web viewtumor-suppressor genes. gene mutations. definition: causes: errors in replication. mutagens....

Biology 12Mrs. Knowles

DNA & Gene expression: Chapters 24 & 25

Discovery of DNA

1. Chargaff’s rule

2. Hershey and Chase experiment

3. Francis & Crick’s model

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Structure of DNA

Polynucleotide with three subunits:

1)

2)

3)

Purines:

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Pyrimidines:

Double helix:

Complementary base pairing:

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Antiparallel strands

Replication

Purpose:

semiconservative process:

STEPS:

1) DNA helicase2) DNA polymerase3) DNA ligase

Results:

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RNA structure

DNA RNASugar

Bases

Strands

Helix?

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Types of RNA:

1) Messenger RNA (mRNA)

2) Ribosomal RNA (rRNA)

3) Transfer RNA (tRNA)

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Checkpoint:

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Differentiate between purines and pyrimidines including examples of each.

What three components make up DNA?

What are the structural differences between ribose and deoxyribose? Between thymine and uracil?

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Gene expressionOverall goal:

Overall process:

Gene:

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Transcription

Recall that the overall goal is:

Location of transcription:

1) Synthesis of mRNAPromoter region:

RNA polymerase

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2) Processing of mRNA (primary -> mature mRNA)A) Cap

B) Poly-A tail

C) Introns removed, exons joined together

Introns:

Exons:

Ribozyme:

3) Mature mRNA leaves nucleus

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Translation

Overall purpose:

The triplet code:

Why triplet?

Codon:

Start codon:

Stop codons:

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tRNA:

its role:

anticodon:

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Ribsomes

Made of:

Made at:

Binding sites:

Polyribosome:

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Steps in translation:

1) Chain initiationWhat is involved:

Step 1:

Step 2:

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2) Chain elongation

Step 3:

Step 4:

Step 5:

Step 6:

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3) Chain termination

Step 7:

Step 8:

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Levels of gene control

1) Unpacking of DNA

2) Transcription

3) mRNA processing

4) translation

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5) protein activity

6) signaling between cells

When gene control fails: cancer

Characteristics of cancer cells:

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Proto-oncogenes

Tumor-suppressor genes

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Gene mutations

Definition:

Causes:

i. Errors in replication

ii. Mutagens

iii. transposons

Types of mutations:

i. Frameshift mutations

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ii. Point mutations

DNA Technology

1) Cloning

i) Reproductive cloning

ii) Therapeutic cloning

2) Recombinant DNA (rDNA)

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3) Polymerase chain reaction

4) Fingerprinting

Biotechnology-genetic engineering

1) Transgenic bacteria

2) Transgenic plants

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3) Transgenic animals

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