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chapter 4 biological molecules - Coggle Diagram
chapter 4 biological molecules
carbohydrates
made out of the elements carbon, hydrogen & oxygen
sugars (soluble in water)
single sugars
glucose - found in plants & animals
have the same chemical formula, atoms arranged diff in the molecules, so they have diff chemical & biological properties
fructose - usually found in plants, rare in animals
small molecules, cannot be digested anymore, can pass through cell membrane and absorbed into the cells
double sugars ( made out of 2 molecules of single sugars bonded tgt
maltose - germinating grains, contains 2 glucose molecules
sucrose - contain 1 glucose molecule & 1 fructose molecule
can split into single sugar by enzyme
complex carbohydrates
starch - contain several thousands of glucose molecules , unbranched and branched structure
unbranched give blue-black color in iodine solution
storage form of carbohydrates in plants, only when needed then it digested to glucose to provide energy for the cell activities
cellulose - contain thousands of glucose molecules joined tgt
cellulose cell wall protect plants from bursting
glycogen - branched molecule, glucose
storage of carbohydrates in mammals, also digested when needed
as a source & store of energy
how to test for reducing sugars, starch, fats, proteins
reducing sugars - glucose, fructose, galactose, maltose, lactose, will produce brick-red precipitate when boiled with BENEDICT SOLUTION
starch can be detected by iodine test, if got starch it will produce a blue-black color
fats can be detected by the ethanol emulsion test, a cloudy white emulsion is formed
proteins can be detected by biuret test, biuret reagent a blue solution, when proteins are present it will turn deep purple
proteins - made out of carbon, hydrogen, oxygen, nitrogen
present in all cells, largest & complicated molecules in all food substances
built up from simpler compounds known as amino acids
have different sizes & shapes to joined tgt to form a long thread-like structure ( a string of beads ) and it folded to form three dimensional shape to perform its function
cannot directly absorb proteins as it is too large to take in the molecules to pass through the cell membrane, so must be broken down by enzymes during digestion
can be found in animal & plant foods
make new cytoplasm, used for growth and repair of worn tissues, make enzymes
didn't get enough proteins with get deficiency disease called kwashiorkor
fats - made out of carbon, hydrogen, oxygen
less oxygen in proportion to hydrogen compare to carbohydrate
is made out of 1 molecule of glycerol & 3 molecules of fatty acids
sources- animal/ plants fats, foods that are rich in fats
functions- a source & store of energy especially for animals, insulating material to prevent heat loss, reduce water loss from the skin surface
DNA (deoxyribonucleic acid)
complex
carries genetic info for development
consists 2 parallel strands, each strands consists of a sequence of bases, the bases of one strand join to the bases of another strand, holding 2 strands tgt, then it twisted to form a double helic
bases A,C,G,T, A pair with T, C pair with G