Question

what are the main steps of pcr?

1. primer annealing at 55 to 65 oc
2. after one cycle, dna molecules are doubled
3. denaturation of the dna at 94 to 98 oc
4. primer extension at 72 oc

question 14
dna band pattern diagram (image of a gel)
lane source band pattern (from top to bottom/horizontally)
1 crime scene sample
2 suspect a
3 suspect b
4 suspect c
(each represents a dna band. the positions indicate fragment sizes. each color represents one sample.)
which suspect, if any, left their dna at the crime scene?
a suspect a
b suspect b
c suspect c
d no matching samples

Explanation:

In DNA fingerprinting (gel electrophoresis), if a suspect's DNA band pattern matches the crime - scene sample's pattern, it indicates they left their DNA. Here, visually comparing the band patterns:

• Suspect A (Lane 2) has a green - colored pattern. The crime - scene sample (Lane 1) has a red pattern. No match.
• Suspect B (Lane 3) has a blue pattern. No match with the red crime - scene pattern.
• Suspect C (Lane 4) has a grey pattern. No match with the red crime - scene pattern.

Answer:

d. No matching samples