Searching for the “Secret of Life” Pre-lecture review 1.Fundamental unit of all living things?...
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Searching for the “ Secret of Life ” Pre-lecture review 1. Fundamental unit of all living things? The cell 2. Organelle that controls the cell? Nucleus 3. Structures found in the nucleus that carry hereditary information? Chromosomes 4. What are chromosomes made of? DNA wrapped around histones (proteins) 5. What molecule carries “the code of life”? DNA 6. How does DNA control the activity of the cell? Producing proteins that regulate cell fuctions or become part of the cell
Searching for the “Secret of Life” Pre-lecture review 1.Fundamental unit of all living things? The cell 2.Organelle that controls the cell? Nucleus 3.Structures
Searching for the Secret of Life Pre-lecture review
1.Fundamental unit of all living things? The cell 2.Organelle that
controls the cell? Nucleus 3.Structures found in the nucleus that
carry hereditary information? Chromosomes 4.What are chromosomes
made of? DNA wrapped around histones (proteins) 5.What molecule
carries the code of life? DNA 6.How does DNA control the activity
of the cell? Producing proteins that regulate cell fuctions or
become part of the cell
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Nucleic Acids DNA & RNA Chapter 12
Slide 3
I.DNA A.Discovery * Read section 12-1 in your textbook and
summarize the following sections: 1.Griffith and Transformation
2.Avery and DNA 3.The Hershey-Chase Experiment
Slide 4
B.Components 1.DNA is made of repeating sub-units called
nucleotides 2.Nucleotides have 3 parts: a.A nitrogenous base
b.5-carbon sugar (deoxyribose) c.A phosphate group What does DNA
stand for? Deoxyribonucleic Acid
Slide 5
Phosphate group Deoxyribose Nitrogenous base DRAW: Nucleotide
Structure Why are they called nitrogenous bases?
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Purines Pyrimidines AdenineGuanine CytosineThymine Phosphate
group Deoxyribose What is the difference between purines and
pyrimidines? Draw Fig. 12-5 pg 291 3. Two types of bases: a.Purines
(Adenine and Guanine) b.Pyrimidines (Cytosine and Thymine)
Slide 7
C. Base Pairing and DNA Structure 1.Chargaffs Rule of Base
Pairing a.Opposing bases always pair the same: Adenine (A) pairs
with Thymine (T) Guanine (G) pairs with Cytosine (C) What would be
the complementary base sequence for the strand of DNA below? A C G
G T T A C A A T G A TGC C AAT G T TAC T
Slide 8
2.Structure a.The overall shape of DNA is described as a double
helix (a twisted ladder) What force holds the two strands together?
Hydrogen bonds Nucleotide Sugar-phosphate backbone Key Adenine (A)
Thymine (T) Cytosine (C) Guanine (G)
Slide 9
b.The sugar-phosphate backbone is held together by covalent
bonds Hydrogen bonds Nucleotide Sugar-phosphate backbone Key
Adenine (A) Thymine (T) Cytosine (C) Guanine (G) DRAW Fig. 12-7, pg
294
Slide 10
DNA Nucleotide and Bonding Movie
Slide 11
D.Discovery of DNA Structure 1.In the early 1950s British
scientist Rosalind Franklin discovered the helical structure of DNA
using x-ray diffraction 2.In 1953, James Watson and Francis Crick
(using Franklins images) developed the double helix model for DNA
and won the Nobel Prize
Slide 12
E.How does DNA control living systems? 1.Genes are segments of
DNA that code for proteins that control traits 2.DNA codes for the
amino acid sequence in proteins 3.Every three bases codes for one
amino acid = codon Examples: TTT codes for phenylalanine GAA codes
for leucine TGG codes for tryptophan DRAW
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F. DNA Replication 1.Controlled by series of enzymes 2.Helicase
enzymes are produced and unzip the parent DNA by breaking the
hydrogen bonds. 1.Controlled by series of enzymes 2.Helicase
enzymes are produced and unzip the parent DNA by breaking the
hydrogen bonds. DRAW
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3.DNA polymerase starts to form two new daughter strands by
base pairing free nucleotides with those on the exposed parent
strands, then proofreads the new strands DRAW
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4.Finally, two new strands form. Each is made of one strand of
parent and one strand of daughter DNA. DRAW
Slide 17
Growth Replication fork DNA polymerase New strand Original
strand DNA polymerase Replication fork Original strand New strand
Nitrogenous bases DRAW FIG.12-11, pg 298
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Slide 19
DNA REPLICATION SONG
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II. RNA: The Other Nucleic Acid What does RNA stand for?
Ribonucleic Acid Differences between DNA and RNA 1.RNA contains
ribose instead of deoxyribose. 2.RNA can be in single-stranded or
double-stranded forms. 3.RNA is found in both the nucleus and
cytoplasm. DNA is only in the nucleus.
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4.RNA contains uracil (U) instead of thymine (T)
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B. Three Kinds of RNA 1.Messenger RNA (mRNA) a.Copies the DNA
code in the nucleus and carries the message to the ribosomes
b.Single stranded
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2. Transfer RNA (tRNA) a.Each tRNA consists of ~90 nucleotides
b.It transfers amino acids to the ribosome and places them in the
correct position in the protein
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3.Ribosomal RNA (rRNA) a.Part of the ribosome involved in the
synthesis of tRNA Draw Fig. 12-2, pg 300
Slide 25
fromtoto make up also calledwhich functions toalso called which
functions to can be RNA Messenger RNA Ribosomal RNA Transfer RNA
mRNACarry instructions rRNA Combine with proteins tRNA Bring amino
acids to ribosome DNARibosomeRibosomes DRAW: RNA Concept Map