Dna structure and function (notes)

DNA Structure and Function

Biology IMr. Nettles

Today’s Agenda – Wed. Oct. 9, 2011

Warm-up

Mini-Lesson

Summarization and Homework Questions

A. Enzymes are converted into products by the reactions they catalyze.

B. Enzymes lower the activation energy of reactions.C. One enzyme can catalyze many different reactions.D. An enzyme is used once and then destroyed by the

cell.

Which best describes how enzymes function

in the body?

Cellular Energy

Warm-Up (Nov. 9)

A. move substances across the cell membrane

without the use of ATP.B. move from low concentration to high

concentration by diffusion.C. move small molecules through the cell

membrane by osmosis.D. move substances from a low concentration to

high concentration through the use of energy.

In active transport, carrier proteins

Cellular Energy

Warm-Up (Nov. 9)

A. absorb excess energyB. release unused energyC. increase the reaction rateD. regulate product reactivity

Which best describes the role of enzymes in

a chemical reaction?

Cellular Energy

Warm-Up (Nov. 9)

Today’s Objectives

I will identify the structure of DNA. (How it looks)

I will articulate the function of DNA. (What it does)

I will explore DNA replication. (How it is made)

What is DNA?

DNA is a large molecule that directs the making of proteins in the cell.

The proteins made control all the activities and processes in the cell.

Where is DNA located?

DNA is located in the nucleus of the cell.

How does DNA look?DNA forms a double

helix. It looks like a twisted

braid.

DNA is a nucleic acid, so it’s made up of nucleotides.

How is DNA made?

DNA is made through a process called DNA replication.

DNA copies itself during S phase of the cell cycle.

Steps of DNA Replication

1. The two strands of DNA separate or “unzip”.

1. Each “old strand” creates a “new strand” by base pairing.

1. The enzyme, DNA polymerase, checks for errors and repairs the new DNA molecule

Nucleotides and Base Pairing

Nucleotides are made up of three parts: a five – carbon sugar a phosphate group a nitrogenous base

DNA nucleotides can have one of four different nitrogenous bases: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C).

Nitrogenous Base Pairing: A pairs with T (Apples grow on Trees). C pairs with G ( Cars need Gas).

Video about Genetic Engineering