Unit 1 Home Lab 1: Metric system

Unit 1 Home Lab 1: Metric system

Points: 40p

 

Name:

 

Purpose (4p)

 

 

 

 

Lab Summary (6p)

 

 

 

 

 

 

Lab Answers (14p)

1. Using a metric ruler, determine the length of the items in Table 1.1 below:

 

In the final column, you are to estimate your measurement precision. To do this, measure each item a second or even third time. How close are the measurements? If there is a range of values for the length you measure, record the average difference between measurement values as your uncertainty. If your measured value for a given object appears the same after repeated measurements, this does not necessarily mean that your uncertainty is zero. Look closely at your ruler or measurement device and estimate the smallest unit of length that you would be able to discriminate with it. Every measurement device has limits. For instance, very few people use a ruler with a precision greater than 1/3 or 1/2 of a millimeter; in many cases, even this precision is difficult or impossible to obtain. Typically +/- 1 mm is standard for measuring flat objects with a ruler, but this uncertainty can be expected to go up when the object has significant curvature or its length is not quite so well defined.

 

To measure the circumference (length around) of your head or thigh, wrap a piece of string around it and mark where the string meets itself. Then lay the string out flat and measure the length with your ruler.

 

Table 1.1. Metric measurements and uncertainties.

	meters	cm	mm	inches	Uncertainty ?
Your favorite shoe	.254	25.4	254	10	2.54
Your index finger	0.0762	7.62	76.2	3	7.62
A pencil	0.1524	15.24	152.4	6	1.524
Fingernail of your pinky	0.003175	0.3175	3.175	1/8	.3175
Width of a credit card
The circumference of your thigh
The circumference of your head

2. Measure and record volume in Table 1.2.

 

Estimate the rough volume of your head by using the circumference (denoted C) and multiplying out this formula (based on the volume of a sphere =4pr³/3 = C³/(6p²)):

 

Volume ? 1/59 × C × C × C = C³/59

 

Estimate the uncertainty in your head volume (?V, called “delta V”) calculation by using the uncertainty in your measurement of the circumference of your head (denoted ?C) and multiplying through the following formula:

 

?V ? 3/59 × C × C × ?C = 3/59 × C² × ?C

 

Table 1.2. Head volume and uncertainty estimates.

Circumference (C)	Uncertainty in Circumference (?C)	Head Volume   ? 1/59 C3	Uncertainty in Head Volume (?V) ? 3/59 × C2 × ?C

 

 

3. Complete the conversions in Table 1.3. The first row has been done.

 

Table 1.3. Length conversions.

Length	km	m	miles	feet
2.0 km	2.0	2,000	1.24	6,562
705 m		705
3.25 miles			3.25
300 ft				300

 

 

4. Complete the conversions in Table 1.4.

 

Table 1.4. Mass conversions.

Weight	kg	g	pounds (lbs)
5.0 kg	5.0
400 g		400
50 pounds			50

 

 

 

5. Complete the conversions in Table 1.5.

 

Table 1.5. Volume conversions.

Volume	liters	ml	gallons
6.0 liters (l)	6.0
600 ml		600
3 gallons			3

 

 

6. Complete the conversions in Table 1.6.

 

Table 1.6. Temperature conversions.

Temperature	°C	°F
100 °C	100
27 °C	27
-2 °C	-2
27 °F		27
95 °F		95
-40 °F		-40

 

 

7. Population biologists use the term “Doubling time” to refer to how long it takes a population to double in size. This concept is particularly useful when the average time for a given individual to reproduce is fairly constant in a species. Consider a bacterial population that can reproduce by dividing into two daughter cells (binary fission) from an original single individual cell. Assume a doubling time of ten minutes and fill out the following table. At time zero there is one bacterium, ten minutes later there are two bacteria, ten minutes after that there are 4 bacteria, etc. Fill in the blanks in Table 1.7.

 

Table 1.7. Population growth.

Number of Bacteria	1	8			First exceeds 10,000
Time	0	30 min	1 hour	2 hour

 

Unit 1 Home Lab 2: Enzymes

Points: 40p

Name:

Purpose (4p)

Lab Summary (6p)

Lab Answers (14p)

1. Fill in the following table. Compare all cups. Use relative terms to describe the size and number of bubbles in each cup. For instance, describe the Number of Bubbles using the terms: No bubbling, Moderate bubbling, Good bubbling, Very good bubbling. To describe average bubble size use the terms: Very small, Small, Large, or Very large. To describe pH without access to pH detectors, simply use the pH chart earlier in this chapter to describe each as acidic, neutral,or basic. To describe the Catalase Activity, use your data on the size and number of bubbles to estimate the amount of gas produced in the Catalase mediated process. Use the following terms: Very Low, Low, Moderate, High, Very high

 

Table 2.1. Catalase reaction observations.

Cup	Number of Bubbles	Size of Bubbles	pH	Catalase Activity
1
2
3
4

 

 

2. Bubbling indicates the formation of what chemical?

 

 

3. Describe the activity of Catalase as pH increases. Do you think that other enzymes are likely to behave in this way as well? Why or why not.

 

 

4. Assume that you have a pH meter which would enable you to very accurately measure the pH of a solution. Describe an experimental design that would allow you to pinpoint the exact pH at which Catalase is the most active.

 

 

5. Regarding cup #1:

a) Describe the utility of cup #1 as a control.

b) What other material did you introduce to this cup? Describe what you observed. How does Catalase activity in the material you investigated compare to potato?

Unit 1 Home Lab 3: Cellular Respiration

Points: 40p

Name:

Purpose (4p)

Lab Summary (6p)

Lab Answers (14p)

1. List the following experimental materials:

a) Kind of yeast used:

b) Kind of water used:

c) Average temperature of the water bath during the experiment:

d) Average room temperature during the experiment (estimate if necessary):

e) Duration of yeast solutions exposure to bath:

 

2. List your results in Tables 3.1 – 3.4.

 

Table 3.1. Independent variables and experimental conditions.

Bottle	Sugar	Yeast	Water	Yeast solution height (in cm)	To be heated in warm water bath?
1	1 teasp	2 teasp	¼ cup		No. Leave this bottle at room temp.
2	1 teasp	2 teasp	¼ cup		Yes.
3	1 teasp	2 teasp	¼ cup		Yes. Replicates bottle #2
4	1/3 teasp	2 teasp	¼ cup		Yes.
5	No Sugar	2 teasp	¼ cup		Yes.
6			¼ cup

 

Table 3.2. Observations of dependent variables.

Bottle	Balloon size	Yeast growth	Other observations
1
2
3
4
5
6

 

 

 

Table 3.3. Balloon size and solution height measurements.

Bottle	Circumference, C (cm)	Uncertainty in C, ?C	Radius (long axis, R; cm)	Uncertainty in R, ?R	New height of yeast solution (in cm)
1
2
3
4
5
6

 

 

3. In Table 3.4, record yeast growth and estimated volume of each balloon on Bottles 1-6.

 

a. Yeast growth = New height (in Table 3.3) – Original height (in Table 3.1)

 

b. If the balloon did not inflate, it has a volume of zero.

 

c. To estimate the volume of each balloon, use the following formula for the approximate volume of an ellipsoid with a horizontal circumference C and long axis radius R (from Table 3.3):

 

Volume ? 2/19 × (C × C × R)

 

d. To estimate the fractional uncertainty in the volume, use this formula:

 

?V ? 2 × (?C +?R) / C

 

Table 3.4. Yeast growth and balloon volume.

Bottle	Independent Variable	Yeast growth: (Change in solution height)	Balloon Volume (cm3)	Uncertainty in Balloon Volume estimate (?V)
1	No heating
2	Control 1
3	Control 2
4	1/3 teaspoon sugar
5	No sugar
6

 

 

4. Outline the experimental questions in this yeast activity (in a paragraph or two).

 

5. Describe what is measured by the balloon volume. How does it correlate with yeast growth?

 

6. Compare Bottles # 2 & 3. Are they very different? Discuss the utility of having a duplicate measurement when considering the precision of your experimental technique.

 

7. Compare Bottles # 1 to 2 & 3 and discuss the effect of temperature on cellular respiration in yeast.

 

8. Compare Bottles # 2, 3, 4, 5 and discuss the effect of sugar on cellular respiration in yeast.

 

9. Discuss results obtained with your experimental Bottle #6 in comparison with the other experimental conditions.

 

10. In a paragraph or two, describe your conclusions, thoughts about what you learned about cellular respiration, and/or things that went wrong.

Unit 1 Home Lab 4: Genetics and DNA

Points: 40p

Name:

Purpose (4p)

Lab Summary (6p)

Lab Answers (14p)

 

1. Describe what you can see in the final DNA extraction solution. Is the precipitant bubbly or stringy? Does it stick together or does it form many islands?

 

2. List your phenotype for the tongue rolling, ear attachment, and hitch-hiker thumb traits in Table 4.1. Use the following notation:

a) If you can roll your tongue, then your phenotype is R. If you cannot, then your phenotype is r.

b) If your earlobes are unattached, then your phenotype is U. If your earlobes are attached, then your phenotype is u.

c) If you do not have a hitch-hiker thumb, then your phenotype is H. If you do have a hitch-hiker thumb, then your phenotype is h.

 

Use the information above to determine your possible genotypes and record them in Table 4.1. Notice that the phenotype for a given trait is recorded with a single letter, whereas the genotype requires two letters per trait.

 

Then, using what you have figured about your genotype, infer the different possible genotypes that your parents could have had. For instance, if you determine that your possible genotype for earlobe attachment is UU or Uu,then the possible parental genotypes are:

 

Possible parents of UU: UU ×UU; UU ×Uu; Uu × Uu

Possible parents of Uu: UU ×Uu; UU × uu; Uu × Uu; Uu × uu

 

For this question, do not ask your parents about their phenotypes! You will do this in question 3. Question 2 is an exercise in inference based on your understanding of genetics.

 

 

 

 

Table 4.1. Personal phenotype and genotype; inferred possible parental genotypes.

Trait	Your Phenotype	Your possible Genotypes	Inferred possible parental genotypes
Tongue rolling (R or r)
Earlobe attachment (U or u)
Hitch-hiker thumb (H or h)

 

 

 

3. Complete Table 4.2 for you, any blood relatives that you can ask (i.e., parents, siblings, children, etc.), and at least five unrelated “Others” (e.g., spouse, friends, co-workers, etc.). As before, phenotypes for a given trait are recorded with a single letter. You may wish to report separately on your children and spouse in Table 4.3.

 

Table 4.2. Observed parental, sibling, and other’s phenotypes,

Trait	Mother’s Phenotype	Father’s Phenotype	Relatives’ Phenotype(s)	Others’ Phenotype(s)
Tongue rolling (R or r)
Earlobe attachment (U or u)
Hitch-hiker thumb (H or h)

 

 

In Table 4.2, are there any traits that are particularly common or uncommon among you and your relatives, compared to the unrelated others?