Bio 9C: Thursday, 2.17.11Title: RNA Structure and Function

Homework: Read pages 302-306 in the textbook. Take active reading

notes, paying attention to important vocabulary terms and to the following purpose questions: How does the genetic code work? What are the steps of translation? Do Now:

Today’s Objectives: Describe the major structural differences

between DNA and RNA Differentiate between structure and function

differences between the types of RNA

RNA: STRUCTURES & FUNCTIONS

PHA Biology 9Moretti and Dickson

RNA Structure & Function of Different Types

RNA Structure: Base Pairing

4 Nitrogen Bases in RNA: Adenine Guanine Uracil Cytosine

RNA –> DNA Base Pairing: A ---- U G ---- C

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

RNA Structure: DNA vs. RNA

3 Major Structural Differences

DNA RNADeoxyribose Sugar Ribose Sugar

Double StrandSingle Strand (generally)

Uses Thymine (T) Uses Uracil (U)Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

Types of RNA: Overview

Type of RNA Basic Function

Messenger RNA (mRNA)

Copy genes on the DNA (transcription)

Transfer RNA (tRNA)

Translate mRNA into a proteinCarry amino acid to the ribosome

Ribosomal RNA (rRNA)(we will not focus on rRNA)

Part of the ribosome

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

Basic Structure: Single Strand of RNA

Basic Function Make a copy of DNA instructions to

make a protein Takes those instructions from DNA to

Ribosome to make a protein Every 3 bases is a Codon

Remember: Small enough to leave

the nucleus. DNA is too big!

Types of RNA: Messenger RNA (mRNA)

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

Basic Structure: Coiled RNA strand Amino Acid attached to the

top Anti-codon on the bottom

Basic Function: Transfer amino acids to the

ribosome to make a protein Anti-codon on tRNA

matches/ reads codon on mRNA

Types of RNA: Transfer RNA (tRNA)

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

Types of RNA: Transfer RNA (tRNA)

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

Decoding the Genetic Code

The Genetic Code

The 64 Codons that code for Amino Acids

Objectives for Class:• Use the genetic code to translate a DNA or RNA sequence into an amino acid sequence to

make a protein.

Reading The Genetic Code mRNA codons are 3 bases

long and specify a particular amino acid.

To use the wheel, the 1st base (letter) of codon matches the biggest letter and you move out from the middle to read the rest of the codon.

Therefore, the 2nd base in the codon is the second biggest letter (the one in the middle ring) and the 3rd base In the codon is the smallest letter (the one in the outer ring).

The arrows show the direction you should read it.

The Genetic Code

Complete Part I of the “Decoding the Genetic Code!” Activity.(we will review the first 3 examples of question 1 after you have had a chance to complete them)

Objectives for Class:• Use the genetic code to translate a DNA or RNA sequence into an amino acid sequence to

make a protein.

Reading The Genetic Code: ExamplesFollow along with the

examples in your packet!

Example 1: CAG

1st base = C 2nd base = A 3rd base = G

Therefore theamino acid is…

Glutamine!

Example 2: GUU

Valine

Reading The Genetic Code: Longer Example

Example 3: GCCAGCUAG

Step 1: Break it into 3-letter sections (codons)

GCC AGC UAG

Step 2: Decode each codon

GCC = Alanine

AGC = Serine UAG = STOP

(end of protein sequence)

1

2

3

Bio 9C: Friday, 2.18.11Title: Transcription and Translation with RNA

Homework: No Homework over the break!

Do Now: In your notebook: If you had a DNA sequence of T A C A G C T,

what would the matching RNA sequence be? Hit the space bar to see the answer…

A U G U C G A

Today’s Objectives: Demonstrate your understanding of DNA, the Cell

Cycle and Mitosis

MCAS Prep Question

The mold Aspergillus flavus grows on grain. A. flavus produces a toxin that binds to DNA in the bodies of animals that eat the grain. The binding of the toxin to DNA blocks transcription, so it directly interferes with the ability of an animal cell to do which of the following?

A. Produce ATP using energy released from glucose and other nutrient

B. transport glucose across the cell membrane into the cytoplasm

C. Transfer proteins from the endoplasmic reticulum to Golgi complexes

D. Send protein-building instructions from the nucleus to the cytoplasm and ribosomes

Overview: What is the hidden message in Part II

of the homework assignment? “Give Neighbor High 5”

Homework Review Question

Objectives for Class:• Describe the purpose and major steps of transcription• Describe the purpose and major steps of translation

Overview: A DNA gene is copied in the

form of mRNA Occurs in the nucleus

Steps: 1. RNA Polymerase separates

DNA strands2. RNA Polymerase moves along

one of the DNA strands (template)

3. RNA Polymerase makes mRNA by attaching RNA nucleotides that match the DNA template mRN

A

Transcription Detail

Objectives for Class:• Describe the purpose and explain the major steps of transcription.

Types of RNA: Messenger RNA (mRNA)

mRNA (the orange strand)

DNA (the red & green strands)

Objectives for Class:• Describe the major structural differences between DNA and RNA• Differentiate between structure and function differences between the types of RNA

t RNA

mRNA

t RNA

Ribosom

e

Codons & AntiCodons

Codon 3 base sequence on

mRNA that specifies a single amino acid to be added to the polypeptide (protein)

Anticodon 3 base sequence

on tRNA that are match up with the mRNA codon

Objectives for Class:• Describe

Polypep

tide

Anticodon

Codon

Amino Acid

Translation Detail Overview:

mRNA copy provides instructions for assembling amino acids into a protein

Occurs at the ribosome

Steps: 1. mRNA enters the ribosome2. tRNA molecules bring amino

acids to the ribosome 3. tRNA anticodons match with

mRNA codons to put amino acids in the right order

According to the Genetic CodeObjectives for Class:• Describe the purpose and major steps of transcription• Describe the purpose and major steps of translation

Translation

Objectives for Class:• Describe the purpose and major steps of transcription• Describe the purpose and major steps of translation

Transcription & Translation

Transcription

TranslationObjectives for Class:• Describe the purpose and major steps of transcription• Describe the purpose and major steps of translation

Transcription and Translation: Video

Objectives for Class:• Describe the purpose and major steps of transcription• Describe the purpose and major steps of translation

Transcription and Translation Video: 17_13ProteinSynthesis.mpg

Bio 9C: Monday, 2.28.11Title: Transcribe and Translate a Gene Computer Lab

Homework: Pass in the codons and amino acid decoding practice

homework Complete Part II of the Transcription & Translation

Computer Lab

Do Now: Sign into a computer and turn around with your back

to the computers to wait for your next instructions.

Today’s Objective: Use the steps of transcription and translation to turn

a section of DNA into a protein.

Transcribe and Translate a Gene Computer Lab

Transcription

Translation

Objectives for Class:• Use the steps of transcription and translation to turn a section of DNA into a protein.

Procedure: Log onto

http://gslc.genetics.utah.edu/units/basics/transcribe/ Scroll down to the middle of the homepage and click

on the link entitled “Are you ready to transcribe a DNA sequence and translate it into a protein?”

A DNA sequence should appear on the screen. Transcribe the DNA strand by entering the corresponding RNA bases for the original strand. The new mRNA strand will now appear on the screen.

Locate the “start” codon and click on it with your mouse. The mRNA sequence will now move to the top of the field and a flashing box will appear around the “start” codon.

Using the “Universal Genetic Code” to the right, find the amino acid that corresponds with the three-base mRNA codon. Click on the appropriate amino acid and drag it to the corresponding mRNA codon (signaled by the flashing box). Repeat until the mRNA sequence has been Translated.

Answer the Review and Analysis questions for Part I as you complete the lab.

Answer the Review and Analysis questions for Part II after the computer portion of the lab is completed.

Remember R-groups?