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DO NOW QUESTIONS What are the 4 bases? How many bonds are between them? © 2012 Pearson Education, Inc.

Objective SWBAT… describe how DNA structure leads to genes and proteins. © 2012 Pearson Education, Inc. NGSS HS-LS1-1 Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells. 

What is a gene? A gene is a certain amount of DNA which “codes for ” a specific protein. © 2012 Pearson Education, Inc.

What are genes? Genes are made up of DNA. Genes get passed from parents to offspring (parents to babies). © 2012 Pearson Education, Inc.

How are genes and DNA related? Genes are the basic unit of genetics. Human beings have approximately 20,000 genes! © 2012 Pearson Education, Inc.

How are genes and DNA related? Certain numbers of genes get grouped into long molecules of DNA called chromosomes. © 2012 Pearson Education, Inc.

How are genes and DNA related? © 2012 Pearson Education, Inc.

How are DNA and genes related? All forms of life use a code to change information from DNA into proteins. © 2012 Pearson Education, Inc.

What is the relationship between GENES and DNA?

DNA  proteinsCertain stretches of DNA are genes – protein “recipes” The structure of DNA determines the structure of proteins! © 2012 Pearson Education, Inc.

Think of the bases of DNA like letters. Letters (DNA) form words (genes)....Words form sentences (proteins)....               *endless               combinations

How are DNA and genes related? The diversity of life arises from differences in DNA sequences.We all have different DNA sequences – that’ s what makes us different! © 2012 Pearson Education, Inc.

DNA REPLICATION the process by which DNA makes a copy of itself (cell division) SEMI-CONSERVATIVE - half of the old strand is saved

Separation The strand of DNA is unzipped by helicase.The point of separation is called the replication fork.

Figure 10.5C Overall direction of replication DNA ligase Replication fork Parental DNA DNA polymerase molecule This daughter strand is synthesized continuously This daughter strand is synthesized in pieces 3  5  3  5  3  5  3  5  Primase starts the new strand. DNA Polymerase adds new base pairs

Figure 10.8B_s1 T Strand to be transcribed A C T T C A A A A A T DNA A A T C T T T T G A G G DNA can also be transcribed and translated to obtain amino acids, which create a protein.

DNA -->  RNA -->  Protein Proteins are the building blocks of the organism (traits)

RNA - the messenger  *single strand*ribose sugar *contains no thymine, uracil instead *follows base pair rule, but A ⇒ UDNA:   A  T  A   G  C  G RNA:  

RNA carries the "message" to the ribosomes, where proteins are made

Translation involves switching from the nucleotide “language” to the amino acid “language.” The flow of information from gene to protein is based on a triplet code or three-base “words” called codons. 64 codons are possibleSome repeat. 0 © 2012 Pearson Education, Inc.

Figure 10.8A Second base Third base First base

Figure 10.8B_s3 T Strand to be transcribed A C T T C A A A A A T DNA A A T C T T T T G A G G RNA Transcription A A A A U U U U U G G G Translation Polypeptide Met Lys Phe Stop codon Start codon