What is the true meaning of life?

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Discussion: The Scientific Approach

 
Why is the sky blue? Why do bees sting? Why is the ocean salty? These are questions a young child may ask about the world based on his or her observations and experiences. As children grow older, their inquisitive nature may begin to fade. Anyone involved in the scientific process, however, must continually make observations and ask questions about his or her observations. In addition, scientists suggest possible answers to their questions and then test their ideas to determine if they are correct. This process is known as the scientific method.
 
The scientific method, however, does not answer every question about the universe. For example, it cannot answer questions such as “Is there a god?” or “What is the true meaning of life?” As you begin your exploration of biology this week, you consider the nature of science and how the scientific approach to the world differs from others, such as philosophical or spiritual approaches. Then, you apply this understanding by identifying a situation in which you can apply the scientific method and a situation in which you cannot.
 
To prepare for this Discussion:
 

  • Consider the question posed by the Chapter 1 title of Biology: Science for Life: “Can Science Cure the Common Cold?” Think of a few additional questions science could answer. How do you think science might find answers to these questions?
  • Review Chapter 1, “Can Science Cure the Common Cold?” in Biology: Science for Life, and consider how the scientific method tests ideas and attempts to find answers to questions. For example,
    • What is a hypothesis?
    • How does an experiment test a hypothesis?
    • Why is the experimental process essential to science?

 

  • Review the articles in this week’s Required Resources.
    • In the article “The Nature of Science,” note the characteristics of scientific inquiry—that is, how scientists study phenomena to arrive at evidence-based conclusions.
    • Pay special attention to the Reality Check activity in the article “How Can We Tell Science from Non-Science?” Consider what distinguishes the scientific statements from the non-scientific ones.
      With these thoughts in mind:
      Post by Day 2 a 1- to 2-paragraph response to the Discussion Spark. Important Note: The Discussion Spark and the weekly Discussion topic below will be graded together. You will see one score in your My Grades area.
      Where would you go to search for scientific facts? How can you be sure the facts are based on science?
      Post by Day 4 two or more paragraphs that distinguish the nature of science from non-science and that explain how the scientific method can be used to answer a question or solve a problem.
      Your post should include the following:

 

  • Three characteristics of a scientific approach to the world
  • A real-life example of how the scientific method was or could be applied to solve a problem or answer a question
  • A real-life scenario that cannot be tested scientifically
  • References to at least two sources outside the Required Resources
  • All references cited in APA format

Do onion cells spend the same proportions of time in interphase and mitosis as reported in the Integrating Concepts of Biology textbook for a “typical eukaryotic cell cycle”

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Biology homework help
Instructions: Complete the following pre-lab activity prior to attending lab. You need to print and complete this document and turn it in by the beginning of lab on Thursday.
This week we will be using microscopes and professionally prepared/stained slides to identify the various stages of the cell cycle in onion root tip cells. We will differentiate between interphase (not specifically G1, S, and G2), prophase, metaphase, anaphase, and telophase/cytokinesis (lumped together). Our research questions are as follows:
Q1: Do onion cells spend the same proportions of time in interphase and mitosis as reported in the Integrating Concepts of Biology textbook for a “typical eukaryotic cell cycle” (See Table 3.5 in ICB)?
Q2: Does each stage of mitosis (i.e. prophase, metaphase, anaphase, and telophase/cytokinesis) require the same amount of time to complete?
It is important for you to understand that you will be using a slide that was prepared by taking a thin slice through an onion root tip (example image on right). All the cells were stained, and therefore killed, at the same time regardless of what stage of the cell cycle they were in. We will operate under the assumption that each cell divides whenever it is ready, and is therefore independent of what the cells around it are doing. Therefore, we can consider the cells seen in the slide to be a representative sample of all cells in the root tip. Under this assumption, we can estimate the proportion of time that cells in an onion root tip spend in a particular stage, based on the relative proportions of cells displaying any given stage at the moment the slide was prepared. For example, let’s assume that the cell cycle takes 24 hours (as it does Table 3.5 in ICB) and you are going to identify the stage of cell cycle for 24 cells on the slide. If 8 cells were in some stage of mitosis while 16 were in interphase, you might conclude that onion root tip cells spend 8 out of 24 hours undergoing mitosis, and 16 out of 24 hours in interphase.
Read the Chi-Square Test document so you understand how we can analyze data to answer the research questions listed above. Then, complete the questions below.
1.     Write at least two hypotheses (at least one per research question) that provides a tentative answer to each question above. Make sure the hypotheses have the necessary characteristics of being testable and falsifiable.
 
 
2.     Write a predictive statement (i.e. and if…then…statement) for each of your hypotheses from Question 1. These should be testable and should utilize information that you obtained from Table 3.5 in ICB, so that you can make a reasonably educated prediction.
 
 
 
 
3.     Describe an experimental design (e.g. a plan for the collection of empirical observations) that could be used to test each of your hypotheses.
 
 
 
 
 
4.     Identify the independent and dependent variables, and potential controls, for your experimental design.
 
 
 
 
5.     What values would you use for your expected values in a Chi-Squared Test of your experimental data collected according to question 3?
 
 
 
 
6.     Visit the page http://www.biology.arizona.edu/cell_bio/activities/cell_cycle/cell_cycle.html to become familiar with the appearance of cells in each stage of the cell cycle. Complete the identification of 36 cells, then create a data table below and record the number of cells in each stage.
 
 
 
 
7.     Use a Chi-Square table to compare your values with expected values based on an assumption that cells spend equal time at each stage listed in the table below (this is probably a bad assumption, but will serve our purposes here). Is your distribution of virtual data significantly different than the expected distribution (i.e. equal time in each stage)? **Hint: If I expected an equal number of emails to arrive on each day of the week, and I got a total of 70 emails during the entire week, I should expect 10 emails to arrive each day. (If only I were so lucky to have that few emails each day!!)

Design an experiment to determine the optimal temperature for enzyme function, complete with controls.

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Lab 4: Enzymes
ANSWER KEY
 
Pre-Lab Questions
 
1. How could you test to see if an enzyme was completely saturated during an experiment? (2 pts)
 
To test this, you’d simply see if the reaction was still taking place. If the enzyme was completely depleted, the reaction could no longer occur.
 
2. List three conditions that would alter the activity of an enzyme. Be specific with your explanation. (2 pts)
 
Temperature, salinity, and acidity are three conditions that affect enzyme activity. Specific examples include:
 
Adding a salt packet to an enzyme would alter its activity–salt ions are often necessary for optimal enzyme activity, so too much or too little salt will slow down the rate.
Enzyme activity increases with increasing temperature, until it becomes hot enough to denature the protein (enzymes are proteins), then the activity would cease.
Enzymes have an optimum pH where they function the best. Higher or lower pH than the optimum slows the rate of activity.
3. Take a look around your house and identify household products that work by means of an enzyme. Name the products, and indicate how you know they work with an enzyme. (2 pts)
 
Some examples include: contact lens cleaner (protease), dish soap (amylase), cheese
(rennin), meat (papain), and starch products (amylase).
 
The rest of the questions that are answered:
 
 
Experiment 1: Enzymes In Food
Data Tables and Post-Lab Assessment
Table 1: Substance vs. Starch Presence

Substance Resulting Color Presence of Starch?
Positive Control: Starch    
Negative Control: Student Must Select    
Food Product:    
Food Product:    
Saliva:    

 
 
 
Post-Lab Questions
1.    What were your controls for this experiment? What did they demonstrate? Why was saliva included in this experiment?
 
 
 
2.    What is the function of amylase? What does amylase do to starch?
 
 
 
3.    Which of the foods that you tested contained amylase? Which did not? What experimental evidence supports your claim?
 
 
4.    Saliva does not contain amylase until babies are two months old. How could this affect an infant’s digestive requirements?
 
 
 
5.    There is another digestive enzyme (other than salivary amylase) that is secreted by the salivary glands. Research to determine what this enzyme is called. What substrate does it act on? Where in the body does it become activated, and why?
 
 
 
6.    Digestive enzymes in the gut include proteases, which digest proteins. Why don’t these enzymes digest the stomach and small intestine, which are partially composed of protein?


 
Experiment 2: Effect of Temperature on Enzyme Activity
Data Tables and Post-Lab Assessment
Table 2: Balloon Circumference vs. Temperature

Tube Temperature (°C) Balloon Circumference (Uninflated; cm) Balloon Circumference (Inflated; cm)
1 – (Cold)      
2 – (RT)      
3 – (Hot)      

 
 
 
Post-Lab Questions
1.    What reaction is being catalyzed in this experiment?
 
 
2.    What is the enzyme in this experiment? What is the substrate?
 
 
3.    What is the independent variable in this experiment? What is the dependent variable?
 
 
 
4.    How does the temperature affect enzyme function? Use evidence from your data to support your answer.
 
 
5.    Draw a graph of balloon diameter vs. temperature. What is the correlation?
 
 
6.    Is there a negative control in this experiment? If yes, identify the control. If no, suggest how you could revise the experiment to include a negative control.
 
 
 
7.    In general, how would an increase in substrate alter enzyme activity? Draw a graph to illustrate this relationship.
 
8.    Design an experiment to determine the optimal temperature for enzyme function, complete with controls. Where would you find the enzymes for this experiment? What substrate would you use?

Discuss your opinion on how research on this topic should be funded.

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Biology homework help
Assignment 1: Biology Article
 
One purpose of this assignment is to help you become aware of how biology is related to your everyday life.
http://www.nytimes.com/2009/03/10/health/10well.html?_r=0
Write two to three (2-3) page paper in which you:
1. Summarize the above article in two (2) or more paragraphs, using your own words. Be sure to identify the article using an in-text citation in the body of the paper, as well as a reference in the reference section.
2. Explain how the article relates to this course. Identify which biological concepts from the course and / or text are relevant to the topic covered in the article. Citing the course text, discuss the ways in which this course does (or doesn’t) provide background information to help you understand the article and the larger issues surrounding it.
3. Explain why the article caught your attention. Relate the article to your life and to issues that are important to you. Discuss how or if the scientific knowledge about the topic covered in the article affects you directly or indirectly.
4. Discuss your opinion on how research on this topic should be funded. State whether you think taxpayer monies should support research on this topic or whether such research in this area should be funded by the private sector. Rate the importance of research on this topic, relative to other areas of research.
In addition to the target article, you should use at least two additional resources, such as your textbook or another article. You must have a reference section which contains an APA reference to your chosen article and all other sources. Additionally, you must provide in-text citations (in APA format) to your references in the body of the text. Integrate all sources into your paper using proper techniques of quoting, paraphrasing and summarizing, along with your in-text citations.
Your assignment must follow these formatting requirements:
• Be typed, double spaced, using Times New Roman font (size 12), with one-inch margins on all sides; citations and references must follow APA or school-specific format. Check with your professor for any additional instructions.
• Include a cover page containing the title of the assignment, the student’s name, the professor’s name, the course title, and the date. The cover page and the reference page are not included in the required assignment page length. The specific course learning outcomes associated with this assignment are:
• Use technology and information resources to research issues in biology.
• Write clearly and concisely about biology using proper writing mechanics.