Rules & Bonds

Write in the complimentary bases and connect them with the appropriate number of hydrogen bonds

Rest of the week

• Tomorrow:

2/14: DNA replication Activity

2/15: Quiz on DNA-Scientists & their contribution- DNA structure/composition-DNA replication