Biology Midterm Flashcards
How many meters in 1 meter?
1 meter
How many meters in a centimeter?
10^-2
How many meters in a millimeter
10^-3
How many meters in a micrometer?
10^-6
How many meters in a nanometer?
10^-9
What do you use to measure liquid volume?
a graduated cylinder
If a 50mL graduated cylinder has 20mL in it, how would you read it?
look at the meniscus (dip) at the 20mL mark and make your eyes parallel to it
How would you calculate the volume of a solid object using a graduated cylinder?
inital mL in graduated cylinder minus the elevated mL of liquid+solid together
What kinds of lenses do compound light microscopes have?
ocular lens and objective lens at the same time
What does the compound light microscope help you see?
2D image of a thinly-sliced specimen
What is the magnification range of a compound light microscope?
40x to 1000x
Is the compound light microscope parfocal or parcentric?
it is both
What is parfocal?
once the object is focused on lower power, it is also focused on high power
What is paracentric?
object in focus remains in the center while changing objectives (magnification)
What is the ocular lens used for?
- where you place your eyes to observe the specimen
What is the magnification for the ocular lens?
10x
What is the nosepiece used for?
turning nosepiece moves objective lens into place over specimen being viewed
Where is the nosepiece located?
the rotating disk at the base of the body of the tube where different objective lenses are attached
Where are the objective lenses located?
mounted on the nosepiece
What are the objective lenses used for?
magnification of the viewed image
The longer the objective lens the higher the….
the longer the objective lens the higher the magnifying power
What is the working distance in the context of a microscope?
distance between the objective lens and the surface of slide
Why is oil used for in making a slide?
to eliminate air between lens and slide
Where is the stage located?
under the objective lens
What is the purpose of the stage?
to support the microscope slide
What is an aperture?
hole through which light passes
What is a mechanical stage?
stage that is able to be maneuvered manually for more accuracy
How many controls does the mechanical stage have?
2
Where is the condenser located?
small lens under the stage that directs the light through the speciman
What kind of knob does the condenser have?
condenser adjustment knob that moves condenser vertically
Where is the iris diaphragm located?
series of flat metal plates at the base of the condenser that slide together and create a hole in the condenser
What is the purpose of the iris diaphragm?
regulate the amount of light passing through the condenser
What does the iris diaphragm have?
diaphragm lever that is used to open or close diaphragm to adjust light
What is the first step in using the microscope?
SLOWLY move course adjustment (CA) knob downward until you come into focus
What is the second step in using the microscope?
Once you are in focus on 4X or 10X, YOU ARE AUTOMATICALLY IN FOCUS ON ALL OTHER POWERS! (This feature is called parfocalization)
What is the third step in using the microscope?
DO NOT touch CA knob anymore! If you do, you will lose your focus, and have to repeat the steps and run the risk of hitting the objective lens hitting your slide
What is the fourth step in using the microscope?
Using rotating nosepiece, simply dial-in any higher power objective you wish. High-power objectives will move closer to slide; objective will not hit the slide if you are in focus
What is the fifth step in using the microscope?
If you need to re-focus, use ONLY Fine Adjustment Knob
What is the first step of making a wet mount?
Place specimen on a slide and then add a drop of water or stain
What is the second step of making a wet mount?
Place a cover slip at an angle so that it touches drop of water
What is the third step of making a wet mount?
Slowly lower raised end of cover slip
What reagent tests for proteins?
biuret reagent
What color does the biuret reagent become?
from initial blue to light pink or violet
What is the immediate energy source for living organisms?
carbohydrates
What is the building block of carbohydrates?
monosaccharides
What is 2 monosaccharides linked together?
disaccharide
What is more than 2 monosaccharides linked together?
polysaccharide
What are the energy storage polysaccharides?
starch and glycogen
What reagent tests for starch?
Iodine potassium iodide
What color does iodine potassium iodide reagent become?
tea color to blueish black color
What reagent tests for simple sugars?
Benedict’s solution (5 drops needed) and heating
What colors does benedict’s solution become?
yellow to green to orange to red
What reagent tests for lipids?
sudan red IV
What color is sudan red IV?
red or orange
What indicates the presence of a lipid?
two layers, red on top and white on bottom
What are all cells surrounded by?
plasma membrane
What is the cytoplasm?
semifluid medium inside cell
What do chromosomes do?
carry genes
What do ribosomes do?
make proteins
What do prokaryotes have the eukaryotes don’t?
single circle of DNA
What do eukaryotes have that prokaryotes don’t?
cell wall, cell membrane, flagella, ER, mitochondria, microtubules, centrioles, Golgi complex, nucleus, chloroplasts, vacuoles
At the start of the diffusion lab, what was inside the dialysis tubing and on the outside?
clear glucose and starch solution on the inside of the bag and water + iodine potassium iodide reagent (amber color)
At the end of the diffusion lab, what was inside the dialysis tubing and on the outside?
inside the tubing was black specs at the bottom with a blue/black color and outside the tube the color became less yellow (positive for glucose)
Why did the starch stay in the dialysis tubing but iodine moved in?
Iodine diffused into bag because solution inside bag turned dark blue.Iodine is a smaller molecule than starch, therefore, iodine is more likely to pass through the semipermeable membrane
Why did the glucose go outside the dialysis tubing?
Glucose will be present in the beaker and in bag. It diffuses from a higher concentration to a lower concentration in the beaker and it is a small molecule that can cross the membrane
What happens to a cell in hypertonic solutions?
the cell shrinks
What happens to a cell in hypotonic solutions?
the cell bursts
What happens to a cell in an isotonic solution?
no change in cell volume
What solution is used to keep animal blood cells stable?
NaCl aka saline solution
What percentage does NaCl have to be in order for it to be isotonic with red blood cells?
0.9%
What percentage does NaCl have to be in order for it to be hypertonic with red blood cells?
greater than than 0.9%
What is crenation?
when red blood cells shrink and shrivel up
What percentage does NaCl have to be in order for it to be hypotonic with red blood cells?
less than 0.9
What is hemolysis?
when red blood cells swell and burst
What is the tonicity of plant cell water?
hypotonic
When placed in a hypotonic solution, what happens to the plant cell?
central vacuole gains water and exerts turgor pressure, the cytoplasm including chloroplasts are pushed up against the cell wall
What solution of NaCl does a plant cell need to be hypertonic?
10%
If a plant cell is placed in a hypertonic solution, what happens?
central vacuole loses water, Cytoplasm including chloroplasts, pulls away from cell wall
What does the effectiveness of antiacids do?
Test the ability of OTC (over the counter) products to absorb excess H+
In the enzyme lab, what is enzyme is involved in the degradation of hydrogen peroxide?
catalase
What does catalase break down?
hydrogen peroxide (H2O2)
What is released from the breakdown of hydrogen peroxide?
water and oxygen
In the tube with the catalase and hydrogen peroxide, why did the reaction work?
Substrate and enzyme are both present
In the tube with the water and hydrogen peroxide, why didn’t the reaction work?
enzyme not present
In the tube with catalase and sucrose solution, why didn’t the reaction work?
correct substrate not present
How do you increase the number of enzyme-substrate formations?
increase amount of enzyme per amount of substrate
Once all the substrate is bound to the active site, what happens?
reaction will no longer accelerate with increasing enzyme concentration
When does the enzyme activity increase in relation to substrate concentration?
when substrate concentration increases
When is the max rate achieved with enzymes?
when all active sites of an enzyme are filled with substrate•Increased substrate concentration after this point will not increase rate of reaction
What is it called when all enzymes have been occupied with a substrate?
the enzyme is saturated
When does enzyme activity increase in relation to temperature?
when temperature increases because higher temperatures cause more effective collisions between enzymes and substrates
What happens to enzymes when the temperature increase beyond a certain point?
enzyme activity levels out•Loss of enzyme structure and function occurs = denaturation•Loses 3D shape (tertiary structure)
How can pH affect enzyme structure?
Extremes of pH can denature an enzyme by altering its structure and thus its function because Affects hydrogen bonding and enzyme changes shape, leading to reduced enzyme activity•Disrupts 3D shape = denaturation
What do BOTH eukaryotic and prokaryotic cells have in common?
plasma membrane, DNA, ribosomes, cytoplasm
What the formula/equation for the breakdown of hydrogen peroxide?
catalase
2 H O ———> 2 H O + O
2 2 2 2
