BI101 Homework Unit 1
BI101 Unit 1 Homework Assignment
ALL INSTRUCTIONS AND GRADING RUBRIC ARE POSTED HERE
Complete the following and submit the Word document by midnight Sunday. Remember to include complete citations for all sources used to answer each question.
- Explain how the following types of bonds are formed, and give an example of each:
- ionic bond
- covalent bond
- hydrogen bond
- Life as we know it could not exist without water. All the chemical reactions of life occur in aqueous solution. Water molecules are polar and are capable of forming hydrogen bonds with other polar or charged molecules. As a result, water has the following properties:
- H2O molecules are cohesive; they form hydrogen bonds with each other.
- H2O molecules are adhesive; they form hydrogen bonds with polar surfaces.
- Water is a liquid at normal physiological (or body) temperatures.
- Water has a high specific heat.
- Water has a high heat of vaporization.
- Water’s greatest density occurs at 4°C.
Complete the table below, illustrating how these properties of water above are related to the phenomena listed below. More than one property may be used to explain a given phenomenon. You also need to explain how each property is responsible for each phenomenon.
(e.g., A, B, C…)
|During the winter, air temperatures in the northern United States can remain below 0°C for months; however, the fish and other animals living in the lakes survive.||[[[[[[[||[[[[[[[|
|Many substances, for example, salt (NaCl) and sucrose, dissolve quickly in water.||[[[[[[||[[[[[|
|When you pour water into a 50-ml graduated cylinder, a meniscus forms at the top of the water column.||[[[[[||[[[[[|
|Sweating and the evaporation of sweat from the body surface help reduce a human’s body temperature.||[[[[[||[[[[[|
|Water drops that fall on a surface tend to form rounded drops or beads.||[[[[[[||[[[[[[|
|If you touch the edge of a paper towel to a drop of colored water, the water will move up into (or be absorbed by) the towel.||[[[[[[||[[[[[[|
3. In agricultural areas, farmers pay close attention to the weather forecast. Right before a predicted overnight freeze, farmers spray water on crops to protect the plants. Use the properties of water to explain how this works. Be sure to mention why hydrogen bonds are responsible for this phenomenon.
4. The following are pH values: cola-2; orange juice-3; beer-4; coffee-5; human blood-7.4. Which of these liquids has the highest concentration of OH-?
5. List the four major classes or groups of biologically important macromolecules and explain one reason for the importance of each.
6. Explain what denaturing of a protein is and what conditions might cause it.
7. Describe three differences between DNA and RNA.
The following Grading Rubric will be used to score your homework:
|1||Correctly describes the three chemical bonds explained and provides a good example of each.||0-6|
|2||Applies the properties of water to the various scenarios correctly.||0-6|
|3||Explains how water’s bonds work to protect crops from freezing.||0-2|
|4||Demonstrates an understanding of pH.||0-2|
|5||Clearly identifies the four important biological macromolecules and a reason for their importance.||0-4|
|6||Describes denaturation and its causes.||0-2|
|7||Identifies the three major differences between DNA and RNA.||0-3|