copyright © 2009 pearson education, inc., publishing as benjamin cummings protein synthesis ...
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Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Gene—DNA segment that carries a blueprint for building one protein
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Gene—DNA segment that carries a blueprint for building one protein
RNA is needed for protein synthesis
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Gene—DNA segment that carries a blueprint for building one protein
RNA is needed for protein synthesis
Transfer RNA (tRNA) .
Ribosomal RNA (rRNA) .
Messenger RNA (mRNA) .
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Gene—DNA segment that carries a blueprint for building one protein
RNA is needed for protein synthesis
Transfer RNA (tRNA)--Transfers amino acids to ribosome for building the protein
Ribosomal RNA (rRNA)--Helps form the ribosomes where proteins are built
Messenger RNA (mRNA)--Carries instructions for building protein from nucleus to ribosome
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You will need to know…
The functions of:
mRNA tRNA rRNA
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Transcription and Translation
Transcription
Translation
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Transcription and Translation
Transcription
Translation
GCC TTT ATA AGG CAT DNA
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription and Translation
Transcription
TranslationAUG CCU UAU AAA …
GCC TTT ATA AGG CAT DNA
mRNA
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription and Translation
Transcription
Transfer of information from DNA’s base sequence to the complimentary base sequence of mRNA
Three-base sequences on mRNA are called codons
Translation
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Transcription and Translation
Transcription
Translation (leaves nucleus)AUG CCU UAU AAA …
GCC TTT ATA AGG CAT
AUG CCU UAU AAA …
DNA
mRNA
mRNA
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription and Translation
Transcription
Translation (leaves nucleus)AUG CCU UAU AAA …
GCC TTT ATA AGG CAT
AUG CCU UAU AAA …
Met- Pro- Tyr - Lys …
DNA
Amino acid chain—will become a protein
mRNA
mRNA
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Transcription and Translation
Transcription
Transfer of information from DNA’s base sequence to the complimentary base sequence of mRNA
Three-base sequences on mRNA are called codons
Translation
Base sequence of nucleic acid is translated to an amino acid sequence
Amino acids are the building blocks of proteins
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Path of information:
DNARNAProtein
Transcription: in nucleus
Translation: at a ribosome
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Protein Synthesis
Figure 3.16
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Synthetaseenzyme
Amino acids
Cytoplasm(site of translation)
Correct aminoacid attachedto each speciesof tRNA by anenzyme
Growing polypeptide chain
Nuclear pore
Nuclear membrane
mRNA
As the ribosomemoves along themRNA, a new aminoacid is added tothe growing proteinchain
Released tRNAreenters thecytoplasmicpool, ready tobe rechargedwith a newamino acid
Direction of ribosomeadvance; ribosome movesthe mRNA strand alongsequentially as each codonis read
Small ribosomalsubunit
Portion ofmRNA alreadytranslated
tRNA “head” bearinganticodon
Large ribosomal subunit
Peptide bond
Incoming tRNArecognizes acomplementarymRNA codon callingfor its amino acid bybinding via itsanticodon to thecodon
Codon
AlaPhe
Ser
Gly
Met
C G G
GU UU C UCC AA G CCA U
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Protein Synthesis
Figure 3.16, step 1
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
Cytoplasm(site of translation)
Nuclear pore
Nuclear membrane
mRNA
1) mRNA is formed
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Protein Synthesis
Figure 3.16, step 2
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Cytoplasm(site of translation)
Nuclear pore
Nuclear membrane
mRNA
Small ribosomalsubunit
Large ribosomal subunit
Codon
U G CCA U
2) mRNA leaves nucleus, joins ribosome
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Figure 3.16, step 3
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Synthetaseenzyme
Amino acids
Cytoplasm(site of translation)
Correct aminoacid attachedto each speciesof tRNA by anenzyme
Nuclear pore
Nuclear membrane
mRNA
Small ribosomalsubunit
Large ribosomal subunit
Codon
U G CCA U
3) tRNA linked to amino acid
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Figure 3.16, step 4
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Synthetaseenzyme
Amino acids
Cytoplasm(site of translation)
Correct aminoacid attachedto each speciesof tRNA by anenzyme
Nuclear pore
Nuclear membrane
mRNA
Small ribosomalsubunit
tRNA “head” bearinganticodon
Large ribosomal subunit
Incoming tRNArecognizes acomplementarymRNA codon callingfor its amino acid bybinding via itsanticodon to thecodon
Codon
U G CCA U
4) tRNA carries amino acid to ribosome
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Figure 3.16, step 5
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Synthetaseenzyme
Amino acids
Cytoplasm(site of translation)
Correct aminoacid attachedto each speciesof tRNA by anenzyme
Growing polypeptide chain
Nuclear pore
Nuclear membrane
mRNA
As the ribosomemoves along themRNA, a new aminoacid is added tothe growing proteinchain
Direction of ribosomeadvance; ribosome movesthe mRNA strand alongsequentially as each codonis read
Small ribosomalsubunit
tRNA “head” bearinganticodon
Large ribosomal subunit
Peptide bond
Incoming tRNArecognizes acomplementarymRNA codon callingfor its amino acid bybinding via itsanticodon to thecodon
Codon
AlaPhe
Ser
Gly
Met
C G G
G C UC A G CCA U
5) Ribosome connects amino acid to chain
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Protein Synthesis
Figure 3.16, step 6
Nucleus(site of transcription)
DNA
mRNA specifyingone polypeptideis made onDNA template
mRNA leavesnucleus andattaches toribosome, andtranslationbegins
Synthetaseenzyme
Amino acids
Cytoplasm(site of translation)
Correct aminoacid attachedto each speciesof tRNA by anenzyme
Growing polypeptide chain
Nuclear pore
Nuclear membrane
mRNA
As the ribosomemoves along themRNA, a new aminoacid is added tothe growing proteinchain
Released tRNAreenters thecytoplasmicpool, ready tobe rechargedwith a newamino acid
Direction of ribosomeadvance; ribosome movesthe mRNA strand alongsequentially as each codonis read
Small ribosomalsubunit
Portion ofmRNA alreadytranslated
tRNA “head” bearinganticodon
Large ribosomal subunit
Peptide bond
Incoming tRNArecognizes acomplementarymRNA codon callingfor its amino acid bybinding via itsanticodon to thecodon
Codon
AlaPhe
Ser
Gly
Met
C G G
GU UU C UCC AA G CCA U
Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings
Aptitude Check
Can you:
Describe the structure and function of the cell parts?
Distinguish between types of transport?
Identify the stages of mitosis?
Describe the functions of 3 types of RNA?
Describe the processes of translation and transcription?
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Body Tissues
Tissues--Groups of cells with similar structure and function
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Body Tissues
Tissues--Groups of cells with similar structure and function
Four primary types
Epithelial tissue (epithelium)
Connective tissue
Muscle tissue
Nervous tissue
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Epithelial Tissues
Locations
Body coverings, linings, glands
Functions
Protection
Absorption
Filtration
Secretion
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Epithelium Characteristics
Cells fit closely together and often form sheets
The apical surface is the free surface
The lower surface rests on a basement membrane
Avascular (no blood supply)
Regenerate easily
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Epithelium Characteristics
Figure 3.17a
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Classification of Epithelia
Number of cell layers
Simple—one layer
Stratified—more than one layer
Figure 3.17a
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Classification of Epithelia
Shape of cells
Squamous (flat)
Cuboidal
Columnar
Figure 3.17b
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Simple Epithelia
Simple squamous
Forms membranes lining body cavities, lungs and capillaries
Single layer flat cells
The thinnest epithelium–
promotes diffusion
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Simple Epithelia
Figure 3.18a
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Simple Epithelia
Simple cuboidal
Common in glands and their ducts
Forms walls of kidney tubules
Covers the ovaries
Single layer cubic cellsThicker--promotes
secretion
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Simple Epithelia
Figure 3.18b
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Simple Epithelia
Simple columnar
Often includes mucus-producing goblet cells
Lines digestive tract
Single layer tall cellsBest epithelium for mucus production
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Simple Epithelia
Figure 3.18c
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Simple Epithelia
Pseudostratified columnar
Often looks like a double layer of cells
Sometimes ciliated, such as in the respiratory tract
May function in absorption or secretion
Not really more than one layer
tall cellsCilia move
mucus
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Simple Epithelia
Figure 3.18d
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Stratified Epithelia
Stratified squamous
Cells at the apical surface are flattened
Found as a protective covering where friction is common (skin, mouth and esophagus)
Layers flat cells
Oldest, driest, deadest cells are on the surface
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Stratified Epithelia
Figure 3.18e
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Stratified Epithelia
Stratified cuboidal
Stratified columnar
(can be mixed)
(Two) Layers Cubic cells
Layers Tall cells
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Stratified Epithelia
Transitional epithelium
Shape of cells depends upon the amount of stretching
Lines organs of the urinary system
“Changing”
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Stratified Epithelia
Figure 3.18f
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Glandular Epithelium
Gland--cells responsible for secreting a product
Two types:
Endocrine gland
Exocrine gland
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Glandular Epithelium
Gland--cells responsible for secreting a product
Two types:
Endocrine gland
Ductless: secretions diffuse into blood vessels
Secretions are hormones
Exocrine gland
Secretions empty through ducts to the epithelial surface
Include sweat and oil glands