Lab 1 Exam Flashcards
What are the base unit in the metric system for length, mass, and volume?
-Length: meter (m)
-mass: grams (g)
-volume: liter (L)
What are common metric prefixes and their values?
(Not all but common)
-Kilo- (k): 1,000 (10³)
-Centi- (c): 0.01 (10⁻²)
-Milli- (m): 0.001 (10⁻³)
-Micro- (μ): 0.000001 (10⁻⁶)
-Nano- (n): 0.000000001 (10⁻⁹)
What are the main parts of a compound microscope?
-Ocular lens (eyepiece): Magnifies the image.
-Objective lenses: Different magnifications (4x, 10x, 40x, 100x).
-Stage: Holds the slide.
-Coarse and fine focus knobs: Adjust clarity.
-Light source: Illuminates the specimen
-Condenser: Collects and focuses light from the light source into the specimen.
-Iris diaphragm lever: Controls the opening of the diaphragm/controls the amount of light passing through/contrast.
What are the three objective lenses?
Scanning lens (4x)
Low power lens (10x)
High power lens (40x)
What is the ocular lens magnification?
10x
-4x objective lens times 10 ocular = 40x
-Low power lens 10 x 10 = 100x
-High power lens 40 x 10 = 400x
How to obtain degree of magnification?
Multiply the ocular magnification by the objective lens magnification
What organelles are unique to plant cells?
-Chloroplasts: Photosynthesis.
-Cell Wall: Provides structure.
-Large Central Vacuole: Stores water and nutrients.
Explain the cell lab.
We maceration and added sucrose to peas, centrifuged them and examined a green layer which is cholorplast and a sandy layer which contains the nuclei.
Difference between prokaryotic and eukaryotic cells:
Prokaryotic Cells:
-No nucleus
-No membrane-bound organelles
Eukaryotic cells:
-Has organelles (mitochondria, ER, etc.)
-has nucleus
Define Diffusion
The movement of molecules from high to low concentration until equilibrium is reached.
Define Osmosis
Diffusion of water across a selectively permeable membrane.
What happens to a cell in a hypertonic solution?
Water leaves the cell. Cell shrinks called (plasmolysis in plants and crenation in animals),
What happens in a hypotonic solution?
Water enters the cell. Cells expand, called swelling or turgor, or cytolysis.
What happens in a isotonic solution?
No net water movement. Cell stays the same size.
Explain the cellulose bag experiment.
The cellulose bag showed us how diffusions by a molecular level works and how size affects diffusion. The bag consisted of 5% gluçose 1 % starch. The small glucose monosaccharides were able to move into the water but the polysaccharides of starch had to stay inside of the bag since it is too big to exit the semipermeable membrane.
In what percent concentration did the elodea leaves become hypotonic, hypertonic, and isotonic?
-0.1 % became hypotonic
-0.9% became isotonic
-2.7% became hypertonic
What is the purpose of the anthocyanidin experiment?
To test pH levels by using anthocyanins (pigments in plants) as natural pH indicators.
What color changes indicate pH levels in anthocyanin solutions?
Acidic (pH < 7): Red/Pink
Neutral (pH 7): Purple
Basic (pH > 7): Green/Blue
How is serial dilution used in this experiment?
Serial dilution allowed us to take a highly concentrated solution of acid and base and diluted it into 4.5 ml of water to create different pH concentrations
What happens to anthocyanins in acidic vs. basic solutions?
-In acidic solutions, they donate H⁺ ions (red).
-In basic solutions, they gain OH⁻ ions (blue/green).
What were the different concentrations for the anthocyanin lab?
0.1, 0.01, 0.001, 0.0001 for both HCl and NaOH
The HCl started off very red then become purple
The NaCl starts purple then becomes green but not yellow indicating there is not a strong base present
What is an enzyme?
A biological catalyst that speeds up chemical reactions by lowering activation energy.
How do temperature and pH affect enzyme activity?
-Too high temperature: Denatures enzyme (loses shape, stops working).
-Too low temperature: Slows enzyme activity.
-Optimal pH: Each enzyme has a specific pH range; extreme pH levels denature enzymes.
What was the purpose of the enzyme lab?
To manipulate size, temperature, and pH to see how they affect the reaction rate of enzymes in beef liver.
What are the effects of size on enzyme activity?
Enzyme size is fixed because they are proteins with a specific shape.
However, Larger substrates may have difficulty fitting into the active site, reducing reaction rates
smaller substrates may fit more easily and increase reaction rates and this is due to its higher surface area-to-volume ratio.
What is the effect of pH on enzyme activity?
Each enzyme has an optimal pH at which it works best.
Too acidic or too basic leads to the active site shape changing resulting in enzyme losing function.
What is independent variable?
The variable that is manipulated or changed in an experiment.
-plotted on x-axis
What is the dependent variable?
The variable that is measured and affected by the independent variable.
-plotted on the y-axis
How can you remember which variable goes on which axis?
The independent variable is on the x-axis (think: “I” for input), and the dependent variable is on the y-axis (think: “D” for data or depends on x).
How do you identify the independent and dependent variables in an experiment?
Ask yourself:
What am I changing? (Independent variable)
What am I measuring? (Dependent variable)
In a graph showing how temperature affects the time it takes for ice to melt, what are the independent and dependent variables?
-Independent variable = Temperature (x-axis)
-Dependent variable = Time to melt (y-axis)
