Answer:
The X-shaped structure is made of strands of DNA.
Explanation:
The chromosomes are thread-like structures located in the nucleus of each cell in the body. In a human cell, there are 23 pairs of chromosomes found in the nucleus. Each chromosome is made up of strands of DNA tightly coiled many times around proteins called histones which gives support to its structure.
The chromosomes are X-shaped and are observed only in a cell undergoing division by mitosis or meiosis. Each of these X-shaped chromosomes consists of two identical sister chromatids. The sister chromatids are connected to each other by a region of the chromosome called the centromere. The centromere are located around the depression point of the chromosome which divides the sister chromatids into two regions: long arm called the q arm and a shorter arm called the p arm. During mitosis, spindle fibers attach to this region, and they eventually pull the sister chromatids apart to form two separate chromosomes, one for each daughter cell.
Answer:
The presence of cholesterol in the plasma membranes of some animal cells <u>enables the membranes to stay fluid when cell temperature drops</u>.
Explanation:
Cholesterol is an essential lipid in the basic structure of cell membranes. The membranes must have a fluid structure so that the proteins integrated in them can move ''horizontally'' to interact with their ligands and with other proteins. With excess saturated fat the membranes become rigid, but only with the necessary unsaturated fat the membranes are extremely fluid, and very sensitive to changes in temperature. Cholesterol stabilizes the structure of the membranes; preventing the collapse and crystallization between lipid chains that would lead to loss of fluidity and excessive rigidity in the membrane. By decreasing the temperature; as temperatures drop, fluidity decreases, an effect that partially counteracts the presence of cholesterol.
the answer is the first one A.) Chlorophyll is a chemical found in a chloroplast.
There are two types of HIV viruses, HIV1 and HIV2.
HIV1 is most commonly found (HIV2 is located in Wes America).
HIV1 is usually more likely to progress and get worsen, so the level of immune system activation of the host is higher.
HIV1 has lower CD4 counts and plasma viral loads are higher.
Answer:
It looks like a double helix!
Explanation:
Hope this helped :3
