DNA AND GENESChapter 11

DNA: THE MOLECULE OF

HEREDITYChapter 11, Section 1

DNA Determines an organism’s traits Produces proteins

DNA STRUCTURE Long Polymer of repeating subunits

(nucleotides)

NUCLEOTIDE 3 Parts:

Simple Sugar Deoxyribose

Phosphate Group Phosphate with 4 oxygen

Nitrogenous Base Carbon ring with 1 or more nitrogen Four types:

Adenine (A)Guanine (G)Cytosine (C)Thymine (T)

DEOXYRIBOSE

PHOSPHATE GROUP

NITROGENOUS BASE

NUCLEOTIDE

SUGAR PHOSPHATE BACKBONE Nucleotides form chains Phosphate group of one nucleotide

bonds to sugar of another nucleotide

NITROGENOUS BASES Complementary base pairs held with

weak hydrogen bondsAdenine and ThymineGuanine and Cytosine

JAMES WATSON AND FRANCIS CRICK Discovered DNA structure Double Helix Also involved: Maurice Wilkins and the

other by Rosalind Franklin

NUCLEOTIDE Use white board

MAKE DNA Use white board

MAKE DNA Use laminated pieces

MAKE DNA Use Play-Doh

Circles for PhosphateSquares for SugarTriangles for Nitrogen Bases

GENETIC DIVERSITY Results from the differing sequences of

the four different nucleotides

NUCLEOTIDE SEQUENCES Determine

relatednessevolutionary relationships

What would be closely related to the chimp?

DNA REPLICATION During interphase – before meiosis or

mitosis Four Steps

DNA REPLICATION – STEP 1 DNA double helix unzips Hydrogen bonds between nitrogenous

bases split Result: 2 nucleotide strands with their

nitrogenous bases exposed

DNA REPLICATION – STEP 2

Base Pairing – free nucleotides base pair with exposed nucleotidesAdenine with ThymineGuanine with Cytosine

Result: each strand builds its complement

DNA REPLICATION – STEP 3

Sugar and phosphate parts of adjacent nucleotides bond

Result: new backbone for each strand

DNA REPLICATION – STEP 4

Two molecules of DNA are formed

Semi-Conservative Replication – each new molecule has one strand from the original molecule and one strand that has been newly synthesized from free nucleotides

SEMI CONSERVATIVE REPLICATION One strand of DNA is re-used The other strand is newly constructed

CRASH COURSE VIDEO

FROM DNA TO PROTEIN

Chapter 11, Section 2

PROTEINS Polymer made of amino acids

(monomer) Control bodily functions DNA is responsible for constructing

Use amino acids

DNA Deoxyribonucleic Acid Composed of nucleotides Gives instructions on how to make

protein

RNA Ribonucleic acid Composed of nucleotides Single stranded Sugar = ribose Replaces thymine (nitrogenous base)

with uracilBase pairs with adenine

TYPES OF RNA Messenger RNA (mRNA)

Brings info from DNA in the nucleus to cytoplasm

Ribosomal RNA (rRNA)Ribosomes clamp onto the mRNA and use

its info to assemble the amino acids in the correct order

Transfer RNA (tRNA)Transports amino acids to the ribosome to assemble the protein

CODON On mRNA Each set of three nitrogen bases Codes for a specific amino acid

ANTICODON On tRNA Each set of three nitrogen bases Carries a specific amino acid

PROBLEM SOLVING LAB 11-2 Page 297 Answer all questions

Everyone needs to write answersAnswer can be written in notes

CODONS AND AMINO ACIDS

GENETIC CODE Universal ie: UAC codes for the amino acid

tyrosineALWAYS In bacteria, birch trees, bison and every

other living thing on the planet Evidence that all life on Earth evolved

from a common origin

DIVERSITY OF DNA Four nucleotides 20 Amino Acids Proteins are built from long chains of

DNADNA lined-up end-to-end in all the human

cells of an adult would stretch to about 60 billion miles (about 60 times the distance from the sun to Pluto, the outer most fake planet)

TRANSCRIPTION Double stranded DNA to single stranded

RNA mRNA

Sugar is now ribose Uracil is used (instead of thymine) Occurs in nucleus

Figure 3-181 of 5

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DNA

Gene

Promoter

Triplet 1

Triplet 2

Triplet 3

Triplet 4

1

2

3

4

Com

ple

men

tary

trip

lets

RNApolymerase

1

2

3

4

Codon1

RNAnucleotide

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

mRNAstrand

Codon1

Codon2

Codon3

Codon 4(stop signal)

Figure 3-182 of 5

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DNA

Gene

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

Figure 3-183 of 5

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DNA

Gene

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

Promoter

Triplet 1

Triplet 2

Triplet 3

Triplet 4

1

2

3

4

Com

ple

men

tary

trip

lets

RNApolymerase

1

2

3

4

Figure 3-184 of 5

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DNA

GeneCodon

1

RNAnucleotide

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

Promoter

Triplet 1

Triplet 2

Triplet 3

Triplet 4

1

2

3

4

Com

ple

men

tary

trip

lets

RNApolymerase

1

2

3

4

Figure 3-185 of 5

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

DNA

GeneCodon

1

RNAnucleotide

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

mRNAstrand

Codon1

Codon2

Codon3

Codon 4(stop signal)

Promoter

Triplet 1

Triplet 2

Triplet 3

Triplet 4

1

2

3

4

Com

ple

men

tary

trip

lets

RNApolymerase

1

2

3

4

TRANSLATION From mRNA to protein Takes place at the ribosomes Uses tRNA

TRANSFER RNA Carry Anticodon

Opposite nitrogenous bases from codonUsed to attach to codon on mRNA

Carry 1 specific amino acid

TRANSLATION Happen on ribosome (made of rRNA and

protein) tRNA bring in first amino acid by attaching

it’s anticodon to mRNA’s codon Ribosome moves down Next tRNA brings in next amino acid by

attaching it’s anticodon to mRNA’s codon 2 amino acids bond First tRNA detaches Repeats until protein is constructed

Figure 3-191 of 6

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KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

The small and large ribosomal subunits interlock around the mRNA strand.

Largeribosomalsubunit

A second tRNA arrives at the adjacent binding site of the ribosome. The anticodon of the second tRNA binds to the next mRNA codon.

Stopcodon

Peptide bond

The first amino acid is detached from its tRNA and is joined to the second amino acid by a peptide bond. The ribosome moves one codon farther along the mRNA strand; the first tRNA detaches as another tRNA arrives.

The chain elongates until the stop codon is reached; the components then separate.

Small ribosomalsubunit

Largeribosomalsubunit

Completedpolypeptide

Figure 3-192 of 6

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KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

Figure 3-193 of 6

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KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

The small and large ribosomal subunits interlock around the mRNA strand.

Largeribosomalsubunit

Figure 3-194 of 6

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KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

The small and large ribosomal subunits interlock around the mRNA strand.

Largeribosomalsubunit

A second tRNA arrives at the adjacent binding site of the ribosome. The anticodon of the second tRNA binds to the next mRNA codon.

Stopcodon

Figure 3-195 of 6

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KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

The small and large ribosomal subunits interlock around the mRNA strand.

Largeribosomalsubunit

A second tRNA arrives at the adjacent binding site of the ribosome. The anticodon of the second tRNA binds to the next mRNA codon.

Stopcodon

Peptide bond

The first amino acid is detached from its tRNA and is joined to the second amino acid by a peptide bond. The ribosome moves one codon farther along the mRNA strand; the first tRNA detaches as another tRNA arrives.

Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

Figure 3-196 of 6

KEY

Adenine

Guanine

Cytosine

Uracil (RNA)

Thymine

KEY

NUCLEUS

mRNA

Amino acid

tRNA

Anticodon

tRNA binding sites

Smallribosomalsubunit

mRNA strandStart codon

The mRNA strand binds to the small ribosomal subunit and is joined at the start codon by the first tRNA, which carries the amino acid methionine. Binding occurs between comple-mentary base pairs of the codon and anticodon.

The small and large ribosomal subunits interlock around the mRNA strand.

Largeribosomalsubunit

A second tRNA arrives at the adjacent binding site of the ribosome. The anticodon of the second tRNA binds to the next mRNA codon.

Stopcodon

Peptide bond

The first amino acid is detached from its tRNA and is joined to the second amino acid by a peptide bond. The ribosome moves one codon farther along the mRNA strand; the first tRNA detaches as another tRNA arrives.

The chain elongates until the stop codon is reached; the components then separate.

Small ribosomalsubunit

Largeribosomalsubunit

Completedpolypeptide

MINI LAB 11-1 Page 299 Answer all questions

CRASH COURSE VIDEO

GENETIC CHANGES

Chapter 11, Section 3

MUTATION Any change in the DNA sequence May

have large effect or no effectbe helpful or harmfulcause cancer lead to natural selection and evolutionoccur in reproductive cells or body cells

POINT MUTATION Change in a single base pair in the DNA Ie: THE DOG BIT THE CAT

THE DOG BIT THE CAR

FRAMESHIFT MUTATION Single base is added or deleted from

DNA Shifts the reading of codons by one base Ie: THE DOG BIT THE CAT

THE DOG BIT ETH ECA T

CHROMOSOMAL MUTATIONS Disrupt distribution of genes to gametes

during meiosis Cause nondisjunction

Homologous chromosomes cannot pair correctly when they have an extra or are missing a part

TYPES OF CHROMOSOMAL MUTATIONS Deletion

ABC DEF GHI ABC DFG HI

Insertion ABC DEF GHI ABC BCD EFG HI

Inversion ABC DEF GHI ADC BEF GHI

Translocation ABC DEF GHI and WXYZ WXA BCD EFG HI and YZ

PROBLEM SOLVING LAB 11-3 Page 305 Answer all questions

MINI LAB 11-2 Page 306 Answer all questions

MUTAGEN Anything that is capable of causing

mutations Ie: radiation (X-Rays, UV light, nuclear

energy), chemicals, high temperatures

REPAIRING DNA Mistakes rarely happen When they do, there are repair

mechanismsEnzymes

Greater exposure to mutagen, less chance the mistake will be corrected

TEST 19 Multiple Choice 12 Completion 5 Short Answer/Essay