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IB Biology HL B1.1 Carbohydrates and Lipids Questions

Practise IB Biology HL B1.1 with molecular diagrams and data questions that connect carbohydrate and lipid structure to digestion, storage, membranes and biological function.

Syllabus
First assessment 2025
Course
Biology HL
Level
HL

Exam points

  • Explain how carbon’s four covalent bonds and self-bonding create diverse biological compounds and carbon skeletons, and distinguish molecule classes from carbon, hydrogen and oxygen composition.
  • Explain condensation and hydrolysis in biological molecules, identify disaccharide products, and trace digestive enzymes, substrates, products and absorption.
  • Identify glucose, fructose, galactose and ribose from structures, distinguish alpha- and beta-D-glucose, and relate monosaccharide polarity to transport.
  • Describe starch and glycogen as branched alpha-glucose polymers and compare compact, insoluble carbohydrate and lipid energy stores.
  • Describe cellulose as unbranched beta-glucose chains with 1–4 bonds, hydrogen-bonded microfibrils and plant cell-wall strength.
  • Identify cell-surface glycoproteins as mediators of cell adhesion.
  • Identify non-polar lipids and steroid molecules from hydrophobic structure and fused carbon rings.
  • Identify glycerol, fatty acids, ester bonds and phosphate groups when distinguishing triglyceride and phospholipid structures.
  • Classify fatty acids as saturated, mono- or polyunsaturated, and distinguish cis and trans isomers from double-bond geometry.
  • Identify amphipathic phospholipid heads and tails and explain their orientation in bilayers or surface films.

Covered syllabus points

B1.1.1—Carbon atom propertiesB1.1.2—Macromolecules by condensationB1.1.3—Digestion by hydrolysisB1.1.4—Form and function of monosaccharidesB1.1.5—Polysaccharides as energy storageB1.1.6—Cellulose structure and functionB1.1.7—Glycoproteins in cell-cell recognitionB1.1.8—Hydrophobic properties of lipidsB1.1.9—Formation of triglycerides and phospholipidsB1.1.10—Fatty acidsB1.1.11—Triglycerides functionsB1.1.12—Phospholipid bilayersB1.1.13—Non-polar steroids

Question 1

[Maximum number: 1]

What feature of carbon makes it most suitable as a basis for life?

A

Its abundance in nature

B

Its bonding properties

C

Its reactivity to light

D

Its presence in the early atmosphere of the Earth

Question 2

[Maximum number: 2]

Identify two hydrolysis reactions that occur in the small intestine.

Question 3

[Maximum number: 3]

A wide variety of organic compounds are used by living organisms.

Draw a diagram to show the ring structure of D-ribose.

Question 4

[Maximum number: 4]

Outline how and where energy is stored in plants.

Question 5

[Maximum number: 3]

Plants have cell walls composed of cellulose.

Describe the structure of cellulose molecules.

Question 6

[Maximum number: 1]

Animal cells often secrete glycoproteins as extracellular components. What is a role of these glycoproteins?

A

Adhesion

B

Additional energy reserve

C

Membrane fluidity

D

Water uptake

Question 7

[Maximum number: 1]

Which molecule represents a lipid?

Figure for Question 7 — IB Biology HL

Question 8

[Maximum number: 2]

A triglyceride is shown.

Displayed triglyceride structure with a three-carbon backbone joined through oxygen-containing links to three long hydrocarbon chains; all tail carbon–carbon bonds are shown as single bonds.

Question (a)

(a)

State the two types of molecules that combine to make a triglyceride.

[ 1 ]

Question (b)

(b)

Annotate the diagram, using an arrow to show where a condensation bond has formed during formation of the triglyceride.

[ 1 ]

Question 9

[Maximum number: 1]

State the reason cis and trans fatty acids are said to be unsaturated.

Question 10

[Maximum number: 1]

State which type of organic compounds store the most energy per mass in the human body.

Question 11

[Maximum number: 1]

Which features of phospholipids give them their amphipathic properties?

A

Basic phosphate groups and acidic lipids

B

Acidic phosphate groups and basic lipids

C

Hydrophobic phosphate groups and hydrophilic fatty acids

D

Hydrophilic phosphate groups and hydrophobic fatty acids

Question 12

[Maximum number: 1]

State one example of a steroid hormone.

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