Week 6 Exb 110 2010 color

Week 6 Exb 110 2010 color - EXERCISEMETABOLISM EXB110...

Info iconThis preview shows pages 1–23. Sign up to view the full content.

View Full Document Right Arrow Icon
EXERCISE METABOLISM EXB 110 Gene Transcription
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gene Expression • Genes are lengths of DNA that code for synthesis of RNA – mRNA carries info for how to make a protein • Is transported out of nucleus to ribosomes where proteins are made
Background image of page 2
Gene Expression • Takes place in 2 stages: – Transcription occurs when DNA sequence in a gene is turned into a mRNA sequence – Translation occurs when mRNA sequence is used to make a protein
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Gene Expression • Each nucleus contains 1 or more dark areas called nucleoli – These contain genes actively making rRNA
Background image of page 4
Genome and Proteome • Genome refers to all genes in an individual or in a species • Proteome refers to all proteins produced by a genome
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chromatin • Is made of DNA and its associated proteins (=histones ) • Histones are positively charged and form spools around which negatively charged DNA strands wrap – Each spool and its DNA is called a nucleosome
Background image of page 6
RNA Synthesis • For transcription, RNA polymerase binds to a “start” sequence on DNA and unzips strands – Nearby are promoter regions, which regulate levels of transcription • Transcription factors must bind to promoter to initiate transcription
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
RNA Synthesis • Only one strand of DNA contains the gene and is transcribed – Its bases pair with complementary RNA bases to make mRNA • G pairs with C • A pairs with U • RNA polymerase detaches when hits a "stop" sequence
Background image of page 8
RNA Synthesis • Transcription produces four types of RNA: –pre-mRNA - altered in nucleus to form mRNA –mRNA - contains the code for synthesis of a protein – tRNA (transfer RNA) - decodes the info contained in mRNA –rRNA - forms part of ribosomes
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
RNA Synthesis • Pre-mRNA is much larger than mRNA – Contains non-coding regions called introns – Coding regions are called exons – In nucleus, introns are removed and ends of exons spliced together to produce final mRNA
Background image of page 10
RNA Synthesis • Human genome has <25,000 genes – Yet produces >100,000 different proteins – 1 gene codes for an average of 3 different proteins • Accomplished by alternative splicing of exons – This allows a given gene to produce several different mRNAs
Background image of page 11

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
RNA Synthesis • A newly discovered type of RNA is involved in regulating gene expression – These perform RNA interference (RNAi ) or silencing • Interfere with or silence expression of some genes –s iRNA (s hort i nterfering RNA) and miRNA (mi cro RNA) molecules pair in varying degrees with different mRNAs • Thereby interfering with expression of those mRNAs • 1 miRNA may interfere with up to 200 different mRNAs
Background image of page 12
Protein Synthesis • Occurs one amino acid at a time according to sequence of base triplets in mRNA • In cytoplasm, mRNA attaches to ribosomes forming a polysome where translation occurs
Background image of page 13

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 14
Background image of page 15

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 16
DNA Replication
Background image of page 17

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Background image of page 18
Background image of page 19

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Protein Synthesis • Ribosomes read 3 mRNA bases (= a triplet ) at a time – Each triplet is a codon , which specifies an amino acid – Ribosomes translate codons into an amino acid sequence that becomes a polypeptide chain
Background image of page 20
Background image of page 21

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Protein Synthesis
Background image of page 22
Image of page 23
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 11/02/2010 for the course EXB Exb 110 taught by Professor Aldringomes during the Spring '10 term at UC Davis.

Page1 / 81

Week 6 Exb 110 2010 color - EXERCISEMETABOLISM EXB110...

This preview shows document pages 1 - 23. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online