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Substrate Definition An enzyme acts on a substrate, which is a molecule. The substrate is loaded into the active site of the enzyme, or the area where weak bonds can form between molecules. By exerting forces on the substrate, the enzyme forms an enzyme substrate complex, and the enzyme reacts with the substrate, resulting in … Read more

Vestigial Structures Definition Vestigial structures are various cells, tissues, and organs in a body which no longer serve a function. A vestigial structure can arise due to a mutation in the genome. This mutation will cause a change in the proteins that are required for the formation of the structure. Vestigial Structures Explained Although the … Read more

Substitution Mutation Definition A substitution mutation is a type of replication error during DNA replication which places the wrong nucleotide or sequence of nucleotides in the wrong position. A type of substitution mutation, a point mutation, occurs which a single nucleotide is substituted.  Importantly, a substitution mutation results in DNA of the same length. It … Read more

 of Pedigrees The purpose of a pedigree is to have an easy-to-read chart that depicts a certain characteristic or disorder in an individual. It can be used for a characteristic like having a widow’s peak or attached earlobes, or a genetic disorder like colorblindness or Huntington’s disease.  Besides being used to represent familial characteristics in … Read more

Biochemistry Definition The study of biochemistry is concerned with the chemical reactions occurring within organisms. Both biology and chemistry are incorporated into it. During the early 20th century, biochemistry became a separate discipline. In addition to proteins, lipids, and carbohydrates, biochemists study enzymes and DNA, which are important in metabolism. History of Biochemistry Despite the … Read more

Chloroplast Definition The chloroplast, found only in algal and plant cells, is a cell organelle that produces energy through photosynthesis. The word chloroplast comes from the Greek words khloros, meaning “green”, and plastes, meaning “formed”.  It has a high concentration of chlorophyll, the molecule that captures light energy, and this gives many plants and algae … Read more

The Basics The Goliath birdeater is the world’s largest spider, by weight. Technically, the giant huntsman spider has longer legs – but it weighs considerably less! While this massive tarantula is called a “bird-eater,” this name is actually a bit of a misconception. Goliath birdeaters rarely, if ever, eat birds! That being said, goliath tarantulas … Read more

Monohybrid Cross Definition A monohybrid cross is a genetic mix between two individuals who have homozygous genotypes, or genotypes that have completely dominant or completely recessive alleles, which result in opposite phenotypes for a certain genetic trait. Monohybrid crosses are used by geneticists to observe how the offspring of homozygous individuals express the heterozygous genotypes … Read more

Pseudostratified Columnar Epithelium Definition Pseudostratified columnar epithelia are single-layered tissues that appear to have multiple layers, especially in cross section. These epithelial cells have nuclei at different levels, giving the appearance of stratification. Despite the fact that this tissue consists of a single layer of cells, each cell is in contact with the basement membrane, … Read more