Lab Midterm Flashcards
In a controlled experiment, all variables are held constant except the one being tested.
True
When graphing your data, place the dependent variable on the_____axis.
Y
When utilizing the scientific method there are two types of variables. They are
dependent and independent
Match the following
Hypothesis
Experiment
Analysis
Report
Hypothesis
possible explanation to a problem
Experiment
carry out strategy chosen in hypothesis; collect measurements
Analysis
graph or make calculations
Report
sharing results
A(n)_________is a scientific test often carried out under controlled conditions.
experiment
In order to come to reliable conclusions about any lab experiment, you need to use
scientific method
Before you begin a scientific experiment, you should
record the data
report on the results
state a hypothesis
decide on a strategy for carrying out experiment
state a hypothesis
decide on a strategy for carrying out experiment
Formulating a true hypothesis is far less important than coming up with a good strategy to test the hypothesis.
True
When graphing data the independent variable should be placed upon the X-axis.
True
Match the steps of the scientific method to the correct number of the step.
Step 1
Step 2
Step 3
Step 4
Step 1
Hypothesis
Step 2
Experiment
Step 3
Analysis
Step 4
Report
Place the four methods of the scientific method in order.
Hypothesis-Experiment-Analysis-Report
How is a control group treated in a scientific experiment?
The control group receives all the same treatments except the experimental (independent) variable.
In an experiment determining the effects of antibiotics on the treatment of pneumonia in mice, two groups of mice with pneumonia are compared. One group, group A, receives no antibiotic, and the other group, group B, receives 10 mg/kg of body weight of a new antibiotic. Besides the administration of the antibiotic, there are no differences between the two groups of mice. What is the purpose of group A?
to calculate an approximate concentration of antibiotic to use in treating pneumonia in humans
In which phase of the scientific method is the strategy carried out and measurements collected?
experiment
What should your hypothesis represent?
a possible explanation for a problem or observation
Which question can you ask yourself to determine the dependent variable of an experiment?
What factors will I keep the same?
What is easiest to measure?
Which will I measure in the experiment?
Which factor in the experiment will change the least?
Which will I measure in the experiment?
When utilizing the scientific method, there are two types of variables. They are ______________________
dependent and independent.
When graphing your data, it is important that you _____________
place the independent variable on the X-axis.
Imagine that you wish to compare two different diets that will be fed to tadpoles raised in a lab. One diet is meat-based fish food, and the other is the traditional diet of boiled lettuce. You want to see if the meat-based diet will be associated with an increase in the average weight of the tadpoles. In your experiment, you keep all other factors, such as tadpole density per pan, temperature, pH, and the amount of food the same. The only difference between your control and experimental groups is the type of food the tadpoles receive.
What is the independent variable for the tadpole diet experiment?
diet
Some students consume large amounts of caffeinated drinks to help them stay alert when studying. You notice that many who engage in this practice seem to do poorly on exams. Suppose you want to investigate the relationship between caffeine consumption and exam performance. Which of the following statements would be an appropriate hypothesis?
Students who consume large amounts of caffeine while studying have lower exam scores than those who consume less caffeine.
Match the following numbers on the microscope to the name of the part.
part #1
arm
part #2
fine and coarse adjustment knob
part #3
base
part #4
eyepiece
part #5
revolving nosepiece
part #6
objectives
part #7
slide holder
part #8
stage
part #9
condenser
part #10
iris Diaphragm lever
part #11
light
Most cells are too small to be viewed with the unaided eye.
True
Which of the following biological samples can be viewed microscopically in a beginning lab type setting? Check all that apply.
DNA molecule
bacteria
algae
human body cell
plant cell
bacteria
algae
human body cell
plant cell
Please match the appropriate definition with the correct answer.
Magnification
Contrast
Resolution
Magnification
apparent increase in the image size
Contrast
ability to distinguish an object from the background
Resolution
ability to distinguish fine detail of an image
The ocular (eyepiece) lens magnifies the image
10x
Please match the objective lens with its appropriate magnification power.
4x
10x
40x
100x
4x
scanning power objective
10x
low power objective
40x
high power objective
100x
oil immersion objective
The total magnification of an image is determined by multiplying the power of the objective lens only.
False
Under which objective lens is the field of view the smallest?
4x
40x
100x
10x
100x
If you have a microscope with a 5x ocular lens and a 40x objective lens, what is the total magnification of the image?
200x
Which of the following parts of a compound microscope is adjusted to regulate the amount of light coming through the specimen?
revolving nosepiece
diaphragm
ocular lens
objective lens
diaphragm
Which of the following parts of a compound microscope is nearest the observer’s eye when using the microscope?
objective lens
revolving nosepiece
ocular lens
base
ocular lens
The lowest power objective of a compound microscope (and some microscopes don’t have this objective) has a magnification of
4x
Always begin examining microscope slides with which power objective?
high
low
This is a temporary preparation useful in viewing living organisms or tissues.
wet mount
At high power, always use which adjustment knob to focus the image?
fine
The pH of a substance can be measured by using pH paper or a pH meter.
True
Which of the following scientist first proposed the pH scale?
Watson
Crick
Sorensen
Pasteur
Sorensen
The term______refers to the chemical potential of hydrogen.
pH
The range of numbers on the pH scale would be
0-14
Identify the following as acidic, basic or neutral on the pH scale by matching.
Water
Battery Acid
Drain Cleaner
Vomit
Hand Soap
Soda
Blood
Orange Juice
Spit
Coffee
Milk
Chicken Soup
Water
neutral
Battery Acid
Acidic
Drain Cleaner
Basic
Vomit
Acidic
Hand Soap
Basic
Soda
Acidic
Blood
Basic
Orange Juice
Acidic
Spit
Basic
Coffee
Acidic
Milk
Acidic
Chicken Soup
Acidic
The pH of a neutral substance would be 6.
False
A substance when tested with pH paper indicates a pH of 4. Another substance yields a pH of 2. Which one is the more acidic?
pH2
A substance when tested with pH paper indicates a pH of 4. Another substance yields a pH of 2. Which one is the more acidic?
an acid
A substance with a pH value above 7 would be a base.
True
What are the main types of cells based upon presence or absence of nucleus? (choose all that apply)
bacteria
prokaryotes
eukaryotes
plant
animal
prokaryotes
eukaryotes
Plant cells often have a large membrane-bound sac that is used for storing water and other substances called
central vacuole
Match the structure to function
nucleus
Golgi
lysosomes
mitochondria
chloroplasts
vacuole
nucleus
instructions for protein synthesis and cell reproduction
Golgi
packages proteins for export from cells
lysosomes
digest worn-out organelles and cell debris, digest material taken up by endocytosis
mitochondria
“powerhouse” of the cell; ATP synthesis
chloroplasts
site of photosynthesis
vacuole
regulates water levels in plant cell
Prokaryotes lack a true______.
nucleus
All plant cells contain centrioles.
False
Examples of prokaryotes include: (choose all that apply)
bacteria
animals
Archaea
plants
bacteria
Archaea
When viewing Elodea under a microscope, what is the most likely identity of green, round structures inside of the cell?
chloroplasts
Ribosomes are the site of
protein synthesis
The specialized structure that stores pigments, water, inorganic ions and maintains turgor pressure is the
central vacoule
Which of the following is located outside of the cell membrane and provides structural support to plant and prokaryotic cells?
cell wall
Which structure surrounds the cytoplasm of the cell and separates the interior of the cell from the external environment?
plasma membrane
Which cellular structures were visible in the Elodea leaf viewed in the lab? (choose all that apply)
cell wall
chloroplasts
centrioles
central vacuole
cell wall
chloroplasts
central vacuole
Which function is associated with chloroplasts?
photosynthesis
The structure that easily distinguishes a plant cell from an animal cell is
chloroplasts
Which of the following are found in both plant and animal cells? (choose all that apply)
mitochondria
Golgi complexes
endoplasmic reticulum
chloroplasts
centrioles
mitochondria
Golgi complexes
endoplasmic reticulum
In simple diffusion, molecules move from an area of ____ concentration to an area of ____ concentration.
high; low
Since the cell membrane allows some molecules to pass through it and will not allow others, it can be described as ________.
selectively permeable.
In dialysis, the cleansing of wastes from the blood is achieved by _________________
simple diffusion across a semi-permeable membrane.
Proteins do not pass through plasma membranes because ____________________
they are very large molecules.
Following a meal, glucose must move from the gut lumen, where there is a high glucose concentration, through membrane proteins and into intestinal cells, where there is a relatively low glucose level. This movement is called ___________________
facilitated diffusion.
Chambers A and B are placed next to each other but are separated by a film similar to a cell membrane. Chamber A contains 80% carbon dioxide, and Chamber B contains 20% carbon dioxide. Which of the following will occur?
Some carbon dioxide will move from chamber B to chamber A.
Tonicity ___________
is the comparison of relative concentrations of two solutions, separated by a selectively permeable membrane.
Why is it a good idea to soak wilted lettuce in cool water before serving it?
The water is a hypotonic solution relative to the cytoplasm in the plant cells, so the plant cells will gain water, and the lettuce will become crisper.
When you receive fluid in the hospital, it is often a 0.9% saline solution. What would happen if the nurse used distilled water instead?
The distilled water solution would be hypotonic to your blood cells, so they would gain water, swell, and possibly burst.
When brown iodine is exposed to starch, it turns dark purple. In an experiment, you placed a cornstarch solution in a small bag made of dialysis tubing. Next, you placed the bag in a beaker of water containing ten (10) drops of iodine. If the solution in the dialysis tubing bag turned dark purple (Select all that apply)_______________.
the bag was selectively permeable.
the iodine moved into the bag.
the bag was permeable to cornstarch.
the cornstarch moved into the beaker.
the bag was permeable to iodine.
the bag was selectively permeable.
the iodine moved into the bag.
the bag was permeable to iodine.
