Biology Qs

Ca2+ ions have two fewer electrons, giving them a positive charge. They are most likely to form ionic bonds.

Suspension: heterogeneous, solute un-dissolved and will settle (examples: blood, cytoplasm). Colloidal: solute equally distributed but not entirely broken down (examples: insulin, gelatin). Solution: solute entirely dissolved/evenly dispersed in solvent (examples: urine, synovial fluid).

Surface tension, caused by polar attraction between the different molecules.

DNA loses its structure and therefore ability to replicate without phosphorous. It is also essential for energy storage (ATP/ADP) and bone growth and health.

One way to make such a division is based on the function of these molecules within the body; lipids, proteins, and carbohydrates are all ingested and generally used as fuel for the body, whereas nucleic acids perform a different function. Molecular structure could also be used: nucleic acids, proteins, and lipids are all chain molecules, carbohydrates are not.

6)

The membrane is fluid in that various substances can pass through it, so it is not solid, and a mosaic because it is composed of many different heterogeneous elemnts.

7)

The mitochondria -- without supplying energy, none of the other cell functions could be carried out.

8)

Diffusion refers to the tendency of molecules to spread out evenly amongst each other due to their kinetic energy. Osmosis is the balancing out of the concentration of two solutions -- usually in water -- through a membrane.

9)

They could also be acting as clotting agents in the event of a cut/tear, or possibly isolate an area of weakness or infection through clustering around it.

10)

A red blood cell needs to be this permeable to facilitate the transfer of nutrients. It works because the body's salinity and blood concentration in general is kept very consistent by other organs/mechanisms.

11)

Homeostasis refers to the natural tendency of the body to maintain certain vital characteristics (temperature, acidity, etc.). Allostasis refers to achieving the same balance, but is a response to a large change in the balance of one or more of these aspects rather than to the constant subtle changes of homeostasis. In this way, allostasis can be seen as a way of restoring homeostasis.