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Learning outcomes:• State the elements in the cell• List the chemical compounds in the cell• Explain the importance of organic
compounds in the cell• Explain the importance of water in the cell.
UNDERSTANDING THE CHEMICAL COMPOSITION OF THE CELL
UNDERSTANDING THE CHEMICAL COMPOSITION OF THE CELL
ELEMENT IN THE CELL
• All living and non living things are made of substances called element
• The four most common elements (96%) 1) Carbon (C)2) Oxygen (O)3) Hydrogen (H)4) Nitrogen (N)
• Chief element (4%) Calcium (Ca) Potassium (K) Phosphorus (P) Sulphur (S) Chlorine (Cl) Magnesium (Mg)
• Trace element (0.01%) Copper (Cu)Iodin (I)Iron (Fe)
Is substances composed of only one kind of atom which cannot be broken into simpler substance by chemical reaction.
Element Functions
Animal cells Plant cells
Hydrogen,carbon,oxygen,nitrogen
Synthesis of organic compound, for example, protein,lipids and nucleic acids
Sulphur Component of some proteins
Sodium •regulates osmotic in cells•helps in transmission of nerve impuls
•not required
Magnesium •Involved in protein synthesis.•As a cofactors for some enzymes
•required for the synthesis of chlorophyll•activate enzymes in cells
Ferum •involved in the synthesis of red blood cells and synthesis of respiratory enzymes
•synthesis of chlorophyll•act as an electron carrier during photosythesis and respiration
Calcium •required for formation of strong bones and teeth•Helps in contraction of muscle cells•Promotes blood clotting
•Synthesis of cell walls(cellulose)•Helps maintain the semi-permeable plasma membranes.
Phosphorus •Formation of bones and teeth.•Helps in the contraction of muscle sells•Synthesis of ATP •An essential component of nucleic acids(DNA/RNA)
•Promotes cell division•Synthesis of ATP and nucleic acids•Induces the formation of flowers and seeds
Pottassium •Required in muscle contractions and transmission of nerve impulses
•Synthesis of carbohydrates•Activates certain enzymes
Chlorine •Synthesis of HCl by gastric glands in the stomach which destroys pathogens and maintains pH of the stomach
•Photolysis of water during light reaction in photosynthesis
THE IMPORTANCE OF CHEMICAL COMPOUND
COMPOUNDS IMPORTANCE
Carbohydrates •A primary source of energy in cells•Starch is the main energy store of carbohydrates in plant cells•Glycogen is the main energy store of carbohydrates in animal cells•Cellulose forms the main constituent of the cell wall
THE IMPORTANCE OF CHEMICAL COMPOUND
COMPOUNDS IMPORTANCE
Protein •The basic unit of proteins are amino acid•Function : build new cells for growth and repair damaged tissues•Required in the synthesis of enzyme, antibody and hormone•Form structural components such as keratin in skin, collagen in bones and skin and myosin in muscle fibres•Important components of the plasma membrane•Involved in the synthesis of haemoglobin in red blood cells
THE IMPORTANCE OF CHEMICAL COMPOUND
COMPOUNDS IMPORTANCE
Lipids
Examples :
Fat, oil, waxes, phospholipids and steroid
15% of protoplasm is made up of lipids
•Fats and oils are important source of energy•The layer of adipose tissue underneath the skin insulates the bodies of animal against low temperature •Act as a solvent for fat soluble vitamins such as Vitamin A, D, E , K•Phospholipids form a major constituent of the plasma membrane•Wax prevent water loss in plants and infection by pathogens
THE IMPORTANCE OF CHEMICAL COMPOUND
COMPOUNDS IMPORTANCE
Nucleic acids• nucleotide is a building block of nucleic acids• 2 type of nucleic acids :
i) deoxyribonucleic acids (DNA)
ii) ribonucleic acids (RNA)
•Store genetic information •Consists of a nitrogenous base, a pentose sugar and a phosphate group•DNA – double stranded polynucleotide, twisted around each other to form double helix. Found in nucleus, chloroplast and mitochondria•RNA – found in cytoplasm, ribosome and nucleus, copies information carried by DNA for use in protein synthesis, a single stranded of polynucleotide
Phosphate group
Pentose sugar
Nitrogenous base
DNA Structure
DNA consists of two molecules that are arranged into a ladder-like structure called a Double Helix.
A molecule of DNA is made up of millions of tiny subunits called Nucleotides.
Each nucleotide consists of:1. Phosphate group2. Pentose sugar3. Nitrogenous base
Nucleotides
Phosphate
PentoseSugar
NitrogenousBase
Nucleotides
The phosphate and sugar form the backbone of the DNA molecule, whereas the bases form the “rungs”.
There are four types of nitrogenous bases.
Nucleotides
A
Adenine
T
Thymine
G
Guanine
C
Cytosine
Nucleotides
Each base will only bond with one other specific base.
Adenine (A)Thymine (T)
• Cytosine (C)Guanine (G)
Form a base pair.
Form a base pair.
DNA Structure
Because of this complementary base pairing, the order of the bases in one strand determines the order of the bases in the other strand.
DNA Structure
To crack the genetic code found in DNA we need to look at the sequence of bases.
The bases are arranged in triplets called codons.
A G G - C T C - A A G - T C C - T A G
T C C - G A G - T T C - A G G - A T C
DNA Structure
A gene is a section of DNA that codes for a protein.
Each unique gene has a unique sequence of bases.
This unique sequence of bases will code for the production of a unique protein.
It is these proteins and combination of proteins that give us a unique phenotype.
Protein
DNA
Gene
Trait
Your Task
Draw a flow chart to show how to get from:
The important of
in the cell
Medium of biochemical reactions
Universal solvent
Transport medium
Maintaining body temperature
Support
Maintaining osmotic balance andturgidity
Lubrication
High surface andcohesion
The importance of water
Solvent • Water is the universal solvent of many biological
molecules because the properties of its molecules
Maintaining osmotic balance and turgidity • It helps in maintaining the osmotic balance
between the blood and interstitial fluid• In plants, it helps the cells to be turgid,
turgidity provides support in plants
The importance of water
Moisture • Water provides moisture to respiratory
surface• This enables respiratory gasses to
dissolve
Lubrication
• Mucus (composed mostly of water)assits the movement of food substances in the intestinal tract
• Synovial fluid lubricates the joint
The importance of water
Maintaining body temperature• It helps to keep a relatively constant body
temperature for optimum enzymatic activities
Medium for biochemical reaction
• Water act as a medium for biochemical reaction
The importance of water
Transport medium• It is an agent for transport medium in blood,
lymphatic, excretory and digestive systems• It helps to remove waste products
CARBOHYDRATES
Diagram A
Diagram C
Diagram B
Glucose + Glucose Maltose + Water
Glucose + Fructose Sucrose + Water
Glucose + Galactose Lactose + Water
Two monosaccharides joined together through condensation
Condensation Reaction
Condensation
Condensation
Condensation
Each of the condensation reactions involves the removal of one water molecule
Maltose + Water Glucose + Glucose
Sucrose + Water Glucose + Fructose
Lactose + Water Glucose + Galactose
Hydrolysis Reaction
Hydrolysis
Hydrolysis
Hydrolysis
Disaccharides can be broken down to their constituent monosaccharides through hydrolysis
Hydrolysis is a chemical reaction that involves the breaking up of large molecules
by adding water to them
Sugar Observation Inference
Glucose A brick-red precipitate is formed
Glucose is reducing sugar
Sucrose (without dilute hydrochloric acid)
The colour of the Benedict’s solution remains unchanged
Sucrose is non-reducing sugar
Sucrose (boiled with dilute hydrochloric acid)
A brick-red precipitate is formed
A positive result with Benedict’s solution can only be obtained if the sucrose solution is first boiled with dilute hydrochloric acid
Differentiating between REDUCING and NON-REDUCING
SUGAR
PROTEINS
• Basic units of proteins – amino acids
• Long chains of amino acids – polypeptides
• Function :-– Build new cells for growth– Renew damaged tissues– Required in the synthesis of enzymes,
antibodies, hormones, haemoglobin– Form keratin (skin), collagen (bones), myosin
(muscle tissues)– Components of the plasma membrane
A very short polypeptide chain
Amino acids
Peptides bond
TYPES OF PROTEIN STRUCTURE
TYPES OF PROTEIN STRUCTURE
PRIMARY STRUCTURE
TERTIARY STRUCTURE
QUARTERNARY STRUCTURE
SECONDARY STRUCTURE
• linear sequence of amino acids in a polypeptides chain
• the polypeptides chain that is
coiled to form
• an alpha helix (a-helix) chain or
• folded into beta pleated (B-pleated)
• hold together by hydrogen bonds
• the helix chains or the beta pleated sheets are coiled or folded into three dimensional shape of a polypeptide chain
• enzymes, hormones, plasma proteins, antibodies
• 2 or more tertiary structure polypeptide chains are arrange to form a functional and complex protein molecule
• Haemoglobin (4 polypeptide chains)
PROTEIN STRUCTURE
LIPIDS
* Complex organic
compound
* Cholesterol
* Sex hormones
(testosterone,
oestrogen, progesteron
e)
Structure of triglycerides
• Triglycerides is an ester
• Formed through 1 molecule of glycerol and 3 molecules of fatty acids
• Fatty acids are either saturated or unsaturated
• Fats and oils
Unsaturated Fats• The fatty acids in unsaturated fats have at least one double bonds between the carbon atoms
Saturated Fats• The fatty acids do not have any double bonds between the carbon atoms Saturated
fats
Saturated fats
Saturated fats
Saturated Fats
Unsaturated Fats
•Solids at room temperature (butter)
• Raises the levels of LDL (bad cholesterol) in the blood
• Lower the levels of HDL (good cholesterol) in the blood
• Liquid at room temperature (corn oils)
• Lower the levels of LDL (bad cholesterol) in the blood
• Increases the levels of HDL (good cholesterol) in the blood
Learning Objectives• State what enzymes are• Explain why enzymes are needed in life processes• List the general characteristics of enzymes• Relate the name of enzyme to substrate• State sites where enzymes are synthesized• State the meaning of intracellular enzymes and extracellular enzymes• Explain the involvement of specific organelles in the production of
extracellular enzymes• Explain the effects of pH, temperature, enzyme concentration and substrate
concentration• Explain the mechanism of enzyme action• Relate the mechanism of enzyme action with pH, temperature, enzyme
concentration and substrate concentration• Explain the uses of enzymes in daily life and industry using examples
What is enzyme?
Have you seen these products?
What is enzyme?
Enzyme is biological catalyst that regulate cellular
reactions and speed up biochemical reaction
What is biochemical reaction?
• Biochemical reaction is called metabolism
• Biochemical reactions occur in a cell simultaneously at all times
• Metabolic reaction :
Reaction
Substrate Product
Type of metabolic reaction
Anabolism Catabolism
Build complex molecules Example : photosynthesis
Breakdown complex moleculesExample : digestion
Naming of enzyme
• According to the name of the substrate it catalyses
• Adding the suffix …ase at the end of the name of their substrates
• Example
Substrate Enzyme
Lactose Lactase
Sucrose Sucrase
Lipid Lipase
Example :
Sucrose + water glucose + fructoseSucrase
Substrate
Enzyme
Products
Pepsin Trypsin Rennin
Enzymes that were named before a systematic way of naming enzymes
was formulated
The general characteristics of enzyme
• All enzymes are protein • Enzymes speed up biochemical
reactions• Enzymes are not changed or destroyed
by the reactions • Enzymes are highly specific (can only
catalyse specific substrate only, have specific site)
• Enzymes are needed in small quantities
• Most of metabolic reaction by enzyme are reversible
• Enzyme activities can be slowed or completely stopped by inhibitor
• Enzymes require helper molecules called cofactor (inorganic or organic)
Temperature Temperature
Enzyme concentration
Enzyme concentration
Substrate concentrationSubstrate
concentration
pHpH
Factor affecting enzyme activity
Factor affecting enzyme activity
Temperature
• Temperature low, enzyme reaction slow• Temperature increase, more collisions
between enzyme and substrate molecules, the reaction is accelerated
• Every 10°C rise in temperature, the rate of reaction is doubled
• up to the optimum temperature, the enzyme reaction at maximum rate
• Beyond the optimum temperature, enzyme is denatured
Temperature
pH
• Different enzymes, different optimum pH
• pH changes, protein (enzyme) conformation changes, the charge at active site is altered
• The ability to bind is reduced
• Optimum pH : the reaction at maximum rate
pH
Substrate concentration
• Substrate concentration is high, the reaction is high
• More substrate are available to bind active site of enzyme
• The reaction is rise to maximum rate until not enough enzyme supply
• Thus, the enzyme becomes a limiting factor
• To increase the reaction is increase the concentration of enzyme
Substrate concentration
Enzyme concentration
• Enzyme concentration is high, the reaction is high
• More enzyme molecules are available• The reaction will increase till a
maximum rate is reached• After maximum rate, the concentration
of substrate become a limiting factor• The rate of reaction will increase if
there is more substrates supply
Enzyme concentration
The sites of enzyme synthesis
• Ribosomes is the site of enzyme synthesis
• The information is carried by DNA
• The different sequences of bases in DNA are codes to make different protein
Types of enzymes
• Synthesised and retained in the cell for the use of the cell itself • Found in the cytoplasm, nucleus, mitochondria and chloroplast• Example : oxidoreductase catalyses
Synthesised in the cell but secreted
from the cell to work externally
Intracellular enzymes Extracellular enzymes
Production of extracellular enzymes
Mitochondria
Secretory vesicle
Transport vesicle
Ribosome
Nucleus
Rough endoplasmic reticulum
Golgi apparatus
Where are the location of enzyme production?
Protein synthesis in
ribosome
Transport vesicle
Rough ER
Golgi apparatus
Plasma membrane
Secretory vesicle
Production of extracellular enzymes
Protein are synthesised in the ribosomes
Protein are transported through the space between rough ER
Protein depart from rough ER and wrapped in vesicle
The vesicle fuse with the membrane with Golgi apparatus and empty their content
into membranous of Golgi apparatus
The protein are further modified during their transport in Golgi apparatus
The protein then will wrapped with secretory vesicle
The secretory vesicles bud off from Golgi apparatus and travel to the plasma membrane
The vesicles fuse with plasma membrane before releasing the protein outside the cell as enzyme
The mechanism of enzyme
The mechanism of enzyme
Enzyme Enzyme-substrate
complexEnzyme Products Substrate + +
‘LOCK AND KEY’ HYPOTHESIS
Substrate molecule represents the ‘key’Enzyme molecule represents the ‘lock’
A specific substrate arrives at active site of enzyme molecule
The substrate molecule binds to the active site to form an enzyme-substrate complex
The enzyme catalyses the substrate to form products, which then leaves the active site
The enzyme molecule is now free to bind more substrate molecules
The mechanism of enzyme
The Uses of Enzymes in Daily life and Industry
• Enzyme technology: the use of enzymes in industrial processes
• It can be isolated from cells and function outside the cell.
• It can be obtained from plants and animals mostly from bacteria and fungi in large quantities
Baking industry
Baking industry
Dairy product Dairy product
Fish & meat industry
Fish & meat industry
Medical analysis
Medical analysis
Processing food
Processing food
Paper industryPaper industry
Leather tanning industry
Leather tanning industry
Textile industryTextile industry
Biological detergent
Biological detergent
Brewing industry
Brewing industry
The uses ofenzymes
The uses ofenzymes
87
UsesType of Industry Enzymes used
Protease
Cellulase
Amylase
Tenderises meat
Removes the skin of fish
Softening vegetables
Extracts agar jelly fromseaweed
Removal of seed coatsfrom cereal grains
Production of sweets,beverages and chocolates
Foodprocessingindustry
88
UsesType of Industry Enzymes used
Foodprocessingindustry
Detergents
Rennin
Lactase
Protease
Solidifies milk proteins
Hydrolyses lactose to makeice-cream
Dissolve protein stains inclothes
89
UsesType of Industry Enzymes used
Amylase
Pancreatictrypsin
Microbialtrypsin
Trypsin
Removes starch that isused as stiffeners fromfabrics
Treats inflammation
Dissolves blood clots
Removal of hair from animalhides
Textile industry
Medicalindustry
Leatherproducts