Show Advanced Search


Containing Text
- - -
Filter by author or institution
Filter by publication date
October, 2006
Filter by journal section

Filter by science education


Enzyme Activity - Student Protocol

JoVE 10586

Baseline Peroxidase Enzyme Experiment
To begin, the baseline for the peroxidase enzyme reaction must be determined. Make the substrate by adding 7 mL of distilled water to a clean test tube and then add 0.2 mL of guaiacol. Note: Guaiacol is a color-changing indicator that becomes more yellow-orange as the enzyme reaction progresses.
Next, add 0.3…

 Lab Bio

Photosynthesis - Student Protocol

JoVE 10566

Plant Pigment Chromatography
NOTE: In this experiment you will separate pigments from spinach leaves using chromatography paper. Individual pigments travel along the paper at different rates and may have different colors. By calculating the relative distance the pigments travel, their resolution factor, and comparing them with literature values, you can …

 Lab Bio

Hardy-Weinberg & Genetic Drift - Student Protocol

JoVE 10560

Class Simulation
Begin by opening a new spreadsheet file. Following the Hardy-Weinberg equation where p is the frequency of a dominant allele A in a population, and q is defined as the frequency of a recessive allele B, input frequency p of allele A into cell B2, and frequency q of allele B into cell B3.
Assign the value 0.5 to cell C2.

 Lab Bio


JoVE 10669

The potential for a solution to donate or accept hydrogen ions determines whether it is an acid or a base. Acidic solutions donate protons, whereas bases or alkaline solutions can accept protons. Pure water has equal numbers of hydrogen ions to give protons and hydroxide ions to receive them, making it a neutral solution.

pH is a measure of the acidity or basicity of a water-based solution, determined by the concentration of hydrogen ions. In one liter of pure water, there are 1x10-7 moles of hydrogen ions. However, the extensive range of hydrogen ion concentrations present in water-based solutions makes measuring pH in moles cumbersome. Thus, a pH scale was developed in which moles of hydrogen ions are converted using the negative of the base 10 logarithm. The pH of pure water, then, is 7, representing a neutral solution. Most solutions have a pH between 0 and 14, but some solutions, like carborane (with a pH of -18), exceed this. One liter of carborane has 1x1018 moles of hydrogen ions. When free, unbound hydrogen ions accumulate, as with carborane, the solution is acidic, and the pH value falls below 7. Coffee, lemon juice, and gastric acid (digestive juices) are acidic solutions, with pHs around 4.5, 2.5, and 1.5, respectively. Solutions with pH values above 7 have lower hydrogen ion concentrations and are alkaline. In

 Core: Biology

Using a pH Meter

JoVE 5500

Source: Laboratory of Dr. Zhongqi He - United States Department of Agriculture

Acids and bases are substances capable of donating protons (H+) and hydroxide ions (OH-), respectively. They are two extremes that describe chemicals. Mixing acids and bases can cancel out or neutralize their extreme effects. A substance that is neither acidic…

 General Chemistry

Serial Dilutions and Plating: Microbial Enumeration

JoVE 10507

Source: Jonathan F. Blaize1, Elizabeth Suter1, and Christopher P. Corbo1
1 Department of Biological Sciences, Wagner College, 1 Campus Road, Staten Island NY, 10301

Quantitative assessment of prokaryotes can be onerous given their abundance, propensity for exponential proliferation, species diversity within a population, and specific …


Sexual Selection and Mate Choice - Student Protocol

JoVE 10616

Sexual Selection Class Simulation
Note: In this activity, you and your classmates will portray a sexually reproducing population consisting of an equal number of male and female animals. You will simulate several different mating scenarios to determine how relative quality, attractiveness, sex, and parental commitment affect mate choice and reproductive …

 Lab Bio
More Results...