Question

for questions 1 - 3, identify the function of each enzyme in dna replication (hint: not all options will be used)

1. helicase:
2. dna polymerase:
3. ligase:

a. read the dna template and assemble nucleotides
b. connect the newly synthesized dna fragments.
c. prevent the dna from getting tangled
d. separate the double - stranded dna into single strands.
for questions 4 - 8, match the letters to the correct component of the dna replication fork in the diagram below.

1. dna polymerase:
2. dna ligase:
3. topoisomerase:
4. leading strand:
5. lagging strand:

b.h.2: structure and function of dna in cells
9 transgenic organisms are..
a. likely to die soon after birth.
b. unlikely to have frameshift errors.
c. organisms with several mutations.
d organisms with altered genetic code

Explanation:

1. Helicase unwinds the double - stranded DNA by breaking the hydrogen bonds between base pairs, which is equivalent to separating the double - stranded DNA into single strands.
2. DNA Polymerase reads the DNA template and assembles nucleotides in a complementary manner to synthesize new DNA strands.
3. Ligase connects the newly synthesized DNA fragments (such as Okazaki fragments on the lagging strand) by forming phosphodiester bonds.
4. In the diagram, DNA Polymerase is represented by component A. It is involved in the synthesis of new DNA strands by adding nucleotides.
5. DNA Ligase is not explicitly labeled in the given diagram description, but if we assume based on function (connecting fragments), there is no clear match in the provided diagram labels. However, if we consider the general role, in DNA replication, it acts on fragments.
6. Topoisomerase (not labeled in the given options for the first three questions but relevant for DNA replication to prevent tangling). In the diagram, if we assume based on function (preventing tangling), there is no clear match in the provided labels. But if we consider the overall replication machinery, it is an important enzyme.
7. The leading strand is synthesized continuously. In the diagram, if we assume based on the direction of synthesis (5' - 3' towards the replication fork), there is no clear label. But if we consider the strand that is synthesized without interruption (in a simple sense), we need to refer to the diagram's orientation.
8. The lagging strand is synthesized discontinuously as Okazaki fragments. In the diagram, if we assume based on the presence of Okazaki fragments (as labeled in the diagram), the strand with Okazaki fragments is the lagging strand.

For question 9:

• Transgenic organisms are organisms with altered genetic code. They have foreign DNA inserted into their genome. They are not likely to die soon after birth (a is wrong), not necessarily have frameshift errors (b is wrong, frameshift is a type of mutation not a general characteristic of transgenics), and not just having several mutations (c is wrong, it's about foreign DNA insertion, which is a specific type of genetic alteration).

Answer:

1. d
2. a
3. b
4. A
5. (No clear label in the given diagram for ligase based on the provided labels)
6. (No clear label in the given diagram for topoisomerase based on the provided labels)
7. (No clear label in the given diagram for leading strand based on the provided labels, but if we assume based on continuous synthesis direction (not shown in labels), it's not directly identifiable from the given labels)
8. (The strand with Okazaki fragments, but no clear label in the given options for the letters A - E for this specific identification)
9. d. Organisms with altered genetic code