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        Q.1. Carbohydrates are a major component of our daily diet. 45- 65% of the diet should constitute of it. Carbohydrates are ...

Biochemistry - Online Course

 

 

 

 

Q.1. Carbohydrates are a major component of our daily diet. 45- 65% of the diet should constitute of it. Carbohydrates are digested to monosaccharides in the small intestine.

i) Which monosaccharide is considered as the basic fuel of body?    

Ans:i=  Glucose:  Glucose is a monosaccharide having one sugar unit is considered as a fundamental or basic fuel of body.

ii) Classify monosaccharides on the basis of carbon number.                             

Ans: ii=  Classification of monosaccharides on the basis of carbon number:

·        Trioses                C+C+C   3 C containing

·        Tetroses              C+C+C+C  4 C containing

·        Pentose              C+C+C+C+C   5 C containing

·        Hexoses              C+C+C+C+C+C 6 C containing

·        Heptoses            C+C+C+C+C+C+C 6 C containing

iii) Write down the names of two disaccharides  

Ans: iii= Names of Two disaccharides:

·        Maltose

·        Sucrose

iv)  What do you mean by Homopolysaccharides? Give two examples        

Ans: iv= Homopolysaccharides: Homo= same , poly = many units , saccharides= sugar. So Homopolysaccharides is the type of polysaccharide  having same poly saccharides units.

Examples: 1. Starch

                    2.Insulin

v) Explain the Amylosecomponent of starch.        

Ans:V=  Amylose component of starch:

·        It’s the unit of starch.

·        Form by the polymerization of Alpha D-Glucose with the removal of Water molecule.

·        It form 15 to 20 % of starch.

·        It contains 50 to 5000 glucose units.

·        It stores carbohydrates in plants.

·        It give blue color with iodine by forming hydrated micelles.

Q.2. Proteins are macromolecules, consisting of one or more long chains of amino acid residuesbonded together by peptide bonds. These perform a vast array of functions within organisms.

i) Define Amino acids.                                                                                        

·        Ans:i=  Amino acid:      Amino Acids are the building blocks of proteins

·        It’s the organic compounds having two functional group an amino group and carboxyl group

·        300 different amino acids but only 20 have responsible for proteins synthesis.

·        Genetic codes occur for them.

·         These are the small units having information for proteins synthesis.

·        Incredibly diverse function but structure hold a common base.

·        Hemoglobin, Enzymes, Elastin, Collagen etc are some examples.

ii) Classify amino acid on the basis of nutritional requirements

along with 4 examples each                                                                        

Ans:ii=     Amino acids classification on the basis of Nutritional requirements along with four examples;

ü Essential Amino Acid: Those amino acid in which the carbon skeleton cannot be synthesized by human body so it will take in food.

Examples:

·        Isoleucine

·        Lysine

·        Valine

·        Tryptophan

ü Semi Essential Amino acids: The amino acids in which Carban skeleton is synthesized by human body but it will also take from food or some time synthesized by human body and some times take from food.

Examples:

·        Arginine

·        Histidine

·        Threonine

·        Methionine

ü Non Essential Amino acids: The amino acids which are synthesized by human body and not take from food.

Examples:

·        Alanine

·        Asparagine

·        Glycine

·        Serin

iii) Name the different levels of structural organization  of proteins               

Ans: iii= Level of structural organizations of proteins:

1.     Primary structure

2.     Secondary structure

·        Alpha helix

·        Beta sheet

3.     Tertiary structure

·        Domain

·        Turn

·        Loops

4.     Quaternary structure

·        Homodimer

·        Heterodimer

iv) What do you mean by conjugated proteins? Give two examples      

Ans :iv=   Conjugated proteins:  Proteins combine with the non proteins group which is called prosthetic group as a result some other proteins are formed called conjugated proteins

Examples:

·        Lipoprotein.  Form from lipid and proteins combining.

·        Glycoprotein. Form from glucose and proteins combining.

·        Metalloproteinase. Form from metals and proteins combining.

·        Chromoproteins.  Form from pigments combining with proteins.

Q.3. carbohydrates are metabolized by the body to generate energy and to make storage products for use in fasting state. This is accomplished by different pathways

i) Write down the three irreversible steps of glycolysis                       

Ans: i=    Irreversible steps of Glycolysis:

·        Conversion of glucose into glucose 6 phosphate:

It’s the first step in Glycolysis. In this glucose is converted into glucose 6 phosphate by an enzymatic action of glucose hexokinase and with combining with ATP.

Glucose+ATP ___glucose hexokinase ======   glucose 6 phosphate .

·        Conversion of fructose into 1,6 bi phosphate:

This is the 3rd step in Glycolysis . Fructose is converted into 1,6 biphosphate by the action of enzyme phosphohexo kinase. ATP combine with fructose.

Fructose+ ATP __ (phosphohexo kinase) ======= 1,6 biphosphate.

·        Conversion of Phosphoenol pyruvate into pyruvate:

This is the last step in Glycolysis.  PEP is converted into pyruvate or pyruvate into PEP by the action of enzyme pyruvate kinase ATP is form here from ADP.

PEP+ADP __(pyruvate kinase)===== pyruvate + ATP.

ii) What are the precursors for gluconeogenesis                                       

Ans : ii= Precursors of gluconeogenisis:

Following are the precursors of gluconeogenisis.

·        Glucogenic Amino acids

·        Lactate

·        Glycerol

·        Pyruvate

·        Propinoate

·        Alanine

·        Glutamine

·        Oxaloacetate.

iii) Calculate the amount of energy produced by 1 molecule of acetyl

CoA in TCA cycle                                                               

Ans: iii= Amount of energy produce by 1 molecule of acetyl CoA in TCA:

·        As we know one NADH molecule give us 3 ATPs.

·        And one FADH molecule give us 2 ATPs.

·        In TCA we have 3 NADH so 3×3= 9 ATPs

·        One ATP is already present in TCA.

·        So total ATPs produce is 2+9+1= 12.

·        12 ATPs produce from only one Acetyl CoA .

·        In TCA we have Acetyl CoA and succinyl CoA so 12×2=24 which is total ATPs

·        Here energy calculations for only one Acetyl CoA which produce 12 ATPs.

·        One ATPs produce 7.3 kcal/mole energy so 12 will be produced

·        12×7.3= 87.3 kcal/moles from one Acetyl CoA in TCA and 21228 calories per moles.

Q.4. Proteins are the building blocks of a body and lipids are a rich source of energy. Both of these components are metabolized in body by various metabolic pathways to yield different products.

i) Write down the first step of urea cycle along with the enzyme                   

Ans: i=  first Two steps of urea cycle along with enzymes:

1.     Synthesis of carbomyl phosphate:

·        NH4+ is condense with CO2 with the help of enzyme carbomyl phosphate synthase 1 of the mitochondria catalyases

·        This step use 2 ATP.

·        Its an irreversible step

·        Another N- Acetylglutamate  for this activity

·        Another enzyme carbomyl phosphate synthase 2 involved in pyrimidine synthesis present in cytosol.

·        It except amino group from glutamine and does required N-Acetylglutamate.  

 

ii)  What is the net energy yield from β Oxidation of Palmitic Acid?             

Ans: ii=  Net energy yield from B Oxidation of Palmitic Acid :

·        Oxidation of Palmitic acid yields 7 NADH + 7 FADH2 + 8 acetyl-CoA in 7 cycles of mitochondrial beta oxidation. Every acetyl-CoA yields 3 NADH + 1 FADH2 + 1 GTP = ATP during Krebs cycle. Considering an average production of 3 ATP/NADH and 2 ATP/FADH2 using the respiratory chain, we have 131 ATP molecules. However we have to used 2 ATP molecules for the initial activation of every fatty acid that is going to be oxidized in the mitochondria. So net yield is 129 ATPs.

·        So 129 ATPs produced

·        As we know 1 ATP gives us 7.3 kcal/mole energy so 129 will be produce 129×7.3= 941.7 kcal/moles .

 

iii) What do you mean by reverse cholesterol transport?                                

·        Ans: iii= Reverse cholesterol transport:                                                                              A mechanism by which the body removes excess cholesterol from the peripheral tissues and delivered them to the liver , where it will be redistributed to others tissues or remove md from the body by gallbladder.

·        HDL is involved in RCT.

 

 

 

 

 i) Apoenzyme and holoenzyme                                                                    

Ans: i=   Apoenzyme:   

·        Apo enzyme is referred to the protein part of enzyme.

·        It is an inactive enzyme.

·        Become active when cofactors is combine.

·        The function of Apoenzyme  is when a cofactors is binding with a proteins so its become active enzyme so its speed up a bio chemical reactions.

Holoenzyme: 

·        It’s a biochemically active compound

·        Its is formed by the combination of enzyme with coenzyme.

·        Holoenzyme====== Apoenzyme + coenzyme= protein part+ non protein part.

ii) ATP synthase   2

Ans: ii=  ATP synthase: 

·        It is an enzyme.

·        Involves in the production of ATP from ADP.

·        It converts the energy of proton H+ into the synthesis of ATP.

·        It produce one ATP per 3 H+.

·        ADP+pi+3H+______ ATP+ Water+3H.

iii) HDL                                                                                                       

Ans: iii= High density lipoprotein:  

·        One of the type of lipoprotein

·        It is the smallest of lipoprotein particles

·        It is the densest because it contains the highest portion of proteins to lipids.

·        It is produced or synthesized in the liver and small intestine.

·        Its secretion contains little cholesterol and no cholesteryl esters.

·        Involved in RCT .

·        Protect body from heart diseases.

iv)Isoenzymes                                                                                         

Ans: iv= Isoenzymes:

·        Its is the form of enzyme.

·        Differ in Amino acids composition

·        Catalyzed the same chemical reactions.

·        Example is lactate dehydrogenase .

·        Two polypeptide chains are present.

·        Used to meet the metabolic rate of different tissues.

·        Its have different kinetics parameters or regulatory properties.

 

v) Epimers                                                                                                 

Ans: V=  Epimers:

·        If two monosaccharides differs in configuration around only one specific C atom  ( with exception of carbonyl C)

·        They have two chiral centers but differs in configuration in only one chiral center.

·        Examples is:   Glucose and galactose are carbon 4 Epimers

·        Glucose and mannose are carbon 2 Epimers

                                   

 

 

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