Download Chapt21 Lecture 13ed Pt 1

Human Biology
Sylvia S. Mader
Michael Windelspecht
Chapter 21
DNA Biology
and Technology
Lecture Outline
Part 1
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
1
DNA Biology and
Technology
2
Points to ponder
• 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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Points to ponder
• 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
What does DNA do?
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
DNA structure: A review
• 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
DNA structure
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
5′ end
P
3′ end
phosphate
T
purine base
A
S
S
P
T
A
P
G
T
T
C
P
S
S
T
P
T
A
5′
4′
G
S
T
P
b. Ladder structure
Figure 21.1 The structure of DNA.
OH
4′
S
5′
P
5′
C
P
3′ end
3′
OH
S
A
S
1′
2′
3′
S
P
1′
S
P
C
2′
A
S
S
P
3′ end
5′ end
P
P
a. Double helix
pyrimidine base
O
C
4′
S
C
3′
C
2′
C
1′
deoxyribose
5′ end
c. One pair of bases
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21.1 DNA and RNA Structure and Function
How is DNA replicated?
• The 2 strands unwind as the _________ are
broken.
• Complementary nucleotides are added to
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.
A
A
T
G
G
C
C
G
A
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21.1 DNA and RNA Structure and Function
DNA replication
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
5′
3′
G
C
G
C
G
A
T
A
region of parental
DNA double helix
T
A
C
G
A
A
DNA
polymerase
enzyme
G
G
C
C
T
G
A
region of
replication:
new nucleotides
are pairing
with those of
parental strands
region of
completed
replication
3′
new
strand
5′
old
strand
old
strand
Daughter DNA double helix
new
strand
daughter DNA double helix
Figure 21.2 Semiconservative replication.
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21.1 DNA and RNA Structure and Function
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
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
RNA structure
Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.
G
P
G
S
U
A
P
Base is
uracil instead
of thymine.
U
C
S
P
A
S
P
C
S
ribose
Figure 21.4 The structure of RNA.
one nucleotide
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21.1 DNA and RNA Structure and Function
Types of RNA
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large ribosomal
subunit
met
polypeptide
ser
polypeptide
ala
tryp
asp
val
tRNA
P site
anticodon
A site
G U A
small ribosomal
subunit
codon
C A U
G A C
anticodon
mRNA
a. An mRNA is threaded between
ribosomal subunits and a
polypeptide extends to the side.
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.
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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