# Bio Lab Exam #1

What is the difference between a positive control and a negative control?

POSITIVE CONTROL expects a positive resut, for example adding Benedicts reagent to a solution known to contain sugar like glucose, it changes color.
NEGATIVE CONTROL expects a negative result, for example adding the reagant to a solution known to NOT cont

How do you determine if a scientific source is reliable?

1. Gather further information, don't rely on just one report.
2. Understand and define all terms.
3. Question the methods used to derive the data.
4. Question the conclusions (are they based on the data collected)
5. Uncover any bias
6. Are the results co

What steps are included in a good experiment?

- Testability and Repeatability
- Proper Controls
- One Variable
- Sample Size
- Correlation and Causation

What is the difference between hypothesis and scientific theory?

A HYPOTHESIS is formed to explain observations in the natural world. The hypothesis may then be tested using the steps in the scientific method.
A THEORY is a broad and comprehensive statement about the world that is supported by the accumulation of a gre

Determine the control: Researchers set up an experiment to determine the amounts of different kinds of fat in the adipose tissue of 79 patients who had experienced heart attacks. These amounts were compared with the data for 167 patients who had not exper

EXPERIMENTAL GROUP: patients who had heart attacks
THEY ONLY DIFFER IN THE OCCURRENCE OF THE HEART ATTACK

Celsius to Fahrenheit
Fahrenheit to Celsius

c=5/9(f-32)
f=9/5(c+32)

Calculate Chi-Square (x2)

(observed-expected)2/expected

Degrees of Freedom

Number of variables - 1

Using the chi-square Values chart, determine if a hypothesis should be accepted or rejected?

Find 5% (p=.05) and if the chi-square is LESS THAN that number you ACCEPT your hypothesis because it will deviate on 5% of the time, but if it is GREATER THAN that number you would REJECT your hypothesis because it could deviate more than 5% of the time.

Benedict's Test

The presence of a yellow, orange, red, brown, or blue/green precipitate indicates the presence of a MONOSACCHARIDE. The darker the color the more monosaccharides are present.
POSITIVE RESULTS: Starch, Glucose, Prune Juice, Potato Slice, Glucose+A.A, Milk

Lugol's Test

A change to blue or black indicates the presence of POLYSACCHARIDES.
POSITIVE RESULTS: Starch, Potato Slice, Starch+A.A.
NEGATIVE RESULTS: Water, Glucose, Onion Juice, Glucose +A.A, Milk

Grease Spot Test

Tests for the presence of LIPIDS
POSITIVE RESULTS: Oil (stained)
NEGATIVE RESULTS: Water (disappeared)

Lipase Test

Test for LIPIDS
Note the color of the tubes after 1 hour, added 0.1 N HCI drop into the tube until the color changes pink.
TESTING FOR: tubes that showed a pH after 1 hour at 37 C and why?
POSITIVE RESULTS: Tube 2 that only had lipase in it
NEGATIVE RESUL

Biuret's Agent

Tests for the presence of protein, peptide bonds.
POSITIVE RESULTS: egg albumin
NEGATIVE RESULTS: water, starch, glucose, amino acid

Ninhydrin

Testing for amino acids. If amino acids are present the spot on the filter paper will turn purple.
POSITIVE RESULTS: Amino 1&2
NEGATIVE RESULTS: Water

Voltage Regulator

allows you to adjust the intensity of the light source

Condenser

concentrates the light on the specimen

Iris Diaphragm

controls the amount of light and together with the condenser affects the sharpness of the image

Objective lenses

magnifies the image

Ocular lenses

magnifies the image

Revolving nosepiece

allows you to change objective lenses

Diopter ring

allows you to adjust the focus of the left ocular lens independently of the right lens

Stage

holds the slide

moves the slide on the stage

Coarse focus knob

Fine focus knob

Things you should NOT do with a microscope

-use the coarse adjustment knob unless the 4X objective is in place -change objective lenses by rotating them
-decrease the distance between the lens and the slide when focusing - use anything except lens paper to clean lenses-remove eyepieces-touch lense

Things you should do with a microscope

-plug the microscope in and set the voltage regulator to about half its maximum intensity
-adjust the interpupillary distance and the diopter ring
-turn on the light and adjust the diaphragm
-be sure the smallest (4X) objective is in place before insertin

How do various objectives influence the diameter of the microscope field?

The diameter of the field decreases as the magnification increases. The decrease is the same factor as the increase. Example changing from 4X to 10X objective is an increase of 2.5 (4x2.5=10) so there is a decrease in diameter of 2.5

Gram Positive

Bacteria that stain purple to black and are more susceptible to penicillin. Gram+ are either rod or cocci (round) Example from lab S.epidermidis

Gram Negative

Bacteria that stain pink to red and more susceptible to streptomycin. Gram- are rods, coccus, or spiral. Example from lab E.coli

How did we test the different antibiotics and antiseptics?

1. Use a swab to gather bacteria from culture tube.
2. Wipe the swab onto the agar in the petri dish, swab the entire plate.
3. Repeat these steps with your 2nd petri dish
4. Place 4 antibiotic discs on petri dish 1
5. Choose 4 antiseptics (lysol,crest) f

Kingdom Protista

Amoeba and Volvox

Kingdom Plantae

Elodea leaf cells

Kingdom Fungi

Rhizopu

Dialysis Experiment

3 bags put in a beaker of distilled water for 60 min. Bag 1 10ml of distilled water, bag 2 10ml 10% sucrose solution, bag 3 10ml 20% sucrose solution. Weight before and after. All weight increased, but 20% sucrose the most. 20% solution was hypertonic so

Plasmolysis in Elodea

Placed elodea cells under microscope and viewed, then added hypertonic solution (5-10% NaCl) The chloroplasts clumped together in the center when the solution was added(hypertonic). Then added water again (deplasmolysis) until chloroplasts return to norma

Plasmolysis in Red Onion Cells

Took a piece of red onion epidermis and placed under microscope with a drop of water. Observed the vacuole and then added NaCl solution (hypertonic) which caused the water to rush out of the vacuole and it shrunk. When we added water (hypotonic) back to t

Plasmolysis in carrots

Filled 2 beakers, 1 with water and 1 with NaCl solution, placed carrot sticks inside. Carrots in the water remained stiff were hypotonic and remained stiff. Carrots in the NaCl solution became limp, hypertonic.

Effect of Molecule size on Diffusion

The rate of diffusion of large molecules is slower than that of small molecules.

Effect of Solute concentration on Osmosis

If the solute concentration is increased then the rate of osmosis will slow down

Rennin Experiment

ENZYME: rennin SUBSTRATE: milk
VARIABLE TESTED FOR: temperature
BASIC RESULT: Optimum temp is 37 degrees celsius

Urea Experiment

ENZYME: urease SUBSTRATE: ammonia
VARIABLE TESTED FOR: time for color change to occur
BASIC RESULT: The more enzymes added, the faster the solution changed from acidic to basic

Potato experiment

ENZYME: catalase SUBSTRATE: hydrogen peroxide
VARIABLE TESTED FOR: Changing the pH of the solution
BASIC RESULT: Activity is highest at lower pH

Jello experiment

ENZYME: pineapple SUBSTRATE: jello
VARIABLE TESTED FOR: did the jello set?
BASIC RESULT: Only one that set was the control, the boiled pineapple had been denatured

Chemiosmosis

Chemiosmosis is the diffusion of hydrogen ions (protons) across the biological membrane via the ATP synthase (a transport protein) due to a proton gradient that forms on the other side of the membrane. The proton gradient forms when the hydrogen ions accu

Phosphorylation

The creation of a phosphate derivative of an organic molecule. This is usually achieved by transferring a phosphate group from a TP. The process of adding a phosphate to a molecule, and occurs in RESPIRATION and PHOTOSYNTHESIS

Light Dependent Reactions (light dependent reaction)

Take place in the thylakoid membrane of chloroplast
1. Electrons used are generated by splitting water
2. When water is split, O2 is released
3. Solar energy is gathered by the pigments
4. As electrons travel down an electron transport chain, the energy r

Calvin benson cycle (light independent reaction)

1. 6 CO2 molecules enter the cylce and are used to make one glucose
2. The Calvin-benson cycle requires ATP and NADPH (from light dependent reactions) to make the glucose

Equation for Photosynthesis

6 CO2 + 12 H2O
LIGHT
C6H12O6 + 6O2
Photosynthesis has 2 parts:
1)light dependent reaction, 2) light independent reaction
Light dependent reactions convert solar energy to chemical energy (stored in ATP and NADPH)