Gene structureDNA replication

Figure 7.4A

Figure 7.5

• The DNA double helix has grooves: a wide major groove and a narrow minor groove.

•• - These provide DNA-

binding proteins access to base sequences.

DNA Structure

Figure 7.6

• RNA differs from DNA:

• - Usually single-stranded

• - Contains ribose sugar

• - Uracil replaces thymine

RNA Structure

Figure 7.4B

• Bacteria pack their DNA into a series of loops or domains, collectively called the nucleoid.

• - Loops are anchored by histone-like proteins

The Bacterial Nucleoid

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 7.18a

Figure 7.18b

• Animation: DNA Replication

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DNA Replication

Figure 7.19

Figure 7.21

• 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

Analysis of DNA