DNA and Genetics

DNA and Genetics

Cells put molecules together in the same way you might build a toy, or a cabinet. They follow a set of directions.

Two scientists named Rosalind Franklin and Maurice Wilkins used x-ray to study DNA. They noticed that DNA has a

double-helix shape

Four Nucleotides Shape DNA

DNAs twisted zipper shape is because of molecules called nucleotides.

Nucleotides are molecules made of a nitrogen base, a sugar, and a phosphate group.

The Nitgrogen bases bond and form the teeth of the zipper. There are four nitrogen bases. Adenine (A), cytosine (C), thymine (T) and guanine (G). (A) and (T) always bond together. (C) and (G) always bond together

How DNA Replicates

When a cell divides, all chromsomes are copied to the new cell. The process of copying a DNA molecule to make another DNA molecule is called replication.

JUNK DNA!?

About 97% of DNA on a human chromosome does not form a gene. Scientists don't currently know their purpose, or if they have functions that are important to cells. This is called Junk DNA.

RNA?

Proteins are important for every cellular process and DNA carries genes that provide instructions on making proteins.

RNA is a type of nucleic acid that carries the code for making proteins from the nucleus to the cytoplasm.

There are three types of RNA. Messenger RNA (mRNA), transfer RNA (tRNA) and Ribosomal RNA (rRNA)

Translating RNA Code

Making a protein from mRNA is like using a secret code.

Proteins are made of amino acides and the order of the nitrogen bases in the mRNA determines the order of the amino acides in the protein.

https://www.youtube.com/watch?v=JQByjprj_mA&ab_channel=AmoebaSisters

Mutations

There are 46 human chromosomes that contain up to 25,000 genes. Sometimes, when DNA replication occurs, mistakes can happen that cause mutations.

Mutations are changes in the nucleotide sequence of a gene.

Mutations can be natural mistakes that are often corrected by our cells, but can also be triggered by exposure to things like radiation or ultraviolet light.

Results of Mutation

Mutations can cause things like genetic disorders like Down Syndrome. However, not all genetic mutations are bad.

Results of Mutations

About 1 to 2 percent of the human population has red hair. Research shows red hair usually results from a mutation in a gene called MC1R, which codes for the melanocortin-1 receptor. The pigment found in red hair that makes it red is called pheomelanin