Answer:
They have uncoiled to form long, thin strands.
Explanation:
Chromosomes are present in cell nucleus and consist of chromatin. Genes are present in linear order on chromosomes. The chromosomes become visible under the microscope as distinct structures during cell division. When cells are not dividing, the chromosomes decondense to loose their individuality and make the mass of chromatin.
Chromatin is complex of DNA and packing proteins. As the cells enter the prophase stage of cell division, condensation of chromatin occurs and individual chromosomes become visible under microscope. Before that (during interphase), chromosomes are not visible as they are present in decondensed form.
DNA model given by Watson and Creek in the year of 1953 gave a very detailed study regarding the structure of B DNA which is valid till date and is essentially corroborating with Chargaff's data and Xray diffraction pattern.
<h3><u>Explanation:</u></h3>
The DNA is the most common nucleic acid found in the living organisms as a genetic material. As stated by Watson and Creek, this DNA contains a double helical structure with two sugar phosphate backbones and the nitrogen bases getting projected from it inwards. The backbones are formed of ribose sugar and phosphate and joined together with a phosphodiester bond. The ribose sugar is attached to phosphates at its 3' and 5' Carbon atoms. The nitrogen bases found in DNA are Adenine, Guanine, Thymine and Cytosine. The Adenine has two hydrogen bonds with thymine and guanine has 3 hydrogen bonds with cytosine.
Each full turn of a helix is 34A and each base pair is 3.4A apart. The distance between two strands of DNA is 20A.
Chargaff's rule regarding the equal amount of adenine and thymine as well as guanine and cytosine is matching with this structure. All the other rules also do match with this DNA structure.
If the heat is applied by open flame, the slow boil-off of alcohol vapor can burn off without exploding or igniting the leaf bath.
Answer:
Enzymes greatly affect reaction rate in the cells because it speed up the chemical process.
Explanation:
Enzymes are the substances which act as a catalyst during a chemical reaction. Enzyme speed up the chemical process by attaching with the molecules in the reaction and when the process completed it is detached from the molecules. No decrease occurs in the size of enzyme after the reaction is completed.
