chemical basis of life-2

chemical basis of life-2

revision quiz

Multiple Choice

How many elements are there in a living body?

• 25

• 92

• 180

• 130

Open Ended

organic compounds are?

Multiple Select

Examples for inorganic compounds

• H₂O

• CO₂

• CH₄

• C₆H₁₂O₆

Multiple Choice

not a bio-molecule

• carbohydrates

• water

• lipid

• protein

Multiple Select

what are the inorganic molecules in living body?

• water

• minerals

• gases

• Lipids

Multiple Choice

most abundant organic compound on earth?

• protein

• Carbohydrates

• minerals

• vitamins

Multiple Select

elements in Carbohydrates are ;

• Carbon

• Nitrogen

• Hydrogen

• Oxygen

Open Ended

three types of carbohydrates are

Multiple Choice

What is the structural unit of cellulose, starch and glycogen?

• lactose

• glucose

• maltose

• sucrose

Multiple Select

products of Glucose + Fructose is

• Maltose

• Lactose

• Sucrose

• Water

Multiple Choice

polysaccharide present in cell wall of plant cells in fibers

• Glycogen

• starch

• sucrose

• cellulose

Multiple Choice

what is the monosaccharide known as 'fruit sugar'

• Fructose

• Glucose

• Galactose

• starch

Multiple Choice

monosaccharide which does have any sweet

• Glucose

• Fructose

• Galactose

• water

Open Ended

write two significance of Carbohydrates.

Test to identify Carbohydrates

• Starch test

• Test for Glucose

• Test for Sucrose

starch test

• Small amount of food is obtained and grind well with water. Purplish blue color appears

• A drop of Iodine solution is added to the above solution.

• Purplish blue color appears

Test for Glucose

• A solution of Glucose is obtained into a test tube

• Few drops of Benedict solution to the above solution is added

• The above solution is immersed in a water bath and heated.  

• Can observe color changes as below.

• Blue->Green-> Green yellow-> Orange-> Brick red precipitate

Test for Sucrose

• A sucrose solution is obtained into a test tube.

• Few drops of Benedict solution is added to it.

• The test tube is immersed in a water bath and heated. No color change.

• Few drops of diluted Sulphuric acid (H₂ SO₄ ) is added to a freshly prepared sugar solution and heated.

• Next few drops of Benedict solution is added to it.

• Blue->Green-> Green yellow-> Orange-> Brick red precipitate

Open Ended

what is the difference between test for Glucose and test for Sucrose?

Multiple Select

Main elements in protein are

• Carbon

• Hydrogen

• Nitrogen

• Oxygen

Multiple Select

foods rich with protein

• yams

• meat

• rice

• egg white

Proteins

• essential constituent in all living cells

• Carbon(C) Hydrogen (H), Oxygen (O) and Nitrogen (N) are always present in proteins

• sometimes Sulphur(S) can be also present

• Protein is a complex molecule made up of polymerized amino acid molecules

• foods rich with protein are meat, Fish, egg white, cereal

Significance of protein

• As an energy source

• To make structural components

• As enzymes 

• As hormones

• As antibodies

Test to identify proteins (Biuret test)

• A solution made by grinding dhal or an egg white is obtained into a test tube

• An extra amount of Sodium hydroxide (NaOH) and then few drops of Copper Sulphate is added into it.(CuSO₄ )

• Solution turn to purple color

Enzymes

• The special proteins (organic catalysts) that are produced within the organism to increase the rate of bio-chemical reactions are known as enzymes.

• activity of enzyme is to catalyze the bio-chemical reactions

Open Ended

what are lipids?

Lipids

• fats and oils

• Lipids which are solid at room temperature are called fats and liquids are called oils.

Multiple Choice

color change in protein test (biuret test)

• pink

• red

• purple

• no color change

Multiple Choice

color change in protein test (biuret test)

• pink

• red

• purple

• no color change

Multiple Select

chemicals used in Biuret test

• NaOH

• CaCl

• CuSO₄

• Cu(OH)₂

Multiple Select

main constituent elements in lipids

• carbon

• Hydrogen

• Nitrogen

• Oxygen

• Carbon, Hydrogen and Oxygen are constituent elements in lipids

• But a lipid contains much less oxygen than a carbohydrate.

Open Ended

example for a lipid

• Lipids are insoluble in polar solvents including water

• soluble in organic solvents

• Ground nut, coconut, gingelly, butter and margarine are examples for foods which contain lipids.

Open Ended

how does lipids form?

• Fatty acids and glycerol react to form Lipids.

• Fatty acids + Glycerol --> Lipids +Water

Significance of lipids

• As an energy source

• To form different structural components

• For conservation of water

• To maintain the body temperature

• To protect internal body organs

• To synthesize some hormones

Test for Lipids (Sudan III test)

• Some amount of gingelly oil or coconut oil is added into a test tube.

• Sudan III reagent is added into it.

• Appearance of red fat globules