[Free Registration/Login may be required to access all resource tools.] The process of DNA replication is not always 100% accurate. Sometimes the wrong base is inserted in the new strand of DNA. This wrong base could become permanent. A...

[Free Registration/Login may be required to access all resource tools.] Cloning is the process of creating an exact replica of an organism. The clone's DNA is exactly the same as the parent's DNA. Bacteria and plants have long been able...

[Free Registration/Login may be required to access all resource tools.] DNA must replicate (copy) itself so that each resulting cell after mitosis and cell division has the same DNA as the parent cell. DNA replication occurs during the S...

[Free Registration/Login may be required to access all resource tools.] A Punnett square is a special tool derived from the laws of probability. It is used to predict the offspring from a cross, or mating between two parents. Learn more...

[Free Registration/Login may be required to access all resource tools.] Mendel laid the foundation for modern genetics, but there were still a lot of questions he left unanswered. What exactly are the dominant and recessive factors that...

[Free Registration/Login may be required to access all resource tools.] Your body has many ways to protect you from pathogens. Your body's defenses are like a castle. The outside of a castle was protected by a moat and high walls. Inside...

[Free Registration/Login may be required to access all resource tools.] What determines if a baby is a male or female? Recall that you have 23 pairs of chromosomes-and one of those pairs is the sex chromosomes. Everyone has two sex...

[Free Registration/Login may be required to access all resource tools.] In all of Mendel's experiments, he worked with traits where a single gene controlled the trait. Each also had one allele that was always dominant over the recessive...

[Free Registration/Login may be required to access all resource tools.] The DNA sequence contains the instructions to place units called amino acids into a specific order. When these amino acid are assembled in that specific order,...

[Free Registration/Login may be required to access all resource tools.] Barking, purring, and playing are just some of the ways in which dogs and cats behave. These are examples of animal behaviors. Animal behavior is any way that...

[Free Registration/Login may be required to access all resource tools.] How do birds reproduce? We know that chickens lay eggs. But how do they do that? Learn more about bird reproduction in this learning module produced by CK-12.

[Free Registration/Login may be required to access all resource tools.] Cancer is a disease that causes cells to divide out of control. Normally, the body has systems that prevent cells from dividing out of control. But in the case of...

[Free Registration/Login may be required to access all resource tools.] Has this ever happened to you? A student sitting next to you in class has a cold. The other student is coughing and sneezing, but you feel fine. Two days later, you...

[Free Registration/Login may be required to access all resource tools.] Why is animal communication important? Without it, animals would not be able to live together in groups. Animals that live in groups with other members of their...

[Free Registration/Login may be required to access all resource tools.] A pedigree is a chart that shows the inheritance of a trait over several generations. A pedigree is commonly created for families, and it outlines the inheritance...

[Free Registration/Login may be required to access all resource tools.] A population is a group of organisms of the same species, all living in the same area and interacting with each other. Since they live together in one area, members...

[Free Registration/Login may be required to access all resource tools.] A terrestrial biome is an area of land with a similar climate that includes similar communities of plants and animals. Different terrestrial biomes are usually...

[Free Registration/Login may be required to access all resource tools.] The mRNA, which is transcribed from the DNA in the nucleus, carries the directions for the protein-making process. mRNA tells the ribosome how to create a specific...

[Free Registration/Login may be required to access all resource tools.] Carbon is one of the most common elements found in living organisms. Chains of carbon molecules form the backbones of many molecules, such as carbohydrates,...

[Free Registration/Login may be required to access all resource tools.] A person's genome is all of his or her genetic information. In other words, the human genome is all the information that makes us human. Learn more about the human...

[Free Registration/Login may be required to access all resource tools.] What does the word "communication" make you think of? Talking on a cell phone? Texting? Writing? Those are just a few of the ways in which human beings communicate....

[Free Registration/Login may be required to access all resource tools.] DNA is located in the nucleus. Proteins are made on ribosomes in the cytoplasm. Remember that information in a gene is converted into mRNA, which carries the...

[Free Registration/Login may be required to access all resource tools.] Problems can occur with red blood cells, white blood cells, platelets, and other parts of the blood. Many blood disorders are genetic, meaning they are inherited...

[Free Registration/Login may be required to access all resource tools.] Sometimes understanding how common a gene is within a population is necessary. Or, more specifically, you may want to know how common a certain form of that gene is...