Bio201 Lab Review Exercise worth 8 points KEY Lab Section 001 Due Friday November 15th at 12 noon Directions Answer the questions below in this document and save a copy entitled BIO201 Review Exercise YOUR NAME then e mail in a copy to me iec1896 uncw edu This exercise is due Friday November 15th at 12 noon via e mail with the subject line Bio201 Review Feel free to e mail it in early At noon on Friday I will e mail out a key with all the answers so you can check to make sure you understand all the questions and concepts Feel free to work with others in your class consult your notes lab manual or textbook while working on this exercise this is to help you review While you may work together and consult resources on this exercise as always make sure all your answers are in your own words If you copy directly from a book or someone else you are plagiarizing and you will not receive credit for the exercise While there isn t a question on this exercise that asks you to graph data make sure you can graph data by hand I suggest reviewing all the graphs you made for your exercises to see what you got points off for so you don t make the same mistakes on the exam 1 Using the graph below calculate rate of reaction Show how you get your answer Absorbance as a Function of Time 0 9 0 8 0 7 Absorbance 0 6 0 5 0 4 0 3 0 2 0 1 0 0 2 4 6 8 10 Time min Rate slope of a line rise run change in y change in x 12 14 We will use the points marked in red and purple for our calculation but any two points can work Change in y 0 8 0 38 0 42 Change in x 12 4 8 0 42 8 0 0525 min 1 units are per minute Note that values determine from graph are approximate For the y value of the purple point values such as 0 39 and 0 4 are also acceptable If you used slightly different values or different points you may have gotten a slightly different rate but it should be around 0 05 2 Using the graph below how much of substance X would be in a sample that had an absorbance of 0 4 Explain describe how you got your answer In order to determine the amount of substance X there is in a sample with an absorbance of 0 4 we use the Beer Lambert Law The Beer Lambert Law states that absorbance is proportional to concentration of a solution or amount of solute All we need to do is find 0 4 on the y axis absorbance and find where our line of best fit the diagonal black line crosses this value The corresponding x value is the amount of substance X present in this case 0 74 Again values near this such as 0 75 are acceptable 3 What is a standard curve A standard curve is the relationship shown graphically between the amount of a substance and the absorbance of a wavelength of light in other words the graph from question 2 is a standard curve 4 What is an absorbance spectrum An absorbance spectrum is how much light of varying wavelengths a substance absorbs In other words it s a graph of absorbance as a function of wavelength for a particular substance 5 What is a control in an experiment Why do we use a control A control is what we compare our experimental trials to it is identical to experimental trials except for the variable being manipulated In the control trial the manipulated variable or independent variable is kept at normal ambient or zeroed conditions The control trial allows us to determine that the results we see in our other trials are due to the variable we manipulated 6 What does a low pH reading mean vs a high pH reading Are there more or less H ions in each situation A low pH reading means that there are more H ions in than a solution with a higher pH A solution with a low pH is more acidic than a solution with a high pH 7 How many more H ions are in a solution with a pH of 8 vs a pH of 10 A solution with a pH of 8 has 100 times more H ions than a solution with a pH of 10 a pH increase of 1 on the pH scale indicates a 10 fold increase in the number of H ions 8 What is a buffer A buffer is a solution whose pH changes very little when a strong acid or base is added to it 9 What are the three things that can occur when light hits a solution Light can be either absorbed reflected bounced back which is the color we see when we look at an object or transmitted passes through 10 What does the spectrophotometer measure The spectrophotometer measures absorbance of a defined wavelength of light unitless 11 State and explain the Beer Lambert Law The Beer Lambert Law A abc or Absorbance absorptivity coefficient path length concentration The Beer Lambert Law demonstrates that concentration of a solute in solution is linearly proportional to the amount of light that solution absorbs 12 What are the four types of biological molecules What are the biological purposes of each The four types of biological molecules are carbohydrates lipids fats proteins and nucleic acids Carbohydrates are primarily for burning for energy and energy storage Fats are primarily for energy storage Proteins primarily serve as enzymes Nucleic acids carry code for genetic information 13 Which of the 4 types of biological molecules did we learn to test samples for in this lab course Fats reducing sugars proteins and starch 14 Define quantitative and qualitative What is the key difference between these two terms Quantitative tests measure something specific resulting in a value Qualitative tests gather information without measuring something i e noting color 15 Label the indicated part of the microscope in the image below 1 2 3 5 4 6 7 8 9 10 11 12 13 1 Ocular lens 2 Body tube 3 Revolving nosepiece 4 Arm 5 Objective lens 6 Course focus adjustment knob 7 Stage 8 Fine focus adjustment knob 9 Stage adjustment knobs 10 Iris diaphragm 11 Light power switch 12 Condenser 13 Illuminator 16 What type of microscope is this This is a compound light microscope 17 Briefly describe the best way to focus a compound microscope 1 Place your slide on the stage center it and make sure the ocular lenses are a comfortable distance apart for your eyes and that the light source is not too bright but still illuminates that stage 2 Make sure you are using the objective lens with the lowest magnification and use the course focus adjustment knob to bring the lens as far as possible from the slide 3 Look through the ocular lenses and slowly turn the course …