Question

carbohydrates are composed of which atoms in a ratio of 1:2:1?
a. carbon, oxygen, nitrogen
b. carbon, hydrogen, oxygen
c. nitrogen, hydrogen, carbon
d. oxygen, hydrogen, carbon

which carbohydrate provides structural support in plant cell walls?
a. sucrose
b. starch
c. lactose
d. cellulose

which monosaccharide is commonly found in fruits like oranges and berries?
a. fructose
b. sucrose
c. glucose
d. galactose

Explanation:

First Question:

Carbohydrates have a general formula of \( C_n(H_2O)_m \), so the atoms are Carbon (C), Hydrogen (H), and Oxygen (O) in a 1:2:1 ratio (for simple sugars). Option a has Nitrogen (not in carbs), option c has Nitrogen, option d's order is different but the key is the elements. Option b has C, H, O which matches.

Sucrose is a disaccharide (table sugar), starch is energy storage in plants, lactose is milk sugar, cellulose is the structural component of plant cell walls, made of glucose units linked in a way that provides rigidity.

Fructose is the monosaccharide commonly found in fruits (it's fruit sugar). Sucrose is a disaccharide, glucose is blood sugar (also in fruits but fructose is more associated with fruit sweetness), galactose is in milk.

Answer:

b. Carbon, Hydrogen, Oxygen

Second Question: