Saturday, November 05, 2005

Chapter 2 Insights and Objectives

This chapter teaches us the minor chemistry of Biology- the SPONCH elements are crucial to know. The properties of water are also important. Have a passing knowledge of the different types of bonds.
2.1.1 State that the most frequently occurring chemical elements in living things are carbon, hydrogen and oxygen.
The most frequently occurring chemical elements in living things are carbon, hydrogen and oxygen. (SPONCH)
2.1.2 State that a variety of other elements are needed by living organisms including nitrogen, calcium, phosphorus, iron and sodium.
A variety of other elements, including nitrogen, calcium, phosphorus, iron and sodium (Maggies SPONCH CaFe) are needed by living organisms. (don't forget magnesium!)
2.1.3 State one role for each of the elements mentioned in 2.1.2:
Nitrogen- Part of DNA
Calcium-Strengthens bones and teeth
Phosphorus- Used in ATP, the energy of cells
Iron- binds Oxygen in Hemoglobin!
Sodium- Transports nerve impulses to nerve cells
2.1.4 Outline the differences between an atom and an ion
An atom has the same amount of protons as electrons, so it is neutral in charge. An ion has either a positive or negative charge because there are unequal numbers of electrons and protons. A positive ion is called a cation, while a negative ion is called an anion. (from Nease IB Biology)
2.1.5 Outline the properties of water that are significant to living organisms, including transparency, cohesion, solvent properties and thermal properties. Refer to the polarity of water molecules and hydrogen bonding where relevant.
- Water is transparent, allowing light to permeate its surface, allowing aquatic plant life to conduct photosynthesis.
- Water is cohesive, as the hydrogen bonds hold water together due to their polar properties. This allows surface tension on water.
- Water is a good solvent. Its H bond pull most polar molecules apart. It dissolves many organic and inorganic material.
- Water molecules are unable to more due to H bonds. Since heat is the measurement of cell movement, water does not heat very quickly or well. This high specific heat (the heat at which it change states) has sustained stable habitats to many organisms, because large amounts of energy is required to heat up and water and change its state.
2.1.6 Explain the significance to organisms of water as a coolant, transport medium and habitat, in terms of its properties. (Verbatim from Nease)
Water's high specific heat allows it to absorb large amounts of energy and act as an insulator for all living things. For example, our bodies use water in the for of sweat to lower body temperature. The sweat absorbs a large amount of heat, and then evaporates carrying that heat away from the body.


Anonymous Anonymous said...

This was very helpful.

3:49 AM  

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