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80 terms

Biology Lab Quiz 1

Definition of Science
the orderly process of posing and answering questions about the natural world through repeated and unbiased experiments and observations
Scientific Method (8)
1. Make insightful observations
2. Pose and clarify testable questions
3. Formulate hypotheses
4. Experimentation to gather data
5. Quantify data
6. Test the hypotheses
7. Refine hypotheses and re-test
8. Answer questions and make conclusions
Observation 1: Fungi often grow on leftover food
Observation 2: Fungi such as mold and yeast grow more on leftover bread than on leftover meat
Observation 2 is most useful for further investigations
Posing/Clarifying testable questions
Which nutrients can yeast most readily metabolize? --> What classes of biological molecules are most readily absorbed and metabolized by yeast? --> Does yeast absorb and metabolize carbs better than it absorbs and metabolizes proteins?
a statement that clearly states the relationship between biological variable
A good hypothesis (3)
* identifies the organism or process being investigated
* identifies the variables being recorded
* implies how the variables will be compared
hypothesis can never be ____ ____
proven true
null hypothesis
states that there is no difference and is testable; most common way to state a clear and testable hypothesis
A well designed experiment
links a biological response to different levels of the variable being investigated
levels of the variable
treatment variable
tested variable; independent
response variable
dependent variable
repeated measures of each treatment under the same conditions
controls (3)
standards for comparisons; verify that the biological response we measure is a function of the variable being investigated and nothing else; replicates with all of the conditions of an experimental treatment EXCEPT the treatment variable
Analyze data: mean
single number that represents the central tendency of the response variable; the average
simplest measure of variations; difference between smallest and largest (extreme measurements)
wide range
indicates much variation in the data
sum of squared deviations
E top N bottom i=1 ((measurement of individual sample) - (the sample mean)) squared
sum of squared deviations divided by N-1 where N= the total number of samples
standard deviation
helps to understand the spread or variation among replicated treatments; calculate the mean, calculate the deviation of each sample from the mean, square each deviation, then sum the deviations
Test the hypotheses: significantly different
the differences between means must be due to the treatment and not just due to natural variation; if so, hypothesis is rejected; usually done with statistical methods
Metric system
used virtually everywhere except the US; used to make measurements
1 cal
4.18 joules
1 joules
0.2389 cal
1 inch
2.54 cm
1 kg
2.2 pounds
1 gal
4 quarts
1 gal
3.8 liters
1 mi
1.6 km
1 quart
0.95 liters
1 pint
0.47 liters
1 ounce
28 grams
1 fl ounce
30 milliliters
1 ft
30.48 cm
1 yd
0.9144 m
1 cup
0.24 L
1 mi
5280 ft
1 kg
1000000 mg
1 ft cubed
28316.8466 milliliters
1 mL
1 cm cubed = 1 g
25 micrometers
2.5 times 10 to the -3 power cm
25 times 10 to the -4 power cm
10 to the -1
10 to the -2
10 to the -3
10 to the -6
10 to the -9
10 to the -12
10 to the 6
10 to the 9
basic unit of length
basic unit of volume
basic unit of mass
degrees C
basic unit of temperature
curved interface due to the surface tension and the adhesion of water to the sides of the cylinder
way to organize, summarize and describe data
the middle value of a group of measurements when arranged in order from greatest to least
consist of solute dissolved in solvent
substance dissolved in solvent
substance that dissolves solute
concentration of solute expressed as
percentage of total solution (weight/volume)
How many grams of sucrose would you dissolve in water for a total volume of 500 mL to make a 5% (weight/volume) solution?
500 X 0.05 = 25g
most common measure of concentration
standard measure of the amount of a chemical; one mole of any substance had 6.02 X ten to the 23 molecules
molecular weight
the sum of the atomic weights of its component element
1 M solution
contains one mole of a chemical in 1 L solution has 6.02 X 10 to 23 molecules
1 mM
in terms of milliliters
How many grams of NaCL (molecular weight = 58.5 g mole 10 to -1) would you dissolve in water to make a 0.5 M NaCl solution with 500 mL final volume?
58.5 X 0.5 X 0.5 = 14.625 g
Stock Solutions
solutions in concentrations
spreading a given amount of solute throughout a larger solution
initial vol X initial molarity = final vol X final molarity
How many mL of concentration (18 M) sulfuric acid are required to prepare 750 mL of 3 M sulfuric acid?
18(V) = (3M)(750)
V = 125 mL
H+ plus OH-
= 10 to -14
release H+ when dissolved in water therefore increasing concentration of H+ in solution; low pH number
remove H+ from solution therefore decreasing concentration of H+ in solution; high pH number
H+ increases
OH- proportionately less
pH =
-log [H+]
if pH goes up, concentration of H+
goes down
mixtures of a weak acid and a weak base that combine with a strong acid or strong base to limit changed in pH