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Explore the intricate world of DNA, the genetic blueprint that holds the instructions for building organisms. From chromosomes and genes to protein synthesis, delve into the fundamental process of life. Understand how DNA replicates, codes for traits, and undergoes transcription and translation to create proteins, the building blocks of life.
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DNA, RNA, and PROTEIN SYNTHESIS DNA is a molecule that carries the instructions for how to make an organism DNA, genome, instructions, blueprint, chromosomes, genes All MEAN DNA!!!! THEY ALL HAVE TO DO WITH DNA
DNA is organized into bundles called CHROMOSOMES. Humans have 46 chromosomes CHROMOSOMES have segments on them that code for certain qualities (eye color, hair color) The segments or areas are called GENES and they code for all of an organisms TRAITS or characteristics
DNA is found in, and cannot leave the nucleus (too big). Gametes = sperm/egg The types of cells that carry information from parents to offspring are called gametes. Gametes are sex cells, sperm and egg. Humans and their cells have 46 chromosomes. 23 come from mom (egg), 23 come from dad (sperm). • Since it has such important information it is guarded in the nucleus of cells. • DNA carries information from parents to offspring (kids)
DNA (DeoxyRiboNucleic Acid) is made up of nucleotides that repeat. • Each nucleotide is made of 3 parts: 1.Nitrogen base 2.Deoxyribose sugar group De=without Oxy= Oxygen Ribose=sugar 3.Phosphate group
There are 4 nitrogen bases:Adenine (A), Cytosine (C), Thymine (T), and Guanine (G)The sequence of nitrogenous bases determines the traits that will appear. The sequence of codons (3 letter codes)
DeoxyribonucleicAcid (DNA) the Double Helix The sugar and phosphate groups make up the outside part of the ladder. The base pairs make up the inside “steps” of the ladder.
Watson & Crick were the first to successfully show the structure of DNA. (Double Helix) According to Chargaff’s rule: A pairs to TC pairs to G The bases are found in a 1:1 ratio adenine bonds with thymine guanine bonds with cytosine The two halves of the DNA strand are called complementary because they pair together
Reasons why cells divide Mitosis/Cell Division • The cell becomes too big. • The larger a cell becomes, the more demands the cell places on its DNA • Also, a larger cell has more trouble keeping up with the needs of the cell • Cells will continually divide during the growth of an organism.
The process by which cells divide • Before a cell divides it must make an exact “copy” or “replica” of it’s DNA. • The copy or replica of DNA is made during the S-Phase of Interphse. • After Interphase is complete the cell can divide by Mitosis. • Cell Division or Mitosis allows organisms to grow larger while cells remain small
Next new nucleotides are added to each side until 2 identical strands are made (remember A to T and C to G) Original Strand Opens/Unzips Original Strand The “new” strand will line up in here “New” Strand Original Strand
Replication / Mitosis Mitosis results in 2 identical “daughter” cells Each has all 46 chromosomes An exact copy of the original
Protein Synthesis • 1. DNA is the “code” – the instructions for how to make PROTEINS, the main structures of the body. • 2. DNA is in the nucleus of the cell, but PROTEINS are made in the cytoplasm by RIBOSOMES. • Remember, DNA cannot leave the nucleus. • We need a way to get the DNA out of the nucleus to the ribosomes. Protein synthesis happens in 2 steps.
Protein Synthesis Step 1: Transcription • The DNA strand in the nucleus separates. • In order to get “BIG” DNA out of the nucleus we must re-write it as a messenger (RNA). • This RNA acts as a messenger (mRNA) that carries the instructions out of the nucleus to the ribosome • When the genetic code (DNA) is copied/re-written to messenger RNA, mRNA this is called transcription.
RNA has Ribose as its sugar instead of Deoxyribose It is Single Stranded, meaning that it is only half of the ladder (double helix) RNA has Uracil as a base instead of Thymine Guanine – Cytosine Adenine – Uracil (no T, Thymine in RNA) Rna (ribo-nucleic-acid)
Step 2: Translation We translate 3 letter codons into an amino acid chain. • mRNA attaches to a RIBOSOME • Every 3 letter group on a strand of mRNA is a CODON which codes for an AMINO ACID - amino acids are the building blocks of proteins (20 of them; 9 are essential) AMINO ACIDS 3. The RIBOSOME “reads” the mRNA, then transfer RNA (tRNA) brings the correct AMINO ACID to form the protein chain 3 letter CODONS on mRNA tell what the AMINO ACID will be
Mitosis vs. Meiosis Meiosis results in 4 genetically Different haploid cells. Haploid means half The Gametes (sex cells) have ½ the info Mitosis results in 2 identical “daughter” cells Each has all 46 chromosomes
NameDate Biologyclass pd.Write about DNA. What is DNA?What is the structure and parts of DNA?How is DNA used to make proteins in protein synthesis