1. Don’t let this happen to
you!!

2. RNA
Ribonucleic Acid

3. Structure of RNA
 Single stranded
 Ribose Sugar
 5 carbon sugar
 Phosphate group
 Adenine, Uracil, Cytosine, Guanine

4. Types of RNA
 Three main types
 Messenger RNA (mRNA) – transfers
DNA code to ribosomes for translation.
 Transfer RNA (tRNA) – brings amino
acids to ribosomes for protein synthesis.
 Ribosomal RNA (rRNA) – Ribosomes are
made of rRNA and protein.

5. Transcription
 RNA molecules are produced by copying part
of the nucleotide sequence of DNA into
complementary sequence in RNA, a process
called transcription.
 During transcription, RNA polymerase binds to
DNA and separates the DNA strands. RNA
polymerase then uses one strand of DNA as a
template from which nucleotides are
assembled into a strand of mRNA.

6. How Does it Work?
 RNA Polymerase looks for a region on
the DNA known as a promoter, where it
binds and begins transcription.
 RNA strands are then edited. Some
parts are removed (introns) - which are
not expressed – and other that are left
are called exons or expressed genes.

7. The Genetic Code
 This is the language of mRNA.
 Based on the 4 bases of mRNA.
 “Words” are 3 RNA sequences called
codons.
 The strand aaacguucgccc would be
separated as aaa-cgu-ucg-ccc the amino
acids would then be Lysine – Arginine –
Serine - Proline

8. Genetic Codes

9. Translation
 During translation, the cell uses information
from messenger RNA to produce proteins.
 A – Transcription occurs in nucleus.
 B – mRNA moves to the cytoplasm then to the
ribosomes. tRNA “read” the mRNA and obtain
the amino acid coded for.
 C – Ribosomes attach amino acids together
forming a polypeptide chain.
 D – Polypeptide chain keeps growing until a
stop codon is reached.

10. MUTATIONS
Changes in DNA that affect genetic
information

11. Mutations
 Gene mutations result from changes in a
single gene. Chromosomal mutations
involve changes whole chromosomes.

12. Gene Mutations
 Point Mutations – changes in
one or a few nucleotides
 Substitution
 THE FAT CAT ATE THE RAT
 THE FAT HAT ATE THE RAT
 Insertion
 THE FAT CAT ATE THE RAT
 THE FAT CAT XLW ATE THE RAT
 Deletion
 THE FAT CAT ATE THE RAT
 THE FAT ATE THE RAT

13. Gene Mutations
 Frameshift Mutations – shifts
the reading frame of the
genetic message so that the
protein may not be able to
perform its function.
 Insertion
 THE FAT CAT ATE THE RAT
 THE FAT HCA TAT ETH ERA T
H
 Deletion
 THE FAT CAT ATE THE RAT
 TEF ATC ATA TET GER AT
H

14. Chromosome Mutations
 Changes in number and structure of entire
chromosomes
 Original Chromosome ABC * DEF
 Deletion AC * DEF
 Duplication ABBC * DEF
 Inversion AED * CBF
 Translocation ABC * JKL
GHI * DEF

15. Significance of
Mutations
•Most are neutral
• Eye color
• Birth marks
• Some are harmful
• Sickle Cell Anemia
• Down Syndrome
• Some are beneficial
• Sickle Cell Anemia to Malaria
• Immunity to HIV

16. What Causes
Mutations?
 There are two ways in which DNA can
become mutated:
 Mutations can be inherited.
 Parent to child
 Mutations can be acquired.
 Environmental damage
 Mistakes when DNA is copied

17. Chromosome Mutations
 Down Syndrome
 Chromosome 21 does
not separate correctly.
 They have 47
chromosomes in stead
of 46.
 Children with Down
Syndrome develop
slower, may have heart
and stomach illnesses
and vary greatly in their
degree of inteligence.

18. Chromosome Mutations
 Cri-du-chat
 Deletion of material on 5th
chromosome
 Characterized by the cat-like
cry made by cri-du-chat
babies
 Varied levels of metal
handicaps

19. Sex Chromosome
Abnormalities
 Klinefelter’s
Syndrome
 XXY, XXYY, XXXY
 Male
 Sterility
 Small testicles
 Breast enlargement

20. Sex Chromosome
Abnormalities
 XYY Syndrome
 Normal male traits
 Often tall and thin
 Associated with antisocial and behavioral
problems

21. Sex Chromosome
Mutations
 Turner’s Syndrome
 X
 Female
 sex organs don't
mature at
adolescence
 sterility
 short stature

22. Sex Chromosome
Mutations
 XXX
 Trisomy X
 Female
 Little or no visible differences
 tall stature
 learning disabilities
 limited fertility

25. Some mutations even
make it on SNL!