Our Grade 10 Biology [Life Sciences] Notes Set is a colourful, practical guide for terms 1 to 4. It contains all the notes needed to achieve a successful completion of the degree. All notes are clearly organized and easy to navigate. Our notebook is an excellent tool to help the learner achieve con...
, CHEMISTRY OF LIFE
9(
ORGANIC COMPOUNDS
→ carbon (C), hydrogen (H) & oxygen (O)
CARBOHYDRATES Z Atoms of carbon, hydrogen & oxygen
Z MAIN FUNCTION = provides energy to living organisms
CLASSES:
1. MONOSACCHARIDES
[ > simple / single sugars (e.g., glucose) = basic units]
TEST : Benedict solution / Fehling A & B solution [reddish brown]
2. DISACCHARIDES
[ > union of single sugars = double sugars (e.g., sucrose) > TWO SUGARS]
E.g. : Milk = lactose
Sugar cane = sucrose
GLUCOSE : FRUCTOSE : SUCROSE :
3. POLYSACCHARIDES
STARCHES:
Z Store energy in organisms : 100th glucose molecules connected
Z Stored in PLANT CELLS > stored in liver & muscles
TEST : iodine solution = blue-black
CELLULOSE:
Z MAIN COMPONENT of plant cell walls [not in animals]
Z Similar structure to starch BUT > cannot digest & obtain energy >
forms FIBER / coarseness in diet
TEST : Schultz solution = purple
GLYCOGEN:
LIPIDS (FATS) Z Carbon, hydrogen and oxygen [sometimes also phosphorus (P)]
TEST : organic solvents
SATURATED FATS UNSATURATED FATS
> animals > plants
> solid (room temperature) > liquid (room temperature)
E.g., lard & butter
NUCLEIC ACID:
> high blood cholesterol & heart
an organic compound containing the
disease elements carbon, hydrogen, oxygen,
NUCLEIC ACID Z NITROGEN-CONTAINING COMPOUNDS nitrogen and phosphorus.⇨
Polynucleotide [DNA & RNA]
FUNCTION = controls the structure +
Two types of nucleic acids:
functions of a cell
u deoxyribonucleic acid
STRUCTURE: (DNA)
→ carbon, hydrogen, oxygen, nitrogen & phosphorus u ribonucleic acid (RNA)
→ made up of nucleotides
RNA DNA
→ nucleolus, cytoplasm & → nucleus / core
ribosomes → store hereditary information
→ build proteins from amino
acids
ENZYMES Z Proteins that act as CATALYSTS
Z Catalyst [ → substance that accelerates rate of chemical
reaction]
[SENSITIVE TO TEMPERATURE AND pH LEVELS]
ROLE [enzymes]:
Z Regulate CHEMICAL REACTION in living cells
Z Connect molecules & break molecules
Z Without enzymes = metabolic rate too slow for survival
, HOW DO ENZYMES WORK?
[“lock and key model”]
Z Enzymes = region with specific shape [ACTIVE REGION]; substrate
molecule (enzyme acts) > shape matches active region [enzyme +
substrate FIT TOGETHER]
Z Enzyme & substrate > connected = chemical reaction > product /
result = detached from enzyme & can then BE USED AGAIN
SENSITIVE TO TEMPERATURE:
↑ temperature = ↑ reaction rate
MORE ↑ temperature = shape of active region changed
[denatured]
** ENZYMES CANNOT FUNCTION IF THEY ARE DENATURED!
↓ temperature = ↓ reaction rate
[no denature]
SENSITIVE TO pH:
[pH → measure of how conductive / alkaline a substance is]
** If the medium in which the enzyme works changes (too acidic /
alkaline) = denatured
ENZYMES [EVERYDAY LIFE]:
Z Washing powder > protein-digesting enzymes > stains are broken
down into soluble molecules > solution of washing powder + water
dissolves
Z Manufacture of products:
W Baby food : DIGESTIVE ENZYME
W Beer brewing industry : starch → sugar (fermentation)
W Rubber industry : evolves oxygen from peroxide > latex
W Dairy industry : DIGESTIVE ENZYME
W Fruit juice: breakdown of cellulose + pectin > clarified
W Bread baking : breakdown of starch in flour > yeast produces
carbon dioxide > bread rice
PROTEINS Z Carbon, hydrogen, oxygen & nitrogen (sometimes sulphur,
phosphorus & iron)
[SENSITIVE TO TEMPERATURE AND pH LEVELS]
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