IB BIOLOGY ACTUAL TEST PAPER 2026
QUESTIONS AND SOLUTIONS GRADED A+
●● phospholipid.
Answer: The phospholipids are not "true fats" because they have one of
the fatty acids replaced by a phosphate group
●● natural fat.
Answer: protect and insulate body organs (major source of stored energy
in the body)
●● steroid.
Answer: Steroids are lipids because they are hydrophobic and insoluble
in water, but they do not resemble lipids since they have a structure
composed of four fused rings
●● carbohydrate.
Answer: compound made up of carbon, hydrogen, and oxygen atoms;
major source of energy for the human body
●● nucleic acid.
Answer: macromolecule containing hydrogen, oxygen, nitrogen, carbon,
and phosphorus. Forming DNA and RNA
,●● lipids.
Answer: macromolecule made mainly from carbon and hydrogen atoms
to form 3 fatty acids and a glycerol; includes fats, oils, and waxes
Lipids are a group of organic molecules that are insoluble in water but
soluble in non-polar organic solvents
Common lipids include triglycerides (fats and oils), phospholipids and
steroids
●● active site.
Answer: the active site is the region of an enzyme where substrate
molecules bind and undergo a chemical reaction
●● glycogen.
Answer: Glycogen is a multibranched polysaccharide of glucose that
serves as a form of energy storage in animals and fungi
●● cellulose.
Answer: Cellulose is a long chain of linked sugar molecules that gives
wood its remarkable strength. It is the main component of plant cell
walls, and the basic building block for many textiles and for paper.
, ●● starch.
Answer: A naturally abundant nutrient carbohydrate, (C6H10O5)n,
found chiefly in the seeds, fruits, tubers, roots, and stem pith of plants,
notably in corn, potatoes, wheat, and rice, and varying widely in
appearance according to source but commonly prepared as a white
amorphous tasteless powder.
●● glycerol.
Answer: Glycerol is a simple polyol (sugar alcohol) compound. It is a
colorless, odorless, viscous liquid that is widely used in pharmaceutical
formulations. Glycerol has three hydroxyl groups that are responsible for
its solubility in water and its hygroscopic nature. The glycerol backbone
is central to all lipids known as triglycerides. Glycerol is sweet-tasting
and is non-toxic.
●● fatty acid.
Answer: Any of the group of a long chain of hydro carbon derived from
the breakdown of fats (through hydrolysis). It has a single carboxylic
group and diphatic tail
●● monosaccharide.
Answer: A single sugar molecule such as glucose or fructose, the
simplest type of sugar.
●● disaccharide.
QUESTIONS AND SOLUTIONS GRADED A+
●● phospholipid.
Answer: The phospholipids are not "true fats" because they have one of
the fatty acids replaced by a phosphate group
●● natural fat.
Answer: protect and insulate body organs (major source of stored energy
in the body)
●● steroid.
Answer: Steroids are lipids because they are hydrophobic and insoluble
in water, but they do not resemble lipids since they have a structure
composed of four fused rings
●● carbohydrate.
Answer: compound made up of carbon, hydrogen, and oxygen atoms;
major source of energy for the human body
●● nucleic acid.
Answer: macromolecule containing hydrogen, oxygen, nitrogen, carbon,
and phosphorus. Forming DNA and RNA
,●● lipids.
Answer: macromolecule made mainly from carbon and hydrogen atoms
to form 3 fatty acids and a glycerol; includes fats, oils, and waxes
Lipids are a group of organic molecules that are insoluble in water but
soluble in non-polar organic solvents
Common lipids include triglycerides (fats and oils), phospholipids and
steroids
●● active site.
Answer: the active site is the region of an enzyme where substrate
molecules bind and undergo a chemical reaction
●● glycogen.
Answer: Glycogen is a multibranched polysaccharide of glucose that
serves as a form of energy storage in animals and fungi
●● cellulose.
Answer: Cellulose is a long chain of linked sugar molecules that gives
wood its remarkable strength. It is the main component of plant cell
walls, and the basic building block for many textiles and for paper.
, ●● starch.
Answer: A naturally abundant nutrient carbohydrate, (C6H10O5)n,
found chiefly in the seeds, fruits, tubers, roots, and stem pith of plants,
notably in corn, potatoes, wheat, and rice, and varying widely in
appearance according to source but commonly prepared as a white
amorphous tasteless powder.
●● glycerol.
Answer: Glycerol is a simple polyol (sugar alcohol) compound. It is a
colorless, odorless, viscous liquid that is widely used in pharmaceutical
formulations. Glycerol has three hydroxyl groups that are responsible for
its solubility in water and its hygroscopic nature. The glycerol backbone
is central to all lipids known as triglycerides. Glycerol is sweet-tasting
and is non-toxic.
●● fatty acid.
Answer: Any of the group of a long chain of hydro carbon derived from
the breakdown of fats (through hydrolysis). It has a single carboxylic
group and diphatic tail
●● monosaccharide.
Answer: A single sugar molecule such as glucose or fructose, the
simplest type of sugar.
●● disaccharide.
