DNA and DNA Replication

DNA

What did Oswald Avery discover about DNA?

• Avery and other scientists discovered that the nucleic acid DNA stores and transmits the genetic information from one generation of an organism to the next.

Multiple Choice

What did Avery (The Scientist) discover about DNA?

• DNA stores and transmits the genetic information from one generation of an organism to the next.

• DNA has a look of a double Helix

The Components and Structure of DNA

• DNA is a long molecule made up of units called nucleotides

• Nucleotides are made up of 3 basic components: (1) a 5-carbon sugar (2) A phosphate group (3) a nitrogenous group

• There are 4 kinds of nitrogenous bases in DNA

• 1) Adenine

• 2) Guanine

• 3) Cytosine

• 4) Thymine

The Double Helix

• Rosalind Franklin was able to take X-Rays beams on DNA to find a distinct pattern

• James Watson and Francis Crick took these results and were able to build a structural model of DNA

• This model of DNA was a Double Helix, in which two strands were wound around each other

• Hydrogen Bonds could form between certain nitrogenous bases and provide just enough force to hold the two strands together

• Base pairing- hydrogen bonds can only form between certain Nitrogenous bases

• Adenine <--> Thymine

• Guanine <--> Cytosine

Multiple Select

What are the four nitrogenous bases found in DNA?

• Adenine

• Thymine

• Glucose

• Guanine

• Cytosine

Fill in the Blanks

What is the name of the model that Watson and Crick came up with to describe a DNA molecule?

Multiple Choice

Which of the following will pair with Adenine?

• Guanine

• Thymine

• Cytosine

Multiple Choice

Which of the following will pair with Cytosine?

• Thymine

• Guanine

• Adeine

Chromosomes and DNA Replication

DNA and Chromosomes

• Prokaryotic Cells lack nuclei and many of the organelles found in Eukaryotes (HUMAN cells are Eukaryotic )

• Eukaryotic DNA is more complicated then Prokaryotic Cells and is LOCATED in the cell nucleus in the form of a number of chromosomes

• ***Human cells have 46 Chromosomes

• Eukaryotic chromosomes contain both DNA and protein tightly packed together to form a substance called chromatin

• Chromatin consists of DNA that is tightly coiled around proteins called histones

DNA Replication

• Each strand of the DNA double helix has all the information needed to reconstruct the other half by the mechanism of base pairing

• If you could separate the two strands, the rules of base pairing would allow you to reconstruct the base sequence of the other strand.

• DNA replication occurs in hundreds of places

• During DNA replication, the DNA molecule produces two new complementary strands. Each strand of the double helix serves as a template for the new strand

• Before a cell divides, it duplicates its DNA in a copying process called replication

• DNA Replication is carried out by a series of enzymes

• These enzymes "unzip" a molecule of DNA

• The unzipping occurs when the hydrogen bonds between the base pairs are broken and the two strands of the molecule unwind.

• The principal enzyme involved in DNA replication is called DNA polymerase

• DNA polymerase also "proofreads" each new DNA strand, helping to maximize the odds that each molecule is a perfect copy of the original DNA

Multiple Choice

Where is Eukaryotic DNA generally located?

• In the cytoplasm

• In the nucleus

• In space

Fill in the Blanks

During DNA replication, the DNA molecule produces

(how many?) new complementary strands.

Fill in the Blanks

Each strand of the double helix serves as a

for a new strand.

Multiple Choice

What is the principal enzyme involved in DNA replication

• glucose

• fructose

• DNA Polymerase

• Lactase

Multiple Choice

What is the principal enzyme involved in DNA replication

• glucose

• fructose

• DNA Polymerase

• Lactase