Gene structure
DNA replication
Figure 7.4A
Figure 7.5
DNA Structure
• The DNA double helix
has grooves: a wide
major groove and a
narrow minor groove.
•
• - These provide DNAbinding proteins
access to base
sequences.
Figure 7.6
RNA Structure
• RNA differs from DNA:
•
- Usually single-stranded
•
- Contains ribose sugar
•
- Uracil replaces
thymine
Figure 7.4B
The Bacterial Nucleoid
• Bacteria pack their DNA into a series of loops or
domains, collectively called the nucleoid.
•
- Loops are anchored by histone-like proteins
Figure 7.8
DNA Replication
• Replication of cellular DNA in most cases is
semiconservative.
•
- Each daughter cell receives one parental
and one newly synthesized strand.
Figure 7.13
Figure 7.14
Figure 7.15
Figure 7.18b
Figure 7.18a
DNA Replication
• Animation: DNA Replication
Click box to launch animation
Figure 7.19
Figure 7.21
Analysis of DNA
• Restriction
endonucleases cleave
DNA at specific
recognition sites, which
are usually 4 to 6 bp and
palindromes.
•
•
- May generate blunt
or staggered ends
Figure 7.27A
Analysis of DNA
• Agarose gel
electrophoresis can
be used to analyze
the DNA fragments
obtained by
treatment with
restriction enzymes.
Figure 7.27B
Analysis of DNA
• The polymerase chain reaction (PCR) can
produce over a million-fold amplification of
target DNA within a few hours.
Figure 7.29