Sylvia S. Mader
Michael Windelspecht
Chapter 21
DNA Biology and Technology
Lecture Outline
Part 1
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• What are 3 functions of DNA?
• Review DNA and RNA structure.
• What are the 3 major types of RNA and their functions?
• Compare and contrast the structure and function of DNA and RNA.
• How is DNA replicated?
• Describe transcription and translation in detail.
• Describe the genetic code.
• Review protein structure and function.
• What are the 4 levels of regulating gene expression?
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• What did we learn from the Human Genome
Project, and where do we go from here?
• What is ex vivo and in vivo gene therapy?
• Define biotechnology, transgenic organisms, genetic engineering, and recombinant DNA.
• What are some uses of transgenic bacteria, plants, and animals?
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21.1 DNA and RNA Structure and Function
1. It ___________ to be passed on to the next generation.
2.
DNA ________ information.
3. It undergoes ___________ to provide genetic diversity.
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21.1 DNA and RNA Structure and Function
• It is a ___________________ .
• DNA is composed of repeating ____________
(made of a pentose sugar, phosphate, and a nitrogenous base).
• Sugar and phosphate make up the backbone, while the ________ make up the “rungs” of the ladder.
• Bases have _________________ : cytosine (C) pairs with guanine (G), and adenine (A) pairs with thymine (T).
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21.1 DNA and RNA Structure and Function
5 ′ end
P
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T A
3 ′ end phosphate pyrimidine base
S
S P
T
P
P C
G
S
S
P
P
S
T
C G
A
S
P
P
5 ′ end
P
5 ′
4 ′
3 ′
S
OH
2 ′
1 ′
T
S
S
P
S
A
T
P
P
S
A
C
5 ′
C
4 ′
S
O
C C
3 ′ 2 ′
C
1 ′ deoxyribose
3 ′ end
5 ′ end purine base
A
3 ′ end
1 ′
2 ′ 3′
OH
S
4 ′
5 ′
P b. Ladder structure c. One pair of bases a. Double helix
Figure 21.1 The structure of DNA.
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21.1 DNA and RNA Structure and Function
• The 2 strands unwind as the _________ are
A T broken.
A
G
C
C
G
G • Complementary nucleotides are added to
A each strand by DNA polymerase.
• Each new double-stranded helix is made of
1 new strand and one old strand
(__________________________).
• The sequence of bases makes each individual unique.
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21.1 DNA and RNA Structure and Function
Copyright
© The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
5′ 3 ′
C
G
G
A
C
A
T
G region of parental
DNA double helix
T
C
A
C
A
G
A
A
C
G
G
G
T
DNA polymerase enzyme region of replication: new nucleotides are pairing with those of parental strands old strand
5′ new strand daughter DNA double helix
Figure 21.2 Semiconservative replication.
region of completed replication new strand
3 ′ old strand
Daughter DNA double helix
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21.1 DNA and RNA Structure and Function
• It ______________.
• RNA is composed of repeating nucleotides.
• Sugar-phosphate is the backbone.
• Bases are A, C, G, and _______ (U).
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21.1 DNA and RNA Structure and Function
• 3 types of RNA
– ______________ (mRNA) carries genetic information from DNA to the ribosomes.
– ______________ (rRNA) joins with proteins to form ribosomes.
– ____________ (tRNA) transfers amino acids to a ribosome where they are added to a forming protein.
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21.1 DNA and RNA Structure and Function
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
P
G
G
S U
C
A
P
U
Base is uracil instead of thymine.
S
P
A
S
P
C
S ribose one nucleotide
Figure 21.4 The structure of RNA.
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21.1 DNA and RNA Structure and Function
large ribosomal subunit
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© The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
polypeptide met polypeptide ser ala tryp val tRNA
P site anticodon
C A
G U
U
A G A C
A site codon anticodon small ribosomal subunit a. An mRNA is threaded between ribosomal subunits and a polypeptide extends to the side.
mRNA b. A ribosome has two binding sites where codons bind to anticodons. A tRNA bearing a polypeptide is at the P site. A new tRNA amino acid is approaching the A site.
asp c. A tRNA amino acid is coming to the ribosome. Upon arrival, its anticodon, CUG, will bind to its codon, GAC.
Figure 21.9 The roles of all three forms of RNA in translation.
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