Download - Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Protein Synthesis Gene—DNA segment that carries a blueprint for building one

Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings

Protein Synthesis

Gene—DNA segment that carries a blueprint for building one protein


Protein Synthesis


RNA is needed for protein synthesis


Protein Synthesis



Transfer RNA (tRNA) .

Ribosomal RNA (rRNA) .

Messenger RNA (mRNA) .


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


You will need to know…

The functions of:

mRNA tRNA rRNA


Transcription and Translation

Transcription

Translation



Transcription

Translation

GCC TTT ATA AGG CAT DNA



Transcription

TranslationAUG CCU UAU AAA …

GCC TTT ATA AGG CAT DNA

mRNA



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



Transcription

Translation (leaves nucleus)AUG CCU UAU AAA …

GCC TTT ATA AGG CAT

AUG CCU UAU AAA …

DNA

mRNA

mRNA



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



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


Path of information:

DNARNAProtein

Transcription: in nucleus

Translation: at a ribosome


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


Protein Synthesis

Figure 3.16, step 1


DNA



Nuclear pore

Nuclear membrane

mRNA

1) mRNA is formed


Protein Synthesis

Figure 3.16, step 2


DNA




Nuclear pore

Nuclear membrane

mRNA



Codon

U G CCA U

2) mRNA leaves nucleus, joins ribosome


Protein Synthesis

Figure 3.16, step 3


DNA



Synthetaseenzyme

Amino acids



Nuclear pore

Nuclear membrane

mRNA



Codon

U G CCA U

3) tRNA linked to amino acid


Protein Synthesis

Figure 3.16, step 4


DNA



Synthetaseenzyme

Amino acids



Nuclear pore

Nuclear membrane

mRNA





Codon

U G CCA U

4) tRNA carries amino acid to ribosome


Protein Synthesis

Figure 3.16, step 5


DNA



Synthetaseenzyme

Amino acids




Nuclear pore

Nuclear membrane

mRNA






Peptide bond


Codon

AlaPhe

Ser

Gly

Met

C G G

G C UC A G CCA U

5) Ribosome connects amino acid to chain


Protein Synthesis

Figure 3.16, step 6


DNA



Synthetaseenzyme

Amino acids




Nuclear pore

Nuclear membrane

mRNA


Released tRNAreenters thecytoplasmicpool, ready tobe rechargedwith a newamino acid



Portion ofmRNA alreadytranslated



Peptide bond


Codon

AlaPhe

Ser

Gly

Met

C G G

GU UU C UCC AA G CCA U


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?


Body Tissues

Tissues--Groups of cells with similar structure and function


Body Tissues

Tissues--Groups of cells with similar structure and function

Four primary types

Epithelial tissue (epithelium)

Connective tissue

Muscle tissue

Nervous tissue


Epithelial Tissues

Locations

Body coverings, linings, glands

Functions

Protection

Absorption

Filtration

Secretion


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


Epithelium Characteristics

Figure 3.17a


Classification of Epithelia

Number of cell layers

Simple—one layer

Stratified—more than one layer

Figure 3.17a


Classification of Epithelia

Shape of cells

Squamous (flat)

Cuboidal

Columnar

Figure 3.17b


Simple Epithelia

Simple squamous

Forms membranes lining body cavities, lungs and capillaries

Single layer flat cells

The thinnest epithelium–

promotes diffusion


Simple Epithelia

Figure 3.18a


Simple Epithelia

Simple cuboidal

Common in glands and their ducts

Forms walls of kidney tubules

Covers the ovaries

Single layer cubic cellsThicker--promotes

secretion


Simple Epithelia

Figure 3.18b


Simple Epithelia

Simple columnar

Often includes mucus-producing goblet cells

Lines digestive tract

Single layer tall cellsBest epithelium for mucus production


Simple Epithelia

Figure 3.18c


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


Simple Epithelia

Figure 3.18d


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



Figure 3.18e



Stratified cuboidal

Stratified columnar

(can be mixed)

(Two) Layers Cubic cells

Layers Tall cells



Transitional epithelium

Shape of cells depends upon the amount of stretching

Lines organs of the urinary system

“Changing”



Figure 3.18f


Glandular Epithelium

Gland--cells responsible for secreting a product

Two types:

Endocrine gland

Exocrine gland


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

Download - Copyright © 2009 Pearson Education, Inc., publishing as Benjamin Cummings Protein Synthesis Gene—DNA segment that carries a blueprint for building one

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