The light-dark cycle caused by the rising and setting of the sun is responsible for what are called circadian rhythms. These are biological processes that show a cycle of around 24 hours, the time between consecutive rising of the sun. Experiments have shown that without the external cue of sunlight, the circadian rhythms of organisms tend to break down. These can be reset by being re-exposed to these cues. Jet lag is due in part to a re-setting of the circadian rhythm, as you travel to a different time zone, your body has to become used to a different timing of night and day. <span> </span>
Does nature really hurt itself? does nature want to be ruined? if I would be a nature I will kick those people that have nothing to do but hurt me. Pollution is a result of human activities. it is a problem caused by many.
<span>The answer is B. The stolon are hyphae that run horizontally and join one sporangiophore (vertically oriented hyphae with sporangia at tips) –with rhizoids as the ‘roots’ - with the other sporangiophore in the fungi population. They are analogous to rhizoids in eukaryotic runner plants. The attached diagram visually demonstrates this <span>description.</span></span>
The four levels of protein structure are distinguished from one another by the degree of complexity in the polypeptide chain. A single protein molecule may contain one or more of the protein structure types: primary, secondary, tertiary, and quaternary structure. 1. Primary Structure: describes the unique order in which amino acids are linked together to form a protein.
2. Secondary Structure: refers to the coiling or folding of a polypeptide chain that gives the protein its 3-D shape. There are two types of secondary structures observed in proteins. One type is the alpha (α) helix structure. This structure resembles a coiled spring and is secured by hydrogen bonding in the polypeptide chain. The second type of secondary structure in proteins is the beta (β) pleated sheet. This structure appears to be folded or pleated and is held together by hydrogen bonding between polypeptide units of the folded chain that lie adjacent to one another
3. Tertiary Structure: refers to the comprehensive 3-D structure of the polypeptide chain of a protein.
4. Quaternary Structure: is the structure of a protein macromolecule formed by interactions between multiple polypeptide chains. Each polypeptide chain is referred to as a subunit. Proteins with quaternary structure may consist of more than one of the same type of protein subunit.
Answer: Nucleotides
Explanation: DNA is made up of molecules called nucleotides. Each nucleotide contains a phosphate group, a sugar group and a nitrogen base. The four types of nitrogen bases are adenine (A), thymine (T), guanine (G) and cytosine (C).
