DNA RNA The Genetic Code blueprint of Life

DNA & RNA The Genetic Code & blueprint of Life

DNA: The Genetic Code v genetic code – manner in which cells store program they pass from one generation to the next DNA, RNA, & Protein Synthesis 9/24/2021 2

DNA: The Genetic Code v Transformation – process by which genetic material absorbed from environment is added to or replaces part of a bacterium’s DNA, RNA, & Protein Synthesis 9/24/2021 3

DNA, RNA, & Protein Synthesis 4

DNA: The Genetic Code v British scientist, Frederick Griffith (1928) v Why is Griffith’s work on transformation important in identifying DNA as genetic material? v indicated that material from heat-killed, diseasecausing bacteria transformed live harmless bacteria into disease-causing type v Based on this information, Avery, Macleod, & Mc. Carthy concluded that DNA is carrier of genetic Information DNA, RNA, & Protein Synthesis 9/24/2021 5

DNA: The Genetic Code v How did Hershey & Chase show that DNA was molecule that carried genetic code (1952) v tagged DNA on some bacteriophages w/ radioactive phosphorus & protein coats of other bacteriophages w/ radioactive sulfur v bacteriophages then exposed to bacteria v bacteria cells contained large amounts of radioactive phosphorous but little sulfur v Conclusion: bacteriophage DNA enters bacterial cell; DNA carries genetic material for making bacteriophages DNA, RNA, & Protein Synthesis 9/24/2021 6

DNA: The Genetic Code v DNA (deoxyribonucleic acid) – nucleic acid that stores & transmits genetic information from 1 generation of an organism to the next by coding for production of a cell’s proteins v "the blueprint of life” v contains code, or instructions, for building an organism & ensures organism functions correctly DNA, RNA, & Protein Synthesis 9/24/2021 7

The Structure of DNA, RNA, & Protein Synthesis 9/24/2021 8

The Structure of DNA What Evidence do Scientists have of the DNA Structure? v Rosalind Franklin: (early 1950 s) X-ray imaging v Francis Crick & James Watson: (1953) 3 -D models of DNA Structure DNA, RNA, & Protein Synthesis 9/24/2021 9

The Structure of DNA polymer formed from nucleotide units v Long chains linked by Dehydration Synthesis v DNA Make up chromosomes v code for genes v v 3 Basic parts of Nucleotide: v v v 5 -Carbon Sugar (deoxyribose) Phosphate Group Nitrogenous Bases DNA, RNA, & Protein Synthesis 9/24/2021 10

Nucleotides that Make Up DNA Fundamental Structure of Nucleotide DNA, RNA, & Protein Synthesis 9/24/2021 11

The Structure of DNA v contains 4 types of Nitrogenous Bases v Purines adenine (A) v Guanine (G) v v Pyrimidines thymine (T) v Cytosine (C) v v nucleotides joined together to form long chain DNA, RNA, & Protein Synthesis 9/24/2021 12

The Structure of DNA v contains 4 types of Nitrogenous Bases v Purines adenine (A) v Guanine (G) v v Pyrimidines thymine (T) v Cytosine (C) v v nucleotides joined together to form long chain DNA, RNA, & Protein Synthesis 9/24/2021 13

The Structure of DNA v Shape: double-helix v twisted ladder v v v ladder sides: alternating sugars (deoxyribose) & phosphates rungs of ladder: nucleotides Base-Pair Rule: Nucleotides pair in specific way v Adenine (A) pairs to Thymine (T) v Guanine (G) pairs to Cytosine (C) DNA, RNA, & Protein Synthesis 9/24/2021 14

DNA BASE PAIRS DNA, RNA, & Protein Synthesis 9/24/2021 15

DNA Base Pairing DNA, RNA, & Protein Synthesis 9/24/2021 16

The Structure of DNA v Nitrogenous bases on each strand of DNA are positioned exactly opposite each other v Base Pairing – attraction between complementary nitrogenous bases that produces a force that holds 2 strands on DNA double helix together DNA, RNA, & Protein Synthesis 9/24/2021 17

DNA, RNA, & Protein Synthesis 9/24/2021 18

DNA, RNA, & Protein Synthesis 9/24/2021 19

DNA, RNA, & Protein Synthesis 9/24/2021 20

DNA, RNA, & Protein Synthesis 9/24/2021 21

DNA, RNA, & Protein Synthesis 9/24/2021 22

DNA, RNA, & Protein Synthesis 9/24/2021 23

DNA, RNA, & Protein Synthesis 9/24/2021 24

The Structure of DNA v rungs of ladder can occur in any order (as long as base-pair rule is followed) v E. G. , stretch of DNA could be AATGACCAT which would code for a different gene than a stretch that read GGGCCATAG v billions of bases (nucleotides) in cells, which code for all the things an organism needs to function. DNA, RNA, & Protein Synthesis 9/24/2021 25

DNA, RNA, & Protein Synthesis 9/24/2021 26

DNA, RNA, & Protein Synthesis 9/24/2021 27

DNA, RNA, & Protein Synthesis 9/24/2021 28

DNA: REPLICATION New strand DNA polymerase Original strand DNA polymerase Growth Replication fork Nitrogenous bases Replication fork New strand DNA, RNA, & Protein Synthesis 9/24/2021 Original strand 29

DNA: Replication v Replication – process by which DNA is duplicated before a cell divides DNA, RNA, & Protein Synthesis 9/24/2021 30

DNA: Replication v Why does DNA need to copy? v v Cells divide for an organism to grow or reproduce, every new cell needs a copy of DNA or instructions to know how to be a cell. DNA replicates right before a cell divides. DNA replication is semi-conservative. when it makes a copy, ½ of old strand is always kept in new strand. This helps reduce number of copy errors. DNA, RNA, & Protein Synthesis 9/24/2021 31

DNA: Replication Process v STEP 1: v 2 original strands of DNA separate by unwinding v occurs through action of an enzyme that breaks hydrogen bonds between strands v 2 areas on either end where DNA separates is REPLICATION FORK DNA, RNA, & Protein Synthesis 9/24/2021 32

DNA: Replication Process v STEP 2: Another enzyme adds the correct complimentary bases to each strand v v At replication fork, DNA polymerase moves along DNA Strands adding nucleotides As DNA polymerase moves along, 2 strands of DNA form DNA, RNA, & Protein Synthesis 9/24/2021 33

DNA: Replication Process v STEP 3: v DNA Polymerase continues until all nucleotides have been added v 2 new identical molecules of DNA are formed v Another enzyme connects all pieces of DNA together DNA, RNA, & Protein Synthesis 9/24/2021 34

Original Template Strand = RED DNA, RNA, & Protein Synthesis 9/24/2021 New Strand = BLUE 35

DNA: Replication Proofreading v At end of Replication, DNA polymerase goes through DNA to make sure there are no errors v This prevents mistakes in DNA sequences v Mutations- Change in DNA sequence DNA, RNA, & Protein Synthesis 9/24/2021 36

RNA v Ribonucleic Acid (RNA) – nucleic acid made of a single chain of nucleotides that acts as a messenger between DNA & ribosome & carries out process by which proteins are made from amino acids v Many forms of RNA but 3 main types are involved in expressing genetic code v Disposable copy of a segment of DNA, RNA, & Protein Synthesis 9/24/2021 39

Structure of RNA v 3 Basic parts of Nucleotide: v v 5 -Carbon Sugar (ribose) Phosphate Group Nitrogenous Bases 4 Nitrogenous Bases v v 1. adenine (A) 2. Guanine (G) 3. Cytosine (C) 4. uracil (U) DNA, RNA, & Protein Synthesis 9/24/2021 40

Nucleotides That Make Up RNA Fundamental Structure of Nucleotide DNA, RNA, & Protein Synthesis 9/24/2021 41

Structure of RNA v WHICH PAIR TOGETHER From DNA to m. RNA? v ADENINE pairs with URACIL v CYTOSINE pairs with GUANINE DNA, RNA, & Protein Synthesis 9/24/2021 42

RNA BASE PAIRING DNA, RNA, & Protein Synthesis 9/24/2021 43

Types of RNA v 3 major kinds of RNA v m. RNA (messenger RNA) - "copies" & "carries” genetic code out from nucleus; only one strand v r. RNA (ribosomal RNA) - framework for ribosomes, which synthesize proteins v t. RNA (transfer RNA) - transports amino acids from cytoplasm to ribosomes to build proteins DNA, RNA, & Protein Synthesis 9/24/2021 44

DNA Vs. RNA v 3 differences between RNA & DNA: v v v RNA is single stranded & DNA is double stranded In RNA, uracil (U) replaces thymine (T) which is found in DNA RNA contains the sugar, ribose, & DNA contains deoxyribose DNA, RNA, & Protein Synthesis 9/24/2021 45

DNA Vs. RNA v Physical Differences: v v v DNA: double helix RNA: single strand Chemical Differences: v v DNA: deoxyribose sugar & thymine RNA: ribose sugar & uracil DNA, RNA, & Protein Synthesis 9/24/2021 46

DNA, RNA, & Protein Synthesis 9/24/2021 47

DNA, RNA, & Protein Synthesis 9/24/2021 48

DNA, RNA, & Protein Synthesis 9/24/2021 49

DNA Vs. RNA DNA, RNA, & Protein Synthesis 9/24/2021 50