Bio 111 Lab Exam 1

Exp 1: In spectrophotometry, [1] is the fraction of light that passes through the sample while [2] is the fraction of light that does not pass through the sample.

1 = transmittance 2 = asorbance

Exp 3: Place the following steps of aerobic respiration in order.

1. Glycolysis 2. Oxidation of pyruvate 3. Krebs/citric acid cycle 4. Electron transport chain

Exp 4: Place the movement of electrons in order through the light reactions of photosynthesis, from the molecule that is split to generate them to the molecule that will act as the final electron acceptor.

1. H2O 2. Photosystem II 3. Electron transport chain 4. Photosystem I 5. NADP+

Exp 2: Place the steps of measuring a sample's absorbance in order from 1-5.

1. Set wavelength on spectrophotometer. 2. Wipe the cuvette containing the blank and insert it into the spectrophotometer. 3. Adjust absorbance/transmittance dials till the readings are 0. (Then remove cuvette.) 4. Wipe the cuvette containing the sample and insert it into the spectrophotometer. 5. Record absorbance reading.

Exp 1: You have a stock solution that is 119 mg/mL and you need 10 mL of a working solution that is 33 mg/mL. What volume of stock solution will you need to dilute to have 10 mL of working solution at the above concentration? State your answer to two decimals and do not include units in your answer.

2.77

Exp 3: If you have a sugar with a molecular weight of 435 g/mol, how many grams would you need to add to 465 mL of water to create a 115 mM solution?

23.26

Exp 1: Match the following terms with their definitions (answers may be used more than once or not at all). Standard curve

A graph where properties of known samples are plotted.

Exp 1: Match the following terms with their definitions (answers may be used more than once or not at all). Molar weight

A measure of mass

Exp 1: Match the following terms and definitions (answers may be used more than once or not at all). Aliquot

A portion of something

Exp 3: Match the following experiment components to their role in the experiment. Respirometer

A tool to measure the consumption of gas.

Exp 3: What was the general procedure?

Activity 1: Determined the effect of temperature on respiration rate. Add KOH to dry beans and soaked beans.

Exp 1: For the experiment measuring concentrations of BSA using spectrophotometry, the blank will include which of the following?

All accept the BSA stock

Exp 2: How do changes in substrate concentration affect product production and enzyme activity?

An increase in substrate concentration causes an increase in product production/ the rate of reaction,but at a certain point the proteins start to denature and the rate goes back down again. This can be seen in my graph of the Relationship of the ONPG Concentration and Activity, as Activity increases as substrate is increased but then starts to go back down after a certain point.

Exp 1: Match the following terms and definitions (answers may be used more than once or not at all). Spectrophotometer

An instrument for measuring the amount of light that passes/does not pass through a sample.

Exp 1: Match the following terms and definitions (answers may be used more than once or not at all). micropipette

An instrument to measure and deliver very small volumes with high accuracy and precision.

Exp 3: Which of the following statements about cellular respiration are TRUE?

Anaerobic respiration produces fewer ATP than aerobic respiration.

Exp 2: How do changes in enzyme concentration affect product production and enzyme activity? Did you observe any limits to activity?

As enzyme concentration is increased, the rate of the reaction and enzyme activity is increased as well. Just like with substrate concentration, there reaches a point where denaturation starts to begin and the rate of reaction slows back down, except this is not seen in my graph because that point was not yet reached

Exp 2: What did the graphs show?

As substrate (ONPG) concentration increased, activity increased until a certain point where it started to decrease again. As enzyme volume increased, activity continued to increase.

Exp 2: Which of the following would not be expected to have an effect on the activity of ß-galactosidase?

BSA concentration Absorbance

Exp 1: Which of these reagents binds to protein to create a color change that you can measure?

Bradford reagent

Exp 2: What is the purpose of lysis buffer in the experimental reactions?

Breaks open cells by disrupting the cell membrane.

Exp 2: Which of the following are true about spectrophotometers?

Can measure how much light is absorbed by a solution. Can measure how much light passes through the sample (transmittance). Works by shining light of a specific wavelength through the sample.

Exp 4: Which microorganism will be used in this week's experiments?

Chlamydomonas

Exp 3: Match the following experiment components to their role in the experiment. dry beans

Control

Exp 2: Which of these statements are true about micropipettors?

Dispense very small and precise volumes of fluid. The first stop is used to draw the desired volume into the tip. Have a specific range of volumes which each size micropipette can handle. The second stop is used dispense fluid from the tip.

Exp 2: Which bacteria is the source of the enzyme used in this week's experiments?

Escherichia coli

Exp 3: Match the following experiment components to their role in the experiment. soaked beans

Experimental sample

Exp 3: Which sugar would work best for proofing (starting) yeast for baking? Why?

Glucose would be the best sugar because it can be directly used without any enzymes

Exp 1: Match the following terms with their definitions (answers may be used more than once or not at all). Accuracy

How close a result is to the correct/standard value.

Exp 1: Match the following terms with their definitions (answers may be used more than once or not at all). Precision

How variable a measurement is (for example, if you are measuring the same value on three occasions).

Exp 4: My hypothesis on the effect of DCMU and sodium azide on motility in Chlamydomonas:

I hypothesize that with DCMU, Chlamydomonas have motility because some photosynthesis is still able to happen. I hypothesize that with sodium azide, Chlamydomonas do not have motility because photosynthesis is not possible

Exp 4: Is it possible to record a wavelength for white light and dark? Why or why not?

It's not possible to record a wavelength for white light because it absorbs all colors. Black is also not able to be recorded because it is not a possible color of wavelength.

Exp 3: Match the following experiment components to their role in the experiment. Water bath

Keeps samples at a constant temperature.

Exp 2: What was the general procedure?

Lab Activity 1: Dilute ecoli culture and add to microcentifuge tubes and add lysis reagent. Transfer tubes to tubes with Z buffer. Add ONPG and record time until it turns yellow. Add sodium carbonate and record time. You are recording what happens when the substrate concentration is changed. Lab Activity 2: Repeat Activity 1 but change enzyme concentration instead of substrate.

Exp 3: During the process of glycolysis, the potential chemical energy released by the breakdown of glucose is stored as

NADH and ATP

Exp 1: Look at the final two values of your standard curve on the scatterplot, do they correlate strongly with the rest of your data? Why or why not?

No they do not correlate strongly because the second to last point is smaller than the point before and so the graph dips down, and then the last point is more than double the point before so it sky rockets up again.

Exp 4: Photosynthesis uses, releases, and produces different molecules. Use/release/production of which of the following causes the floating spinach disks measured in the photosynthesis and wavelength experiment?

O2

Exp 2: The subtrate is

ONPG (ortho-nitrophenyl-ß-galactoside)

Exp 1: elect the appropriate pipette to use for each of the following volumes. 340 µL

P1000

Exp 1: elect the appropriate pipette to use for each of the following volumes. 874 µL

P1000

Exp 1: elect the appropriate pipette to use for each of the following volumes. 15 µL

P20

Exp 1: elect the appropriate pipette to use for each of the following volumes. 57 µL

P200

Exp 4: Which of the following materials from this week's lab require special safety consideration (be more careful with them than normal!)?

Sodium azide DCMU

Exp 4: Which of the following statements about the Chlamydomonas experiment are TRUE?

Sodium azide is a metabolic poison inhibits the mitochondrial electron transport chain. Movement of Chlamydomonas will be used to test the effect of metabolic poisons.

Exp 4: Which are required for photosynthesis to occur?

Sunlight Water Carbon dioxide

Exp 4: In the wavelength and photosynthesis experiment, what is the purpose of the beaker left in the dark?

The beaker in the dark is a control because it has all the experiment components but photosynthesis should not occur without light.

Exp 1: Which statement correctly describes, in general, a blank used to 0 (zero) the spectrophotometer?

The blank includes everything in your experimental samples except what you want to measure.

Exp 1: What was your final R2 value? What does this tell us about the precision of your measurements?

The final R^2 value was .854. This is not very close to 1, so this tells us that the measurements were not very precise.

Exp 1: How does your determined concentration compare to the concentration of protein listed on the milk carton?

The milk concentration is 33.3ug/uL. The determined concentration is 213 ug/uL. Some errors that could have been made in the lab that caused this difference was not cleaning the cuvette, not using a blank,dilution calculation errors, etc

Exp 2: Are there any problems with the experimental set up for determining enzyme activity? How reproducible are the results (try comparing the variability of results within your lab)? What(besides technical error) could account for this variability, and how might one control for any extra variables?

The results are reproducible, but there probably will be some variability in the exact numbers of the measurements, seen in how the data that other students got varies. This could be due to several technical and nontechnical errors. Some examples are: during the spectrophotometer absorbance measurements, the cuvette was not wiped off properly or put in facing the right way or a blank may not have been used to calibrate it. When recording the time of the color change, errors could have been made by getting distracted and missing the first few seconds when it changes. Also, errors could have been made during the dilutions and not being precise enough with the micropipette. Some nontechnical errors that could have been made are the temperatures in the labs not being the same, as temperature could speed up or slow down a reaction. This could be controlled by making sure the temperature in all of the labs are kept constant

Exp 1: Match the following terms and definitions (answers may be used more than once or not at all). Cuvette

The tubes which hold sample inside the spectrophotometer.

Exp 3: Are these yeast using fermentation or oxidation to produce CO2? Briefly explain.

They are using fermentation. The buret is closed and there is little oxygen so the yeast is breaking down the sugar molecules to produce the CO2

Exp 1: What is the general procedure?

Used a pipette and measured protein vs absorbance and created a standard curve. Part B measured protein concentration in milk.

Exp 1: What happens to your R2 values if you exclude the last two values in the curve? Does that change the concentrations of your unknown? If so, which should you use to calculate the unknown concentration in milk?

When the last two values are excluded, the R^2 value goes up so it's more precise. It does not change the concentrations of the unknown. You should use the edited data without the last two points because it's more precise.

Exp 4: Select the wavelengths that will be tested for their effect on photosynthesis.

White light Green light Blue light Red light

Exp 4: Why was the white light and dark treatment included in the experiment?

White light and dark light were used as controls for this experiment.

Exp 3: Which microorganism will be used in the fermentation experiments?

Yeast

Exp 4:Did the data you collected in Table 2 support or refute your hypothesis? Why?

Yes, because in the tube with DCMU, the color shifted from the left side to being spread out evenly again as time went on, but in the tube with sodium azide, it stayed completely dark the whole time because there was no motility

Exp 2: Experiment 1 this week will examine the effect which substrate [a] has on enzyme [b]. Experiment 2 will instead vary [c] concentration. Both experiments will utilize the [d] to measure changes in [e].

a - concentration b - activity c - enzyme d - spectrophotometer e - absorbance

Exp 2: Enzymes bind [a], which fit into a spot called the [b]. The enzyme then [c] a biochemical reaction, [d] the rate at which the reaction takes place.

a - substrates b - active site c - catalyzes d - speeding up

Exp 1: When creating a serial dilution from 1/10 to 1/1000, the first dilution will be [a] part sample and [b] parts diluent (what you dilute the sample in). The second dilution will be one part [c] and nine parts [d]. The final dilution will be one part [e] and nine parts diluent.

a = 1 (one) b = 9 (nine) c = 1/10 dilution d = diluent e = 1/100 diluent

Exp 3: In general, a slight increase in temperature will [a] the rate of cellular respiration. This is most directly due to [b] increasing in [c] conditions.

a- accelerate b- enzyme activity c- warmer

Exp 3: [a] is an overarching term that includes all processes living organisms use to produce [b].

a- cellular respiration b- ATP

Exp 4: Photosynthesis results in the production of [b], which is the primary energy source in cells. The byproduct of photosynthesis is [a].

a- oxygen b- glucose

Exp 4: Which wavelength of light was most effective for photosynthesis?

blue light

Exp 2: Ortho-nitrophenol production can be measured with a spectrophotometer due to which of the following characteristics?

color

Exp 2: The colorless product is

galactose

Exp 4: Which wavelength of light was least effective for photosynthesis?

green

Exp 2: The product which you will measure via spectrophotometry is

ortho-nitrophenol

Exp 3: This week's experiment will examine cellular respiration by measuring [x] consumption. Meanwhile, any [y] produced by the cells will react with KOH (potassium hydroxide) to form non-gaseous molecules.

x- O2 (oxygen) y- CO2 (carbon dioxide)

Exp 1: The [x] is used when pulling the desired volume into the tip. The [y] is used to dispense the full volume out of the tip.

x- first stop y- second stop

Exp 2: The enzyme is

ß-galactosidase