unit 9 Flashcards
the chemical reaction that provides energy and substances required for continued cell growth.
metabolism
what are the metabolic reactions
anabolic and catabolic
If energy in cells are used to join small molecules to build larger ones, such reactions are termed
anabolic
When complex molecules are broken down to small ones with release of energy, reaction is called
catabolic
ATP
(adenosine triphosphate) is a nucleotide, providing energy for most of the energy-consuming activities of the cell.
It is one of the monomers used in the synthesis of RNA.
ATp
What do ATP and ribose form together
nucleoside adenosine
what are the basic building blocks for atp
carbon hydrogen nitrogen oxygen phosphorus
ATP is manufactured as a result of several cell processes including
fermentation, respiration and photosynthesis
what happens when ATP is removed by hydrolysis
energy is released
leaving ADP
Because of the energy released when ATP undergoes hydrolysis the bond between the second and third phosphates is commonly described as
a high energy bond
but its really due to the high energy
when ADP is recharged in the mitochondria what does it come out as
ATP
The total human body content of ATP that is recycled everyday is
50 grams
ultimate source of energy for constructing ATP is
food
the carrier and regulation-storage unit of energy
ATP
in atp is hydrolysis slow or fast in the presence of ATP and why?
slow
This insures that its stored energy is released only in the presence of the appropriate enzyme.
what cell functions is ATP used for
transport
mechanical
chemical
transport cell function
moving substances across cell membranes
mechanical cell function
supplying the energy needed for muscle contraction.
chemical cell function
supplying the needed energy to synthesize the multi-thousands of types of macromolecules that the cell needs to exist.
Small molecules which can enhance the action of an enzyme are
coenzymes
can coenzymes catalyze
no
what are coenzymes
These are organic non-protein molecules that bind with the protein molecule to form the active enzyme
A number of water-soluble vitamins such as vitamins B1, B2 and B6 are
coenzymes
NAD+ (nicotinamide adenine dinucleotide) is a
coenzyme where Vitamin niacin is bonded to ribose and ADP.
NADH + H+ —> (=)
NAD+ + 2.5 ATP
NADP (nicotinamide adenine dinucleotide phosphate) is used in
anabolic reactions.
• FAD (Flavin adenine dinucleotide) has a nucleotide ____ and vitamin ____
adenosine diphosphate and B2
FADH2 —> (=)
FAD + 1.5 ATP
CoA is made up of
vitamin B5, phosphorylated ADP and aminoethanethiol
Acetyl CoA is the
the thioester formed, when CoA bonds to acetyl group.
The compounds in the respiratory chain that remove hydrogen ions and electrons from NADH are classified as
electron carriers
enzyme Q is what
an electron carrier in the respiratory chain
what happens to glucose in our blood stream
it undergoes degradation which is an anarobic procces
This process where a 6 carbon glucose molecule is broken down to yield 2 molecules of 3 carbon pyruvate, is called
glycolysis
how many reactions does glycolysis undergo and what are they called
10
first 5 are called the energy investing phase
second five are the energy generating phase
reaction 1 glycolysis
Phosphorylation.
add phosphate group to a molecule derived from ATP. Causing 1 ATP to be consumed.
enzyme hexokinase catalyzes the phosphorylation of many six-membered glucose-like ring structures.
Glucose (C6H12O6) + hexokinase + ATP → ADP + Glucose 6-phosphate (C6H11O6P1)
is an example of
phosphorylation
Reaction 2 glycolysis
Isomerization
enzyme phosphoglucoisomerase converts glucose 6-phosphate into its isomer, fructose 6-phosphate. The reaction involves the rearrangement of the carbon-oxygen bond to transform the six-membered ring into a five-membered ring.
Glucose 6-phosphate (C6H11O6P1) + Phosphoglucoisomerase → Fructose 6-phosphate (C6H11O6P1)
is an example of
isomerization
reaction 3 glycolysis
phosphorylation
Fructose-6-phosphate is converted to fructose-1,6-bisphosphate (FBP).
what enzyme catalyzes rn 3 in glycolysis
phosphofructokinase (PFK).
Fructose 6-phosphate (C6H11O6P1) + phosphofructokinase + ATP → ADP + Fructose 1, 6-bisphosphate (C6H10O6P2)
is an example of what reaction
rn 3 phosphorylation
reaction 4 of glycolysis
clevage
The enzyme aldolase splits fructose 1, 6-bisphosphate into two sugars that are isomers of each other. These two sugars are dihydroxyacetone phosphate and glyceraldehyde phosphate.
Fructose 1, 6-bisphosphate (C6H10O6P2) + aldolase → Dihydroxyacetone phosphate (C3H5O3P1) + Glyceraldehyde phosphate (C3H5O3P1)
is an example of
clevage
reaction 4 glycolysis
Isomerization
The enzyme triose phosphate isomerase rapidly inter-converts the molecules dihydroxyacetone phosphate and glyceraldehyde phosphate. Glyceraldehyde phosphate is removed as soon as it is formed to be used in the next step of glycolysis.
Dihydroxyacetone phosphate (C3H5O3P1) → Glyceraldehyde phosphate (C3H5O3P1)
is an example of
isomerazation
reaction 6 glycolysis
Oxidation & Phosphorylation
The enzyme triose phosphate dehydrogenase serves two functions in this step. First the enzyme transfers a hydrogen atom from glyceraldehyde phosphate to nicotinamide adenine dinucleotide (NAD+), which is the oxidizing agent, to form NADH. Next triose phosphate dehydrogenase adds a phosphate (P) from the cytosol to the oxidized glyceraldehyde phosphate to form 1, 3-bisphosphoglycerate. This occurs for both glyceraldehyde phosphate molecules, produced in step 5.
A. Triose phosphate dehydrogenase + 2 H- + 2 NAD+ → 2 NADH + 2 H+
B. Triose phosphate dehydrogenase + 2 P + 2 glyceraldehyde phosphate (C3H5O3P1) → 2 molecules of 1, 3-bisphosphoglycerate (C3H4O4P2)
are an example of
reaction 6 oxidation and phosphorylation
rn 7 glycolysis
phosphate transfer
1,3 bisphosphoglycerate is converted to 3-phosphoglycerate by the enzyme phosphoglycerate kinase (PGK).
This reaction involves the loss of a phosphate group from the starting material. The phosphate is transferred to a molecule of ADP that yields our first molecule of ATP. Since we actually have two molecules of 1,3 bisphosphoglycerate (because there were two 3-carbon products from stage 1 of glycolysis), we actually synthesize two molecules of ATP at this step. With this synthesis of ATP, we have cancelled the first two molecules of ATP that we used, leaving us with a net of 0 ATP molecules up to this stage of glycolysis.
2 molecules of 1,3-bisphoshoglycerate (C3H4O4P2) + phosphoglycerokinase + 2 ADP → 2 molecules of 3-phosphoglycerate (C3H5O4P1) + 2 ATP
is an example of
rrn 7 phosphate ransfer
rn 8 glycolysis is
isomerization
a simple rearrangement of the position of the phosphate group on the 3 phosphoglycerate molecule, making it 2 phosphoglycerate.
The molecule responsible for catalyzing this reaction is called phosphoglycerate mutase (PGM).
The reaction mechanism proceeds by first adding an additional phosphate group to the 2′ position of the 3 phosphoglycerate. The enzyme then removes the phosphate from the 3′ position leaving just the 2′ phosphate, and thus yielding 2 phosphoglycerate. In this way, the enzyme is also restored to its original, phosphorylated state.
a mutase is
A mutase is an enzyme that catalyzes the transfer of a functional group from one position on a molecule to another.
2 molecules of 3-Phosphoglycerate (C3H5O4P1) + phosphoglyceromutase → 2 molecules of 2-Phosphoglycerate (C3H5O4P1)
is what reaction
rn 8 isomerization
rn 9 glycolysis
dehydration
The enzyme enolase removes a water molecule from 2-phosphoglycerate to form phosphoenolpyruvic acid (PEP). This happens for each molecule of 2-phosphoglycerate.
2 molecules of 2-Phosphoglycerate (C3H5O4P1) + enolase → 2 molecules of phosphoenolpyruvic acid (PEP) (C3H3O3P1)
example of
rn 9 dehydration
rn 10 glycolysis
Phosphate Transfer
The enzyme pyruvate kinase transfers a P from PEP to ADP to form pyruvic acid and ATP. This happens for each molecule of PEP. This reaction yields 2 molecules of pyruvic acid and 2 ATP molecules.
2 molecules of PEP (C3H3O3P1) + pyruvate kinase + 2 ADP → 2 molecules of pyruvic acid (C3H4O3) + 2 ATP
is an example of
rn 10 phosphate transfer
all the stages of glycolysis
1) phosphorylation
2) isomerization
3) phosphorylation
4) cleavage
5) isomerization
6) oxidation/phosphorylation
7) phosphate transfer
8) isomerization
9) dehydration
10) phosphate transfer
tricarboxylic acid cycle (krebs cycle)
1) formation of citrate
2) isomerization
3) oxidation/decaboxylation
4) oxidation/decarboxylation
5) hydrolysis
6) oxidation
7) hydration
8) oxidation
reaction 1 krebs cycle
Formation of Citrate
The first reaction of the citric acid cycle is catalyzed by the enzyme citrate synthase. In this step, oxaloacetate is joined with acetyl-CoA to form citrate, a tertiary alcohol. Once the two molecules are joined, a water molecule attacks the acetyl leading to the release of coenzyme A from the complex.
reaction 2 krebs cycle
Isomerization The next reaction of the citric acid cycle is catalyzed by the enzyme aconitase. In this reaction, a water molecule is removed from the citric acid and then put back on in another location.(dehydration followed by hydration) This transformation yields the molecule isocitrate, a secondary alcohol.
reaction 3 krebs cycle
Oxidation & Decarboxylation Two events occur in reaction 3 of the citric acid cycle. In the first reaction, we see our first generation of NADH from NAD. The enzyme isocitrate dehydrogenase catalyzes the oxidation of the –OH group at the 4’ position of isocitrate to yield an intermediate which then has a carbon dioxide molecule removed from it to yield alpha-ketoglutarate.
rn 4 krebs cycle
Decarboxylation & Oxidation
Alpha-ketoglutarate loses a carbon dioxide molecule and coenzyme A is added in its place. The decarboxylation occurs with the help of NAD, which is converted to NADH. The enzyme that catalyzes this reaction is alpha-ketoglutarate dehydrogenase. The resulting molecule is called succinyl-CoA.
step 5 krebs cycle
hydrolysis
The enzyme succinyl-CoA synthetase catalyzes the fifth reaction of the citric acid cycle. In this step a molecule of guanosine triphosphate (GTP) is synthesized. GTP synthesis occurs with the addition of a free phosphate group to a GDP molecule (similar to ATP synthesis from ADP). In this reaction, a free phosphate group first attacks the succinyl-CoA molecule releasing the CoA. After the phosphate is attached to the molecule, it is transferred to the GDP to form GTP. The resulting product is the molecule succinate.
GTP is
GTP is a molecule that is very similar in its structure and energetic properties to ATP and can be used in cells in much the same way.
step 6 krebs cycle
oxidation
The enzyme succinate dehydrogenase catalyzes the removal of two hydrogens from succinate in the sixth reaction of the citric acid cycle. In the reaction, a molecule of FAD, a coenzyme similar to NAD, is reduced to FADH2 as it takes the hydrogens from succinate. The product of this reaction is fumarate. FAD, like NAD, is the oxidized form while FADH2 is the reduced form. FAD oxidizes carbon-carbon double and triple bonds while NAD oxidizes mostly carbon-oxygen bonds.
rn 7 krebs cycle
hydration
Water is added to fumarate during step seven, and L-malate is produced. Catalyst used is fumarase.
reaction 8 krebs cycle
Oxidation
In the final reaction of the citric acid cycle, we regenerate oxaloacetate by oxidizing L–malate with a molecule of NAD to produce NADH. The catalyst used is malate dehydrogenase.
basis of krebs cycle
1) acetyl-CoA, is oxidized to two molecules of carbon dioxide.
2) Three molecules of NAD were reduced to NADH.
3) One molecule of FAD was reduced to FADH2.
4) One molecule of GTP (the equivalent of ATP) was produced.
Electron transport is
the series of reactions taking place in mitochondria of the cell
This includes the electron transfer from NADH and FADH2 to electron carriers and finally to O2 provide energy for
ATP synthesis
ATP and ADP levels in the cells control
the activity of electron transport.
Oxidation of NADH yields how much ATP
2.5 ATP
FADH2 yields how much ATP
1.5 ATP
when is oxidative phosphorylation completed.
When energy from electron transport is combined with the synthesis of ATP
Complete oxidation of glucose from the above processes and direct phosphate yields how much ATP
32
Oxidative-phosphorylation is the use of
electrons falling from the hydrogen in glucose to the oxygen in a living cell.
What provide the energy necessary to pump H+ ions
falling electrons
When these H+ ions fall back, this energy is used to
attach a phosphate group (phosphorylate) to ADP to make the high energy molecule ATP, which the cell can now use again to do vital work.
Digestion is
catabolic process where large molecules are converted into smaller ones.
How are carbs digested
First the carbohydrates are broken down using the enzyme, amylase to maltose, glucose and dextrins (3 to 8 glucose units).
what stops carbohydrate digestion in the stomach
low ph
Enzyme in the pancreas
pancreatic amylase convert dextrins into maltose and glucose
Enzymes produced in the mucosal lines of small intestine
The enzymes are maltase, lactase and sucrose respectively. The resultant monosaccharides are absorbed into bloodstream and carried to the liver.
where are fructose and galactose converted into glucose
the liver
Body fat is the major source of
stored energy
. Digestion of fats begin in the
small intestine
Bile salts with both hydrophilic and hydrophobic regions are secreted from
gall bladder into small intestine. These interact with both hydrophobic fat and aqueous solution (hydrophilic) in small intestine.
emulsification
Bile break fat into smaller droplets called micelles
Pancreatic lipases from pancreas, hydrolyze
triacylglycerols into monoacylglycerols and fatty acids.
Most of the energy stored in the human body is in the form of
triacylglycerols
They recombine within the intestinal wall to form triacylglycerol back which when coated with protein and phospholipids, form
chylomicrons.
Are chylomicrons polar or nonpolar
This is polar which makes it soluble in bloodstream.
Lipase hydrolyze triacylglycerol to
glycerol and fatty acids
Fatty acid is further oxidized to
acetyl CoA for ATP synthesis
Digestion of protein begins in the
stomach
how does digestion of protein begin
It begins with the hydrolysis of peptide bonds in the denatured protein which reached the stomach
how is protein digested
is made possible by the enzyme, pepsin. The polypeptides enter small intestine, where pH is about 7-8. Thus pepsin is inactivated, due to the lower pH value. (pepsin acts at pH 1-2).
Proteases
break the polypeptides to amino acids and dipeptides. Through active transport along the small intestine lining, the amino acids are absorbed into the bloodstream.
`1. The first stage of catabolism is
digestion of large molecules.
The middle stage of catabolism is the point at which
acetyl CoA is produced
Protein synthesis takes place in
on the ribosomes.
- The synthesis of glycogen can be classified as a
Anabolic reaction
- The final products of catabolic reactions are
a. carbon dioxide, water, and ammonia
- The hydrolysis of ADP to give AMP and Pi, releases approximately the same amount of energy as
a. ATP → ADP + Pi.
- Muscle contraction is an example of a
a. Catabolic process
- Muscle contraction requires
a. Calcium Ion and ATP
- NAD+ participates in reactions that produce
a. a C=O bond.
- FAD is a coenzyme which usually participates in
a. formation of carbon-carbon double bonds.
- Coenzyme A is a molecule whose function is to
a. Produce acyl groups for reaction
- An enzyme that can facilitate the breakdown of starch into smaller units is
a. Amylase
- The digestion of carbohydrates goes from
a. polysaccharides to dextrins to glucose.
- In the process of glycolysis, glucose is converted to
pryuvate
- The overall process of glycolysis
a. produces 2 ATP molecules
Which of the following metabolic pathways can occur in the absence of oxygen?
glycolysis
- When one glucose molecule undergoes glycolysis it generates
a. 2 ATP and 2 NADH.
- The primary energy source for the brain is
a. Glucose
When combined with electron transport, one turn of the citric acid cycle produces
12 ATP
The citric acid cycle is used in the oxidation of
a. glucose, fatty acids, and proteins.
What electron acceptor(s) is(are) used in the citric acid cycle
b. NAD+ + FAD
When oxygen is in plentiful supply in the cell, pyruvate is converted to
acetyl COA
Which of the three major stages of metabolism includes the citric acid cycle?
stage three
The citric acid cycle takes place in the
mitochondria
The citric acid cycle step that removes the first CO2 molecule is a(n)
oxidative decarboxylation
In the third major step of the citric acid cycle, NAD+ is converted to
NADH
Step 5 of the citric acid cycle is the hydrolysis of succinyl CoA. In this reaction the energy released is used to make
GTP
In the hydrolysis of succinyl CoA in step 5 of the citric acid cycle, CoA is released as to make
GTP
The GTP formed in step 5 of the citric acid cycle is used to make
ATP
In the dehydration of succinate to fumarate in the citric acid cycle, the coenzyme used is
FAD
In step 7 of the citric acid cycle, fumarate is converted to malate by a
hydration reaction
The last step in the citric acid cycle converts malate to
oxaloacetate
What is the correct coefficient for ATP in the complete combustion of glucose?
36
Overall, one turn of the citric acid cycle produces how much ATP
12
In glycolysis, glucose produces 2 pyruvate ions and a total of _______ ATP molecules.
6 ATP
The complete oxidation of glucose produces ________ ATP molecules
36 ATP
acetyl CoA → 2CO2
produces how much ATP
12 ATP
glucose → 2 pyruvate under aerobic conditions
produces how much ATP
6 ATP
glucose → 2 lactate
produces how much ATP
2 ATP
pyruvate → acetyl CoA + CO2
produces how much ATP
3
the process that makes ATP using energy from the electron transport chain
oxidative phosphorylation
the carrier of acetyl (two-carbon) groups coenzyme
coenzyme A
the conversion of glucose to pyruvic acid
glycolysis
the series of reactions that converts acetyl CoA to carbon dioxide and water
citric acid cycle
the series of reactions that produces water
electron transport
the series of reactions that uses electron carriers
electron transport
What is metabolism
the chemical processes that occur within a living organism in order to maintain life.q
Name the type of cells with nucleus
Eukaryotic
What are the final products obtained after the digestion of Carbohydrates
glucose
What are the final products obtained after the digestion of proteins
amnio acids
What are the final products obtained after the digestion of fats
carbs and proteins
Write the equation for the hydrolysis of
ATP to ADP.
ATP(4-)+H20 => ADP(3-) + Pi(2-) + H+
What are coenzymes
Coenzymes bind to the enzyme and assist in enzyme activity
Which are the enzymes for oxidation?
An oxidative enzyme is an enzyme that catalyses oxidation reaction. Two most common types of oxidative enzymes areperoxidases, which use hydrogen peroxide, and oxidases, which use molecular oxygen. They increase the rate at whichATP is produced aerobically.
coenzymes
The active forms of riboflavin, vitamin B 2, are the coenzymes flavin mononucleotide (FMN; Figure 2) and flavin adenine dinucleotide (FAD)
Write the reduced form for FAD
FADH2
Write the reduced form for NAD+
NADH
Write the reduced form for NADP+
NADPH
Vitamin for FAD
B2
Vitamin for NAD+
B3
Vitamin for COA
B5
Where do lactose undergo digestion in our body?
small inestine
What are the reactants and products of glycolysis?
Reactant- glucose
Product- The net end products of glycolysis are two Pyruvate, two NADH, and two ATP
Location of fat digestion and enzyme used
small intestine
lipase
What are the final products of digested fat?
Fatty acids and glycerol
Which are the phosphorylation reactions in glycolysis?
RN 1,3
What are the products from one turn of citric acid cycle?
12 ATP
Name the enzyme that catalyzes reaction of acetyl CoA with oxaloacetate.
coenzyme q
Name the coenzyme that accepts H in the conversion of Isocitrate to alpha ketoglutarate
NAD+
Name the coenzyme that accepts H in the conversion of Succinate to fumarate
FAD
How are glycolysis and citric acid cycle linked to the production of ATP by electron transport?
ATP Yield; In glycolysis is 2, citric acid cycle is 2 and electron transport chain is 34. Remember the ATP created from ETC was originally from the NADH and FADH2 in glycolysis and Citric acid cycle and pyruvate oxidation. In total the theoretical yield is 38 ATP.
How many turns of citric acid cycle are required to oxidize 1 molecule of glucose?
two turns
What is the main function of citric acid cycle in energy production?
Oxidising acetyl CoA producing reduced coenzymes which can be oxidised in the ETC to produce ATP energy
List the differences between beta oxidation and lipogenesis.
Location
Reaction
Carrier
Reducing Power/redox agent
Name the base present in ATP.
Adenine
Glutamate dehydrogenase is the enzyme used in
deamination
New amino acid and a new keto acid are produced as a result of
a) Transamination
List the functions of ATP
ATPs are used as the main energy source for metabolic functions.
What is GTP? In which process is it produced?
Energy transfer. GTP is involved in energy transfer within the cell. For instance, aGTP molecule is generated by one of the enzymes in the citric acid cycle. This is tantamount to the generation of one molecule of ATP, since GTP is readily converted to ATP with nucleoside-diphosphate kinase (NDK).
Transamination-
As a result of transamination reaction, amino group is transferred from an amino acid to keto acid. Thus a new amino acid and a new keto acid are produced. Enzymes used are transaminases or aminotransferases.
Deamination-
Amino group in glutamate is removed as an ammonium ion in the process of oxidative deamination. This is catalyzed by glutamate dehydrogenase, which uses NAD+ as a coenzyme.
Lipogenesis
The production of new fatty acids is called lipogenesis, where acyl carrier protein is used. Synthesis takes place within cytoplasm and initiated when pancreas sense a high level of glucose in blood. As a result, secretion of insulin occurs and glucose is shifted to cells. Enzyme, fatty acid synthase is produced which converts acetyl CoA(initial substrate) into malonyl CoA which is further converted into palmitate, a fatty acid. Cells modify palmitate to make specific fatty acids. Different types of reactions involved are reduction, dehydration and condensation.
Beta oxidation
a. Oxidation takes place in cytoplasm, when blood glucose level is low. Thus, secretion of glucagon takes place and fatty acid is the initial substrate. Enzymes cut off fatty acids from triglycerides and these fatty acids are absorbed into the cytoplasm and further into mitochondria. As a result of oxidation, hydration and cleavage, the final product is acetyl CoA.
phosphorylation
It is the process of adding a phosphate group to a molecule derived from ATP. As a result, 1 molecule of ATP is consumed. The reaction occurs with the help of the enzyme hexokinase, an enzyme that catalyzes the phosphorylation of many six-membered glucose-like ring structures.
Chylomicrons
This is polar which makes it soluble in bloodstream.
coenzyme
9) Small molecules which can enhance the action of an enzyme are coenzymes. They cannot by themselves catalyze a reaction but they can help enzymes to do so. These are organic non-protein molecules that bind with the protein molecule to form the active enzyme. A number of water-soluble vitamins such as vitamins B1, B2 and B6 serve as coenzymes.
Digestion is a
catabolic process where large molecules are converted into smaller ones
First the carbohydrates are broken down using the
enzyme, amylase to maltose, glucose and dextrins (3 to 8 glucose units).
what stops carbohydrate digestion
The low pH in stomach
Enzyme in the pancreas, _____ convert dextrins into maltose and glucose.
pancreatic amylase
Enzymes produced in the mucosal lines of small intestine hydrolyze maltose, lactose and sucrose. The enzymes are
maltase, lactase and sucrose
The resultant of the digestion of carbohydrates
monosaccharides are absorbed into bloodstream and carried to the liver. Finally fructose and galactose are converted into glucose at liver.
major source of stored energy
Body fat
Digestion of fats begin in the
small intestine.
Bile salts with both hydrophilic and hydrophobic regions are secreted from
gall bladder into small intestine.
These interact with both hydrophobic fat and aqueous solution (hydrophilic) in small intestine.
bile salts
Bile break fat into
smaller droplets called micelles through a process termed, emulsification.
Pancreatic lipases from pancreas, hydrolyze
triacylglycerols into monoacylglycerols and fatty acids.
Most of the energy stored in the human body is in the form of
triacylglycerols.
They recombine within the intestinal wall to form triacylglycerol back which when coated with protein and phospholipids, form
chylomicrons
chylomicrons
This is polar which makes it soluble in bloodstream. Lipase hydrolyze triacylglycerol to glycerol and fatty acids. Fatty acid is further oxidized to acetyl CoA for ATP synthesis.
Digestion of protein begins in the
stomach
digestion begins with the
hydrolysis of peptide bonds in the denatured protein which reached the stomach.
the hydrolysis of peptide bonds is made possible by the enzyme
pepsin
The polypeptides enter small intestine, where pH is about
7-8
what inactivates pepsin
pepsin is inactivated, due to the lower pH value. (pepsin acts at pH 1-2).
break the polypeptides to amino acids and dipeptides.
proteases
the amino acids are absorbed into the bloodstream how
Through active transport
The production of new fatty acids is called
lipogenesis
what carrier protein is used in lipogenisis
acyl
lipogenisis synthesis takes place within
cytoplasm
what initiates synthesis during lipogenisis
initiated when pancreas sense a high level of glucose in blood.
what is secreated when he pancreas senses a high level of glucose
secretion of insulin occurs and glucose is shifted to cells
what enzyme is produced during lipogenesis which converts acetyl CoA(initial substrate) into malonyl CoA which is further converted into palmitate
fatty acid synthase
palmitate,
a fatty acid
Cells modify palmitate to
make specific fatty acids.
what different types of reactions are involved in lipogenesis
reduction, dehydration and condensation
BETA Oxidation takes place where and when
in cytoplasm, when blood glucose level is low
results of oxidation
hydration and cleavage, the final product is acetyl CoA.
Amino acids are degraded to
substrates that enter energy-producing pathways
Hydrolysis of peptide bonds is made by the enzyme
pepsin
Enzymes, ____ complete the hydrolysis of peptides to amino acids.
trypsin and chymotrypsin
Denaturation of proteins is done by
HCl.
The process of breaking down proteins and synthesizing new ones is called
protein turnover
The amount of protein broken down is equal to
the amount reused.
Only a small amount of our energy needs is supplied by
amino acids
When carbohydrates and fat stores are exhausted, energy is extracted from
amino acids
Body cannot store
nitrogen, and the extra amino acids are excreted.
a diet insufficient in protein leads to a
negative nitrogen balance
When dietary protein exceeds the nitrogen needed for protein synthesis, excess amino acids are
degraded
The amino group is removed to yield a
keto acid, which can be converted to an intermediate for other metabolic pathways.
Degradation of amino acids occurs primarily in the
liver
transamination reaction,
amino group is transferred from an amino acid to keto acid
Enzymes used during degradation of proteins and amino acids
transaminases or aminotransferases
Amino group in glutamate is removed as an ammonium ion in the process of oxidative
deamination.
deamination is catalyzed by
by glutamate dehydrogenase, which uses NAD+ as a coenzyme
CITRIC ACID CYCLE reactions
dehydration & hydration, oxidation & reduction, hydrolysis
Krebs cycle 1. FORMATION OF CITRATE enzyme reactants products
Enzyme: citrate synthasereactants: oxalo acetate and acetyl CoAproducts: citrate & CoA
Krebs cycle 2. isomerization enzyme reactant product
enzyme: aconitase
reactant: citrate
product: isocitrate
krebs cycle 3. oxidation and decarboxylation enzyme reactant product
enzyme: isocitrate dehydrogenase
reactant: isocitrate product: alpha-ketoglutarate
krebs cycle 4. DECARBOXYLATION & OXIDATION enzyme reactant product
enzyme: alpha ketoglutarate dehydrogenase
reactant: alpha keto glutarate
product: succinyl CoA
Krebs cycle 5. HYDROLYSIS enzyme reactant product
enzyme: succinyl CoA synthetase
reactant: succinyl CoA
product: succinate
Krebs Cycle 6. OXIDATION Enzyme Reactant Product
enzyme: succinate dehydrogenase
reactant: succinate
product: fumarate
Krebs Cycle 7. HYDRATION Enzyme Reactant Product
enzyme: fumarase
reactant: fumarate
product: malate
Krebs Cycle 8. OXIDATION Enzyme Reactant Product
enzyme: malate dehydrogenase
reactant: malate
product: oxaloacetate
Catabolic reactions stages
STAGE 1 : DIGESTION
STAGE 2 : DEGRADATION & OXIDATION
STAGE 3 : OXIDATION
STAGE 1 : DIGESTION
Enzymes in digestive tract hydrolyze larger molecules into smaller ones
STAGE 2 : DEGRADATION & OXIDATION
Digested products broken down to pyruvate and acetyl CoA
STAGE 3 : OXIDATION
Coenzymes produced as a result of citric acid cycle leads to the formation of ATP.
glycerol & fatty acids are broken down by
beta oxidation
monosaccharides are broken down by
glycolysis
amino acids are broken down by
transamination
Nucleotide used in synthesis of RNA
ATP
ATP sugar
ribose
bond between ribose & phosphate
Phosphate ester bond
bond between PO4 groups
2 phosphate anhydride bonds
bond between adenine & ribose
Glycoside bond
coenzyme reactions OXIDATION
Gain of oxygen
Loss of hydrogen
Loss of electrons
Energy released
Oxidoreductases:
catalyze oxidation /reduction reactions (oxidase, dehydrogenase)
Transferases
catalyze transfer of a functional group b/w compounds (transaminase, kinase)
Hydrolase
catalyzes hydrolysis by splitting a compound into 2 products (protease, lipase, nuclease)
Lyase
catalyze addition or removal of a group without hydrolysis (decarboxylase, deaminase, dehydratase, hydratase)
Isomerases
catalyze rearrangement within a substrate (epimerase)
Ligases:
catalyze joining of 2 substrates using ATP (synthetase, carboxylase)
