Download What is a genome?

What is a genome? •  The complete set
of genetic
instructions (DNA
sequence) of a
species
DNA (deoxyribonucleic acid) •  Nucleic acid molecule that carries gene9c informa9on for all living things •  Chromosomes and genes are made of DNA •  Genes are DNA segments that instruct the cell how to build a protein •  DNA is in the shape of a double helix (twisted ladder) – HAS 2 STRANDS •  Made up of small units called nucleo9des DNA double helix shape Structure of a Nucleo3de (3 main parts) Nitrogenous base (A,T,G,C) Phosphate group DEOXYRIBOSE (sugar) Structure of DNA •  Nucleo9des are linked together by phosphate groups and deoxyribose sugars (sides of molecule) •  The 4 nitrogenous bases make up the inner part of the molecule: Adenine (A), Thymine (T), Guanine (G), Cytosine (C) Deoxyribose Deoxyribose is found in DNA, while ribose is found in RNA and ATP mun.ca Chargoff’s Rules for Complementary Base‐pairing A
G
T
C
Hydrogen
bonds hold
both strands
together
* Adenine pairs with Thymine
* Guanine pairs with Cytosine
Structure of DNA April 25, 1953
Watson and Crick
publish their discovery of
structure of the DNA
molecule
DNA Replica9on •  Process by which DNA copies itself before cell division •  DNA Molecule is “unzipped” between bases by enzymes called helicases •  DNA polymerase enzymes copy each strand to make 2 new iden9cal DNA molecules •  DNA ligase joins fragments of DNA together •  See DNA Replica9on Tutorial for more details Overview of DNA replica9on hYp://library.thinkquest.org DNA Polymerase
New Strand Replication fork
Original
Strand
The Genetic Code From Genes to
Proteins
RNA (ribonucleic acid) •  Brings gene9c instruc9ons from nucleus to the ribosomes •  Is single stranded •  Has uracil (U) instead of thymine (T) ‐ all other bases are same as DNA •  Has ribose sugar instead of deoxyribose •  There are 3 types of RNA: bio‐world.com Types of RNA •  mRNA (messenger) ‐ carries gene9c instruc9ons from nucleus to ribosomes •  tRNA (transfer) ‐ brings amino acids to ribosomes to help construct proteins •  rRNA (ribosomal) ‐ makes up part of the ribosome structure Transcrip9on •  Process by which RNA (specifically mRNA) is made from DNA •  Happens in the nucleus •  RNA polymerase enzymes make RNA using DNA •  A pairs with U, and G pairs with C •  RNA can leave the nucleus a`er it is made dna‐sequencing‐service.com Transcription (continued) - process by which mRNA is
made from DNA!
ATTGAACG
UAACUUGC
(DNA)
(RNA)
Leaves
nucleus
*C pairs with G, U pairs with A
DNA that does not code for a
protein is called an DNA that codes for a
protein is called an mRNA splicing •  Newly transcribed RNA contains introns and exons •  Introns are cut out while exons are spliced together •  Complete mRNA is able to leave nucleus to be translated into protein at ribosomes course1.winona.edu Transla9on •  mRNA code is used to make a protein •  Happens at the ribosome •  Ribosome reads the mRNA sequence 3 bases at a 9me (every 3 bases is a codon) •  Each codon represents a par9cular amino acid •  tRNA molecules bring the correct amino acid to the ribosome •  The amino acids are linked together to make a protein dna‐sequencing‐service.com