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GRADE 12 BIOLOGY EXAM REVIEW
QUESTIONS AND ANSWERS 2025
Dehydration synthesis - correct answer- A reaction at which two
molecules combine to create a larger molecule taking out H2O.
Hydrolysis - correct answer- A reaction at which a compound
reacts with water to produce other compounds.
Redox - correct answer- A chemical reaction where atoms gain
or lose electrons (LEO the lion says GER)
Neutralization reaction - correct answer- Where an acid and a
base reacts to form H2O.
Lipids - correct answer- Made out of carbon, hydrogen and
oxygen. The role of the lipids is to insulate the organs and
joints. The are made up of ester bonds.
Protein - correct answer- Made out of amino acids and bonds
are peptide bonds, the protein form enzymes, cell surface
markers and cell membrane are protein channels.
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Carbohydrates - correct answer- Made up of hydrogen, carbon
and oxygen, it is the main source of energy, and the bonds are
glycosidic linkages.
[->types of carbs= Monosaccharide= one sugar, Disaccharide=
2 sugars, Polysaccharide= many sugars (3 or more).]
Nucleic Acid - correct answer- Organisms store hereditary and
genetic information that determine structural and functional
characteristic.
Enzymes - correct answer- Lower activation energy and are
catalyst. Factors affecting the reactions are temperature, ph,
and concentration.
(Enzyme shape) = Non-competitive- Does not compete for an
active site.
= Competitive- Able to enter active site to block normal
substrate for
Glycolysis - correct answer- Happens in cytoplasm. 2 ATP are
used to make 2 ADP in investment phase, 2 NAD are used to
make 2 NADH and in payoff phase 4 ATP are used to make
ADP and 2 H2O's are taken out.
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Pyruvate Oxidation - correct answer- This occurs in the
mitochondrial matrix 2 pyruvate and a NAD forms 2 NADH ,2
CO2 and 2 acetyl coa
Krebs - correct answer- Happens in mitochondrial matrix. 3
NADPH is made, 2 CO2 is made, 1 FADH is made, and 1 ATP
is made.
Oxidative phosphorylation - correct answer- Involves a series of
redox reaction, O2 is used to oxidize electron carriers FADH
and NADH to produce ATP.
ETC - correct answer- Happens in the inner mitochondrial
membrane, and involves use of high energy to push H+ from
the stroma to the inner Thylakoid space.
Chloroplast - correct answer- Found mainly in the cell of the
mesophyll (interior tissue of the leaf).
Within the chloroplast you have the thylakoid, granum, and
stroma.
GRADE 12 BIOLOGY EXAM REVIEW
QUESTIONS AND ANSWERS 2025
Dehydration synthesis - correct answer- A reaction at which two
molecules combine to create a larger molecule taking out H2O.
Hydrolysis - correct answer- A reaction at which a compound
reacts with water to produce other compounds.
Redox - correct answer- A chemical reaction where atoms gain
or lose electrons (LEO the lion says GER)
Neutralization reaction - correct answer- Where an acid and a
base reacts to form H2O.
Lipids - correct answer- Made out of carbon, hydrogen and
oxygen. The role of the lipids is to insulate the organs and
joints. The are made up of ester bonds.
Protein - correct answer- Made out of amino acids and bonds
are peptide bonds, the protein form enzymes, cell surface
markers and cell membrane are protein channels.
,2 | Page
Carbohydrates - correct answer- Made up of hydrogen, carbon
and oxygen, it is the main source of energy, and the bonds are
glycosidic linkages.
[->types of carbs= Monosaccharide= one sugar, Disaccharide=
2 sugars, Polysaccharide= many sugars (3 or more).]
Nucleic Acid - correct answer- Organisms store hereditary and
genetic information that determine structural and functional
characteristic.
Enzymes - correct answer- Lower activation energy and are
catalyst. Factors affecting the reactions are temperature, ph,
and concentration.
(Enzyme shape) = Non-competitive- Does not compete for an
active site.
= Competitive- Able to enter active site to block normal
substrate for
Glycolysis - correct answer- Happens in cytoplasm. 2 ATP are
used to make 2 ADP in investment phase, 2 NAD are used to
make 2 NADH and in payoff phase 4 ATP are used to make
ADP and 2 H2O's are taken out.
, 3 | Page
Pyruvate Oxidation - correct answer- This occurs in the
mitochondrial matrix 2 pyruvate and a NAD forms 2 NADH ,2
CO2 and 2 acetyl coa
Krebs - correct answer- Happens in mitochondrial matrix. 3
NADPH is made, 2 CO2 is made, 1 FADH is made, and 1 ATP
is made.
Oxidative phosphorylation - correct answer- Involves a series of
redox reaction, O2 is used to oxidize electron carriers FADH
and NADH to produce ATP.
ETC - correct answer- Happens in the inner mitochondrial
membrane, and involves use of high energy to push H+ from
the stroma to the inner Thylakoid space.
Chloroplast - correct answer- Found mainly in the cell of the
mesophyll (interior tissue of the leaf).
Within the chloroplast you have the thylakoid, granum, and
stroma.
