LAB 1

Question 1

What is photosynthesis?

Answer 1

the process by which green plants convert carbon dioxide and water into glucose by using sunlight energy absorbed by chlorophyll in chloroplasts.

Question 2

Word Equation

Answer 2

Carbon dioxide + Water ————> Food(glucose) + oxygen

Question 3

Chemical Equation

Answer 3

6CO2 + 6H2O ———> C6H12O6 + 6O2

Question 4

Glucose

Answer 4

a simple sugar and soluble in water, is a reactive substance and therefore is not a great storage molecule. For this reason, glucose is converted into starch in order to be stored.

GLUCOSE-
used to produce respiration.
stored as starch.
used to make other substances like amino acids.
converted to sucrose for transportation.

Question 5

Why do we test for starch?

Answer 5

because it is less reactive, making it easier and more reliable (than glucose) to obtain findings to show the presence of carbohydrates in the leaf and to show that photosynthesis has taken place.

Question 6

Why is the leaf placed in boiling water?

Answer 6

to remove the cuticle (the waxy layer of a leaf) and as a result the leaf softens.

Question 7

Why was the leaf placed in alcohol?

Answer 7

to remove the chlorophyll in order to properly identify the starch present in the leaf

Question 8

Why did the alcohol turn green?

Answer 8

alcohol is a solvent and a leaf is porous, the alcohol dissolved the chlorophyll (a green pigment) in the leaf which in turn caused the alcohol to become green.

Question 9

Why do we use iodine solution?

Answer 9

we test for starch using iodine solution since it turns blue-black or purple when it comes into contact with starch. The iodine turns this colour due to its reaction with the amylase in the polysaccharide, starch.