8th Grade Living EnvironmentArdito/Sweeney

Study Guide -- Genetics

Structure of DNADNA has 3 parts:PhosphateSugar - DeoxyriboseNitrogenous bases

We picture it like this:

phosphate

sugar nitrogenousbase

This group of the parts of DNA is called a nucleotide.Nucleotides are the building blocks of DNA.

There are four nitrogenous bases Adenine Thymine Guanine Cytosine

One molecule of DNA contains about 3 billion of these bases.

These nitrogenous bases follow certain rules about how to pair up Adenine always pairs up with Thymine Guanine always pairs up with Cytosine

Genes are segments of a chromosome that contain the recipe for a specific trait. Genes are found on all 46 human chromosomes. These recipes are for the proteins that cause that specific trait.

Genetics Study Guide, Page 1 of 4

DNA ReplicationRight before cell division, the chromosomes in the cell make copies of themselves. This is called DNA Replication.

This process follows the following steps:

The goal of this project is to make a perfect copy of the cellʼs DNA.

DNA Versus RNA

DNA RNA

3 basic parts:Sugar - DeoxyribosePhosphateNitrogenous Bases

3 basic parts:Sugar - RibosePhosphateNitrogenous Bases

4 nitrogenous bases:adeninethymineguaninecytosine

4 nitrogenous bases:adenineuracilguaninecytosine

Double Stranded Single Stranded

One type Two types:mRNA - carries the DNA message to the ribosometRNA -

3 Billion bases long mRNA - Many bases longtRNA - 3 bases long

Genetics Study Guide, Page 2 of 4

Protein SynthesisProtein Synthesis is the process where the genetic code is translated in order to make the proteins necessary for a specific trait or function.

The process follows the following steps:

Genetics Study Guide, Page 3 of 4

MutationsMutations are any change to the genetic code.The change in the genetic code will lead to a different protein being made.

There are three types of mutations we have learned about:Insertions - a base gets added to the genetic codeDeletions - a base gets removed from the genetic codeSubstitutions - one base gets swapped for another base

Mutations can be helpful or harmful.

Mutations can be caused by a few things. These are called mutagenic agents. The most common one is radiation.Radiation changes the structure of the DNA. And this change in structure changes the genetic code.Mutations can also happen spontaneously.

Genetic EngineeringGenetic Engineering is the process by which the genetic code can be intentionally changed.It is accomplished by taking the section of desired DNA and adding it to the DNA of a bacterium. Then, the modified bacteria are let loose in the person, which would result in the new DNA being incorporated into the old DNA.

Genetics Study Guide, Page 4 of 4