DNA and RNA
 p.
10 DNA/RNA Vocabulary
 p. 11 DNA/RNA Structures
 p. 12 Complementary Base-Pairing
 Deoxyribonucleic
Acid
 Double-stranded
 Double-helix
structure
 Made of nucleotides - each nucleotide has 3
parts (remember PBS)



Phosphate group
Bases – Adenine (A), Guanine (G), Cytosine (C),
Thymine (T)
Sugar – 5-carbon sugar called deoxyribose
 Only
one type of DNA
 Ribonucleic
Acid
 Single-stranded
 Made of nucleotides also



Phosphate group
Bases – Adenine (A), Guanine (G), Cytosine (C),
Uracil (U)
Sugar – 5-carbon sugar called ribose
 Three



types of RNA
mRNA – messenger RNA
tRNA – transfer RNA
rRNA – ribosomal RNA
 Turn
the page sideways, and complete a Venn
Diagram summarizing the similarities and
differences between DNA and RNA.
DNA
RNA
DNA
 Adenine
pairs with Thymine; Cytosine pairs
with Guanine
 In
RNA, Adenine pairs with Uracil
 Erwin
Chargaff (Chargaff’s Rule) determined
that the amount of Adenine is equal to the
amount of Thymine and the amount of
Cytosine is equal to the amount of Guanine.
 So…



%A = %T
%C = %G
A+T+C+G = 100%
Do some math…
If Adenine makes up 23% of the DNA, how much Cytosine is there?
+
+
A = 23
T
C
G
100
A = 23
T = 23
C
G
100
If A = 23, then T = 23
46
100 – 46 = 54
54 ÷ 2 = 27
Answer: 27% Cytosine
Replication
•
•
•
•
Copying DNA
Where? In the nucleus
When? S phase of Interphase
1 Strand  2 Complementary Strands
Remember:
A pairs with T
G pairs with C
Replication - Remember:
A pairs with T
G pairs with C
1. TTA CGG TAG AAT CCC CGG
AAT GCC ATC TTA GGG GCC
Replication – Check Your Answers
1. TTA
AAT
2. ATA
TAT
3. CCG
GGC
4. TAG
ATC
5. GGA
CCT
CGG
GCC
GTA
CAT
GAA
CTT
CAT
GTA
GTA
CAT
TAG
ATC
TTG
AAC
AAT
TTA
AAC
TTG
CCA
GGT
AAT
TTA
ACC
TGG
CGA
GCT
TAC
ATG
TAT
ATA
CCC
GGG
CGT
GCA
AGT
TCA
GAT
CTA
GAT
CTA
CGG
GCC
AAG
TTC
ATA
TAT
GGA
CCT
CCT
GGA
 James
Watson and
Francis Crick



Discovered the 3dimensional
structure of the DNA
molecule.
Called it the Double
Helix
Rosalind Franklin:
Provided x-ray
evidence of the DNA
helix structure.
2
strands twisted
together like a
ladder.
 Complementary
strands– fit
together but are
opposites.
 DNA





Double strand
Sugar: Deoxyribose
Location: ONLY in the
nucleus.
Job: A list of
instructions
Nitrogen-containing
bases:




Adenine
Guanine
Cytosine
Thymine
 RNA





Single strand
Sugar: Ribose
Location: Throughout
the cell
Job: Carries out
instructions of DNA
Nitrogen-containing
bases:




Adenine
Guanine
Cytosine
Uracil
 There
is only ONE
type of DNA
 There
RNA…
are 3 types of
Messenger RNA
(mRNA): RNA strand
created from the
original DNA strand.
 Ribosomal RNA
(rRNA): Makes up
ribosomes.
 Transfer RNA (tRNA):
carries amino acids
from the cytoplasm to
the ribosome during
protein synthesis.

 There
are weak
hydrogen bonds
that hold the base
pairs together.

They are broken to
allow the molecule
to replicate or be
transcribed.