About this Study Set
This study set covers Organic Chemistry through
25 practice questions.
A collection of questions exploring organic chemical compounds found in animals, plants, and ecosystems. Every question includes the correct answer so you can learn as you go — pick any format above to get started.
Questions & Answers
Browse all 25 questions from the
Organic Chemistry in the Natural World study set below.
Each question shows the correct answer — select a study format above to practice interactively.
1
Which organic acid is primarily responsible for the stinging sensation caused by the defense mechanism of red ants?
-
A
Citric acid
-
B
Formic acid
-
C
Acetic acid
-
D
Lactic acid
2
What is the primary organic compound that makes up the rigid cell walls of terrestrial plants?
-
A
Cellulose
-
B
Chitin
-
C
Glycogen
-
D
Starch
3
Which organic molecule is responsible for the red colour in the blood of vertebrates, functioning as an oxygen carrier?
-
A
Chlorophyll
-
B
Hemoglobin
-
C
Carotene
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D
Melanin
4
Which class of organic compounds serves as the primary structural material for the exoskeleton of crustaceans and insects?
-
A
Proteins
-
B
Lipids
-
C
Chitin
-
D
Nucleic acids
5
What is the main chemical component of the essential oil that gives lavender its characteristic floral scent?
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A
Linalool
-
B
Ethanol
-
C
Methane
-
D
Benzene
6
Which organic polymer is used by spiders to create silk that is stronger than steel by weight?
-
A
Collagen
-
B
Fibroin
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C
Keratin
-
D
Elastin
7
What type of organic molecule is predominantly used by hibernating animals to store long-term energy?
-
A
Glucose
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B
Triglycerides
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C
Amino acids
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D
Nucleotides
8
Which organic compound is synthesised by plants during photosynthesis to store chemical energy?
-
A
Glucose
-
B
Acetone
-
C
Glycerol
-
D
Methane
9
What organic pigment allows marine algae to perform photosynthesis in deep ocean water?
-
A
Fucoxanthin
-
B
Hemocyanin
-
C
Uric acid
-
D
Formaldehyde
10
The bioluminescence observed in fireflies is caused by a chemical reaction involving which organic compound?
-
A
Luciferin
-
B
Cholesterol
-
C
Thymine
-
D
Caffeine
11
Which sulfur-containing amino acid is essential for the formation of hair and feathers in animals?
-
A
Cysteine
-
B
Glycine
-
C
Alanine
-
D
Serine
12
What complex organic molecule acts as the primary genetic material in all living organisms?
-
A
RNA
-
B
DNA
-
C
ATP
-
D
NADPH
13
Which organic acid is commonly associated with the sour taste found in citrus fruits like lemons?
-
A
Citric acid
-
B
Malic acid
-
C
Butyric acid
-
D
Oleic acid
14
What organic compound is secreted by skunks as a primary defense mechanism, resulting in a pungent smell?
-
A
Thiols
-
B
Esters
-
C
Ketones
-
D
Aldehydes
15
Which organic molecule, found in the liver, is the primary storage form of glucose in animals?
-
A
Cellulose
-
B
Glycogen
-
C
Starch
-
D
Amylose
16
What organic class does the substance 'wax', used by bees to build honeycombs, belong to?
-
A
Esters
-
B
Alcohols
-
C
Amines
-
D
Ethers
17
Which organic compound gives carrots their vibrant orange colour?
-
A
Beta-carotene
-
B
Anthocyanin
-
C
Chlorophyll
-
D
Xanthophyll
18
What nitrogenous base is specifically found in RNA but replaced by Thymine in DNA?
-
A
Uracil
-
B
Cytosine
-
C
Adenine
-
D
Guanine
19
Which organic compound is the primary component of natural rubber harvested from the Hevea brasiliensis tree?
-
A
Isoprene
-
B
Ethylene
-
C
Acetylene
-
D
Propane
20
What class of organic molecules are the primary building blocks of enzymes in living organisms?
-
A
Proteins
-
B
Lipids
-
C
Carbohydrates
-
D
Hydrocarbons
21
Which organic compound is released by many plants as a volatile signal to attract pollinators?
-
A
Terpenes
-
B
Alkanes
-
C
Alcohols
-
D
Ketones
22
What organic molecule is responsible for the distinct scent of freshly cut grass?
-
A
(Z)-3-hexenal
-
B
Methanol
-
C
Benzene
-
D
Toluene
23
Which organic acid is produced by muscles during anaerobic respiration in mammals?
-
A
Lactic acid
-
B
Citric acid
-
C
Ascorbic acid
-
D
Folic acid
24
What is the main organic component of the shell of an egg?
-
A
Calcium carbonate
-
B
Keratin
-
C
Collagen
-
D
Chitin
25
Which organic compound is used by the body to transport cholesterol through the blood?
-
A
Lipoproteins
-
B
Glycoproteins
-
C
Nucleoproteins
-
D
Chromoproteins
