Phases or components
Your textbook describes two
sequential phases of interaction between organisms and their environments that
have existed since god's creative work began. Organisms interact with their
environments in different ways. Different organisms of a biological community cooperate
and compete for habitats and share the resources in that habitat.
Diatoms are made of silica (hydrated silicon dioxide)
Answer: It means to guide and regulate chemical and physical parameters to keep your body or environment in a constate state for proper functioning.
Explanation: This is called homeostasis. The body has systems in place to monitor its components such as cells, organs and any other molecule needed to maintain life and good health. The body needs to maintain its temperature at 37°C, pH of blood at 7.4, water balance, osmotic pressure, growth rate and tissue repairs whenever it dictates the need, danger of infection or injury.
All of these form an integral part of a healthy living organism and it needs to always be stable, regulated and monitored. This is called maintaining homeostasis.
I remember the secondary structure by visualizing it. Understand that primary structure is just the order of the amino acids. The tertiary structure is the 3dimensional configuration of the whole protein molecule with multiple interactions guiding its fold (disulfide bonds, ionic interactions, hydrogen bonds, van der walls). Secondary structure is a step towards the conformation of the protein where it is made up of either alpha-helices or beta-pleated sheets. The alpha helices look like a spiraling staircase while the beta-pleated sheets look like a repetition of long loops. These two structures hold itself by hydrogen bonds.