BIOL 1011 Midterm

Which biological molecule is composed of long chains of hydrocarbons and is water‑insoluble?

lipids

Why is an experiment usually repeated at least three times?

to demonstrate that the results are due to the independent variable and not something else

Select the items that will be located on the three shelves behind the workbench.

1. Instruments 2. Materials 3. Containers

Select the lab instruments that will be used to quantify a chemical reaction.

1. Pressure gage 2. Thermometer 3. Balance

Identify the characteristics of science and the scientific approach to the study of the world around us.

1. Testable 2. Reproducible 3. Falsifiable

The specificity of an enzyme is determined by its three‑dimensional shape. Which environmental conditions can affect an enzyme's shape?

1. temperature 2. pH

Which photosynthetic organism is to be used for this laboratory?

Elodea

Select the organisms that contain food vacuoles for digestion.

- Amoeba - Paramecium

Complete the statement describing Experiments 1 and 2 of the Photosynthesis lab. The rate of photosynthesis and cellular respiration of an Elodea plant specimen will be quantified by measuring the net amount of __________ produced or consumed by the plant in __________.

1. oxygen 2. maximum light and in the dark

Select the foods that supported weight gain in mice.

1. raw steak 2. apple slices 3. cooked steak

Select the essential inputs needed by plants for photosynthesis.

1. water 2. carbon dioxide 3. sunlight

Which cell type contains the organelles required for photosynthesis?

Spirogyra

Which solution should be used to test for the presence of lipids?

Sudan III solution

Which statement is true about the active site present in enzymes?

The active site increases the rate of product formation.

Which part of a plant primarily absorbs the light that powers photosynthesis?

leaves

Which of the following solutions can be used as a negative control for all the biological molecule assays?

water

In Experiment 1, a student measures 7.46 mL7.46 mL of oxygen (O2)(O2) produced at 20 °C20 °C and a light intensity of 5. In Experiment 2, the student measures 1.38 mL1.38 mL of oxygen (O2)(O2) consumed at 20 °C20 °C and a light intensity of 0. What was the total volume of O2O2 produced by the process of photosynthesis in the Elodea branch?

8.84 mL

What is the equation used to calculate the total optical magnification?

total optical magnification = ocular power x objective power

How will the enzyme activity be measured in the experiment?

the amount of oxygen gas produced

In the biological molecule assays, which solution requires heating to near boiling to produce a color change?

Benedict's solution

Trypsin is an enzyme that breaks proteins into smaller peptides by cleaving the proteins at the amino acids arginine and lysine. If trypsin is added to albumin, what test would show that the enzyme was working?

Biuret solution, which would be purple when only albumin was present, would change to a pinkish purple after trypsin broke some bonds and peptides accumulated.

What is the role name for photosynthetic organisms in ecosystems?

producers

In setting up Experiment 2, a student inadvertently adds 10 mL10 mL of 3% H2O23% H2O2 instead of 5 mL5 mL to the test tube that already contains 5 mL5 mL of water. This gives the student a total volume of 15 mL15 mL of diluted H2O2H2O2 solution in the test tube. Calculate the final concentration of H2O2H2O2 in the test tube.

H2O2H2O2 concentration = 2

Classify each phrase as describing either the light‑dependent or light‑independent reactions of photosynthesis.

Light-Dependent Reactions: - uses sunlight - uses chlorophyll - uses water - produces oxygen gas Light-Independent Reactions: - uses carbon dioxide - produces carbohydrates

Which statement describes carbohydrates?

compounds containing aldehydes or ketones with at least two hydroxyl groups that function as an important source of energy as well as a structural component in plant cell walls

Which of the foods tested in Experiment 5 (Biological Molecules) contains lipids?

whole milk

Fill in the number of each reactant and product in the summary equation of photosynthesis. ____CO2CO2 + ____ H2O⟶H2O⟶ ____ C6H12O6C6H12O6 + ____ O2

1. 6 2. 6 3. 1 4. 6

A researcher is maintaining Coleus plants in a temperature- and light‑controlled growth chamber that gets no outside light. The researcher must maintain the health of the plants but does not want the plants to grow much larger over time. The researcher is going to grow the plants at 30 °C30 °C and a light intensity setting of 4. The researcher wants to calculate the minimum number of hours of light at setting 4 that are needed so that the consumption of sugar and oxygen (O2)(O2) by respiration will not exceed the production of sugar and oxygen by photosynthesis. The average rate of O2O2 consumption by respiration in these plants at 30 °C30 °C is 2.50 mL/hour.2.50 mL/hour. The average rate of O2O2 production by photosynthesis in these plants at 30 °C30 °C and light setting 4 is 17.25 mL/hour17.25 mL/hour (this value is total O2O2 output not counting what is used by the plants in respiration). For how long should the researcher expose the plants to light each day to maintain plant health without causing further growth?

3.5 hours

A student adds another temperature, 50 °C,50 °C, to the experiment that examines the effect of temperature on the rate of photosynthesis. At this temperature, there is no change in gas volume in the syringe during the 60 minutes. Why was no O2O2 gas produced at 50 °C?

The enzymes needed for photosynthesis become denatured at high temperatures.

How does the three‑dimensional shape of the enzyme impact enzymatic activity?

Enzyme shape determines the type of substrate that binds the active site.

Identify the one rule for performing experiments in the laboratory.

Everything revolves around containers.

Identify the Experiment 1 procedure that will be used to determine that a reaction has taken place.

Observe that the temperature in the flask has gone up following the addition of the second chemical.

Sort the different cell types that will be viewed during the lab according to their category: plant, animal, or protist.

Plant: - onion root Animal: - cardiac muscle - cheek cells Protist: - amoeba - paramecium - euglena

Identify the procedure that would determine the precise optimal temperature for catalase function.

Test O2 production using narrower temperature intervals between 21.5 °C and 60 °C.

Which statement describes the relationship between air volume in the sealed flask and the air pressure?

There is an inverse relationship between the air volume in the sealed flask and the air pressure.

Complete the statement by identifying the plant light box settings for Experiment 1. The plant light box in Experiment 1 must be set to a time of ____ minutes, a temperature of ____, and light intensity setting of ____.

1. 120 2. 20 C 3. 5

Salivary amylase acts on starch to break it down into the disaccharide maltose. If salivary amylase was reacted with 2% starch solution until the starch was completely digested, which test results would be expected?

1. Benedict's test: red 2. Lugol's iodine: no color change

Arrange the steps that should be done when the experiment is finished from first to last step.

1. Empty each used container into the waste container under the sink. 2. Place each empty container into the sink. 3. Return instruments to the Instruments shelf. 4. Complete and submit the lab assignment.

Select the mechanisms that indicate a chemical reaction has occurred.

1. Formation of a precipitate 2. Release of gas bubbles 3. Change in mass or volume 4. Change in color 5. Change in temperature

Select the PPE items that are required for entering the virtual laboratory.

1. Gloves 2. Goggles 3. Lab coat

Arrange the steps needed to add a specific volume of a solution to a flask from first to last.

1. Go to the Containers shelf and click the arrows to view all contents of the shelf. 2. Click the appropriate item on the Containers shelf and drag it down to the workbench 3. Go the the Materials shelf and click the arrows to view all contents of the shelf. 4. Click the appropriate solution bottle on the Materials shelf and drag it down to the container on the workbench. 5. In the pop-up window that appears, type the required volume of the solution into the text box and click add. 6. Observe the liquid that appears at the bottom of the flask.

What temperature is optimal for catalase function?

40 C

Using the microscope that is used in this lab with a 40X40X objective lens, a scientist views a cell. What is the total optical magnification of that cell?

400x

In this lab (Photosynthesis), you measure the net rate of gas exchange for the combined processes of photosynthesis and cellular respiration by measuring oxygen volume using a gas syringe. Why are you able to specifically measure the volume of oxygen in these experiments?

Carbon dioxide is highly soluble in water, whereas oxygen is relatively insoluble in water.

In the virtual laboratory simulations, how do you add a substance to a container?

Drag the substance from the shelf to the container and release it.

As the volume of gas decreases in the sealed flask, the air pressure is expected to increase. True or False?

True

Select the definition of a hypothesis.

a possible explanation or outcome that is both testable and disprovable

In Experiment 1 (Scientific Method), which food source provided the most weight gain in the mice?

apple slices

Like many enzymes, catalase functions across a range of pH values. A student performs an experiment to determine the pH at which catalase functions the most quickly and efficiently. The target pH value is the pH optimum. What additional pH buffers should the student test to determine the pH optimum for catalase?

buffers with pH 7, 8, 9, and 11

Which type of cell has a membrane-bound nucleus and is divided into organized and membranous internal compartments?

eukaryotes

If you tested a glucose solution and a sucrose solution using Benedict's solution, what might the contrasting colors be and why?

glucose, a reducing sugar, is red. Sucrose, a nonreducing sugar, is blue.

Which of the foods tested in Experiment 5 (Biological Molecules) contains the least amount of protein?

onion juice

Match each description to the appropriate buffer based on the buffer's pH value.Each buffer may have more than one applicable description.

pH = 1 - most acidic - highest H ion concentration pH = 5.5 - moderately acidic pH = 7 - neutral pH = 7.4 - slightly alkaline pH = 13 - most alkaline - highest OH ion concentration

Which of the foods tested in Experiment 5 (Biological Molecules) contains starch?

potato juice

Recall Experiment 3. Explain the observation of a net loss of mass from the flask by the end of the reaction between HCl and zinc.

the loss of some of the hydrogen gas

Complete the statement. Based on the total amount of magnification required to observe at least one or more entire cell in the field of view, the __________ is the largest cell type of the cells examined, and only __________ magnification was needed to fill the field of view.

1. Amoeba 2. 10X

Which food sources were experimental treatments in this lab?

1. Apple slices 2. Raw steak 3. Uncooked macaroni

In Experiment 3, what was the maximum temperature reached after 25 g25 g of zinc was added to a flask with 100 mL100 mL of 6 M6 M HCl?

21.5 C

What maximum temperature did the mixture reach after adding the 1 M NaOH to the 6 M HCl?

26.7 C

Match the type of cells with the description of the exterior structures.

A cell wall made of cellulose: - onion root - Spirogyra Appendages for locomotion: - Amoeba - Paramecium - Euglena Neither a cell wall nor appendages for locomotion: - Human cheek cell

Which statement best illustrates a scientific hypothesis for the lab (Scientific Method)?

The mouse gains the most weight from apple slices.

Sort the statements according to whether they describe a positive or a negative control.

Positive Control: - Expected to react to experimental treatment - A negative result indicates an experimental error Negative Control: - Does not receive experimental treatment - A positive result indicates an experimental error

Sort the statements according to whether they represent qualitative or quantitative data.

Qualitative: - Students in the front of the classroom like homework more than students in the back. - Red roses have the strongest scent of any color rose. Quantitative: - The control subject showed no change in weight during the experiment. - Body temperature over 37 degrees Celsius indicates a fever.

A student performs the experiment examining catalase activity, but increases the concentration of H2O2 from 3% to 6% while keeping the concentration of catalase the same. How would using a higher concentration of H2O2 affect the amount of O2 gas produced in the first 15 seconds? Why?

The amount of O2 gas produced would not change significantly because all of the catalase active sites would already be occupied by the substrate, H2O2.

According to your data from Experiment 3 (photosynthesis lab), how did varying light intensity affect the rate of photosynthesis?

The rate of photosynthesis increased as the light intensity increased, approaching a maximum rate at light intensity 4.

A student compares their Experiment 3 results with the results obtained by two classmates. After adding 25 g25 g of zinc to the flask with the HCl, they discover that their results differ from those of their classmates. The student observed a peak temperature of approximately 36 °C36 °C and a final mass of almost 127 g127 g. Both classmates observed a peak temperature of roughly 87 °C87 °C and a final mass of just over 135 g135 g. Identify the most plausible explanation for the difference in the student's and their classmates' results.

The student used the 1 M HCl solution rather than 6 M HCl solution.

What happened to the solution in the flask when NaOH and HCl were mixed?

The temperature of the solution increased right away.

What is the positive control in the experiment to assess food sources and weight gain in mice?

cooked macaroni

Which of the given options is the source of the carbon dioxide utilized by the plant for photosynthesis?

sodium bicarbonate

If a mouse in the three-day experiment gained 3.9 grams from start to finish, what was the average daily weight gain?

1.3 grams per day

In experiment 3, what was the maximum temperature reached after 0.25 g of zinc (Zn) was added to a flask of 100 mL of 6 M hydrochloric acid (HCl)?

22.6 C

Which equation summarizes the reaction being measured in the experiment examining catalase activity?

2H2O2 + catalase --> 2H2O + O2 + heat

How many replicates of an experiment are typically performed?

3

Using the data from Experiments 1 and 4 (photosynthesis lab), which temperature resulted in the greatest production of oxygen gas?

30 C

You are observing a cross-section of animal tissue. Under the 100X objective lens, you count 11 cells from one side of the field of view (FOV) to the other. You remember that the FOV under the 100X objective lens is 0.2 mm0.2 mm. What is the diameter of an individual cell?

18 um

Complete the statements discussing variables in the scientific method. The use of variables in an experiment allows scientists to draw conclusions from the data by removing unrelated effects that could skew the results. The _________ variable is the parameter that is manipulated by the scientist, such as the amount of a reagent added or the time a bacterial colony is incubated. The ________ variable is the parameter that is being tested and measured. In the case of the previous examples, this variable could be the amount of reactant produced or the change in bacterial colony size over time.

1. Independent 2. Dependent

A student investigates the relationship between the volume and pressure of a gas by sealing an Erlenmeyer flask and then adding 10 mL of water to it. Identify possible explanations for no observable change in air pressure during the experiment.

1. Leak in the experimental set-up 2. Failure to close the flask

Place the steps of the scientific method in their typical order (according to the sequence presented in the introduction to the lab).

1. Observation 2. Question 3. Hypothesis 4. Experiment 5. Evaluation

A student realizes that his calculations for mouse weight gain or loss do not match the expected results. Analyze the student's experimental data from the table. Which statements could possibly explain the student's unexpected results?

1. One of the mice lost weight instead of gaining weight as expected 2. The students misread his notes, mistakenly exchanging a "7" and a "1" 3. the student was unaware that one of the mice had a metabolic illness

Place the steps for each experiment examining catalase activity in order from first to last.

1. Prepare a test tube with the hydrogen peroxide solution 2. Add catalase solution to the test tube. 3. Immediately insert a gas syringe 4. Pause the lab and record the gas volume in the syringe 5. Restart the lab for exactly 15 seconds 6. Pause the lab again and record the second volume of gas in the syringe

Select the descriptions that accurately describe the protist cells viewed in the lab.

1. Protists are very diverse in their structural components because, as unicellular organisms, they carry out all life functions. 2. Protists are typically larger than other types of eukaryotic cells.

Complete the statements describing the variables in this lab experiment. In this lab, mice will be fed a variety of different foods to determine the best food for weight gain. The independent variable for this experiment is __________. The dependent variable for this experiment is __________.

1. The choice of food provided. 2. The weight change of each mouse.

Complete the statements. Proteins are polymers of __________ linked together by __________ bonds whereas starch and glycogen are polymers of __________ joined together by __________ bonds.

1. amino acids 2. peptide 3. glucose 4. glycosidic

Arrange the five colors according to the amount of reducing sugar they indicate in a test with Benedict's reagent. Begin with the color indicating the lowest amount of reducing sugar.

1. blue 2. green 3. yellow 4. orange 5. red

Complete the statements. Reducing sugars __________. An example of a reducing sugar is __________.

1. can undergo a redox reaction 2. lactose

Please complete the sentence describing the reaction that will be observed in the simulation. This procedure involves observing how the enzyme, __________, affected the substrate,__________. This reaction yields the products __________.

1. catalase 2. hydrogen peroxide 3. water and oxygen

If you observe a live cell moving under the microscope, what structure might be producing the motion? Select all that apply.

1. cilia 2. pseudopodia 3. flagella

Select the common structures of eukaryotic cells that can be distinguished using the light microscope.

1. cytoplasm 2. plasma membrane 3. nucleus

Enzymes are globular proteins that are critically important in many chemical reactions. Select the true statements about enzymes.

1. enzymes catalyze, or speed up, biochemical reactions 2. enzymes are not used up or changed during reactions 3. enzymes lower the activation energy needed for reactions

Select the products that photosynthesis creates.

1. glucose 2. oxygen

Select the options that indicate when you know that you have increased the microscope's magnification enough

1. maximum magnification has been reached 2. a single cell fills the field of view

Which foods tested in Experiment 5 (Biological Molecules) contain large amounts of reducing sugars?

1. onion juice 2. skim milk 3. whole milk

Select the types of cells that are examined in this (Cell Structure and Function) lab.

1. plant 2. protist 3. animal

Please complete the statement. Undiluted Lugol's iodine appears __________, whereas Lugol's iodine mixed into a starch solution appears __________.

1. reddish-brown 2. dark blueish-black

Which types of molecules does whole milk contain?

1. reducing sugars 2. protein 3. lipids

Select all the data that should be recorded for each type of cell viewed.

1. shape 2. color 3. total magnification 4. cell structure present 5. size

Select the kinds of cells that can photosynthesize.

1. some single-celled protists, such as euglena 2. plant cells 3. green algae

Which of the following biological molecules will be tested for in this (Biological Molecules) lab?

1. starch 2. proteins 3. sugars 4. lipids

Which factors affecting the rate of photosynthesis will be examined in Experiments 3 and 4 (photosynthesis lab) ?

1. temperature 2. light intensity

Identify the three environmental factors that will be examined in the experiment examining catalase activity.

1. temperature 2. substrate concentration 3. pH

What conclusions about the catalase enzyme can be drawn from this experiment?

1. the catalase enzyme is inactive at pH 2 2. catalase functions over a broad pH range

Please complete the statement. Biuret solution turns __________ when it comes in contact with __________.

1. violet 2. proteins