A DNA sequence is amplified by PCR from a small amount of DNA obtained from a crime scene (see figure below left). The PCR product contains two recognition sites for a restriction enzyme called Eco Ri. The positions of the PCR primers are indicated by arrows. The location of the two EcoRI sites and
the beginning and end of the sequence are indicated.
a. Predict the size of the DNA bands you would see on a gel after PCR. No restriction enzyme has been used. How big is the piece of DNA made by
PCR?
b. Predict the size of the DNA bands you would see on a gel after PCR AND digestion with Eco RI. Now the restriction enzyme has been used to cut the
long piece of DNA as shown. How big is each piece?
C. The DNA of three suspects was screened by PCR and digestion with EcoRI. Observe the gel picture on the right below. Which of them would you
identify as being at the crime scene? The long piece of DNA with the two EcoR1 restriction sites is the DNA recovered at the crime scene. Which
subject's fragment pattern matches the crime scene DNA when it is cut with EcoR1?
o

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.

is there any options? maybe im just not seeing them but i need the options to

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a. the law of proportion states the combination of 2 atoms in a specific ratio to produce multiple compounds such as the given statement of question ‘1st compound contains 88.8 % cu ’ indicates 88.8 g of cu is present along with 11.2 g oxygen in 100 g of compound whereas the statement ‘2st compound contains 79.9 % cu ’ indicates 79.9 g of cu is present along with 20.1 g oxygen in 100 g of compound

1st compound contains 88.8 g cu

for cu

m = 63 g /mol

atomic % = 88.8 /63 = 1.42

for o

m = 16 g /mol

atomic % = 11.2 /16 = 0.7

b. the emperical formula of 1st compound is

cu1.4o0.7

cu2o