INTRODUCTION TO BIOLOGY GUIDE 2026
TEST PAPER SOLVED QUESTIONS AND
SOLUTIONS
◉ phospholipids. Answer: Membranes are made of arranged in a
bilayer.
◉ The "heads". Answer: In plasma membrane, Which part of the
molecules is hydrophilic?
◉ phosphate heads. Answer: The __________________ ______________ of
plasma membrane are charged and hydrophilic; therefore they stay
in close contact with the aqueous (watery) solutions inside and
outside of the cell.
◉ No. Answer: Ions of salt (sodium, NA+, and chloride,Cl−
) are highly hydrophilic. Will they easily pass through the layer to
enter or leave a cell?
◉ hydrophobic
Hydrophilic. Answer: The fatty acid tails are______________ and orient
toward each other, forming the hydrophobic core of the membrane.
,____________________ ions will tend to stay in solution on either side of
the membrane and will not cross easily.
◉ True. Answer: The carbon rings that make up steroids are not
hydrophilic.
◉ False. Answer: Steroids are classified as lipids because they are
hydrophilic.
◉ False. Answer: Steroids are composed of fatty acids like
triglycerides and phosopholipids.
◉ Steroids. Answer: __________________are lipids that have unique
structures. _______________are made of four fused carbon rings with
different functional groups and atoms attached to make different
types of steroids such as cholesterol and hormones.
◉ Sex hormones
Bile acids. Answer: Cholesterol is a starting point for making
vitamins A and D. What other important substance(s) are made by
modifying cholesterol?
◉ Unsaturated fats. Answer: have three fatty acids but at least one is
"kinky."
,◉ Saturated fats. Answer: have three straight fatty acids.
◉ Trans fats. Answer: are produced by man to make liquid oils solid
like for the food industry.
◉ Mechanical proteins. Answer: help move substances in a cell from
one place in the cell to another. Also, these proteins help muscles
contract for movement.
◉ Enzymes. Answer: catalyze reactions by lowering the amount of
activation energy needed to get the reaction going.
◉ Hormones. Answer: are proteins that signal another cell or tissue
to do something.
◉ Regulatory proteins. Answer: can activate or inactivate molecules
such as DNA. These proteins regulate what genes are expressed.
◉ Transport proteins. Answer: can move substances in and out of
cell or transport materials throughout the body.
◉ Structural proteins. Answer: provide a fibrous scaffolding in cells
to help the cell maintain is shape and structure.
, ◉ Antibodies. Answer: are proteins that mark disease causing
pathogens for destruction by white blood cells.
◉ Enzymes. Answer: lactase digests lactose, a sugar
◉ Mechanical. Answer: myosin and actin slide over one another to
shorten a muscle fiber
◉ Antibodies. Answer: IgA immunoglobulin, found in tears and
saliva, fight pathogens in the eyes and mouth
◉ Transport. Answer: glucose needs a molecule embedded in the
cell membrane to assist its entry into the cell
◉ Structural. Answer: elastin is a protein in the skin that allows the
tissue to resume its shape
◉ Regulatory. Answer: transcription factor proteins allow for RNA to
be made from DNA
◉ Hormones. Answer: insulin acts as a messenger to "tell" cells to
take in sugar
TEST PAPER SOLVED QUESTIONS AND
SOLUTIONS
◉ phospholipids. Answer: Membranes are made of arranged in a
bilayer.
◉ The "heads". Answer: In plasma membrane, Which part of the
molecules is hydrophilic?
◉ phosphate heads. Answer: The __________________ ______________ of
plasma membrane are charged and hydrophilic; therefore they stay
in close contact with the aqueous (watery) solutions inside and
outside of the cell.
◉ No. Answer: Ions of salt (sodium, NA+, and chloride,Cl−
) are highly hydrophilic. Will they easily pass through the layer to
enter or leave a cell?
◉ hydrophobic
Hydrophilic. Answer: The fatty acid tails are______________ and orient
toward each other, forming the hydrophobic core of the membrane.
,____________________ ions will tend to stay in solution on either side of
the membrane and will not cross easily.
◉ True. Answer: The carbon rings that make up steroids are not
hydrophilic.
◉ False. Answer: Steroids are classified as lipids because they are
hydrophilic.
◉ False. Answer: Steroids are composed of fatty acids like
triglycerides and phosopholipids.
◉ Steroids. Answer: __________________are lipids that have unique
structures. _______________are made of four fused carbon rings with
different functional groups and atoms attached to make different
types of steroids such as cholesterol and hormones.
◉ Sex hormones
Bile acids. Answer: Cholesterol is a starting point for making
vitamins A and D. What other important substance(s) are made by
modifying cholesterol?
◉ Unsaturated fats. Answer: have three fatty acids but at least one is
"kinky."
,◉ Saturated fats. Answer: have three straight fatty acids.
◉ Trans fats. Answer: are produced by man to make liquid oils solid
like for the food industry.
◉ Mechanical proteins. Answer: help move substances in a cell from
one place in the cell to another. Also, these proteins help muscles
contract for movement.
◉ Enzymes. Answer: catalyze reactions by lowering the amount of
activation energy needed to get the reaction going.
◉ Hormones. Answer: are proteins that signal another cell or tissue
to do something.
◉ Regulatory proteins. Answer: can activate or inactivate molecules
such as DNA. These proteins regulate what genes are expressed.
◉ Transport proteins. Answer: can move substances in and out of
cell or transport materials throughout the body.
◉ Structural proteins. Answer: provide a fibrous scaffolding in cells
to help the cell maintain is shape and structure.
, ◉ Antibodies. Answer: are proteins that mark disease causing
pathogens for destruction by white blood cells.
◉ Enzymes. Answer: lactase digests lactose, a sugar
◉ Mechanical. Answer: myosin and actin slide over one another to
shorten a muscle fiber
◉ Antibodies. Answer: IgA immunoglobulin, found in tears and
saliva, fight pathogens in the eyes and mouth
◉ Transport. Answer: glucose needs a molecule embedded in the
cell membrane to assist its entry into the cell
◉ Structural. Answer: elastin is a protein in the skin that allows the
tissue to resume its shape
◉ Regulatory. Answer: transcription factor proteins allow for RNA to
be made from DNA
◉ Hormones. Answer: insulin acts as a messenger to "tell" cells to
take in sugar
