Where is hereditary information found in a cell

Genetic information is passed from generation to generation through inherited units of chemical information in most cases, genes. Organisms produce other similar organisms through sexual reproduction, which allows the line of genetic material to be maintained and generations to be linked.

Variations in characteristics, such as skin or hair colour, result from the population containing a range of genetic information for the characteristic. Characteristics that are not seen may be carried in genetic information recessive by individuals and can be passed on. This means that offspring may display characteristics different from their parents.

The characteristic that is observed may be controlled by a number of genes. There are a large number of possible combinations of genes from both parents. The characteristics of the offspring need not be an intermediate of the two parents. Organisms possess genetic material that contains information for the development of characteristics. This material passes from one generation to the next through reproduction. All plants and animals are made up of cells where the genetic material can be found in the form of genes and chromosomes usually in the nucleus.

Changes to an organism that are a result of or result in genetic mutation alter the genetic makeup of an organism and can be passed on to the next generation. Students need to realise that genetic material is found in all living things and it carries information that directs the organism's functioning.

By studying reproduction students should develop an understanding that genetic information is passed from one generation to another via organised chemical structures. Students need to study examples of changes in genetic information that can arise due to mutation.

They should also study the impact of acquired changes on organisms and develop an understanding that these changes are not inherited because they are not created by genetic changes. For organisms to survive it is important that the information needed for survival is passed on through the generations.

If a population has sufficient variation within its genetic information, it is more likely to respond successfully to changes in the environment. This is critical when cells divide because each new cell needs to have an exact copy of the DNA present in the old cell. Other chapters in Help Me Understand Genetics. Genetics Home Reference has merged with MedlinePlus. Learn more. The information on this site should not be used as a substitute for professional medical care or advice. Contact a health care provider if you have questions about your health.

What is DNA? Interestingly, Miescher did not believe that nuclein was the carrier of hereditary information, because he thought it lacked the variability necessary to account for the incredible diversity among organisms.

Rather, like most scientists of his time, Miescher believed that proteins were responsible for heredity, because they existed in such a wide variety of forms. For multiple decades following Miescher's discovery, most scientists continued to believe that protein, not DNA, was the carrier of hereditary information. This changed in , when biologist Oswald Avery performed a series of groundbreaking experiments with the bacteria that cause pneumonia.

At the time, scientists knew that some types of these bacteria called "S type" had an outer layer called a capsule, but other types called "R type" did not. Through a series of experiments, Avery and his colleagues found that only DNA could change R type bacteria into S type. This meant that something about DNA allowed it to carry instructions from one cell to another. This was not true of any other substances within the bacteria, including protein.

This result highlighted DNA as the "transforming factor," thereby making it the best candidate for the hereditary material. Under normal circumstances, a bacterial cell will reproduce by a form of cell division called binary fission.

When Avery, MacLeod, McCarty, Hershey, and Chase performed their experiments, scientists knew that binary fission involved the copying of the hereditary substance and the redistribution of this substance into two new cells.

So, when DNA was proven to be the material responsible for controlling the operations inside a single cell, it became easier to understand how the process of cell division and the transfer of the DNA could control the characteristics of newly born cells.

Therefore, although they did not state it explicitly, Hershey and Chase had presented experiments that clearly suggested that DNA controls the production of more DNA, and that DNA itself was the substance that directed the construction and function of living things.

This discovery enabled investigators to put together the story of how DNA carries hereditary information from cell to cell. Indeed, the experiments connecting heredity and the structure of DNA were happening in parallel, so the next few years would be an exciting time for the discovery of DNA function. This page appears in the following eBook. Aa Aa Aa. The chemical nature and structure of DNA were not elucidated until the middle of the twentieth century.

Prior to that point, scientists had spent years speculating about which of the many types of molecules within cells contained the hereditary information. Was it protein? Was it something else — perhaps even a molecule they had yet to discover? Eventually, researchers zeroed in on DNA as the substance responsible for the transfer of traits from one generation to the next. From there, the race was on to learn more about this remarkable molecule.

Who first identified DNA?