Answer:
False
Explanation:
A double-helical DNA molecule consists of two DNA strands. A DNA strand has free 5' phosphate at one end and a free hydroxyl group (OH) at its 3' end. A DNA double helix is said to be antiparallel since each end of the double helix has an exposed 5' phosphate on one strand and a free 3' hydroxyl group (OH) on the other. This means that the two DNA strands run in opposite directions. A phosphate group is always esterified to the 5' carbon of the pentose sugar; never at its 3' end.
Answer:
b. they require more oxygen per unit of volume.
Explanation:
Large animals have a specialized organs for exhalation and inhalation of gases due to the requirement of large amount of oxygen for cellular respiration. Respiration is a process in which energy is released in the form of Adenine tri phosphate (ATP) in the mitochondria of the cell with the addition of oxygen. The waste product such as carbondioxide is produced which is removed from the body body through lungs.
Answer:
The best explanation if we observe an epithelial cell with chromosomes are visible and two cell nuclei is that the cell has just gone through telophase but not cytokinesis (option b).
Explanation:
A somatic cell, when found in mitosis, exhibits the chromosomes distributed in both poles and the outline of two nuclei in the telophase phase, just before cytokinesis.
In mitotic telophase:
- Chromatids, which are chromosomes, are found in the cell poles.
- It initiates the formation of the nucleus membrane.
- The chromosomes begin to turn into chromatin.
- Disappearance of the mitotic spindle, duplication of organelles and cytoplasmic invagination.
The division and differentiation of the nuclei in telophase is called karyokinesis. Later, cytokinesis occurs, where the daughter cells are separated.
The other options are not correct because:
<em> a and d. In the other phases described, </em><em><u>S and G1,</u></em><em> no chromosome distribution is observed at the poles.</em>
<em> c. A somatic cell does not experience </em><em><u>meiosis</u></em><em>.</em>
Answer:
A- A pH change can cause the enzyme to change its shape
Explanation:
A rise or fall in the pH of the medium from the optimum of pH 7 usually affect the enzymes' active sites of and therefore the shape and the rate of enzyme activity.
Assuming the pH is too low, the enzyme medium becomes acidic;Acidosis. The high Hydrogen ions concentration interacts with the R-groups of the amino acids moiety of the enzymes, this interaction affects the ionization of the R-groups, disrupting the ionic bonding holding these R-groups in shape.
This results in loss of the 3-Dimensional shape arrangements of the protein molecule and therefore of the active sites. Since active sites of enzymes determines the specificity of the <u>enzymes substrate- complex </u> to give <u>enzyme-product complex,</u> the catalytic activity of the enzymes decreases, <u>the rate of reaction decreases,and products formation stops, and the reaction also stops.</u>
The same is applicable to extremely high pH=Alkalosis.
However, the effective buffer system of the body prevents this scenarios from happening in real sense in the body. Through mopping by the haemoglobin, excretion by the kidney, etc
Answer:
The theory of evolution basically serves to explain the biological evolution of living beings. The theory of evolution basically serves to explain the biological evolution of living beings. This results in the appearance of new species different from the previous ones.
