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Probability Laws

JoVE 10776

The probability of inheriting a trait can be calculated using the sum and product rules. The sum rule is used to calculate the probability of mutually exclusive events. The product rule predicts the probability of multiple independent events. These probability rules determine theoretical probability—the likelihood of events occurring before they happen. Empirical probability, by contrast, is calculated based on events that have already occurred. Although Punnett squares are useful for visualizing the inheritance of one or two traits, they become cumbersome when applied to more complex scenarios. A Punnett square displaying just three traits contains 64 possible crosses. Probability laws enable much more efficient calculations of trait inheritance probabilities. Consider a pregnant woman who wants to understand her child’s risk of inheriting biotinidase deficiency (BTD), an autosomal recessive disease that runs in her family. Infants with untreated BTD exhibit developmental delays, poor muscle tone, skin rashes, and hair loss. Severe cases are associated with seizures and loss of vision and hearing, among other symptoms. Neither the woman nor her parents have BTD, but her brother is affected, meaning that both parents must have one causal gene variant (i.e., both parents are heterozygotes, or carriers). The probability of the wo

 Core: Biology

Genetic Lingo

JoVE 10771

An organism is diploid if it inherits two variants, or alleles, of each gene, one from each parent. These two alleles constitute the genotype for a given gene. The term genotype is also used to refer to an organism’s complete set of genes. A diploid organism with two identical alleles has a homozygous genotype, whereas two different alleles indicates a heterozygous genotype. Observable traits arising from genotypes are called phenotypes, which can also be influenced by environmental factors. An allele is dominant if only one copy is needed to manifest an associated phenotype and recessive if two copies are required for phenotypic expression. Diploid organisms, including humans, most other animals, and many plants, have a duplicate set of chromosomes in somatic (non-sex) cells. These chromosome duplicates are homologous, with similar lengths, centromere positions, and gene locations. Diploid organisms inherit two versions of each gene, one from each parent. These two gene variants, or alleles, are situated at the same relative locus, or position, on two homologous chromosomes. Each chromosome contains many genetic loci, and there are often several possible alleles of a given gene. The two alleles inherited by a diploid organism constitute its genotype at the locus. The term genotype also refers to an organism’s total set of g

 Core: Biology

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

Temperature Dependence- Concept

JoVE 11174

Chemical Kinetics

The reaction rate is the speed at which a chemical reaction occurs. The reaction rate is defined as the change in concentration of a component in the reaction with time. The speed of a reaction depends on several factors, including the concentration of reactants and the temperature at which the reaction is performed. Each reactant contributes to …

 Lab: Chemistry

Concentration Dependence- Concept

JoVE 11171

Chemical Kinetics and the Reaction Rate Law

Chemical kinetics refers to the rate or speed of a chemical reaction. The rate depends on the mechanism, complexity, and number of reactants in the reaction. Reactant concentration also plays a significant role in the rate of a reaction.

The rate law quantifies this relationship through experimentation. Each …

 Lab: Chemistry

Solubility- Concept

JoVE 11159


Solubility describes how much of a solute can dissolve in a given volume of a specific solvent. Solubility is usually reported in terms of solute mass per solvent volume or solute mass per solvent mass. For example, the solubility of sodium chloride in water at room temperature is reported as 36 g per 100 mL of water. If solubility is reported in solute …

 Lab: Chemistry

DC/DC Buck Converter

JoVE 10253

Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT.

While it is simple to step up or down AC voltages and currents using transformers, stepping up or down DC voltages and currents in an efficient and regulated manner requires switching power converters. The DC/DC buck converter chops the input DC …

 Electrical Engineering

Introduction to the Power Pole Board

JoVE 10254

Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT.

DC/DC converters are power electronic converters that convert DC voltages and currents from a certain level to another level. Typically, voltage conversion is the main purpose of DC/DC converters and three main types of conversion exist in a…

 Electrical Engineering

DC/DC Boost Converter

JoVE 10252

Source: Ali Bazzi, Department of Electrical Engineering, University of Connecticut, Storrs, CT.

Boost converters provide a versatile solution to stepping up DC voltages in many applications where a DC voltage needs to be increased without the need to convert it to AC, using a transformer, and then rectifying the transformer output. Boost…

 Electrical Engineering

Le Châtelier's Principle

JoVE 10138

Source: Laboratory of Dr. Lynne O'Connell — Boston College

When the conditions of a system at equilibrium are altered, the system responds in such a way as to maintain the equilibrium. In 1888, Henri-Lewis Le Châtelier described this phenomenon in a principle that states, "When a change in temperature, pressure, or…

 General Chemistry
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