What is the percentage of guanine in a DNA sample containing 20% thymine?
What is the percentage of guanine in a DNA sample containing 20% thymine?
20% plus 20% is 40% of adennine and thymine. From 100% DNA bases subtract 40% and you will get 60%. Then divide this by 2 and you will get 30%. 30% of guanine and 30% of cytosine, because their amounts are equal in the DNA stand.
How much guanine is in a human?
Percentages of bases in DNA
| Organism | Taxon | %G |
|---|---|---|
| Human | Homo | 20.7 |
| Grasshopper | Orthoptera | 20.5 |
| Sea urchin | Echinoidea | 17.7 |
| Wheat | Triticum | 22.7 |
What is the ratio of adenine to guanine?
If 10% of the bases in a molecule of DNA are adenine, then the ratio of adenine to guanine in the same molecule is 1:4.
What will be the percentage of guanine in a DNA molecule having 20% adenine?
We already know the percentage of Adenine which is 20% So, the percentage of Thymine also becomes 20% , they both make a total of 40% and the remaining quantity i.e. 60% gets equally divided between Cytosine and Guanine. i.e. 30% each. Each get’s an equal quantity of 30%. Hence, the correct answer is option (B).
How do you calculate adenine percentage?
According to Chargaff rule,
- Here adenine residues =120, cytosine residues = 120.
- there fore total number of nucleotides = [A] + [T]+ [C]+[G] =120 X 4 = 480.
- In humans, there is approximately 30% adenine.
- According to Chargaff’s rule, [A]+[G]=[C]+[T]
- Here [A]=30% therefore % of [T] is also 30%.
What percent of DNA is adenine?
Correct answer: Adenine always pairs with thymine, so their percentages will be equal. Cytosine always pairs with guanine, so their percentages will also be equal. The sum of all four percentages must equal 100%. We know that the sample is 22% adenine; this tells us it is also 22% thymine.
How does DNA replication begin?
Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.
Can DNA copy itself?
DNA replication is the process by which DNA makes a copy of itself during cell division. The separation of the two single strands of DNA creates a ‘Y’ shape called a replication ‘fork’. The two separated strands will act as templates for making the new strands of DNA.
Which phase does DNA copy itself?
Interphase
What actually happens to DNA before it can be replicated copied?
Before replication can occur, the length of the DNA double helix about to be copied must be unwound. In addition, the two strands must be separated, much like the two sides of a zipper, by breaking the weak hydrogen bonds that link the paired bases.
Why is DNA duplicated well before cell division?
Before a cell divides, its DNA is replicated (duplicated.) Because the two strands of a DNA molecule have complementary base pairs, the nucleotide sequence of each strand automatically supplies the information needed to produce its partner.
Why is it important for DNA to replicate exactly?
The purpose of DNA replication is to produce two identical copies of a DNA molecule. This is essential for cell division during growth or repair of damaged tissues. DNA replication ensures that each new cell receives its own copy of the DNA.
What would happen if DNA did not replicate?
Since the cell is dividing it needs two copies of its DNA – one is kept by the parent cell and the other is passed to the daughter cell. If cells don’t replicate their DNA or don’t do it completely, the daughter cell will end up with no DNA or only part of the DNA. This cell will likely die.
What causes changes in DNA?
Environmental exposure to certain chemicals, ultraviolet radiation, or other external factors can also cause DNA to change. These external agents of genetic change are called mutagens.
What happens if DNA is damaged?
The DNA in just one of your cells gets damaged tens of thousands of times per day. Because DNA provides the blueprint for the proteins your cells need to function, this damage can cause serious issues—including cancer. Fortunately, your cells have ways of fixing most of these problems, most of the time.
Can DNA mutations be repaired?
In contrast to DNA damage, a mutation is a change in the base sequence of the DNA. A mutation cannot be recognized by enzymes once the base change is present in both DNA strands, and thus a mutation cannot be repaired.
Which vitamin helps with DNA repair?
Vitamin B12 and folate have also been found as essential for DNA metabolism. In short folic acid and B12 are required for the maintenance of DNA conformation and methylation patterns.
Are all DNA mutations harmful?
A single mutation can have a large effect, but in many cases, evolutionary change is based on the accumulation of many mutations with small effects. Mutational effects can be beneficial, harmful, or neutral, depending on their context or location. Most non-neutral mutations are deleterious.