explain about part biological molecules in grade 7

1. Biological
Molecules

2. Intoduction
• The basic unit of life is a cells
• Most of our bodies are made up of water
• The cells are made of many different kinds of chemicals
• Chemicals or molecules present in the living organisms are
know Biomolecules
• Biomolecules are compounds of Carbon
• All molecules that contain carbon are called Organic
(except CO2)
• Carbon froms 4 covalent bonds. This allows carbpn to from
molecules with many different shapes

3. • The major classes of biological molecules that are important
for all living things are Carbohydrates, lipids, and protein
. Large biological molecules are called Macromolecules

4. Biological molecules
Carbohydrate
Protein
Lipid

5. Carbohydrates

6. Carbohydrates
• Compounds made of C, H and O
• Function used for energy storage and made Structure
• One gram of carbohydrate release 17KJ(kilojoules) of
energy
• We can test the presence of carbohydrate by adding
Benedict’s Solution (sugar) and iodine (Starch)
• The six Carbon sugar all have the same chemical formula
C6H12O6

7. the simplest class of carbohydrate
are monosaccharides

8. the simplest class of carbohydrate
are monosaccharides
Glyceraldehyde Ribose

9. Monosaccharides
Disaccharides
Polisaccharides
Carbohydrates

10. Monosaccharides
• Monosaccharides are the building blocks of more complex
carbohydrates

11. Disaccharides
• Disaccharides are a combination of two monosacharides
• Disaccharides are formed by Dehydration synthesis

12. Polysaccharide
• Polysaccharides are polymer of monosaccharides
• Polymers are long chain molecules with repeating subunits
• Amylose is an
unbranched chain
and is produced by
plants
• Amylopectin is
branched and also
produced by plants
• Glycogen is highly
branched and
produced by animal

13. Polysaccharide
• Starch is a polymer of α-glucose and readily digestible
• Cellulose is a polymer of β-glucose and indigestible
• Cellulose is a structural polysaccharides and used for the
construction of cell walls in plants

14. Polysaccharide
• Chitin is a polymer of β-
glucose molecules that
have a nitrogen
containing functional
group and also
indigestible
• It is used to build cell
walls in fungi and to build
exoskeletons in
arthropods

15. Testing Carbohydrates

16. Testing Carbohydrates

17. Lipids

18. Lipids
• A chemically diverse class of organic molecules that are
grouped together because they are all largely non polar.
• They are soluble in organic solvent like chloroform,
benzene, acetone, paint thinner but insoluble in water
• Lipids have many function including
- Energing storage
- Cell membrane structure
- Vitamins
- Hormones

19. Lipids
Fatty acids
Neutral fats
phospolipids
Steroids (sterols)

20. Fatty acids
• Long chains carbon molecules with many carbon-hydrogen
bonds and a carboxyl group (COOH) on one end
• They come in two varieties saturated and unsaturated
• Saturated fatty acids have no C=C bonds all carbons in the
chain are bonded to as many hydrogen's as possible
• Unsaturated fatty acids have some C=C bonds in the chain,
the carbon chain is not completely saturated with
hydrogen's

21. Fatty acids
Neutral fats
Phospholipids

22. Neutral fats
• Neutral fats are molecules composed of glycerol (a sugar
alcohol)
• Neutral fats are used for long-term energy storage
• They have caloric value 9,5 Kcal/g

23. Phospholipids
• Structural lipids an integral part of cell membrane
• Structurally similar to triglycerides. One fatty acyd is
replaced by choline group
• The Cholins group has both N and P in its structure

24. Phospholipids

25. Steroids or sterols
• Have a more complex structure than other lipids and a
greater diversity of function
• Cholesterol is an important part of cell membranes
• Hormones is other steroids

26. Testing lipid

27. Proteins

28. Proteins
• The most functional diverse class of biological molecules
• Proteins diversity is the basis of the diversity of life
• Proteins serve as enzyme, for defence, transport, support,
motion ,regulation and storage
• Proteins have a gross caloric value 5,7kcal/g but metabolism of
proteins crates toxic nitrogenous waste that must be
processed for excretion form body
• Proteins are necessary foodstuff for building new proteins
• The test for proteins is called Biuret test
• Proteins molecules are made of long chains of smaller
molecules joined an to end
• The smalles molecules are called amino acids

31. Proteins
• Proteins are polymers of amino acids joined through peptide
bonds
• A polymer of amino acids is called a polypeptide

32. Testing Proteins

33. Thank you
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