Biology Lab Exam 1

(Checks Lab/ Scientific Method) If a hypothesis becomes a theory, that theory is considered to be absolutely true. True False

False

(Microscope Lab) The brightness of the field of view does not change when you move to a higher power objective lens.

False

(Microscope Lab) When switching from one objective lens to another, you must always refocus the image using the coarse-adjustment knob.

False

(Microscope Lab) magnification- resolution-

magnification- zoom resolution- how clear

(Biomolecules Lab) What is a negative control? -A test substance that you know does not have the substance you are testing for -A test substance that you know does have the substance you are testing for -Neither of the above answers accurately describes a negative control. -No answer text provided.

- A test substance that you know does not have the substance you are testing for

(Lab Safety) Which of the following behaviors are not allowed in the laboratory? Choose all that apply. -Scare your friend -Have an early lunch during lab -Treat all reagents/ materials with caution and respect -Tickle your friend

-Scare your friend -Have an early lunch during lab -Tickle your friend

(Microscope Lab) What steps should you take before returning your microscope to the cabinet? Please place the following steps in the correct chronological order (i.e., steps 1-4).

1. Remove the slide from the stage, and ensure all objectives and the stage are clean. 2. Rotate the 4X objective into the working position, and raise the stage to its highest position. 3. Wrap the cord around the base, and replace the dust cover. 4. Using both hands, return the microscope to the cabinet.

(Lab Safety) If you spill or break something, what should you do? -Notify the instructor -Notify those around you -Obtain instructions for proper cleanup -Panic! -All of these answers -3 of these answers

3 of these answers are correct

(Microscope Lab) You view a specimen using the 40X objective lens. What is the total magnification of the image, with the magnifying power of the objective and ocular lenses combined? Assume the microscope is identical to the microscope used in the lab.

40x(10x) = 400x

(Checks Lab/ Scientific Methods) During the lab exercise, you randomly removed several checks and studied the information found on them. Which step(s) of the scientific method was/were modeled by this procedure? -Observation -Questions/ Research -Formulating hypothesis -A and B -B and C

A and B

(pH Lab) Which of the following provides an accurate description of pH? A. It is the negative log of the hydrogen ion concentration in a solution. B. It is a measure of acidity. C. It is the negative log of the hydroxide ion concentration in a solution. D. It is a measure of basicity.

A and B

(Biomolecules Lab) What is a positive Control? -A test substance that you know does not have what you are testing for -A test substance that you know does have the substance you are testing for -A positive control consists of pure water. -The second and third answers are both correct.

A test substance that you know does have the substance you are testing for

(Checks Lab/ Scientific Method) Which of the following choices were also illustrated by the checks lab exercise? -Science is often historical, gathering clues from past events. -Science involves sharing information with others, in order to achieve the best possible explanation. -Scientists are human, thus bias is always a factor. -Scientists will never know all of the facts or see all of the possible evidence.

All of the above

(Enzymes Lab) Enzyme activity can be affected by: -Temperature -pH -The concentration of enzyme and its substrate -All of the above -None of the above

All of the above

(Lab Safety) As a general rule, use ______ when performing laboratory procedures and when handling laboratory reagents and equipment. -Common sense -Caution -Appropriate protective gear -2 of the above -All of the above

All of the above

(Checks Lab/ Scientific Method) What is the best definition of a hypothesis? -A proven, unchanging explanation for a given phenomenon -An educated guess, based on the available data, for a given phenomenon -An explanation that is generally accepted as true, based on exhaustive testing -None of the above accurately define a hypothesis.

An educated guess, based on the available data, for a given phenomenon

(Biomolecules Lab) The Biuret reagent tested for the presence of protein in your food sample. Why were water and egg whites used as samples in this experiment? -Water served as a negative control, and egg whites served as a positive control. -Water served as a positive control, and egg whites served as a negative control. -Pure water contains no protein, while egg whites do contain protein.

Both 1 and 3 are correct

(pH Lab) Using the equation below to help you, please indicate the substance that you were most directly adding to the beaker when you exhaled through the straw. H2O + CO2 ---> H2CO3 --->HCO3- + H

CO2

(Checks Lab/ Scientific Method) Sharing and discussing your data with other groups illustrated the ____________ nature of the scientific process. -Historical -Factual -Collaborative -Biased

Collaborative

(Biomolecules Lab) A surfactant has both ________ and _________ groups and allows an _________ to form between two substances that are normally unmixable. -Hydrophobic, hydrophilic, detergent -acidic , basic, emulsion -Hydrophobic, hydrophilic, emulsion -No answer text provided

Hydrophobic, Hydrophilic, emulsion

(Osmosis Lab) given a chart be able to tell which solution is hypertonic isotonic and hypotinic

Hypotonic- water outside is more, water enters cell Isotonic- water inside and outside is equal Hypertonic- water outside is less, so water leaves cell

(Lab Safety) Where are the eyewash and safety shower? -By the fish tank -In the prep-room (301A) -Along the back wall -This classroom is not equipped with these items.

In the prep room (301A)

(Lab Safety) Which of the following is false: -Food and drinks are not allowed during the laboratory session -Closed toed shoes are required. -Long pants are not recommended. -Gloves and goggles are often required.

Long pants are not recomended

(Biomolecules Lab) If we could perform a qualitative (i.e., color change) test for the presence of nucleic acids in a sample, what substance could you use as a negative control? -Paper -pure water -apple juice -a lettuce leaf

Pure water

(Biomolecules Lab) The iodine potassium iodide (IKI) reagent is used to test for the presence of which biomolecule? -Nucleic Acids -Starch -Simple sugars -Proteins

Starch

(pH Lab) Which of the following substances is the most acidic? Distilled Water pH- 7 Ammonia pH- 11 Black coffee pH- 5 Stomach acid pH- 1

Stomach Acid pH-1

(Osmosis Lab) If a 20% sucrose solution is considered to be isotonic to the solution inside an egg, what would happen if that egg were placed in a 60% sucrose solution?

The egg would lose weight as water moves from inside the egg to the outside.

(Enzymes Lab) Why are enzymes referred to as "biological catalysts"? Please choose the BEST answer for this question.

They increase the rate at which biochemical reactions occur in a cell.

(Checks Lab/ Scientific Method) Why did the procedure require you to create multiple "tentative explanations" as new checks became available? -To model the reality that explanations can change when new information becomes available. -To ensure that at least one of your explanations was correct -To model that science is full of busy work -More than 1 of the above.

To model the reality that explanations can change when new information becomes available.

(Microscope Lab) To view a specimen, you must always start with the lowest power objective lens in the working position.

True

(Lab Safety) What is the last thing you should do before leaving the laboratory? -Wash your hands -Clean up your work area -Finish your snack -Finish your lab quiz

Wash your hands

(Enzymes Lab) The production of product by your newly discovered enzyme is not as high as expected. In order to identify the problem, you test the pH of the reaction solution and determine it to be at 7.5. What could you do in order to increase enzyme efficiency? Refer to the data in the previous question.

You could decrease the pH by adding a base

(pH Lab) Household ammonia (pH 11) is a/an ______. Seawater (pH 8) is a/an _______. _________ is more acidic. The more acidic solution is _______ times more acidic than the other solution (choose from 10/100/1000). This means that the more acidic solution has the indicated amount _______ (choose more or less) H+ ions.

base, base, seawater, 1000, more

(Microscope Lab) When initially bringing your specimen into view, the stage must be at its __________ position, gradually __________ the stage with the __________ adjustment knob until the specimen comes into focus.

highest, lowering, course

(Osmosis Lab) Referencing the previous question, which term most accurately describes the 60% sucrose solution (compared to the solution inside the egg)?

hypertonic

(Biomolecules Lab) Type of Carbohydrate Expected Color Change None No color change Starch No color change Maltose from blue to green Glucose from blue to red, yellow, or orange Given the above chart for the Benedict's test, can you determine whether starch is present in a given food sample?

no

(Enzymes lab) Similar to our lab procedure, you perform an experiment to determine the optimal pH for the function of a newly discovered enzyme. Given the following data, in which color intensity is an indication of the degree of enzyme function, what pH would you conclude is best for optimal enzyme function? Is this optimum pH considered acidic, neutral, or basic?

pH 4, acidic

(pH Lab) Which of the pH indicators used in the lab procedure is best to use if you want a quantitative (i.e. an actual value) measurement -Phenol Red -pH paper -Both indicators will provide a quantitative measurement. -Neither of the indicators will provide a quantitative measurement.

pH paper

(Osmosis Lab) Facilitated diffusion

the movement of molecules across a membrane, from higher to lower concentration, with aid of a protein channel or carrier protein.

(Osmosis Lab) Active transport

the movement of molecules against their concentration gradient

(Osmosis Lab) Simple diffusion

the movement of molecules down their concentration gradient

(Osmosis Lab) Osmosis

the movement of water across a membrane from high to low concentration.

(Osmosis Lab) In the osmosis lab, we worked with deshelled eggs placed in various sucrose solutions. What molecule moved across the egg membrane, resulting in the changes in the weight of the egg?

water