DNA: Replication and Mutation

What is DNA?

DNA = deoxyribonucleic acid DNA is the “blueprint” for the cell

contains the instructions that tells the cell how to do things and what to make

DNA is like blueprints for making a city, which in this case is the cell

RED => COPY INTO NOTEBOOK

Amoeba Cell

What is DNA made of?

DNA is made up of 4 bases:– Adenine (A), Thymine (T), Cytosine (C), Guanine (G)

Rules for DNA Bases:

1. A pairs with T

2. G pairs with C

“Chargaff’s Rules”

Structure of DNA

DNA is made up of two strands (double stranded)

Each strand has the bases connected to a PHOSPHATE BACKBONE

The two strands wrap around each other in a winding staircase manner (helix)

Models of DNA

ACTUAL Pictures of DNA

DNA Replication

In order for you to survive, your cells need to replicate themselves. In order for them to do that, they need to replicate their DNA

Every cell in your body has the same DNA, because every time one of your cells divides, it makes a copy of its DNA to give to the new daughter cells

How does DNA replicate?

The DNA is unzipped and the original strands are used to help make the new molecules – See Demonstration

What are mutations?

MUTATIONS are any changes in the sequence of bases of DNA

Mutations DO NOT lead to this

Mutations COULD lead to this

Colon cancer cells

How do mutations occur?

Sometimes during replication, the cell makes a mistake and adds the wrong base

When the cell replicates its DNA again, the two strands that are produced are no longer exactly the same

This usually will cause the new cell to die, but sometimes it can cause the cell to divide when it is not supposed to cancer

How do mutations occur?

Replication

What can cause mutations to happen more often?