Chapter 5
Chapter 5
DNA and Chromosomes
ML 05-208a
Pg 173-178
ML 05-208b
Pg 180-187
Phosphodiester
Bond
hydrogen
Bond
The
Structure
OF
DNA
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r
→
5
Prime
:
Phosphate
attaches
g-
f
•
5
carbon
sugar
backbone
+
Phosphate
=
back
bond
backbone
•
Antiparallel
(
opposite
polarities
)
,
double
helix
BS
Thymine
•
Nitrogenous
bases
interact
with
each
other
Bd
Guanine
.
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>
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T
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weaker
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to
break
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BB
cytosine
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e
stronger
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harder
to
break
)
Bd
Adenin e
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The
structure
OF
Eukaryotic
chromosomes
-
Eukaryotic
DNA
is
Packed
into
multiple
chromosomes
(
linear
DNA
)
•
chromosome
-
DNA
tightly
coiled
around
Proteins
(
histones
)
•
karyotype
-
a
set
of
all
the
condensed
Pairs
OF
chromosomes
'
one
from
each
Parent
-
Chromosomes
carry
genes
(
genetic
info
)
3
'
5
'
•
Gene
:
basic
unit
of
heredity
sugars
Phosphine
>
nucleotide
sequence
which
codes
For
Protiens
•
Genome
:
DNA
and
genes
-
Specialized
DNA
sequences
for
DNA
replication
•
during
cell
division
,
signals
get
integrated
and
send
cells
Past
GI
checkpoint
'
replication
org.in
-
replication
starts
,
first
specialized
sequence
'
telomeres
-
specialized
sequence
at
the
ends
OF
each
chromosome
,
help
For
full
replication
,
Protection
'
centromeres
-
specialized
sequence
where
microtubules
attach
,
help
pull
chromosomes
to
middle
'
sequences
of
DNA
where
specific
Protiens
bind
and
start
activity
-
interphase
:
when
the
cell
is
not
dividing
,
interphase
chromosomes
are
organized
into
regions
-
DNA
in
chromosomes
is
always
condensed
•
more
condensed
in
mitosis
1
When
cells
replicate
>
than
in
interphase
I
not
replicating
)
-
Chromosome
Packing
levels
DNA
"
madmen
"
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tu
2)
Nucleosomes
:
basic
unit
OF
DNA
Packing
,
When
DNA
wraps
around
Pro
tiene
histones
>
Minimum
m-1
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3)
Chromatin
fibers
NIMBLY
2
⑧
o
o
Histone
4)
chromatin
fiber
loops
-
histone
Hi
Pulls
nucleosomes
together
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Ent
5)
chromosomes
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