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Presentation on theme: "RNA."— Presentation transcript:


2 Review of DNA DNA is a double Helix that is a code for something
What? Structure/Shape explains how it is replicated, but not how genes work. Helicase and DNA Polymerase Chargaff’s Rule Nucleotide 5 Carbon Sugar (Deoxyribose), Phosphate and Nucleic Acid (Guanine, Cytosine, Adenine, Thymine)

3 First Step in Decoding Messages:
Copy DNA (Deoxyribonucleic Acid) into RNA (Ribonucleic Acid) Note: “Deoxyribo” in Deoxyribonucleic Acid is in reference to the 5-Carbon Sugar in the backbone of the molecule Deoxyribose So what do you think the 5-Carbon Sugar is in the backbone of Ribonucleic Acid? Ribose

4 Differences (Between DNA and RNA)
DNA RNA Deoxyribose Ribose Double Stranded Single Stranded Thymine Uracil

5 RNA is a disposable copy of DNA
3 Types of RNA mRNA Messengers – they carry copies of the instructions for proteins. (From Nucleus to Ribosome) rRNA Ribosomal – where the proteins are assembled. Reminder: Ribosomes are made up of protein and RNA tRNA Transfers each amino acid to the ribosome

6 How is a copy made? Transcription RNA Polymerase Where does it start?
“Transcribe” or write a code Only 1 strand is made! RNA Polymerase Separates DNA strands (at Hydrogen bonds) and acts as “Police” in creating the mRNA Where does it start? There are “start sites” called Promoters Just like promoters for events let people know what is going on.

7 Introns Exons Codons “Extra” parts that are cut out of
the final mRNA strand. Exons “Good” parts that are spliced together to make the final mRNA strand Codons 3 (consecutive) nucleotides long Each one specifies for one of 20 amino acids 64 different codons

8 Special Codons: Start Codon: AUG Stop Codons: UAA, UAG, UGA


10 Translation “Translates” from one language to another
Creates a chain of amino acids Known as a protein. It is the process of translating codons (mRNA) by using anti-codons (tRNA) into the amino acids they code for (which makes proteins) Occurs at the Ribosomes Anti-codons are complementary to codons

11 Translation Can you identify the following: 1. mRNA 2. Codon
3. Anti-Codon 4. Amino Acid 5. Protein

12 What is the big picture? DNA is the Master Plan mRNA is the Blueprint
Remains safe in the nucleus mRNA is the Blueprint Disposable copy rRNA is the Building site tRNA are the builders Workers that make the proteins (amino acid chains) DNA makes proteins and proteins express genes!

13 Mutations Changes in the letter sequence of the DNA Chromosomal Gene
Whole chromosome has been changed Change in the number of chromosomes or their structure. Gene Single gene change (one or more letters) Two types Point Frameshift

14 Point Mutation One nucleotide changes – May change the Amino Acid it codes for (and it may not)

15 Frameshift Mutation Typically makes the entire protein not useable.
Deletion Removal of one or more Nucleotides Insertion Addition of a Nucleotide

16 Frameshift Mutation (Continued)


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