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DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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Page 1: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DNA

mRNA

Transcription

Introduction

The Central Dogma of Molecular Biology

Cell

Polypeptide(protein)

TranslationRibosome

Page 2: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DOGMA?

This central dogma was develop by Crick.

This was a hypothesis on how the code was read from DNA then used to make proteins. Scientists did not like this term for this hypothesis because it sounds like a problem!

Page 3: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DOGMA!

Principle, idea, or statement that is considered to be absolutely true. Kind of like a theory!!!!! But Crick called it a DOGMA!!!

DNA ---- RNA ----- Proteins!!!!!!

Page 4: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Central Dogma of Biology

The flow of information in the cell starts at DNA,

Page 5: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

How does DNA determine what you look like?

Page 6: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

What is the purpose for What is the purpose for proteins?proteins?

• antibody: fight diseases

• Muscle contractions

• Enzymes

• Hormones

• Hair, feathers, beaks, nails, horns, etc.

• Egg whites

• Transport proteins: blood(hemoglobin)

Page 7: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein StructureProtein Structure

• Made up of amino acids

• Polypeptide- string of amino acids

• ONLY 20 amino acids are arranged in different orders to make a variety of proteins!!!! Amino acids are in the cytoplasm.

• Assembled on a ribosome

Page 8: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 9: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DNA vs. RNADNA vs. RNA

• DNA • Double Helix• Deoxyribose sugar• Adenine pairs with

Thymine (A-T)• Stays in nucleus

• RNA• Single strand• Ribose sugar• Uracil replaces

Thymine!• Leaves nucleus to

do the work

Page 10: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DNA vs. RNA

DNA RNADeoxyribose RibsoseThymine Uracil is one of the

bases in RNA. There is

thymine no thymine. This means

A goes with U and G still goes with C.

Double Strand Single Strand

Page 11: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Steps to Protein Synthesis1. Transcription – process where

DNA message is changed into mRNA then out of nucleus to the ribosomes!!!

2. Translation – process when mRNA is translated into amino acid chains(protein) on the ribosomes.

Page 12: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

How does a protein get built??

• This is where RNA becomes involved.

• DNA is too large to get out of the nuclear membrane pores.

• SO RNA has to be made to go to the ribosomes!!!

Page 13: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 14: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

SO, HOW DOES AN AMINO ACID CHAIN GET BUILT?

RNA stands for ribonucleic acid

Page 15: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Stars of Translation and Transcription

1. mRNA

2. DNA

3. rRNA

4. tRNA

5. Ribsomes

6. RNA polymerase

Page 16: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Three types of RNA:Three types of RNA:

• 1. mRNA• “messenger” RNA• Carries code for

proteins from DNA• Carries “codon”

• 2. tRNA• “transfer” RNA

• Attaches specific Amino Acids to the protein chain by matching the mRNA codon with the anticodon.

Page 17: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

RNA TRANSCIPTIONThere are three (3) types RNA:1. Messanger RNA – (mRNA) carries messages from the DNA in the nucleus to the ribosomes.

Page 18: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

tRNA2. Transfer RNA – (tRNA) 20 different

kinds which are only able to bond with one (1) specific type of amino acid.

Page 19: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

rRNA3. Ribosomal RNA – (rRNA) major

component (part) of the ribosomes

Page 20: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

3. 3. Ribosomal Ribosomal RNARNA

rRNArRNA• Where Protein

synthesis occurs

Page 21: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

How Does RNA polymerase(complex) know where to start and stop?

• Promoter site: starting point on DNA. Specific base sequences that represents a gene.

• Termination site: Place where RNA polymerase stops!!!

• REMEMBER - only a gene is being read to make mRNA not all of your DNA.

Page 22: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Step 1: Step 1: • RNA polymerase complex attaches to DNA

at special places that serve as the start signal(promoter sites). Only one gene!!!!!

Page 23: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Step 2: Step 2: • DNA splits at site of RNA polymerase.

• RNA polymerase attaches matching bases to form new RNA strand from DNA template.

Page 24: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

• RNA polymerase keeps adding bases making the RNA strand grow…

Page 25: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Step 3:Step 3:• RNA polymerase leaves DNA when reaches

the stop signal.

• RNA strand is released and goes to cytoplasm.

• DNA rewinds itself into the double helix.

Page 26: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Results of TranscriptionResults of Transcription

• Strand of mRNA made from the DNA

Page 27: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

FYI

RNA polymerase doesn’t check for mistakes in the code. Doesn’t cause mutations when there is a few mistakes in proteins unlike replication.

Page 28: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: Protein Synthesis: TranscriptionTranscription

Page 29: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Making mature mRNA Original mRNA transcribed

is not mature mRNA

Exons:readable segments

Of mRNA that go to the

ribsome

Introns: nonreadable

Segments that must be removed before leaving

Nucleus.

Page 30: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Exons vs. IntronsExons vs. Introns

Once introns removed, mRNA is ready to leave the nucleus!!!!

Page 31: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

DNA

Cytoplasm

Nucleus

Eukaryotic Transcription

ExportG AAAAAA

RNA

Transcription

Nuclear pores

G AAAAAA

RNAProcessing

mRNA

Page 32: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Prokaryotic Protein Synthesis

• All occurs in the cyotplasm!!!

Page 33: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Transcription is done…what Transcription is done…what now?now?

Now we have mature mRNA transcribed from the cell’s DNA. It is leaving the nucleus through a nuclear pore. Once in the cytoplasm, it finds a ribosome so that translation can begin.

We know how mRNA is made, but how do we “read” the code?

Page 34: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Translation

Translation is the process of decoding a mRNA molecule into a polypeptide chain or protein.

ALWAYS read mRNA!!!!!!

Three RNAs play the key roles!!

Page 35: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

RNA TRANSLATIONProtein Synthesis: the formation of a protein using information coded on DNA and carried out by RNA in the assembly of amino acids.

Proteins are:a. Amino acids in chains – 20 kindsb. Made of 10’s or 100’s or 1000’s of amino acidsc. Must be arranged in a specific sequence for each

type of proteind. Function & type of protein is determined by amino

acid sequencee. DNA makes RNAf. RNA constructs amino acids

Page 36: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

mRNA - Codons

• Read 3 bases at a time on the mRNA called CODONS!!!!

• Each combination of 3 nucleotides on mRNA is called a codon or three-letter code word.

• Each codon specifies a particular amino acid that is to be placed in the polypeptide chain (protein).

Page 37: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: Translation

Page 38: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

SU

GA

R-P

HO

SP

HA

TE

BA

CK

BO

NE

B A

S E

S

H

PO

O

HO

O

O

CH2NH2N

NH

N

N

HOH

P

O

O

HO

O

O

CH2

NH2

N

N

N

N

H

P

O

OH

HO

O

O

CH2

NH2

N

N

N

N

O

A Codon

GuanineGuanine

AdenineAdenine

AdenineAdenine

Arginine

Page 39: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Start codons and Stop codonsStart codons and Stop codons

• For translation to begin, there is a START codon.

• AUG: is the 3 letter codon that starts the process.

• UAA, UGA, UAG: Stop codons.

Page 40: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Start Codon

• Start codon: codon AUG also serves as the “initiator” codon, which starts the synthesis of a protein.

Page 41: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Stop Codon

• STOP codon: Codon that signal the end of the protein. (UAA, UAG, & UGA

• Besides selecting the amino acid methionine, the codon AUG also serves as the “initiator” codon, which starts the synthesis of a protein

Page 42: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 43: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: Translation

•A three-letter code is used because there are 20 different amino acids that are used to make proteins.

•If a two-letter code were used there would not be enough codons to select all 20 amino acids.

•That is, there are 4 bases in RNA, so 42 (4x 4)=16; where as 43 (4x4x4)=64.

Page 44: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Translation•Therefore, there is a total of 64 codons with mRNA, 61specify a particular amino acid.

• This means there are more than one codon for each of the 20 amino acids.

Page 45: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: Translation

Page 46: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: TranslationTransfer RNA (tRNA)

•Each tRNA molecule has 2 important sites of attachment.

•One site, called the anticodon, binds to the codon on the mRNA molecule.

•The other site attaches to a particular amino acid.

•During protein synthesis, the anticodon of a tRNA molecule base pairs with the appropriate mRNA codon.

Page 47: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

tRNAtRNA• Transfer RNA• Bound to one amino

acid on one end• Anticodon on the

other end complements mRNA codon

• If they do not match then the tRNA is rejected!!!!

Page 48: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

MethionineMet-tRNA

U*

9

262223Pu

16

12Py 10

25

20:1

G*

17:1

Pu

A20:2

1713

20G

A5051

656463

G

62

52

CPu

59

A*

C

Py

T49

39

4142

31

2928

Pu*

43127

U35

38

36

Py*

34

403047:1

47:15

46

Py47:16

4544

47

73CCA

707172

66676869

321

7654

A CU

Anticodon

Page 49: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

tRNA parts

Page 50: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Parts of a Ribosomes - rRNAParts of a Ribosomes - rRNA

Ribosomes are composed of 2 subunits separate in cytoplasm – Large– Small

• Contain 3 binding sites – helps tRNA align to codon.

– E– P– A

Page 51: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Steps of TranslationSteps of Translation• 1. INITIATION:

A.The initiator(start) codon AUG binds to the first anticodon of tRNA, signaling the start of a protein.

B. Two parts of the ribosome join around the tRNA and mRNA.

• The amino acid methionine, the codon AUG also serves as the “initiator” codon, which starts the synthesis of a protein at site P.

Page 52: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 53: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 54: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

TranslationTranslation• 2. ELONGATION: The anticodon of

another tRNA binds to the next mRNA codon at site A, bringing the 2nd amino acid to be placed in the protein. This will continue until stop codon.

• As each anticodon & codon bind together a peptide bond forms between the two amino acids.

Page 55: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 56: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 57: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome
Page 58: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Protein Synthesis: TranslationProtein Synthesis: Translation•3. Termination: The protein chain continues to grow until a stop codon reaches the ribosome, which results in the release of the new protein and mRNA, completing the process of translation. The amino acids are bonded with a peptide bond to form a protein.

•Release factor causes the release of tRNA and mRNA.

Page 59: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

http://staff.jccc.net/pdecell/proteinsynthesis/translation/steps.html

Page 60: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Summary of Translation• Ribosome 2 parts come together.• mRNA attaches to ribosome.• AUG – start codon. • tRNA brings in making anticodon with

amino acid.• rRNA continues to read mRNA and bring

in making tRNA.*Stop codon will stop process. Peptide

bonds will form to make a protein.

Page 61: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

AE

Large subunit

P

Small subunit

Translation - InitiationTranslation - Initiation

fMet

UACGAG...CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA...TAAAAAA5’mRNA

3’

Page 62: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

AE

Ribosome P

CCA

Arg

UCU

PheLeu

Met

SerGly

Polypeptide

Translation - ElongationTranslation - Elongation

GAG...CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA...TAAAAAA5’mRNA

3’

Page 63: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

AE

Ribosome P

PheLeu

Met

SerGly

Polypeptide

Arg

Aminoacyl tRNA

UCUCCA

Translation - ElongationTranslation - Elongation

GAG...CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA...TAAAAAA5’mRNA

3’

Page 64: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

AE

Ribosome P

Translation - ElongationTranslation - Elongation

Aminoacyl tRNA

CGA

Ala

CCA

Arg

UCU

PheLeu

Met

SerGly

Polypeptide

GAG...CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA...TAAAAAA5’mRNA

3’

Page 65: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

AE

Ribosome P

Translation - ElongationTranslation - Elongation

CCA

Arg

UCU

PheLeu

Met

SerGly

Polypeptide

CGA

Ala

GAG...CU-AUG--UUC--CUU--AGU--GGU--AGA--GCU--GUA--UGA-AT GCA...TAAAAAA5’mRNA

3’

Page 66: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

The Genetic CodeThe Genetic Code

Page 67: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

ANYTHING

ACIDAMINE

Protein SynthesisProtein Synthesis

C

O

OHCN

H

HH

C

HO H

C

H

O

CN

H

HH

C

H H

C

H

O

OHCN

H

HH

C

HO H

Serine

C

H

O

OHCN

H

HH

C

H H

AlanineH

C

O

OHC

R

N

H

H

Amino Acid

H2O

Page 68: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

3’

5’

5’

3’

Transcription And Translation In Transcription And Translation In Prokaryotes ALL IN CYTOPLASM!!!Prokaryotes ALL IN CYTOPLASM!!!

Ribosome

Ribosome5’

mRNA

RNAPol.

Page 69: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Transcription vs. Translation ReviewTranscription vs. Translation Review

Transcription• Process by which

genetic information encoded in DNA is copied onto messenger RNA

• Occurs in the nucleus• DNA mRNA

Translation• Process by which

information encoded in mRNA is used to assemble a protein at a ribosome

• Occurs on a Ribosome• mRNA protein

Page 70: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Pigment is produced in the petal cells of the plant as the result of a chemical reaction. A chemical reaction takes place in the cytoplasm of a cell in which a colorless molecule is changed to a different molecule that now absorbs light and reflects red light without assistance. This reaction would take place very slowly and not much pigment would be produced during the life of the plant. As with almost all chemical reactions inside cells, this reaction is catalyzed by an enzyme which speeds up the rate of the reaction hundreds of thousands of times. In the presence of the enzyme, enough pigment is produced to quickly turn the cells and petals of the flower red. Without the enzyme, the cells would essentially stay colorless. With the enzyme, the plant flowers can turn red. The red flower trait is thus the result of the activity of an enzyme.

Page 71: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

http://www.bioinformatics.org/tutorial/1-1.html

Page 72: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

How Is DNA Responsible for What you Look Like or How You Feel?

The DNA in each chromosome makes up many genes (as well as vast stretches of noncoding DNA(introns), the function of which is unknown). A gene is any given segment along the DNA that encodes instructions that allow a cell to produce a specific product - typically, a protein such as an enzyme - that initiates one specific action. There are between 50,000 and 100,000 genes. These PROTEINS determine everything about you. SO your DNA control this code and what you look like!!!! It determines the amino acid codes!!

Page 73: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

MUTATIONSChanges in DNA that affect genetic

information

Page 74: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

Page 75: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

– Deletion• THE FAT CAT ATE THE RAT• TEF ATC ATA TET GER AT

H

H

Page 76: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Sex Chromosome Abnormalities

• XYY Syndrome– Normal male traits– Often tall and thin– Associated with antisocial and behavioral

problems

Page 77: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

Page 78: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

Page 79: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

Page 80: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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.

Page 81: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

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

Page 82: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Sex Chromosome Abnormalities• Klinefelter’s Syndrome

–XXY, XXYY, XXXY

–Male

–Sterility

–Small testicles

–Breast enlargement

Page 83: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Sex Chromosome Abnormalities• XYY Syndrome

–Normal male traits–Often tall and thin–Associated with antisocial and

behavioral problems

Page 84: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Sex Chromosome Mutations

• Turner’s Syndrome– X– Female– sex organs don't

mature at adolescence– sterility– short stature

Page 85: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome

Sex Chromosome Mutations

• XXX

–Trisomy X

–Female

–Little or no visible differences

–tall stature

–learning disabilities

–limited fertility

Page 86: DNA mRNA Transcription Introduction The Central Dogma of Molecular Biology Cell Polypeptide (protein) Translation Ribosome