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DNA and the Language of Life

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DNA and the Language of Life (chapter 11 of

the book)

• CONCEPTS: Genes, chromosomes and the genome

• Genes are made of DNA

• 1 Gene 1 Protein

• Steps from Gene to Protein

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General

Concepts

• A gene is a distinct portion of a cell’s DNA.• Genes are coded instructions for making everything the

body needs, especially proteins.

What Is a Gene?

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• Human beings have about 25,000 genes. Researchers discovered what some of our genes do (some that are associated with disorders such as cystic fibrosis or Huntington’s disease).

• There are many genes whose functions are still unknown.

What Is a Gene?

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What Are Proteins?

• Proteins are chains of chemical building blocks called amino acids.

• A protein could contain just a few amino acids in its chain or it could have several thousands.

• Proteins form the basis for most of what the body does, such as digestion, making energy and growing.

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What Are Chromosomes?• Genes are

packaged in bundles called chromosomes.

• Humans have 23 pairs of chromosomes (for a total of 46).

• Of those, 1 pair is the sex chromosomes (determines whether you are male or female, plus some other body characteristics)

• the other 22 pairs are autosomal chromosomes (determine the rest of the body’s makeup).

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What Is the Human Genome?• The human genome is a complete copy of the

entire set of human gene instructions. • The Human Genome Project, completed in 2003,

identified all the human genes in DNA and stored the information in databases so all researchers everywhere could use it.

Single chromosomes (23)

Pairs of chromosomes (46)

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What Is a Mutation?• Mutation is a change of the nucleotide sequence of

the genome of an organism. • Mutations are unrepaired damage to DNA or to RNA genomes.• Mutation can happen at a nucleotide level or at a chromosome

level• May or may not produce discernible changes in the observable

characteristics (phenotype) of an organism.• Mutations play a part in both normal and abnormal biological

processes including: evolution, cancer, and the development of the immune system. At a nucleotide

level

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DNA and the Language of Life (chapter 11 of

the book)

• CONCEPTS: Genes, chromosomes and the genome

• Genes are made of DNA

• 1 Gene 1 Protein

• Steps from Gene to Protein

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Genes are made of DNA

Mendel didn’t know about DNAGriffith-1928-transforming factor2 BacteriaThe harmful dead changed theharmless living into harmful livingSome “transforming factor” remained active

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Genes are made of DNA• Avery-1944- Transforming factor was DNA

not proteinScientists were skeptical because protein was very prevalent

• Hershey and Chase- Radioactive Virus ExperimentsDNA is The geneticmaterial

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Nucleic Acid Sequence (A,T,G,C)

• Nucleotides (A,T,G,C) are monomers (units) of nucleic acids

• 3 parts: (sugar)• deoxyribose(DNA) or ribose (RNA)

Phosphate groupNitrogenous bases

pyramidinespurines

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DNA and the Language of Life (chapter 11 of

the book)

Summary of dna structure and replication (refresh our memory before learning the processes from gene to protein)

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Nitrogenous bases

pyrimidines Single ring

(Cytosine, Thymine, U)

purines Double Ring (Guanine,A)

Nucleic Acid Sequence (A,T,G,C)

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Nucleic Acid Sequence (A,T,G,C)

• 1950’s• Franklin and Wilkins- DNA helix • Watson and Crick-Double helix

• Base pairings• C-G (Pyrimidine +Purine) fix notes• A-T (Pyrimidine +Purine)

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DNA replication = inheritance• Figure 11-9

During DNA replication, the two strands of the original parent DNA molecule, shown in blue, each serve as a template for making a new strand, shown in yellow. • Replication results in two daughter DNA molecules, each consisting of one original strand and one new strand.

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DNA replication = inheritance

• Figure 11-10• DNA replication both directions

"bubbles." bubbles merge

two daughter DNA

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DNA and the Language of Life (chapter 11 of

the book)

• CONCEPTS: Genes, chromosomes and the genome

• Genes are made of DNA

• 1 Gene 1 Protein

• Steps from Gene to Protein

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1 Gene 1 Protein

One gene, one polypeptide

• The bases: A,T,G,C are the letters in the language of Life• The letters make up words -> genes are the words• The meaning of the Sentences are the polypeptides (proteins)

11.4 Agene provides the information for making a specific protein

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1 Gene 1 Protein

• From Gene to protein….form DNA to amino Acid….

Amino AcidsMONOMER WITH A CENTRAL CARBON ATOM BONDED TO 4 PARTNERS: a H, an Amino group, a carboxyl group and a side group.

Responsible for the chemical properties of

each amino acid.

Amino Acids

Proteins

26 Letters

Many

words

Alphabet

20 AA

Many protei

ns

Polypeptide chains 100 AA

AMINO ACIDSalanine arginin

easparagin

easpartic

acidcysteine

glutamic acid

glutamine

glycine histidine isoleucine

leucine lysine methionine

Phenyl-alanine

proline

serine threonine

tryptophan

tyrosine valine

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1 Gene 1

Protein• Each codon stands for an amino acid. (The table uses

abbreviations for the amino acids, such as Ser for serine.)

• The codon AUG not only stands for methionine (Met), but also for "start“.

• There are also three "stop" codons that do not code for amino acids, but signal the end of each genetic message.

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3 types of RNAmRNA-messenger

tRNA-transfer

rRNA-ribosomal

HOMEWORK

what does each RNA does in the process form gene to protein?

Study the SHORTHAND SYMBOLS FOR AMINO ACIDS.

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DNA and the Language of Life (chapter 11 of

the book)

• CONCEPTS: Genes, chromosomes and the genome

• Genes are made of DNA

• 1 Gene 1 Protein

• Steps from Gene to Protein

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Steps from Gene to Protein

Transcription: DNA to RNA

http://www.dnai.org/a/index.html

Go to interactive screen- reading the code- putting it together -interactive

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RNA splicing• Introns stay IN nucleus• Exons EXit nucleus• mRNA doesn’tContain introns

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Steps from Gene to Protein

Translation: RNA to ProteinFigure 11-191.Translation begins with the attachment of a ribosome and the first tRNA to a "start" (AUG) codon. 2. The ribosome then moves along the mRNA. The polypeptide elongates as an amino acid is added for each codon.3. When the ribosome arrives at a "stop" codon, the completed polypeptide is released

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Gene videos• https://www.youtube.com/watch?v=aOU4hzR3w-A• https://

www.youtube.com/watch?v=qvaAQCLuXHM