This site is 100% ad supported. Please add an exception to adblock for this site.

Biology Lab Mid Term


undefined, object
copy deck
Scientific Method
Make Observations
State Key Questions
State Hypothesis
State Predictions
Conduct Controlled Experiment
Analyze Results
Form Conclusions
What are the 3 variable conditions?
Independent Variable (the condition that is being evaluated for its effect on the dependent variable
Dependent Variable (a factor whose values in different treatment conditions are compared)
Controlled Variable (all other conditions that could affect the results but do not because they are controled by being kept constant)
What are the 2 pars?
Experimental group is exposed to the independent variable

The control group is not expeosed to the independent variable.
What is a solvent?
The dissolving agent of the solution. Water is the most versatile solvent known - a liquid in which chemicals dissolve
What is a Solute?
A substance that is dissolved in a solution - the chemical being dissolved
What is a solution?
the result of adding the solvent and the solute together
What is a Basic Solution?
A solution that has a higher concentration of hydroxide ions than hydrogen ions. A pH of 7 -14
What is an Acidic Solution?
A solution that has a higher concentration of hydrogen ions than hydroxide ions. A pH of 0-7
What is a pH scale?
pH means the potential for hydrogen. A pH scale is the negative logarithm of the hydrogen ion concentration in an aqueous solution
Describe the pH scale?
0-7 Increasingly acidic
1. Battery Acid
2. Digestive juice (stomach acid) lemon juic
3. Vinegar, beer, wine, cola
4. Tomato Juice
5. Black coffee/rainwater
6. Urine
7 (Neutral) Pure Water/Human Blood
8. Seawater
11. Milk of Magnesia
12. Household Ammonia
13. Household Bleach
14. Oven Cleaner
What is a buffer?
A chemical solution that helps to decrease large changes in pH.

A buffer controls the level of acidity or basicity in a solution. If an acid or base is added to a buffer solution, there is hardly any change in pH.
Describe Water
Water is a polar solvent meaning that anything will dissolve in it.

Water molecules are attracted to each other by cohesion and to other molecules by adhesion
What is Cohesion?
the binding together of like molecules often by hydrogen bonds.
What is Adhesion?
the attraction between different kinds of molecules
What is Capillary Action?
cohesion and adhesion lead to capillary action. Capillary action is very important for the movement of water into many living organisms.
What is Specific Heat?
measures how easily the temperature of that substance is changed. it is the number of calories required to change the temperature of 1 ml of the substance 1 degree C
What is the calculation used to measure specific heat?
#ml (of water) x (change in temperature) = # of calories added
What is Heat of Vaporization?
a measure of how much energy is required to convert a substance in liquid phase to gaseous phase.
When is water most dense?
Water is more dense in its liquid phase than in its solid phase. Ice floats.
What is Benedict's Reagent?
A reagent used as a test for the presence of monosaccharides such as glucose and fructose. It is also used for some disaccharides like maltose, more generally for the presence of aldehydes in a solution.
What are the expected results for the Benedict's test?
Benedict's solution + Starch - negative (blue color)

Benedict's solution + partially digested starch - ++ slightly positive (greenish blue color)

Benedict's solution + digested starch ++ partially positive (yellow-orange color)

Benedict's solution + completely digested starch +++ positive (red brick color) (precipitate)
What is an Iodine Test used for?
The Iodine Test is used to test for the presence of starch. Iodine dissolves in an aqueous solution of potassium iodine reacts with the starch producing a deep blue/black color.
What are the expected results for the Iodine Test?
Iodine + starch +++ positive (blue/black color)

Iodine + partially digested starch ++ partially positive (purple/red color)

Iodine + almost completely digested starch + slightly positive (brown-red-orange)

Iodine + completely digested starch - negative (yellow color)

Iodine + no starch - negative (yellow Amber color)
Microscope - What is field of View?
the circle of light that you see when you look through the eyepiece. Where you can see as much of your specimen at one time.
What is a Unicellular cell?
(single cell) with living functions (respiration, digestion, reproduction and excretion) handled by that one cell. Maybe autotrophic (photsynthetic) or heterotrophic (deriving food from other organisms or their by-products)
What are Aggregates?
Random temporary aggregates or clusters of cells
What are colonies?
clusters composed of a consistent and predictable number of cells
What are complex colonies?
have physiological connections and specialization of groups of cells.
What are Multicellular Organisms?
Organisms that have a large number of cells with specialized structure and function with no one cell existing successfully by itself.
What are Daughter Colonies?
small spheres within the larger colony.
What is Diffusion?
A process whereby molecules/particles move from an area where they are inhigh concentration to an area where they are in low concentration.
Influence by temperature control and concentration
What is Passive Transport?
The free flow of water and certain molecules that requires no ATP/energy. e.g. scented candles.
What is Osmosis?
the diffusion of water through a selectively permeable membrane from a region where water is highly concentrated to a region where its concentration is lower.
What is Hypertonic?
a hypertonic cell environment has a higher concentration of solutes outside the cell. Osmosis causes water to flow out of the cell and the cell shrinks or shrivels.
What is Hypotonic?
A hypotonic cell environment is an environment with a lower concentration of solutes than the cytoplasm of the cell. Osmosis causes a net flow of water into the cell causing the swelling and expansion of the cell that may lead to the cell bursting.
What is Isotonic?
Isotonic cellular environment occurs when an equal solute concentration exists inside and outside the cell. Water molecules flow in and out at an equal rate by osmosis causing the cell size to remain the same.
What is Active Transport?
Active transport involves the use of proteins that don't just passively facilitate the transport of substances across the cell membrane, but require the use of cellular energy(usually ATP) to actively pump substances into or out of the cell.
What is Active Transport used for?
1. Generate charge gradients. For example in the mitochondrion, hydrogen ion pumps pump hydrogen ions into the intermembrane space of the organelle as part of making ATP.

2. Concentrate ions, minerals and nutrients inside the cell that are in low concentration outside.

3. Keep unwanted ions or other molecules out of the cell that are able to diffuse through the cell membrane.

In all these cases the key is that active transport uses energy to send substances against the direction they would travel by simple diffusion: that is from a region of low concentration to a region of high concentration.
What is Selectively Permeable Membrane?
A membrane that allows only certain materials to cross it.
What is Permeable Membrane?
A membrane that allows all materials to cross it.
What is Impermeable Membrane?
A membrane that allows no material to cross it.
What is Osmotically Active Substance?
The solution with the highest concentration of solutes

Salt is an osmotically active substance. What this means is that it has the ability to attract water across membranes
What is Osmotic Pressure?
The pressure exerted by the flow of water through a semipermeable membrane separating two solutions with different concentrations of solute.

Deck Info