AP Biology Chapter 8: Metabolism and Enzymes. Kinetic Energy vs. Potential Energy.
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Transcript of Chapter 4 Energy and Cellular Metabolism. About this Chapter Energy in biological systems Chemical...
Chapter 4
Energy and
Cellular Metabolism
About this Chapter
• Energy in biological systems• Chemical reactions• Enzymes• Metabolism• ATP production• Synthetic pathways
Figure 4-1
Energy: Biological Systems
• Energy transfer in the environment
Photosynthesistakes place in
plant cells, yielding:
Radiantenergy
Energy lostto environment
Heatenergy
Energy stored inbiomolecules
Sun
Respirationtakes place in
human cells, yielding:
Energy for work
Energy storedin biomolecules
H2O
+
+
Transfer of radiantor heat energy
Transfer of energyin chemical bonds
KEY
CO2
CO2
CO2 +
H2ON2
Energy: Capacity to Do Work
• Chemical work• Making and breaking of chemical bonds
• Transport work• Moving ions, molecules, and larger particles• Can create concentration gradients
• Mechanical work• Used for movement
Kinetic and Potential Energy
Figure 4-2
Thermodynamic Energy
• First law of Thermodynamics• Total amount of energy in the universe is
constant
• Second law of Thermodynamics• Processes move from state of order to disorder
Figure 4-3
Chemical Reactions: Overview
• Activation energy is the energy that must be put into reactants before a reaction can proceed
• A + B C + D
Chemical Reactions: Exergonic and endergonic
Figure 4-4
KEY
Activation energy
Activation energy
Net freeenergychange
C+D
A+B G+H
Net freeenergychange
E+F
Reactants
Activation of reaction
Reaction process
Products
(a) Exergonic reactions (b) Endergonic reactions
Chemical Reactions: Coupling
Figure 4-5
Enzymes: Overview
• Isozymes • Catalyze same reaction, but under different
conditions
• May be activated, inactivated, or modulated• Coenzymes vitamins• Chemical modulators temperature and pH
Enzymes: Lower activation energy
Figure 4-6
KEY
Net freeenergychange
Activation energy
C+D
ReactantsActivation of reactionReaction processProducts
A+B
Enzymes: Law of Mass Action
Figure 4-9a
Enzymes: Law of Mass Action
Figure 4-9b
Enzymes: Types of Reactions
Table 4-4
Figure 4-10
Metabolism: Overview
• A group of metabolic pathways resembles a road map
Metabolism: Cell Regulation
1. Controlling enzyme concentrations
2. Producing allosteric and covalent modulators
3. Using different enzymes for reversible reactions
4. Isolating enzymes within organelles
5. Maintaining optimum ratio of ATP to ADP
Metabolism: Cell Regulation
Figure 4-11
Feedback inhibition
enzyme 3enzyme 2enzyme 1
Metabolism: Cell Regulation
Figure 4-12
H2OCO2 PO4 PO4
(a)
Carbonic acid Glucose 6-phosphate
Glucose + +Glucose
Glucose 6-phosphate
(c)(b)
carbonicanhydrase
carbonicanhydrase
glucose 6-phosphatase
hexokinasehexokinase
+
Figure 4-13
ATP Production: Overview
• Overview of aerobic pathways for ATP production
Glycerol
Fatty acids
Aminoacids
Aminoacids
Aminoacids
CO2
ADP
Cytosol
Mitochondrion
ATP
ADP
GLYCOLYSIS
Pyruvate
Acetyl CoA
Glucose
H2OO2
High-energy electronsand H+
ELECTRON TRANSPORT SYSTEMATP
ADP
CITRICACID
CYCLE
ATP
High-energyelectrons
Acetyl CoA
Citric acidcycle
Figure 4-14
ATP Production: Glycolysis
Glucose + 2 NAD+ + 2 ADP + P
2 Pyruvate + 2 ATP + 2 NADH + 2 H+ + 2 H20
Glucose 6-phosphate
Fructose 6-phosphate
Fructose 1,6-bisphosphate
Dihydroxyacetonephosphate
ATP
ADP
ATP
ADP
This sectionhappens twicefor each glucosemolecule that begins glycolysis
= Carbon= Oxygen= Phosphate group
(side groups not shown)
Glyceraldehyde 3-phosphate
1, 3-Bisphosphoglycerate
3-Phosphoglycerate
2-Phosphoglycerate
Phosphoenol pyruvate
Pyruvate
ADP
Glucose
H2O
NADH
KEY
ATP
ATP
NAD+
ADP
Figure 4-15
ATP Production: Pyruvate Metabolism
• Pyruvate can be converted into lactate or acetyl CoA
Pyruvate
Acetyl CoA
H and –OH not shown
= Carbon= Oxygen
= Coenzyme A
KEY
Acetyl CoA
Acyl unit
CoA
CoA
Cytosol
Mitochondrialmatrix
Pyruvate
Pyruvate
Lactate
NAD+
CO2
NADH
NADH
NAD+
Anaerobic Aerobic
CITRIC ACIDCYCLE
CoA
Figure 4-16
ATP Production: Citric Acid Cycle
• Acetyl CoA enters the citric acid cycle producing3 NADH, 1 FADH2, and 1 ATP
KEY
High-energyelectrons
Acetyl CoA
Citric acidcycle
Fumarate (4C)
Malate (4C)
Oxaloacetate (4C)
H2O
Side groups not shown
FADH2
NADH
NAD+
Acetyl CoACoA
CoA
CoA
= Carbon
= Oxygen
= Coenzyme A
Citrate (6C)
a Ketoglutarate (5C)
Succinyl CoA (4C)Succinate (4C)
ATP
CO2
CO2
NADH
NADHFAD
NAD+
ADP
CITRIC ACID CYCLE
CoA
GDP + PiGTP
CoA
NAD+
Isocitrate (6C)
CoA
ATP Production: Electron Transport
Figure 4-17
H+
H+
H+H+
Mitochondrialmatrix
Matrix pool of H+
4e–
e–
Innermitochondrial
membrane
ADP+ Pi
CITRICACID
CYCLE
High-energy electrons
O2+2 H2O
ATP
H+
H+
Cytosol
Outermitochondrial
membrane
High-energy electronsfrom glycolysis
H+
Intermembranespace
Energy released during metabolism is captured by high-energy electrons carried by NADH andFADH2.
Energy from high-energy electrons moving along the electron transport system pumps H+ from the matrix into the intermembrane space.
Electrons at the end of theelectron transport system are back to their normal energy state. They combine with H+ and oxygen to form water.
Potential energy captured inthe H+ concentration gradient is converted to kinetic energy when H+ ions pass through theATP synthase. Some of the kinetic energy is captured as ATP.
1
1 2 3 4
2
3
4
ATP
synthase
ELECTRON TRANSPORT SYSTEM
ATP Production: Electron Transport
Figure 4-17, step 1
Mitochondrialmatrix
e–
Innermitochondrial
membrane
CITRICACID
CYCLE
High-energy electrons
Cytosol
Outermitochondrial
membrane
High-energy electronsfrom glycolysis
Intermembranespace
Energy released during metabolism is captured by high-energy electrons carried by NADH andFADH2.
1
1
ELECTRON TRANSPORT SYSTEM
ATP Production: Electron Transport
Figure 4-17, steps 1–2
H+
H+H+
Mitochondrialmatrix
e–
e–
Innermitochondrial
membrane
CITRICACID
CYCLE
High-energy electrons
H+
H+
Cytosol
Outermitochondrial
membrane
High-energy electronsfrom glycolysis
H+
Intermembranespace
Energy released during metabolism is captured by high-energy electrons carried by NADH andFADH2.
Energy from high-energy electrons moving along the electron transport system pumps H+ from the matrix into the intermembrane space.
1
1 2
2
ELECTRON TRANSPORT SYSTEM
ATP Production: Electron Transport
Figure 4-17, steps 1–3
H+
H+H+
Mitochondrialmatrix
Matrix pool of H+
4e–
e–
Innermitochondrial
membrane
CITRICACID
CYCLE
High-energy electrons
O2+2 H2O
H+
H+
Cytosol
Outermitochondrial
membrane
High-energy electronsfrom glycolysis
H+
Intermembranespace
Energy released during metabolism is captured by high-energy electrons carried by NADH andFADH2.
Energy from high-energy electrons moving along the electron transport system pumps H+ from the matrix into the intermembrane space.
Electrons at the end of theelectron transport system are back to their normal energy state. They combine with H+ and oxygen to form water.
1
1 2 3
2
3
ELECTRON TRANSPORT SYSTEM
H+
H+
H+H+
Mitochondrialmatrix
Matrix pool of H+
4e–
e–
Innermitochondrial
membrane
ADP+ Pi
CITRICACID
CYCLE
High-energy electrons
O2+2 H2O
ATP
H+
H+
Cytosol
Outermitochondrial
membrane
High-energy electronsfrom glycolysis
H+
Intermembranespace
Energy released during metabolism is captured by high-energy electrons carried by NADH andFADH2.
Energy from high-energy electrons moving along the electron transport system pumps H+ from the matrix into the intermembrane space.
Electrons at the end of theelectron transport system are back to their normal energy state. They combine with H+ and oxygen to form water.
Potential energy captured inthe H+ concentration gradient is converted to kinetic energy when H+ ions pass through theATP synthase. Some of the kinetic energy is captured as ATP.
1
1 2 3 4
2
3
4
ATP
synthase
ELECTRON TRANSPORT SYSTEM
Figure 4-17, steps 1–4
ATP Production: Electron Transport
NADH and FADH2 ATP by oxidative phosphorylation
ATP Production: Energy Yield
Figure 4-18
2 Acetyl CoA
Citric acidcycle
NADH ATP CO2FADH2
2*+4
–2
2 2
NADH ATP CO2FADH2
2 4
–2
–2
6 2 2
26-28
30-32ATP
6H2O
6CO2
2ATP
0NADH4
AEROBIC METABOLISM C6H12O6 + 6 O2 6 CO2 + 6 H2O ANAEROBIC METABOLISM C6H12O6 2 C3H6O3 (Lactic acid)
* Cytoplasmic NADH sometimes yield only 1.5 ATP/NADH instead of 2.5 ATP/NADH.
TOTALS
TOTALS
GLYCOLYSIS
ELECTRON TRANSPORTSYSTEM
2 Pyruvate
1 Glucose
High-energy electronsand H+
6 O2
2 Pyruvate
2 Lactic acid
1 Glucose
GLYCOLYSIS
ATP Production: Large Biomolecules
• Glycogenolysis• Glycogen• Storage form of glucose in liver and skeletal
muscle• Converted to glucose or glucose 6-phosphate
Figure 4-20
ATP Production: Protein Catabolism and Deamination
(a) Protein catabolism
NADH + H+NAD + H2O
H2OHydrolysis ofpeptide bond
Peptide
Protein or Peptide
Amino acid
Deamination
NH3
Organic acid
Ammonia
Amino acid
(b) Deamination
Glycolysis orcitric acid cycle
NH4+
H+
UreaAmmonia Ammonium
(c)+
+
NH3
ATP Production: Lipolysis
Figure 4-21
Triglyceride
Fatty acid
Cytosol
Lipases digest triglyceridesinto glycerol and 3 fatty acids.
Glycerol becomes aglycolysis substrate.
b-oxidation chops 2-carbonacyl units off the fatty acids.
Glucose
Glycerol
GLYCOLYSIS
Pyruvate
Mitochondrialmatrix
CoA
CoAAcetyl CoA
CO2
CITRICACID
CYCLE
Acyl units become acetylCoA and can be used in the citric acid cycle.
Acyl unit
b-oxidation
11
22
3
3
44
Synthesis: Gluconeogenesis
Figure 4-22
Pyruvate
Glucose
Liver, kidney
GLYCEROL
AMINO ACIDS
AMINO ACIDS
Glucose 6-phosphate
GLUCONEOGENESIS
Glucosesynthesis
LACTATE
Synthesis: Lipids
Figure 4-23
CoA
Fatty acidsynthetase
Glycerol
Fatty acids
Triglyceride
GLYCOLYSIS
Glucose
Acylunit
Glycerol can be made from glucose through glycolysis.
Two-carbon acyl units from acetyl CoAare linked together by fatty acid synthetase to form fatty acids.
One glycerol plus 3 fatty acidsmake a triglyceride.
Pyruvate
Acetyl CoA
1
2
3
1 32
Synthesis: Lipids
Figure 4-23, steps 1
CoA
Glycerol
GLYCOLYSIS
Glucose
Acylunit
Glycerol can be made from glucose through glycolysis.
Pyruvate
Acetyl CoA
1
1
Synthesis: Lipids
Figure 4-23, steps 1–2
Fatty acidsynthetase
Glycerol
Fatty acidsAcylunit
Two-carbon acyl units from acetyl CoAare linked together by fatty acid synthetase to form fatty acids.
2
2
CoA
GLYCOLYSIS
Glucose
Acylunit
Glycerol can be made from glucose through glycolysis.
Pyruvate
Acetyl CoA
1
1
Synthesis: Lipids
Figure 4-23, steps 1–3
CoA
Fatty acidsynthetase
Glycerol
Fatty acids
Triglyceride
GLYCOLYSIS
Glucose
Acylunit
Glycerol can be made from glucose through glycolysis.
One glycerol plus 3 fatty acidsmake a triglyceride.
Pyruvate
Acetyl CoA
1
2
3
1 32 Two-carbon acyl units from acetyl CoAare linked together by fatty acid synthetase to form fatty acids.
Synthesis: DNA to Protein
Figure 4-25
1 GENE ACTIVATION
TRANSCRIPTION
mRNA PROCESSING
TRANSLATION
POST-TRANSLATIONALMODIFICATION
Gene Regulatory proteins
Constitutivelyactive
Induction
Alternativesplicing
ProcessedmRNA
Interference
mRNA
Protein chain
Repression
Regulatedactivity
siRNA
mRNA “silenced”
• rRNA in ribosomes• tRNA• Amino acids
Folding andcross-links
Assembly intopolymeric proteins
Addition of groups: • sugars • lipids • -CH3
• phosphate
Cleavage intosmaller peptides
Cytoplasm
Nucleus
2
3
4
5
Synthesis: DNA to Protein
Figure 4-25, steps 1
1 GENE ACTIVATION
Gene Regulatory proteins
Constitutivelyactive
Induction Repression
Regulatedactivity
Cytoplasm
Nucleus
Synthesis: DNA to Protein
Figure 4-25, steps 1–2
1 GENE ACTIVATION
TRANSCRIPTION
Gene Regulatory proteins
Constitutivelyactive
Induction
mRNA
Repression
Regulatedactivity
Cytoplasm
Nucleus
2
Synthesis: DNA to Protein
Figure 4-25, steps 1–3
1 GENE ACTIVATION
TRANSCRIPTION
mRNA PROCESSING
Gene Regulatory proteins
Constitutivelyactive
Induction
Alternativesplicing
ProcessedmRNA
Interference
mRNA
Repression
Regulatedactivity
siRNA
mRNA “silenced”
Cytoplasm
Nucleus
2
3
Synthesis: DNA to Protein
Figure 4-25, steps 1–4
1 GENE ACTIVATION
TRANSCRIPTION
mRNA PROCESSING
TRANSLATION
Gene Regulatory proteins
Constitutivelyactive
Induction
Alternativesplicing
ProcessedmRNA
Interference
mRNA
Protein chain
Repression
Regulatedactivity
siRNA
mRNA “silenced”
• rRNA in ribosomes• tRNA• Amino acids
Cytoplasm
Nucleus
2
3
4
Synthesis: DNA to Protein
Figure 4-25, steps 1–5
1 GENE ACTIVATION
TRANSCRIPTION
mRNA PROCESSING
TRANSLATION
POST-TRANSLATIONALMODIFICATION
Gene Regulatory proteins
Constitutivelyactive
Induction
Alternativesplicing
ProcessedmRNA
Interference
mRNA
Protein chain
Repression
Regulatedactivity
siRNA
mRNA “silenced”
• rRNA in ribosomes• tRNA• Amino acids
Folding andcross-links
Assembly intopolymeric proteins
Addition of groups: • sugars • lipids • -CH3
• phosphate
Cleavage intosmaller peptides
Cytoplasm
Nucleus
2
3
4
5
Protein: Transcription
Figure 4-26
RNA polymerase binds to DNA.
The section of DNA that containsthe gene unwinds.
RNA bases bind to DNA,creating a single strand of mRNA.
mRNA and the RNA polymerasedetach from DNA, and the mRNAgoes to the cytoplasm.
RNApolymerase
RNApolymerase
mRNA strand released
mRNAtranscript
RNApolymerase
DNA
Sensestrand
Antisensestrand
Site ofnucleotide assembly
Leaves nucleusafter processing
LengtheningmRNA strand
RNA bases
1
2
3
4
Protein: Transcription
Figure 4-27
Introns removedIntrons removed
Transcribed sectionPromoter
DNA
UnprocessedmRNA
Exons for protein #1 Exons for protein #2
Gene
Antisense strand
Sensestrand
TRANSCRIPTION
Protein: Transcription and Translation
Figure 4-28
1
Translation
Termination
Outgoing “empty” tRNA
tRNA
mRNA
Amino acid
Ribosomalsubunits
Completedpeptide
Growingpeptidechain
mRNA Ribosome
Incoming tRNAbound to anamino acid
Anticodon
Transcription
mRNA processing
Attachment of ribosomal subunits
RNApolymerase
DNA
Nuclearmembrane
2
3
4
5
Protein: Transcription and Translation
Figure 4-28, steps 1
1
RNApolymerase
DNA
Nuclearmembrane
Transcription
Protein: Transcription and Translation
Figure 4-28, steps 1–2
1
RNApolymerase
DNA
Nuclearmembrane
2
Transcription
mRNA processing
Protein: Transcription and Translation
Figure 4-28, steps 1–3
1
RNApolymerase
DNA
Nuclearmembrane
2
3
Transcription
mRNA processing
Attachment of ribosomal subunits
Protein: Transcription and Translation
Figure 4-28, steps 1–4
1
Outgoing “empty” tRNA
tRNA
Amino acid
Growingpeptidechain
mRNA Ribosome
Incoming tRNAbound to anamino acid
Anticodon
RNApolymerase
DNA
Nuclearmembrane
2
3
4 Translation
Transcription
mRNA processing
Attachment of ribosomal subunits
Protein: Transcription and Translation
Figure 4-28, steps 1–5
1
Translation
Termination
Outgoing “empty” tRNA
tRNA
mRNA
Amino acid
Ribosomalsubunits
Completedpeptide
Growingpeptidechain
mRNA Ribosome
Incoming tRNAbound to anamino acid
Anticodon
Transcription
mRNA processing
Attachment of ribosomal subunits
RNApolymerase
DNA
Nuclearmembrane
2
3
4
5
Protein: Post-Translational Modification
• Protein folding• Cross-linkage• Cleavage• Addition of other molecules or groups• Assembly into polymeric proteins
Figure 4-29
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Gogli cisternae migrate fromthe cis-face toward the cellmembrane.
Some vesicles bud off thecisterna and move in aretrograde fashion.
At the trans-face, some vesicles bud off to form lysosomes.
Other vesicles becomesecretory vesicles that releasetheir contents outside the cell.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
7
8
10
9
5
6
7
8
10
9
mRNA is transcribed from thegenes in the DNA.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
Figure 4-29, steps 1
Protein: Post-Translational Modification and the Secretory Pathway
1
1
Figure 4-29, steps 1–2
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
2
Figure 4-29, steps 1–3
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
2
Figure 4-29, steps 1–4
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
4
2
Figure 4-29, steps 1–5
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
4
2
5
Figure 4-29, steps 1–6
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
5
6
Figure 4-29, steps 1–7
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Gogli cisternae migrate fromthe cis-face toward the cellmembrane.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
7
5
6
7
Figure 4-29, steps 1–8
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Gogli cisternae migrate fromthe cis-face toward the cellmembrane.
Some vesicles bud off thecisterna and move in aretrograde fashion.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
7
8
5
6
7
8
Figure 4-29, steps 1–9
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Gogli cisternae migrate fromthe cis-face toward the cellmembrane.
Some vesicles bud off thecisterna and move in aretrograde fashion.
At the trans-face, some vesicles bud off to form lysosomes.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
7
8
9
5
6
7
8
9
Figure 4-29, steps 1–10
Protein: Post-Translational Modification and the Secretory Pathway
mRNA is transcribed from thegenes in the DNA.
mRNA leaves the nucleusand attaches to cytosolicribosomes, initiating translation and protein synthesis.
Some proteins are released byfree ribosomes into the cytosolor are targeted to specific organelles.
Ribosomes attached to therough endoplasmic reticulumdirect proteins destined forpackaging into the lumen of the RER.
Proteins are modified as theypass through the lumen ofthe ER.
Transport vesicles move theproteins from the ER to theGolgi complex.
Gogli cisternae migrate fromthe cis-face toward the cellmembrane.
Some vesicles bud off thecisterna and move in aretrograde fashion.
At the trans-face, some vesicles bud off to form lysosomes.
Other vesicles becomesecretory vesicles that releasetheir contents outside the cell.
Cytosolicprotein
Endoplasmicreticulum
Transport vesicle
RetrogradeGolgi-ERtransport
Cis-Golgi complex
Lysosome orstorage vesicle
Trans-Golgicomplex
Secretoryvesicle
Cellmembrane Extracellular space
Cytosol
Cisterna
Nucleus
mRNA
DNA
Ribosome
Growingamino-acid
chain
Targetedproteins
Peroxisome
Mitochondrion
Nuclearpore
1
1
2
3
3
4
5
6
4
2
7
8
10
9
5
6
7
8
10
9
Summary
• Energy• Chemical• Transport• Mechanical
• Kinetic energy• Potential energy
Summary
• Chemical reactions• Reactants• Products• Reaction rate
• Free energy and activation energy • Exergonic versus endergonic reactions• Reversible versus irreversible reactions
Summary
• Enzymes• Definition • Characteristics• Law of mass action• Type of reactions
Summary
• Metabolism• Catabolic versus anabolic reactions• Control of metabolic pathways• Aerobic versus anaerobic pathways
Summary
• ATP production• Glycolysis• Pyruvate metabolism• Citric acid cycle• Electron transport chain
• Glycogen, protein, and lipid metabolism
Summary
• Synthetic pathways• Gluconeogenesis • Lipid synthesis• Protein synthesis• Transcription• Translation• Post-translational modification