Protein, Sources and Properties, Test for protein, Uses of protein, enzymes and their functions.

SECOND TERM E-LEARNING NOTES

SUBJECT: CHEMISTRY

CLASS: SS3

 

WEEK 2

 

WEEK 2


TOPIC: GIANT MOLECULES

CONTENTS:

1. PROTEIN-SOURCES

  1. PROPERTIES.
  2. TEST FOR PROTEIN AND USES OF PROTEIN.
  3. ENZYMES AND THEY FUNCTIONS.

PERIOD 3: PROTEINS

Proteins are one of many 4 main teams of macromolecules or polymers which can be current in all dwelling organisms finishing up varied features wanted by cells. They could be thought to be the merchandise wanted by cells. They could be thought to be the merchandise of successive condensations between the carboxyl group of 1 amino acid and the amino – group of one other amino-acid. The construction of most enzymes signifies that they’re proteins.

Sources

Proteins are present in all dwelling techniques as structural parts and as biologically essential substances akin to hormones enzymes and pigments. Proteins in our meals include primarily amino acids and these are known as top notch proteins. They’re primarily of animal origin. Examples embrace lean meat, fish, eggs, milk, cheese and hen second class proteins are of plant origin and are present in greens, legumes (e.g beans, soya beans), groundnuts, grapes, apple and many others. Instance of proteins contains:

  1. Keratin – a compound of pores and skin, coronary heart and nails
  2. Collagen – a muscle protein
  3. Insulin – a peptide hormone regulating the blood sugar degree.
  4. Elastin – a duef constituent of elastic fibres
  5. Amylase – current in human saliva and able to breaking starch down into sugar
  6. Haemoglobin – a pigment that carries oxygen within the blood, and
  7. Ribonuclease.
  1. Construction and form of proteins

Proteins have nicely outlined constructions. The first constructions of a protein check with the way in which through which the atoms of the protein molecules are joined to 1 one other by covalent bonds to kind chains and cross-linkages between chains. Amino – acids are the essential structural items of proteins. Every amino acid accommodates an amino group (-NH2) and carboxyl (-COOH) in its molecule. A specific protein molecule could include two or extra completely different amino-acids, linked in a sequence that reoccurs recurrently alongside the protein chain. No two proteins have the identical sequence, even when they include the identical sorts of amino-acids.

amino acid

Formation of peptides

The amino-acids that make up[ a macromolecule of protein are linked in such a way that a molecule of water is eliminated between the carboxyl group of one amino acid and the amino group of another, to form an amide called peptide. Thus, combination of two or more amino acids forms peptides, combination of three amino acids form tripeptides, combination of many amino-acids form polypeptides. It is a chain reaction.

peptide bond

Peptide linkage

Evaluation

1. List four (4) sources of proteins and give five examples proteins

  1. Which acid is the smallest unit of protein molecule?
  2. Write the structural formula of an amino-acid molecule.
  3. State the type of reaction that leads to the formation of proteins from their monomers.
  4. What is the product of condensation of several amino-acid molecules?[mediator_tech]

PERIOD 2: PROPERTIES OF PROTEINS

  1. Solubility on water: Most proteins are in soluble in water. These which can be soluble embrace insulin (a hormone), and pepsin (an enzyme). Others kind colloidal answer
  2. Motion of warmth: When an egg white (albumen) wealthy in protein is dissolved in water, if types a colloidal answer. On heating the colloidal answer to a temperature above 50OC, the proteins turn out to be coagulated or precipitated. The proteins are mentioned to be denatured by a course of known as Denaturation.
  3. Hydrolysis: Hydrolysis includes the breaking down of peptide bonds in proteins. When macromolecules of proteins are boiled with acid, alkali or enzyme, they turn out to be hydrolysed, throughout which the peptide hyperlinks within the macromolecules break to offer mixtures of amino-acids. The amino acids shaped will be separated and recognized utilizing paper chromatography technique of separation.

EVALUATION:

  1. What’s the product of hydrolysis of protein?
  2. Outline denaturation.

PERIOD 3: TEST FOR PROTEINS

  1. Biuret Take a look at: When a protein (egg white answer) in a take a look at tube is handled with a number of drops (about 2cm2)of NaOH answer adopted by a number of drops (about 1%) of CuSO4 answer a violet or purple answer signifies the presence of protein
  2. Hundreds of thousands: Put some egg white answer right into a boiling tube and add 2cm3 thousands and thousands reagent; a white precipitate is shaped turns brick-red on heating indicating the presence of protein.
  3. Trioxonitrate (V) acid take a look at: Therapy of an answer of a protein or an amino –acid with concentrated troxonitrate(V) acid provides a white precipitate and heating precipitate dissolve to offer intense yellow colouration.

USES OF PROTEINS

  1. Haemoglobin, a protein within the blood carries oxygen and carbon(N) oxide
  2. Hormones that are liable for the management of organic course of in our physique are additionally proteins.
  3. Enzymes are proteins liable for catalysis of particular organic reactions
  4. Tanning the protein of animal disguise produces leather-based which is utilized in making sneakers, baggage, belts, and many others.
  5. Casein, a milk protein is used within the manufacturing of synthetic wool and silk.
  6. Protein is without doubt one of the courses of meals wanted for a stability eating regimen.

EVALUATION

  1. Point out three exams that may used to determine protein (b) point out two polymers which include nitrogen
  2. Clarify the method of denaturaltion of protein
  3. State the chemical compounds utilized in testing for the presence of protein.

PERIOD 4: ENZYMES

Enzymes They’re natural catalysts liable for the metabolic reactions that happen in dwelling organisms. They protein molecules secreted by dwelling cells. Enzymes contain in hydrolysis are known as hydrolases. They digest meals within the physique. We even have oxidation-reduction enzymes involved with the oxidation of meals within the physique cells. Examples are oxidase, dehydrogenase and oxygenase.

PROPERTIES OF ENZYMES

  1. They soluble in physique tissue.
  2. they’re particular in motion.
  3. They’re temperature delicate. They work greatest betweeb 33-40oC. Above this temperature they get denatured.
  4. They’re pH delicate
  5. They work very quickly.

HOW ENZYMES WORK

  1. Enzyme and substrate molecules come collectively to kind enzyme-substrate complicated.
  2. The substrate within the within the complicated react collectively to kind enzyme-product complicated.
  3. The enzyme-product complicated splitto give enzyme and product.

EVALUATION:

State the properties of enzymes.

GENERAL EVALUATION

OBJECTIVE TEST:

  1. Which of the next compounds or mixtures of compounds is nitrogen not a element ingredient? (a) Pores and skin (b) Enzyme (c) Sugar (d) Cheese.
  2. Which of the next is just not appropriate of glucose and fructose? They (a) are structural isomers (b) Cut back Fehling’s answer (c) Could be obtained by the hydrolysis of starch.

(d) are actually fermented by enzymes

  1. Glucose reduces Fehling’s answer on warming to

(a) copper (I) Oxide (b) Copper (i) oxide (c) copper (I) Chloride

(d) copper (I) Hydroxide

  1. Proteins hydrolyse to (a) polypeptides (b) monopeptides (c) collorids (d) amino acid
  2. Most enzymes are: (a) Inorganic catalyst (b) Proteins (c) Cavohydrates (d) Amines

ESSAY QUESTIONS:

  1. State one predominant distinction between a monosaccharide and disaccharide.

b. Write the molecular system of glucose

  1. Identify the practical teams current in glucose and state which ones makes the compound a decreasing agent.

bi. State what can be noticed when concentrated H2SO4 is added to a pattern glucose

ii. Write an equation for the response in b(i) above.

  1. a. Point out the time period used to explain the conversion of glucose into ethanol by enzymatic motion?[mediator_tech]
  2. When crushed cassava was warmed with hydrochloric acid, a sweet-tasting compound D was obtained. When compound D was handled with enzyme zymase, and the combination distilled, on clear and colourless liquid E was obtained. When liquid E was warmed with ethanoic acid within the presence of few drops of concentrated teraoxosulphate(VI) acid, a compound F with fruity odor was obtained.

a. To what class of compounds does D belong?

b. Identify E and F

c. Write the practical group in F

d Write equation for the response between E and ethanoic acid within the presence of concentrated H2SO4 acid.

  1. a. Point out one pure supply of protein

b. Which acid is the smallest unit of protein?

c. Which is the product of condensation of a number of amino acid molecules?

d. Point out two testS that can be utilized to determine protein.

WEEKEND ASSIGNMENT

A.Define an acceptable laboratory course of for getting ready a dry pattern of glucose crystals ranging from an aqueous answer of starch

B. Clarify why a tightly corked glass bottle crammed to the brim with contemporary palm wine shatters on standing.

c. Draw the constructions of glucose and fructose and state one main distinction between them.

d. Identify a reagent that can be utilized to tell apart between answer of glucose and sucrose

PRE-READING ASSIGNMENT

Learn the notes for the entire time period

WEEKEND ACTIVITY

Discover ways to draw the next constructions

a. Straight chain kind (b) cyclic type of (I) Glucose (ii) fructose

b. sucrose (c) starch.

 

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