RIO BIO 156 PRACTICE EXAMS 2025/2026 QUESTIONS AND
ANSWERS GRADED A+
✔✔Tight junction - ✔✔a firm seal between two adjacent animal cells created by protein
adherence
✔✔Vesicle - ✔✔A small, membrane-bound sac that functions in cellular storage and
transport; its membrane is capable of fusing with the plasma membrane and the
membranes of the endoplasmic reticulum and Golgi apparatus.
✔✔How cells obtain Energy - ✔✔cells obtain energy from 1) the breakdown of glucose
and 2) the breakdown of triglycerides.
cells turn to protein for energy when others are not available.
✔✔Endergonic reaction - ✔✔When energy is required
Reaction that absorbs free energy from its surroundings.
✔✔Exergonic reaction - ✔✔Chemical reaction that releases energy; opposite of
endergonic reaction.
✔✔Activation energy - ✔✔the minimum amount of energy required to start a chemical
reaction
✔✔ATP - ✔✔(adenosine triphosphate) main energy source that cells use for most of
their work
✔✔Adenosine triphosphate - ✔✔ATP
Ribonucleotide
✔✔Adenosine - ✔✔Adenosine;
a nucleoside; a combination of ribose and adenine; serves as a neuromodulator in the
brain
✔✔Enzyme - ✔✔A protein that acts as a biological catalyst to speed up a chemical
reaction.
✔✔Substrate - ✔✔Molecule(s) specifically acted upon by an enzyme.
✔✔Active site - ✔✔Pocket (domain) in an enzyme where substrates bind and a reaction
occurs.
, ✔✔Each enzyme works best within a characteristic range of - ✔✔Temperature, PH and
Salt concentration
✔✔Cofactor - ✔✔A metal ion or a coenzyme that associates with an enzyme and is
necessary for its function.
✔✔Coenzyme - ✔✔An organic cofactor, can be changed by the reaction.
✔✔Reactions can run in both the forward and the reverse directions depending on -
✔✔Concentrations of reactants and products, Feedback inhibition, Allosteric sites in
tertiary protein structure
✔✔Electron transfer chain - ✔✔Array of enzymes and other molecules that accept and
give up electrons in sequence, thus releasing the energy of the electrons in steps.
✔✔Feedback inhibition - ✔✔Mechanism by which a change that results from some
activity decreases or stops the activity.
✔✔Metabolic pathway - ✔✔Series of enzyme-mediated reactions by which cells build,
remodel, or break down an organic molecule.
✔✔Autotroph - ✔✔Organism that makes its own food using carbon from inorganic
molecules such as CO2, and energy from the environment.
✔✔Chlorophyll alpha - ✔✔Main photosynthetic pigment in plants.
✔✔Heme - ✔✔iron-based, pigment part of hemoglobin
✔✔Heterotroph - ✔✔An organism that cannot make its own food.
✔✔Photosynthesis - ✔✔Metabolic pathway by which most autotrophs capture light
energy and use it to make sugars from CO2 and water.
Conversion of light energy from the sun into chemical energy.
✔✔Pigment - ✔✔An organic molecule that can absorb light of certain wavelengths.
✔✔Wavelength - ✔✔Distance between the crest of two successive wave of light.
✔✔Photosystem - ✔✔light-collecting units of the chloroplast
✔✔Stroma - ✔✔Semifluid matrix between the thylakoid membrane and the two outer
membranes of a chloroplast.
ANSWERS GRADED A+
✔✔Tight junction - ✔✔a firm seal between two adjacent animal cells created by protein
adherence
✔✔Vesicle - ✔✔A small, membrane-bound sac that functions in cellular storage and
transport; its membrane is capable of fusing with the plasma membrane and the
membranes of the endoplasmic reticulum and Golgi apparatus.
✔✔How cells obtain Energy - ✔✔cells obtain energy from 1) the breakdown of glucose
and 2) the breakdown of triglycerides.
cells turn to protein for energy when others are not available.
✔✔Endergonic reaction - ✔✔When energy is required
Reaction that absorbs free energy from its surroundings.
✔✔Exergonic reaction - ✔✔Chemical reaction that releases energy; opposite of
endergonic reaction.
✔✔Activation energy - ✔✔the minimum amount of energy required to start a chemical
reaction
✔✔ATP - ✔✔(adenosine triphosphate) main energy source that cells use for most of
their work
✔✔Adenosine triphosphate - ✔✔ATP
Ribonucleotide
✔✔Adenosine - ✔✔Adenosine;
a nucleoside; a combination of ribose and adenine; serves as a neuromodulator in the
brain
✔✔Enzyme - ✔✔A protein that acts as a biological catalyst to speed up a chemical
reaction.
✔✔Substrate - ✔✔Molecule(s) specifically acted upon by an enzyme.
✔✔Active site - ✔✔Pocket (domain) in an enzyme where substrates bind and a reaction
occurs.
, ✔✔Each enzyme works best within a characteristic range of - ✔✔Temperature, PH and
Salt concentration
✔✔Cofactor - ✔✔A metal ion or a coenzyme that associates with an enzyme and is
necessary for its function.
✔✔Coenzyme - ✔✔An organic cofactor, can be changed by the reaction.
✔✔Reactions can run in both the forward and the reverse directions depending on -
✔✔Concentrations of reactants and products, Feedback inhibition, Allosteric sites in
tertiary protein structure
✔✔Electron transfer chain - ✔✔Array of enzymes and other molecules that accept and
give up electrons in sequence, thus releasing the energy of the electrons in steps.
✔✔Feedback inhibition - ✔✔Mechanism by which a change that results from some
activity decreases or stops the activity.
✔✔Metabolic pathway - ✔✔Series of enzyme-mediated reactions by which cells build,
remodel, or break down an organic molecule.
✔✔Autotroph - ✔✔Organism that makes its own food using carbon from inorganic
molecules such as CO2, and energy from the environment.
✔✔Chlorophyll alpha - ✔✔Main photosynthetic pigment in plants.
✔✔Heme - ✔✔iron-based, pigment part of hemoglobin
✔✔Heterotroph - ✔✔An organism that cannot make its own food.
✔✔Photosynthesis - ✔✔Metabolic pathway by which most autotrophs capture light
energy and use it to make sugars from CO2 and water.
Conversion of light energy from the sun into chemical energy.
✔✔Pigment - ✔✔An organic molecule that can absorb light of certain wavelengths.
✔✔Wavelength - ✔✔Distance between the crest of two successive wave of light.
✔✔Photosystem - ✔✔light-collecting units of the chloroplast
✔✔Stroma - ✔✔Semifluid matrix between the thylakoid membrane and the two outer
membranes of a chloroplast.
