DNA Replication and Protein Synthesis DNA Genetic material

DNA Replication and Protein Synthesis

DNA • Genetic material found in the nucleus • Stands for deoxyribonucleic acid • Lacks a oxygen, has ribose (sugar), and nucleotides (nucleic acid)

DNA structure: DNA is double helixed- it has 2 strands twisted together -When unwound it looks like a ladder

DNA composition: • DNA is made up of units called nucleotides. • Each nucleotide is made up of a: – 1. phosphate, – 2. sugar, and a – 3. nitrogen base (there are 4 types)

4 nitrogen bases in DNA: 1. 2. 3. 4. Adenine (A) Cytosine (C) Guanine (G) Thymine (T)

A=T and C=G **The combinations of these bases determine the genetic code (each person has a unique code) -Each is held together by a hydrogen bond

How is DNA Replicated in Mitosis/Meiosis DNA never leaves nucleus 1. DNA unwinds and is split apart 2. A copy is made of each strand (this occurs in the nucleus of the cell)

Snork Worksheet Write this on a separate sheet) • DNA A C C G G T T A G C C G A G G G m. RNA t. RNA A. A. trait

How new PROTEINS are made in the cell?

1. DNA is copied by RNA (called Transcription) -RNA has the same base pairs as DNA except uracil replaces Thymine (A=U, G=C)

Proteins from DNA contd. 1. DNA is copied to RNA in the nucleus. 2. The RNA is taken to the ribosomes. The RNA is then used to make proteins.

2. Proteins are made from the RNA (called Translation) -When RNA has finished copying DNA in nucleus the RNA goes to the surface of the ribosomes (This RNA is called messenger RNA) -The RNA enters the ribosome and proteins are made from the m. RNA copy (t. RNA)

How are proteins made from DNA? • The sequence of DNA will code for certain proteins • Each set of 3 bases will code for 1 amino acid Ex. AAA codes for the protein lysine • A set of 3 bases that codes is called a codon

DNA T a C A G C T A C G C A RNA

2. contd. -The codon that tells translation to start is AUG -The codon to stop is UAA