Answer:
Proteins and lipids exist as separate but loosely attached molecules that can move around
Explanation:
Cell membranes are mainly composed of lipids, proteins, and also carbohydrates. Phospholipids are the most abundant type of lipid and the main constituent of the cell membranes. Membrane proteins are divided into two types according to their interactions with the cell membrane: 1-integral (intrinsic) and peripheral (extrinsic) proteins. These peripheral proteins are loosely attached by ionic bonds or calcium bridges with the phosphate heads of the phospholipids; whereas integral membrane proteins contain side chains that interact with fatty acyl groups of the phospholipids. Cell membrane fluidity indicates how easily lipids (e.g., phospholipids and cholesterol) and proteins (e.g., intrinsic proteins) diffuse laterally in the cell membrane. This fluidity is affected by the amount of cholesterol, temperature, and the ratio of unsaturated to saturated fatty acids. Saturated fatty acids have no double bonds in the hydrocarbon chain, whereas unsaturated fatty acids have at least one double bond (these double bonds increase fluidity). Moreover, higher temperatures increase membrane fluidity, whereas cholesterol molecules function to regulate membrane fluidity: at high temperatures cholesterol molecules stabilize the membrane, whereas at low temperatures intercalate between phospholipids, thereby preventing them from clustering together.
The answer is : A ) separate DNA fragments
The viral uses the host cell to make new viral parts .
Answer:
<h2>Ethylene is a gaseous hormone in plants, it is a fruit ripening hormone.</h2>
Explanation:
Ethylene is a chemical signal through which ripening fruits trigger the ripening process in fruits, Studies on components of ethylene signaling have shown a linear transduction pathway leading to the activation of ethylene response factors. However, the whole pathway by which ethylene selects the ripening-related genes and interacts with other signaling pathways to regulate the ripening process still not yet fully known. Most fruits produce ethylene that starts the ripening process. Its level in under-ripe fruit is very low, but as fruit develop, the production of ethylene become larger that speed up the ripening process of fruit.
