Genetic Code BIOLOGY 2021 Lesson Objectives By the

Genetic Code BIOLOGY 2021

Lesson Objectives By the end of this lesson you should be able to: Summarize the experiments that led to the discovery of the genetic code Describe the relationship between DNA, genes and chromosomes Describe the role of DNA replication in transmitting genetic information.

Words to Know Genetic code- a set of instruction in DNA that translates genetic information from genes, in the form of a triplet codon, to amino acids, for the synthesis of proteins Genetics- the study of heredity in organisms Codons-the sequences of three bases that form a unit of the genetic code in DNA that determines a specific amino acid Genes- the segments of DNA that are the basic units of heredity in organisms and are transferred from parent to offspring.

How as the genetic code discovered, and what role does it play in genetics today? Genetic Information All the genetic information within an organism is found in its DNA codes for the genetic information through the genetic code, a set of instruction in DNA that translates genetic information in a triplet codon for the synthesis of proteins.

The Discovery of DNA 1860’s: Friedrich Miescher identified DNA 1940 s: Erwin Chargaff created a rule for DNA bases Adenine levels equal thymine levels Guanine levels equal cytosine levels 1952: Rosalind Franklin created a photo of DNA structure 1953: James Watson and Francis Crick created an accurate model of DNA

Cracking the Code The genetic code was discovered by Marshall Nirenberg and J. Heinrich Matthaei in 1961. The genetic code was based on codons, sequences of three bases that form units of the genetic code in DNA that determines a specific amino acid Amino acids are used to make proteins

The Genetic Code Most organisms contain the same codons in DNA The order of the codon makes organisms different

Diversity among organisms As the DNA is copied, you end up with two identical strands of DNA One stays in the parent cell Ones goes in the offspring cell Each cell has exactly the same information for making proteins That is how DNA gets transmitted to new cells via cell division

Studying heredity Genetics is the study of heredity in organisms

Chromosomes DNA is coiled into chromosomes in the nucleus The number of chromosomes in cell differs depending on the organism Most organisms receive half their chromosomes from their father and half from their mother.

Genes are segments of DNA that are the basic units of heredity in organisms and are transferred from parent to offspring.

The Human Genome Project Real World Connection The project started in 1990. It had these goals: Identify the 20, 000 to 25, 000 genes in human DNA Determine of codons the sequence

Ethics Real World Connection Scientists must consider the ethics behind mapping the human genome—what should be considered ethical, allowable, and in many cases moral Determining specific traits in humans, cures for disease, cloning, etc. Considering society the effects on

How was the genetic code discovered and what role does it play in genetics today? The genetic code was discovered based on the work of any scientists. DNA contains the genetic code, which is a set of instructions in the form of codons for assembling amino acids into the correct order of a protein.

Review: The Discovery of DNA 1860 s: Fredrick Miescher identified DNA 1940 s: Chargaff created a rule for DNA bases 1952: Franklin created a photo of DNA 1953: Watson and Crick created an accurate model of the structure of DNA 1960 s: Nirenberg and Matthaei discovered the genetic code