Week 10
Cellular Respiration ppt
Defined as the flow of electronsm, through or within a membrane, from reduced coenzymes to an external electron acceptor, ususalluy accompanied by the generation of ATP
results in the complete oxidation of substrates to CO2
Drastically increases the yield of ATP form that of glycolysis alone
Takes place mostly in the mitochondria of animals
Electrons are removed from organic substrates and transferred to coenzymes carriers, which the transfer these electrons to oxygen
Oxygen in the terminal are torn acceptor, therefore the overall oxygen-requiring process in known as aerobic respiration
Oxygen is reduced to water
5 stage of Aerobic respiration
Glycolytic pathway
1 glucose is cleaved forming 2 pyruvate molecules
Pyruvate oxidation
Pyruvate is oxidized to acetylene coenzyme A
The citric acid cycle
Oxidation of acetylene CoA to OC2
Stored energy in high energy reduced coenzymes
Electron transport
Electrons are transferred from reduced coenzymes to oxygen, which is coupled with active transport of protons across a membrane
Oxidative phosphorylation
Synthesis of ATP
Mitochondria:
where most of the aerobic repiration occurs
Posses their own DNA that independent of the nuclear DNA
Found in higher numbers in tissues with a high energy demand (Skeletal muscle)
Can replicate themselves due to increase need for ATP (endurance sports)
Only from the Ovum. Sperm cells don;t contribute mitochondria to reproduction
Comprised of
Outer membrane
Not a significant permeability barrier for ions and small molecules
Has transmembrane Chanel proteins called Porins that permit passage of siolutes with molecular weights of up to 5000
Inner membrane
Cristae are in folding of the inner membrane
Creates more surface area, making it 5X larger than the outer membrane
Allow the inner membrane to accommodate large numbers of the protein complexes needed for
Solute transport
Electron transport
ATP synthesis (ATP synthase)
Intercristal spaces
Provide numerous regions where protons can accumulate during the electron transport process
Impermeable to most solutes
Partitions mitochondria into 2 compartments
Intermembrane space
Mitochondrial Matrix
Inner boundary membrane
Portion of the inner membrane adjacent to the intermembrane space
Matrix:
Semifluid found in the interior of the organelle
Contains enzymes, DNA (15,000-20,000 base pairs) and ribosomes
Mutation of mitochondria DNA can lead to human disease (neurodegeneration, mitochondrial myopathies, etc)
Bacteria:
don’t have mitochondria, but may are capable of aerobic respiration, which takes place in the:
Cytoplasm
Contains the enzymes of the citric acid cycle
Plasma membrane
Contains electron transport proteins.
Citric Acid Cylce
AKA Tricarboxylic acid cycle (TCA), or the Krebs Cycle
Before the cycle begins, pyruvate mist pass through portions int he mitochondrial outer membrane into he inter membrane space
Once inside this space, pyruvate is transported across the inner membrane by a specific pyruvate symport protein (co-transported with a proton)
Once inside the mitochondrial matrix, pyruvate is concerted to Acetylene CoA by the pyruvate Dehydrogenase complex (PDH), which consists of
3 different enzymes
5 coenzymes
2 regulatory proteins
This reaction is known as the oxidative decarboxylation of pyruvate
The cycle begins with the entry of acetylene CoA and its chemical reaction with oxaloacetate to form citrate
CoA contains the B5 vitamin: pantothenic acid
Citrate goes from a 6-carbon compound, to a 5- carbon compound, to a 4-carbon compound
Catabolism of Non-carbohydrates
the citric acid cycle also plays a role in catabolism of fats and proteins
As glycogen store are nearing depletion, animalsbegi to catabolize fats
Once fat sores are depleted, animals to catabolize proteins (starvation, marathon runners)
Catabolism of Fats
most fat is stored as Triglycerides
The catabolism begins with their hydrolysis to glycerol and free fatty acids
Glycerol is channeled into the glycolytic pathway by oxidative conversions to dihydroxyacetone phosphate
The fatty acid bonds to CoA to form fatty acrylic CoAs, which are then degraded by B oxidation
The initial energy required in activation step of B oxidation takes place in the cytosol
It involves the 2nd B carbon from the carboxylic acid
The fatty acrylic CoA then enters the mitochondria
In Bacteria, B oxidation occurs solely in the cytoplasm
Byproducts of fat catabolism
excessive fat catabolism can deplete from CoA (there may not be enough CoA to keep up with demands for ATP synthesis
This will lead to the incomplete oxidation of fats and therefore, the accumulation of ketone bodies
Acetone
Acetoacetate
B_hydroxybutyrate
An accumulation of These are bad for your kidneys
The accumulation of ketone bodies is known as Ketosis
Large quantities o ketone ill lower blood pH, results in ketoacidosis
Ketoacidosis is often seen in uncontrolled diabetes
Catabolism of Proteins
Once glycogen and lipid stores are depletes, organisms will begin to catabolize proteins
This process begins with proteolysis (hydrolysis) of te peptide bones lignin amino acids together in a polypeptide chain
Proteolysis requires enzymes called proteases
The end products of proteolysis are small peptides and free amino acids
Peptides are further digested by peptidases
Of the 20amino acids found in proteins, only 3 give use o pyruvate or citric acid cycle intermediates directly
Alanine
Aspartame
Glutamate
All other amino acids require more complicated pathways, but ultimately also come citric acid cycle intermediates
Electron transport
the TCA cycle begins with a reaction between Acetylene CoA and oxaloacetate to form citrate
At the end of their cycles oxaloacetate is reformed
But the time oxaloacetate is reformed, only 10% of the possible number of ATP is formed
The energy for the remaining amount of ATP is stored in the reduced coenzymes NADH and FADH2
The process of coenzyme reoxidation by the transfer of electrons to oxygen
The is process is accompanied by ATP synthesis
NADH+H+1/2O2 _>NAD+ +H2O (Yields 52.4 kcal/mol)
FADH2 + 1/2O2 → FAD + H2O (yields 45.9 kcal/mol)
Electron Transport System (ETS)
A multi-step process involving a series of reversible oxidizable electron carriers that function together
The ETS contains a number or integral membrane proteins situated in the inner mitochondrial membrane of Eukaryotes and the plasma membrane of bacteria
carriers the make up the ETS include
Flavoproterins (FAD)
Iron-suffer proteins
Cytochromes (also contains iron)
Copper-containing cytochromes
Coenzyme Q (ubiquinone)
The only non proteins component of the ETS
Energy yield of Cellular Respiration
~38 ATP Per glucose max
Glycolysis alone yields:
2 ATP
2 Pyruvate acid
2 NADH + H+
DNA and Chromosomes ppt
DNA is found in the nucleus and never leaves the nucleus
DNA is a polymer tht consists of 2 long strands of nucleotides which are monomers
The 2 strands twist around one another to form a twisted ladder called a Double Helix
Nucleotides:
5-carbon sugar (deoxyribose)
A phosphate group
1 or 4 nitrogen-containing aromatic bases
2 categories
Purines
Adenine
Guanine
Pyriidines
Thiamine
Cytosine
The phosphate and sugar components creates the DNA backbone of each strand
Nitrogen-containing bases attach to the sugar component of the backbone
Two strands of DNA are bonded by Hydrogen bonding between their bases
All other bonds in DNA are covalent
The nucleotides of each strand are oriented in opposite directions
Known as the “antiparallel orientation”
Double helix creates major and minor grooves
Regulatory proteins attach to the major grooves
The length of DNA is measured in base pairs (bp) and sometimes in the kilobase (kb) unit
The human genome contains ~3 billion base pairs
The double helix can be twisted upon itself to form a supercoil but can also exist in a non-supercoiled relaxed state
It supercoils during cell division
DNA frequently transitions between he supercoiled and relaxed state, a process catalyzed by enzymes (known as Topoisomerases)
Topoisomerase I will break a single strand of DNA
The DNA rotates, the intact strand passes through the break
Then the break is resealed
Topoisomerase II uses ATP to break both strands
An intact portion of the DNA strand with passed through the break
Then the break is resealed
After uncoiling, the 2 strands of nucleotides can separate fro one another
Separation of the strands is needed for DNA replication and Transcription (RNA synthesis)
DNA Transcription and Translation will be on boards
DNA packaging:
an enormous amount fo DNA must be packed into the nucleus of a cell
To do so, DNA is wrapped around proteins to form chromosomes
Small amounts of additional DNA for nonessential functions are called plasmids
once bound to these proteins, DNA is called chromatin, which appear as fibers under a light microscope
These fibers condense during mitosis and becom recognizable chromosomes
The proteins with the most important role in chromatin structure are call Histones
In addition to histones, chromatin contains nonhistone proteins for enzymatic, structural and regulatory roles
8 Histones bond to form an Octamer
A section of DNA wraps around an octamer creating a Nucleosome (8 histone molecules and 146 base pairs of DNA)
Each histone has an amino acid tail That alter how tightly chromatin is packed
The degree to which chromatin is compacted changed during inferential phases of the cell cycle
Tightly packed chromatin (or Heterochromatin) is transcriptionally inactive
Loosely packed chromatin or euchromatin is transcriptionally active
Histone modification:
each histone molecule has a protruding tail that can be tagged at various locations by adding methyl, acetylene, phosphate, or other functional groups
The combinations of these tags create a histone code
A histone Code
The histone code is read by other proteins that use them as a set of signals for modifying chromatin structure and gene activity
This process can either activate or repress gene expression
Chromosomes
only visible under the light microscope when chromatin is highly condenses (during mitosis)
The narrow part of the chromosome is called the centromere, which plays a role is separation f duplicated chromosomes
The tips of chromosomes are called telomeres, which contains highly repetitive DNA sequences
Telomeres get shorter as you age
Cloned animals are born with shorter telomeres
The genetic makeup of an organism is called its genotype
A picture of one’s compliment of chromosomes is called Karyotype
Phenotype is a organism’s observable characteristics that are attributed to its genotype
Chromosomes contain repeating DNA sequences that do not contribute to the phenotype
Polymorphisms
Most of our DNA is identical to the DNA of other, however there are inherited regions that can vary from person to person
Variations in DNA sequence between individual are termed: polymorphisms
The spaces between genes
Sections of DNA with repeating aromatic bases along the nucleotide chain
The repeating code may appear as:
GGTTACGTTACGTTACGTTAC
Tandem repeats can be categorized by their length:
Satellite DNA
Variable number tandem repeats (VNTRs)
Short tandem repeats (STRs)
STRS are short sequences of DNA that are repeated numerous times
The tetramer “gata” may appear as “gatagatagatagata”
The polymorphisms in STRs are due to the different number of copies of the repeat element that can occur in a population of individuals
D7S280 is one of 30 core CODIS STR genetic loci. This DNA is found on human chromosome 7
The tetrameric repeat sequence of D7S280 is “Gata”
Different alleles of this locus have from 6-15 tandem repeats of the “gata” sequence
Cellular Respiration ppt
Defined as the flow of electronsm, through or within a membrane, from reduced coenzymes to an external electron acceptor, ususalluy accompanied by the generation of ATP
results in the complete oxidation of substrates to CO2
Drastically increases the yield of ATP form that of glycolysis alone
Takes place mostly in the mitochondria of animals
Electrons are removed from organic substrates and transferred to coenzymes carriers, which the transfer these electrons to oxygen
Oxygen in the terminal are torn acceptor, therefore the overall oxygen-requiring process in known as aerobic respiration
Oxygen is reduced to water
5 stage of Aerobic respiration
Glycolytic pathway
1 glucose is cleaved forming 2 pyruvate molecules
Pyruvate oxidation
Pyruvate is oxidized to acetylene coenzyme A
The citric acid cycle
Oxidation of acetylene CoA to OC2
Stored energy in high energy reduced coenzymes
Electron transport
Electrons are transferred from reduced coenzymes to oxygen, which is coupled with active transport of protons across a membrane
Oxidative phosphorylation
Synthesis of ATP
Mitochondria:
where most of the aerobic repiration occurs
Posses their own DNA that independent of the nuclear DNA
Found in higher numbers in tissues with a high energy demand (Skeletal muscle)
Can replicate themselves due to increase need for ATP (endurance sports)
Only from the Ovum. Sperm cells don;t contribute mitochondria to reproduction
Comprised of
Outer membrane
Not a significant permeability barrier for ions and small molecules
Has transmembrane Chanel proteins called Porins that permit passage of siolutes with molecular weights of up to 5000
Inner membrane
Cristae are in folding of the inner membrane
Creates more surface area, making it 5X larger than the outer membrane
Allow the inner membrane to accommodate large numbers of the protein complexes needed for
Solute transport
Electron transport
ATP synthesis (ATP synthase)
Intercristal spaces
Provide numerous regions where protons can accumulate during the electron transport process
Impermeable to most solutes
Partitions mitochondria into 2 compartments
Intermembrane space
Mitochondrial Matrix
Inner boundary membrane
Portion of the inner membrane adjacent to the intermembrane space
Matrix:
Semifluid found in the interior of the organelle
Contains enzymes, DNA (15,000-20,000 base pairs) and ribosomes
Mutation of mitochondria DNA can lead to human disease (neurodegeneration, mitochondrial myopathies, etc)
Bacteria:
don’t have mitochondria, but may are capable of aerobic respiration, which takes place in the:
Cytoplasm
Contains the enzymes of the citric acid cycle
Plasma membrane
Contains electron transport proteins.
Citric Acid Cylce
AKA Tricarboxylic acid cycle (TCA), or the Krebs Cycle
Before the cycle begins, pyruvate mist pass through portions int he mitochondrial outer membrane into he inter membrane space
Once inside this space, pyruvate is transported across the inner membrane by a specific pyruvate symport protein (co-transported with a proton)
Once inside the mitochondrial matrix, pyruvate is concerted to Acetylene CoA by the pyruvate Dehydrogenase complex (PDH), which consists of
3 different enzymes
5 coenzymes
2 regulatory proteins
This reaction is known as the oxidative decarboxylation of pyruvate
The cycle begins with the entry of acetylene CoA and its chemical reaction with oxaloacetate to form citrate
CoA contains the B5 vitamin: pantothenic acid
Citrate goes from a 6-carbon compound, to a 5- carbon compound, to a 4-carbon compound
Catabolism of Non-carbohydrates
the citric acid cycle also plays a role in catabolism of fats and proteins
As glycogen store are nearing depletion, animalsbegi to catabolize fats
Once fat sores are depleted, animals to catabolize proteins (starvation, marathon runners)
Catabolism of Fats
most fat is stored as Triglycerides
The catabolism begins with their hydrolysis to glycerol and free fatty acids
Glycerol is channeled into the glycolytic pathway by oxidative conversions to dihydroxyacetone phosphate
The fatty acid bonds to CoA to form fatty acrylic CoAs, which are then degraded by B oxidation
The initial energy required in activation step of B oxidation takes place in the cytosol
It involves the 2nd B carbon from the carboxylic acid
The fatty acrylic CoA then enters the mitochondria
In Bacteria, B oxidation occurs solely in the cytoplasm
Byproducts of fat catabolism
excessive fat catabolism can deplete from CoA (there may not be enough CoA to keep up with demands for ATP synthesis
This will lead to the incomplete oxidation of fats and therefore, the accumulation of ketone bodies
Acetone
Acetoacetate
B_hydroxybutyrate
An accumulation of These are bad for your kidneys
The accumulation of ketone bodies is known as Ketosis
Large quantities o ketone ill lower blood pH, results in ketoacidosis
Ketoacidosis is often seen in uncontrolled diabetes
Catabolism of Proteins
Once glycogen and lipid stores are depletes, organisms will begin to catabolize proteins
This process begins with proteolysis (hydrolysis) of te peptide bones lignin amino acids together in a polypeptide chain
Proteolysis requires enzymes called proteases
The end products of proteolysis are small peptides and free amino acids
Peptides are further digested by peptidases
Of the 20amino acids found in proteins, only 3 give use o pyruvate or citric acid cycle intermediates directly
Alanine
Aspartame
Glutamate
All other amino acids require more complicated pathways, but ultimately also come citric acid cycle intermediates
Electron transport
the TCA cycle begins with a reaction between Acetylene CoA and oxaloacetate to form citrate
At the end of their cycles oxaloacetate is reformed
But the time oxaloacetate is reformed, only 10% of the possible number of ATP is formed
The energy for the remaining amount of ATP is stored in the reduced coenzymes NADH and FADH2
The process of coenzyme reoxidation by the transfer of electrons to oxygen
The is process is accompanied by ATP synthesis
NADH+H+1/2O2 _>NAD+ +H2O (Yields 52.4 kcal/mol)
FADH2 + 1/2O2 → FAD + H2O (yields 45.9 kcal/mol)
Electron Transport System (ETS)
A multi-step process involving a series of reversible oxidizable electron carriers that function together
The ETS contains a number or integral membrane proteins situated in the inner mitochondrial membrane of Eukaryotes and the plasma membrane of bacteria
carriers the make up the ETS include
Flavoproterins (FAD)
Iron-suffer proteins
Cytochromes (also contains iron)
Copper-containing cytochromes
Coenzyme Q (ubiquinone)
The only non proteins component of the ETS
Energy yield of Cellular Respiration
~38 ATP Per glucose max
Glycolysis alone yields:
2 ATP
2 Pyruvate acid
2 NADH + H+
DNA and Chromosomes ppt
DNA is found in the nucleus and never leaves the nucleus
DNA is a polymer tht consists of 2 long strands of nucleotides which are monomers
The 2 strands twist around one another to form a twisted ladder called a Double Helix
Nucleotides:
5-carbon sugar (deoxyribose)
A phosphate group
1 or 4 nitrogen-containing aromatic bases
2 categories
Purines
Adenine
Guanine
Pyriidines
Thiamine
Cytosine
The phosphate and sugar components creates the DNA backbone of each strand
Nitrogen-containing bases attach to the sugar component of the backbone
Two strands of DNA are bonded by Hydrogen bonding between their bases
All other bonds in DNA are covalent
The nucleotides of each strand are oriented in opposite directions
Known as the “antiparallel orientation”
Double helix creates major and minor grooves
Regulatory proteins attach to the major grooves
The length of DNA is measured in base pairs (bp) and sometimes in the kilobase (kb) unit
The human genome contains ~3 billion base pairs
The double helix can be twisted upon itself to form a supercoil but can also exist in a non-supercoiled relaxed state
It supercoils during cell division
DNA frequently transitions between he supercoiled and relaxed state, a process catalyzed by enzymes (known as Topoisomerases)
Topoisomerase I will break a single strand of DNA
The DNA rotates, the intact strand passes through the break
Then the break is resealed
Topoisomerase II uses ATP to break both strands
An intact portion of the DNA strand with passed through the break
Then the break is resealed
After uncoiling, the 2 strands of nucleotides can separate fro one another
Separation of the strands is needed for DNA replication and Transcription (RNA synthesis)
DNA Transcription and Translation will be on boards
DNA packaging:
an enormous amount fo DNA must be packed into the nucleus of a cell
To do so, DNA is wrapped around proteins to form chromosomes
Small amounts of additional DNA for nonessential functions are called plasmids
once bound to these proteins, DNA is called chromatin, which appear as fibers under a light microscope
These fibers condense during mitosis and becom recognizable chromosomes
The proteins with the most important role in chromatin structure are call Histones
In addition to histones, chromatin contains nonhistone proteins for enzymatic, structural and regulatory roles
8 Histones bond to form an Octamer
A section of DNA wraps around an octamer creating a Nucleosome (8 histone molecules and 146 base pairs of DNA)
Each histone has an amino acid tail That alter how tightly chromatin is packed
The degree to which chromatin is compacted changed during inferential phases of the cell cycle
Tightly packed chromatin (or Heterochromatin) is transcriptionally inactive
Loosely packed chromatin or euchromatin is transcriptionally active
Histone modification:
each histone molecule has a protruding tail that can be tagged at various locations by adding methyl, acetylene, phosphate, or other functional groups
The combinations of these tags create a histone code
A histone Code
The histone code is read by other proteins that use them as a set of signals for modifying chromatin structure and gene activity
This process can either activate or repress gene expression
Chromosomes
only visible under the light microscope when chromatin is highly condenses (during mitosis)
The narrow part of the chromosome is called the centromere, which plays a role is separation f duplicated chromosomes
The tips of chromosomes are called telomeres, which contains highly repetitive DNA sequences
Telomeres get shorter as you age
Cloned animals are born with shorter telomeres
The genetic makeup of an organism is called its genotype
A picture of one’s compliment of chromosomes is called Karyotype
Phenotype is a organism’s observable characteristics that are attributed to its genotype
Chromosomes contain repeating DNA sequences that do not contribute to the phenotype
Polymorphisms
Most of our DNA is identical to the DNA of other, however there are inherited regions that can vary from person to person
Variations in DNA sequence between individual are termed: polymorphisms
The spaces between genes
Sections of DNA with repeating aromatic bases along the nucleotide chain
The repeating code may appear as:
GGTTACGTTACGTTACGTTAC
Tandem repeats can be categorized by their length:
Satellite DNA
Variable number tandem repeats (VNTRs)
Short tandem repeats (STRs)
STRS are short sequences of DNA that are repeated numerous times
The tetramer “gata” may appear as “gatagatagatagata”
The polymorphisms in STRs are due to the different number of copies of the repeat element that can occur in a population of individuals
D7S280 is one of 30 core CODIS STR genetic loci. This DNA is found on human chromosome 7
The tetrameric repeat sequence of D7S280 is “Gata”
Different alleles of this locus have from 6-15 tandem repeats of the “gata” sequence