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Biology Concepts and Applications | 9e

Starr | Evers | Starr

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Chapter 9

From DNA to Protein

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• DNA functions as the inherited directions for a

cell or organism

• RNA is transcribed from DNA

• Proteins are produced by the translation of

RNA

• Proteins cause physical traits

Gene Expression: The process by which

the info in a gene (unit of DNA) guides

assembly of a protein

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Gene Expression

• DNA specifies the

synthesis of

proteins in two

stages

– Transcription

• DNA to RNA

– Translation

• RNA to Protein

Figure 10.9

Figure 9-2a p148

DNA

Nucleotide

Structure

RNA

Nucleotide

Structure

Figure 9-3a p150

Transcription: DNA RNA

Figure 9-7 p152

The Genetic Code

• The genetic code is shared by all organisms.

Therefore, any gene from any organism can be

inserted into the genome of any other organism

and expressed.

Universal Genetic Code

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Translation: mRNA (with help from tRNA)

Protein

8

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transfer RNA (tRNA)

9

anticodon

amino acid

attachment site

© Cengage Learning 2015 Figure 9-11a p155

© Cengage Learning 2015 Figure 9-12b p156

What happens to proteins after a gene

becomes mutated?

Base-pair substitution

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What happens to proteins after a gene

becomes mutated?

12

Base-pair substitution of valine for glutamine results

in abnormal hemoglobin in red blood cells (sickle cell

disease).

© Cengage Learning 2015 Figure 9-12b p156

Frameshift

Mutations:

Deletion

and

Insertion

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Mutations Contribute to Diversity

• Not all mutations are

harmful

– They give rise to the

variation in traits that

is the raw material of

evolution, which

leads to the rich

diversity of genes in

the living world