Discontinuous synthesis of DNA occurs in one strand, because:
1. | DNA molecule being synthesised is very long |
2. | DNA-dependent DNA polymerase catalyses polymerisation only in one direction (5’ → 3’) |
3. | it is a more efficient process |
4. | DNA ligase joins the short stretches of DNA |
The addition of deoxyribonucleotides by DNA polymerase during DNA synthesis is an endergonic process. The source of energy used is:
1. | ATP |
2. | Energy from photons of light |
3. | Entropy created from protein digestion |
4. | The nucleotides themselves |
The difference between ATP and the nucleoside triphosphates used during DNA synthesis is that:
1. | The nucleoside triphosphates have the sugar deoxyribose; ATP has the sugar ribose. |
2. | The nucleoside triphosphates have two phosphate groups; ATP has three phosphate groups. |
3. | ATP contains three high-energy bonds; the nucleoside triphosphates have two. |
4. | ATP is found only in human cells; the nucleoside triphosphates are found in all animal and plant cells. |
Identify the incorrect statement:
1. | The DNA of the bacteriophage ϕ X 174 has 5386 nucleotides. |
2. | Bacteriophage lambda DNA has 48502 base pairs. |
3. | The DNA of Escherichia coli has 4.6 X 103 base pairs. |
4. | Haploid content of human DNA is 3.3 X 109 base pairs. |
While analysing the DNA of an organism a total number of 5386 nucleotides were found out of which the proportion of different bases were: Adenine = 29%, Guanine = 17%, Cytosine = 32%, Thymine = 17%. Considering Chargaff’s rule it can be concluded that:
1. | it is a double-stranded circular DNA |
2. | It is single-stranded DNA |
3. | It is a double-stranded linear DNA |
4. | No conclusion can be drawn |