CHEMICAL COMPOUNDS

IN CELL

Carbohydrate

ProteinsNucleic Acid

Lipids

water

containing C,H and O in the ratio 1:2:1

example

Basic unit

Two forms

DNAImportant for

1.Mantaining cell shape and cell turgidity

2.Medium for chemical reactions in cell

3.Dissolves gases and chemicals in cell

4.Helps to maintain temperature of cells / body

Containing elements

C,H dan O

RNA

Double helix structure of DNA

- Double strands of polynucleotide

Strand 1 Strand 2

-in the chromosomes

-carries genetic information

Single strandl, in the cytoplasm and nucleoplasm. Involves in protein synthesis

DN

A

5C- sugar, phosphate, N-bases

function

Glucose provides energy for cells, cellulose for the synthesis of cell wall , starch and glycogen as reserved food in plants and animals .

elements

cellulose

starchglycogen

Unit asas karbohidrat

glucose

carbohydrate maltose glucose

hydrolysis

condensation

Ratio of C and H is greater than O

example

Fat globules in cell

consists of

Fatty acids glycerol

Saturated fatty acidUnsaturated

fatty acids

- max. number of H atom - no double bonds between C atoms in the carbon skeleton

H3C-C-C-C-C…..C-C-C-COOH

-there are double bonds between C atoms

……C-C=C-C-C…..

Its significance

As food storage in cells and adipose tissue, synthesizing cell membrane , producing energy and disolving vitamins ADEK

Hydrolysis formsGlycerol and

fatty acids

Contains elementsC,H,O and N.

Some poteins contain S and P

Basic unit is

Amino acids

Its significance

Formation of cell protoplasm, keratine in the nails and hairs, collagen helps to support the tendon, ligament. Protein is also a component of plasma membrane, forms haemoglobine, chlorophylls, enzyme, antibody and hormones.

Primary, Secondary, Tertiary and Quartenary. 4 levels

ELEMENTS IN HUMAN BODY

Water

Properties and the importance of water:•Polar molecule – unequal distribution of charges, a universal solvent.•Transport medium in blood, lymph and interstitial fluid. It transports nutrients, excretory wastes, O2, CO2 and urea.•A medium for biochemical reactions

Water• Maintenance of stable internal

environment such osmotic pressure / turgidity of body fluid and body temperature

• Helps lubrication- mucus which is a slimy fluid secreted by body cells contains mostly water.

• Water has high cohesive forces , producing capillary action that helps the transport of water in xylem vessels

WATER

CHEMICAL COMPOSITION OF CELL

LIPID MOLECUL)E (Triglyseride)

PHOSPHOLIPID MOLECULE

Hydrophylic head

Hydrophorbic tail

(attracted by water molecule )

( not attracted by water molecule)Starch molecule

(carbohydrate)

glucose

Polypeptide chain

Part of DNA molecule

Polynucleotide chain 1

Polynucleotide chain 2sugar

phosphate

Nitrogenous base

( Adenine, Tyamine, Cytosine dan Guanine )

Amino acid

CARBOHYDRATES/ POLYSACCHARIDES• Organic compound containing C,H, O in the ratio

1C:2H:1O, formula (CH2O)n • The basic unit is glucose, C6H12O6

• Three types of polysaccharides: 1. Monosaccharides (simple sugar) eg.

. glucose, fructose, galactose - reducing sugar, reduces blue copper .

solution (Benedict solution) to brick red . precipitate.

- soluble in water and fructose is very sweet - glucose is the monomer of polysaccharides

Disaccharides• Complex sugar, consists of two units of

monosaccharides• Exam-: Maltose + water glucose + glucose ples Sucrose + water glucose + fructose Lactose + water glucose + galactose The reaction: (left to right ) is hydrolysis (right to left ) is condensation• Disaccharides are soluble in water. Sucrose, cane sugar is sweet . Maltose is malt

sugar and lactose is milk sugar• Reducing sugar except sucrose.

CARBOHYDRATES - MONOSACCHARIDES

CARBOHYDRATES

CONDENSATION REACTION

Glucose + fructose Glucose + galactose

sucrose lactose

+H2O+H2O

-H2O-H2OReaction X

Reaction Y Reaction YReaction X

What are reactions X and Y?

CONDENSATION REACTION

Glucose + glucose

Condensation reaction

Maltose

C12H22O11

C6H12O6 C6H12O6

H2O hydrolysis+H2O

Glucose + fructose

Condensation reaction

H2OH2O

hydrolysis

Sucrose

C12H22O11

POLYSACCHARIDES

Polysaccharides in glycogen

Polysaccharides in starch

Polysaccharides in starch

The importance of carbohydrates:1.Starch is a food reserves in cells and the principal source of energy for cell metabolism.2.Cellulose is needed in the synthesis of cell wall.

POLYSACCHARIDES A polymer containing 4 and above units of glucose Three types of carbohydrates :

- starch - insoluble, amorphous carbohydrates reserved in plants- glycogen - carbohydrates reserved in animals ,human beings and Yeast. Stored in liver and muscles. Polysaccharide chains are highly branched.- cellulose - structural carbohydrates , principally found in cell wall of plants cells.

• Polysaccharides are broken down into disaccharides and monosaccharides by hydrolysis

Lipids• Types of lipids: Fats, oils, wax, phospholipids and .

steroids.• Fats and oils are triglycerides- an ester formed

from condensation of one molecule of glycerol and 3 molecules of fatty acids

• Waxes are found in waterproof cuticle of leaf epidermis.

• Phospholipids are component of cell membrane• Steroids are complex organic compounds,

including cholesterol and steroid hormones.

Fat / lipids• Saturated fat - Fats containing saturated fatty acids. - saturated fatty acids contains no double

bond in the carbon skleton and the number of H- atoms is maximum.

• Unsaturated fat - fats containing unsaturated fatty acids. - unsaturated fatty acid contain double

bond and it can take an additional H-atoms

LIPID- TRIGLYSERIDES

Reaction XReaction Y Fatty acids

glycerol

Lipids ( triglycerides)

Condensation of one molecule of glycerol and 3 molecules of fatty acids result in the formation of lipids (triglycerides).

Hydrolysis of lipids will form one molecule of glycerol and 3 molecules of fatty acids

PHOSPHOLIPIDS

glycerol

Fatty acids

Fatty acid containing phosphate

Hydrophylic head

Hydrophorbic tails

In water, hydrophylic heads are attracted to water molecules surrounding the phospholipids bilayer. Hydrophobic tails are non-polar, thus not attracted to water molecules and lying facing each other at the internal of the phoslipids bilayer. It is this arrangement of phospholipids bilayers that forms the plasma membrane of a cell.

PHOSPHOLIPIDS

LIPIDS

The importance of lipids in cell?

1. It forms a component of plasma membrane ( fluid mosaic hypothesis) and other membranes in cell

2. Some lipids are in the form of steroids which is important as hormones eg. adrenaline, oestrogen and progesterone

3. Lipids in the skin / subcutaneous fat acts as heat insulator, preventing excessive loss of heat from human body.

4. Excess lipids is stored as subcutaneous fat, in the muscles and adipose tissue

AMINO ACIDS AND PEPTIDE BOND IN PROTEINS

Amino + acids

Amino acids

dipeptides

Hydrolisis, +H2O

condensation

-H2O

polypeptides

Hydrolisis, +H2O

condensation, -H2O

( proteins )

PROTEINS

PROTEINS

4 levels of organisation of protein molecules

-Primary proteins

-Secondary proteins

-Tertiary proteins

-Quartenary proteins

How do they differ from each other?

Types of amino acids• Essential amino acids (9): - essential for body development but cannot

be synthesized in body cells. They are obtained from diet such as beans, meat (the first class proteins)

• Non-essential amino acids (11): - can be synthesized in the body, derived

from other amino acids, mostly found in plants.

NUCLEIC ACIDS

NN

NN

N

S P

S

P

DNA molecule

A double helix structure

One unit of Nucleotide

Consists of sugar ( 5C), phosphate and nitrogenous base.

A single polynucleotide chain

DNA STRUCTURE

PROTEIN SYNTHESIS

PROTEIN SYNTHESISReview on DNA and RNA structure

REPLICATION OF DNA

PROTEIN SYNTHESISStructure of DNASummary of the process

DNA is found in the chromosome ( in the nucleus). It is a double helix strands of polinucleotide chains. Each polynucleotide chain comprises ribose sugar, phosphate and nitrogenous bases- purines ( A,G) and pyrimidines ( C, T)

GENE AND DNA REPLICATION

CHEMICAL COMPOSITION OF CELLS

chemicals in cells

carbohydrates

Proteins Nucleic acids

Lipids

water minerals

Cells chemical compo-sitions- containing elements ….., …….. and …………

In the ratio A:B:C is …………………

examples

functions

Hydrolysed by enzyme

producesThe basic units are

comprises

Of two forms

DNA

Their differences are

Two types

micronutrien

and

exam

ples

Percentage in cell is

%Important for

characteristics3 types

Containing elements

Hydrolysis yields

Functions

Contains elements

Its basic unit isexamples

Is significant in

BIOLOGYFORM 4

ENZYMES

Catalysis and Activation EnergyCofactors – Metal ions, coenzymes and prosthetic groupsEnzyme Inhibitors- competetive and non-competetive inhibitorsClassification AND naming of enzymes

Ener

gy

The propeeties of enzymes

ENZYME – A BIOLOGICAL CATALYST

Defination of enzyme A protein syntesized by specificcells in living organisms that serveas an organic catalyst inbiochemical reactions in the body.

Intracellular Enzymes

Enzymes that are retained in cells and catalyst biochemical reactions in cells / cell metabolism eg. hydrogenase and polymerase enzymes

Extracellular Enzymes

Enzymes that are transported out of the cell for their action outside the cell eg. Hydrolytic enzymes such as amylase, lipase, protease

Energy and chemical reactions

Consider the reaction:

A + B ABA and B are the reactants and AB is the product

The rate of the reaction can be increased by :

increasing the concentration of the reactants

increasing the temperature of the reaction

An increase in the above factors will increase the rate of collision of the reactant molecules.Naming of enzymes:

Substrate name + -ase

Eg. Lipids + -ase ……. lipase

CATALYSIS AND ACTIVATION ENERGYIn laboratory; heating provides the activation

energy for the reaction. This energy is required to overcome the energy barrier for the reactants to react.

In living cells; the energy barrier for the reaction is

overcome by an enzyme. The role of an enzyme is to reduce

the activation energy needed by the substrate molecules before reaction occurs

The substrate molecule will combine with the enzyme molecule at the active site of enzyme molecule, forming an enzyme-substrate complex.

The active site of the enzyme helps to reduce the activation energy for the substrate molecules to enable chemical changes / chemical reaction to take place in order to form the products.

enzyme

substrates

Active site

Allosteric site

products

enzyme

Enzyme-substrate complex

Pote

ntia

l ene

rgy

Progress of reaction

Initial state

Final state

Reaction without enzyme

Reaction with enzyme

Reduction in activation energy

ACTION MECHANISM OF AN ENZYME

Enzyme structure and its action; An enzyme is a globular proteins of a

tertiary or quartenary structure. The substrate molecule binds to the

enzyme molecule at its active site Other parts of enzyme molecule is

called the allosteric site The surface configuration at active

sites is complementary to surface configuration of a specific substrate molecule only i.e it follows the lock and key hypothesis

The formation of enzyme-substrate complex is followed by the reduction in activation energy of the reaction and thus allowing the reaction to form the products.

The active site of the enzyme is now free to combine with another substrate molecule and so forth.

Apart from having an exact three dimensional shape, the active sites also has charged and uncharged amino acids and they are arranged in a correct sequence so that it can enclose as well as arrange the substrate molecule at the active sites of the enzyme molecule.

The induced fit hypthesis- protein molecule, being flexible is able to change shape at the active site so that substrates molecule may fit into it tightly to form enzyme-substrate complex.

Enzyme substrate enzyme-substrate enzyme products (lock) (key)

Lock and Key Hypothesis

Induced Fit Hypothesis

complex

+

Enzyme substrate Enzyme-substrate complex

product

KEY AND LOCK HYPOTHESIS

+

Enzyme substrate Enzyme-substrate

complex is not formed

No product

Active site of an enzyme

Non-substrate is not complementary to active site

(no hydrolytic action by enzyme)

CHARACTERISTICS OF AN ENZYME

Enzyme is a protein molecule and therefore sensitive to heat and pH change

It is a biological / organic catalyst that helps to accelerate the chemical reaction whereas the enzyme itself remains unchanged ( does not take part) at the end of the reaction.

An enzyme is specific for a certain substrate only.

Enzyme reacts in both directions of the (reversible) chemical reaction. It speeds up the reaction but does not determine the direction of the reaction.

The rate of enzyme action is stated in terms of ‘turnover number’. It refers to the number of substrate molecules that are changed by an enzyme molecule to its product in one minute. eg.

catalase 2H2O2 2H2O + O2

The turnover number for a catalase is 6 million. An enzyme can catalyse one reaction at one time reaction rate at t + 100C Q10= = 2 reaction rate at t0C

Temp.

Optimum temperature

3X

2X

1X

Temperature>450C will change surface configuration of enzyme, causing it to denature, esp. at active site

Factors that affect enzyme activity

pH temperature

Enzyme concentration

Substrate concentration

pH

Enzyme concentration

Substrate concentration

Rea

ctio

n ra

te

Rea

ctio

n ra

te

Rea

ctio

n ra

te

Rea

ctio

n ra

te

Optimum pH

4X

2X

1X

pH=-log10[H+]

pH affects distribution of charges at active site

ENZYME INHIBITORS

action reaches its maximum rate.

ENZYME

is

A specific proteins, synthesized in cell and functions as organic catalyst, accelerates chemical reactions within / outside cells

Enzyme characteristics

Some enzymes require

cofactors eg.

Metal ions, coenzymes

Enzyme action

follows

retarded by Enzyme synthesis occurs

Living cells like pancreatic cells

in

in 3 stages

1. Replication

2. Transcription of RNA / mRNA

3.Translation into amino acids

2 types

Intracellular enzymes

examplesPolymerase , synthetase

Affected by pH, temperature, enzyme concentration and substrate oncentration.

temperaturepH

Substrate concentration Enzyme concentration

370C

Enzy

me

activ

ity

Temp.pH7

Enzy

me

activ

ities

Low temp.:

The higher the temp. , the more active the enzyme is. At higer temp.> 450C enzyme denatures.Opt. temp. is 370C

Enzymes

X Y ZEvery enzyme has its own optimal pH. X- pepsin Y-salivary amylase Z- lipase

Enzy

me

activ

ity

Enzy

me

activ

ity

[enzyme][substrate]

E3X

E2X

S1X

S2X

Enzyme action is specific i.e one enzyme for one substrate / one reaction

Enzyme is a proteins- denatured at higher temperature > 450C and at an extreme pH. Enzyme acts best at optimum temperature / pH

Enzyme ia an organic catalyst- doesn’t take part or change in a chemical reaction it involved

An enzyme catalysts a reversible reaction

starch + water maltoseamylase

Lock and key hypotheses lock

key

Enzyme-substrate complex

product

Enzyme inhibitor

Extracellular enzymes

Amylase lipase

[substrate] is limiting factor[enzyme] is limiting factor Optimum pH Optimum temp.

E E ES S

REFLECTION 1

1. What is an enzyme?2. What is meant by : i) the activation energy

iI) the active site of an enzyme 3. What are the factors that can speed up a chemical reaction?4. Why does certain chemical reaction need energy supply ( in

the form of heat ) for the reaction to take place?5. Can we provide external energy such as heat energy for

chemical reactions in the body cells to take place. Why ? What is your suggestion to overcome the problem ?

6. Explain the role of an enzyme in chemical reactions in the body cell.

7. Describe the ‘lock and key’ hypothesis in an enzymic reaction.

REFLECTION 2

1. Sketch a graph to show the effect of the following environmental ( or surrounding) factors on enzyme activity:a) temperatureb) pH c) substrate concentrationd) concentration of an enzyme

2. Describe briefly how the above factors affect the the rate of chemical reaction catalysed by an enzyme.

Mind Map

Factors affecting enzyme activity

temperature

Effect of low temperature on enzyme

Effect of high temperature on enzyme

Enzyme activity at optimum temperaturepH

Enzyme concentration

Substrate concentration

At optimum pH

Extreme pH may cause

The limiting factor is

How it affects?

The limiting factor is

How it affects?

ENZYME TECHNOLOGY

ENZYME TECHNOLOGY

ENZYME

is

A specific proteins, produced in cells and functions as organic catalysts, accelerating the chemical reactions in cells

Characteristics of enzyme

1. 2. 3.

4.5.

Some enzymes require

cofactors

eg.Enzyme action

hypothesis

slowed down byEnzyme is synthe-sized

in

through 3 stages

1.

2.

3.

2 types

examples

Fctors that affect enzyme activities

temperaturepH

Substrate concentration Enzyme

concentration

370C

Enzy

me

activ

ity

Temp.pH7

Enzy

me

activ

ityLow temp.:

The higher the temp. ,……… ………….At higher temp.> 450C the enzyme ……… Opt. temp. is ……..0C

Enzyme

X Y ZEvery enzyme has its own ……. temp.. X,Y and Z are probably………………..

Enzy

me

activ

ity

Enzy

me

activ

ity

[enzyme][substrate]

E3X

E2X

S1X

S2X

The limiting factor is…….. The limiting factor is……..

E E ES SP

ATP MOLECULE

Test tube C Test tube B

Test tube D