CHAPTER 5 BHOW GENES FUNCTION LANGUAGE OF GENES

CHAPTER 5 BHOW GENES FUNCTION

LANGUAGE OF GENES DNA and RNA are made of special molecules: nucleotides Each nucleotide has a special code letter 3 code letters together makes a codon Long chains of codons make genes Genes are instructions for making proteins

DNA IS CODED MESSAGES What is DNA? Deoxyribonucleic acid Looks like a twisted ladder- double helix Double helix is made of nucleotides DNA has 4 nucleotides: A- adenine T- thymine C- cytosine G- guanine

DNA IS CODED MESSAGES The bases (nucleotides) on one side of ladder will match with base on other side of ladder. A bonds with T C bonds with G

DNA IS CODED MESSAGES DNA needs to be copied. This is called DNA replication. Happens during interphase! Genes in DNA code are copied and sent to the cytoplasm, then used to make, repair, or produce things the cell needs

RNA HELPS DECODE THE MESSAGES We can’t make proteins from DNA Must be changed (translated) into RNA! This process is called transcription What is RNA? Ribonucleic acid Like DNA, but a little different Only 1 strand (not double helix) No T (thymine), instead- U- uracil

RNA HELPS DECODE THE MESSAGES 3 types of RNA, but only 2 are important now: Messenger RNA (m. RNA) is the part that is ‘read’ to make the protein Transfer RNA (t. RNA) is the part that brings amino acids (pieces of the protein) to the ribosome to be put together What do we call making protein? Protein synthesis

RNA HELPS DECODE THE MESSAGES Quick note: Codons Made of 3 nucleotides (A, U, C, or G) Each codon is for one specific amino acid The codon tells which t. RNA and amino acid goes next Some codons say “start” and some say “stop”