Which of the following statements about isotopes is true?
A) Isotopes of an element differ in the number of protons.
B) Isotopes of an element have the same atomic mass but different chemical properties.
C) Radioactive isotopes can be both harmful and beneficial in biological contexts.
D) Isotopes always have a neutral charge in nature.
What type of bond involves the sharing of electron pairs between atoms?
A) Ionic bond
B) Covalent bond
C) Hydrogen bond
D) Peptide bond
How does the buffering system in human blood maintain pH stability?
A) By only removing excess OH⁻ ions.
B) By converting bicarbonate ions into carbon dioxide when pH drops.
C) By preventing hydronium ions from forming.
D) By increasing carbonate ion concentrations to absorb hydrogen ions.
−3
What is the pH of a solution with a hydrogen ion concentration of 10
A) 3
B) 7
C) 10
D) 13
Ocean acidification primarily occurs because of which chemical reaction?
A) Dissolution of oxygen in water.
B) Carbon dioxide reacting with seawater to form carbonic acid.
C) Bicarbonate ions forming hydronium ions.
D) Photosynthesis in marine plants.
Which of the following describes a hydronium ion?
A) H⁺
B) OH⁻
C) H₃O⁺
D) CO₃²⁻
What happens to the pH of a solution when the concentration of hydronium ions increases?
A) pH increases.
B) pH decreases.
C) pH remains the same.
D) pH fluctuates unpredictably.
Which functional group is commonly involved in the energy transfer in cells?
A) Hydroxyl
B) Carboxyl
C) Phosphate
D) Amino
How do buffers minimize changes in pH?
A) By creating new hydrogen ions.
B) By absorbing or releasing H⁺ or OH⁻ ions as needed.
C) By altering the temperature of the solution.
D) By stabilizing hydronium ion concentrations.
Which of the following is a consequence of decreased carbonate ion concentrations due to ocean
acidification?
A) Increased calcification in marine organisms.
B) Reduced ability of coral reefs to build skeletons.
C) Neutralization of seawater pH.
D) Enhanced growth of algae.
1. Explain the difference between ionic and covalent bonds. Provide examples of each.
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2. Describe the role of buffers in maintaining blood pH. Include the chemical reactions
involved in the carbonic acid-bicarbonate buffer system.
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3. Discuss the impact of ocean acidification on marine ecosystems. How does increased
atmospheric CO₂ lead to changes in marine biodiversity?
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4. Compare and contrast hydronium ions (H₃O⁺) and hydroxide ions (OH⁻). How do they
influence the pH of a solution?
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5. Explain the significance of functional groups in biological macromolecules. Provide
examples of at least two functional groups and describe their chemical properties and
roles in biomolecules.
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What makes carbon essential for forming a vast number of compounds?
A) Its ability to form ionic bonds with various atoms.
B) Its high electronegativity compared to other elements.
C) Its four valence electrons, allowing it to form covalent bonds.
D) Its ability to form hydrogen bonds with other elements.
Which polysaccharide is used for structural support in plant cell walls?
A) Starch
B) Glycogen
C) Cellulose
D) Chitin
What distinguishes saturated fats from unsaturated fats?
A) Saturated fats contain double bonds in their hydrocarbon chains.
B) Unsaturated fats are solid at room temperature.
C) Saturated fats lack double bonds, making their chains straight.
D) Unsaturated fats are mostly found in animal products.
Which type of glycosidic linkage is found in cellulose?
A) α-1,4
B) β-1,4
C) α-1,6
D) β-1,6
What is the primary function of phospholipids in cells?
A) Energy storage
B) Insulation
C) Forming cell membranes
D) Hormone production
Which protein structure level is characterized by interactions among R groups?
A) Primary
B) Secondary
C) Tertiary
D) Quaternary
What type of bond links amino acids together in proteins?
A) Ionic bonds
B) Hydrogen bonds
C) Glycosidic bonds
D) Peptide bonds
In nucleic acids, what type of bond forms the sugar-phosphate backbone?
A) Hydrogen bond
B) Glycosidic bond
C) Phosphodiester bond
D) Peptide bond
Which of the following nitrogenous bases is found only in RNA?
A) Adenine
B) Guanine
C) Uracil
D) Thymine
What causes the kink in unsaturated fatty acid chains?
A) Single bonds in the hydrocarbon chain
B) Cis double bonds in the hydrocarbon chain
C) Trans double bonds in the hydrocarbon chain
D) The presence of a phosphate group
1. Describe the structure and function of each of the four macromolecules: carbohydrates,
lipids, proteins, and nucleic acids. Provide specific examples for each.
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2. Explain the differences between α-glucose and β-glucose and how they contribute to the
structural and functional differences between starch and cellulose.
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3. Discuss the role of phospholipids in the formation of biological membranes. Include
details about their amphipathic nature and how this property supports membrane
structure.
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4. Describe the process of protein folding through its primary, secondary, tertiary, and
quaternary structures. Explain how denaturation affects protein function.
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5. Explain the relationship between the structure of DNA and its function in storing genetic
information. Include the role of base pairing and the antiparallel orientation of strands.
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Which microscope provides the highest resolution for studying internal cellular
structures?
A) Compound light microscope
B) Scanning electron microscope
C) Transmission electron microscope
D) Fluorescent microscope
What is the primary reason cells must maintain a high surface area-to-volume ratio?
A) To ensure adequate space for organelles.
B) To efficiently exchange materials with their environment.
C) To maintain structural integrity.
D) To store large quantities of nutrients.
Which of the following structures is found in both prokaryotic and eukaryotic cells?
A) Nucleus
B) Ribosomes
C) Mitochondria
D) Lysosomes
What is the role of glycoproteins in the extracellular matrix (ECM)?
A) Synthesizing proteins for cellular repair.
B) Binding integrins to anchor the ECM to the cytoskeleton.
C) Transporting molecules across the plasma membrane.
D) Facilitating movement of cilia and flagella.
What feature of lysosomes enables them to break down macromolecules effectively?
A) Their high calcium ion concentration.
B) The presence of digestive enzymes at a low pH.
C) Their ability to synthesize ATP for enzymatic activity.
D) Their rigid structure that resists pH changes.
How do peroxisomes protect cells from toxic substances?
A) By storing harmful compounds until they degrade naturally.
B) By breaking down hydrogen peroxide into water and oxygen.
C) By generating ATP to remove toxic substances.
D) By synthesizing proteins to detoxify poisons.
Which organelle is responsible for modifying, sorting, and packaging proteins for export?
A) Endoplasmic reticulum
B) Golgi apparatus
C) Lysosome
D) Ribosome
Which cellular component is responsible for the undulating motion of cilia and flagella?
A) Microfilaments
B) Microtubules
C) Intermediate filaments
D) Ribosomes
What distinguishes the rough endoplasmic reticulum (ER) from the smooth ER?
A) Presence of phospholipids on the membrane.
B) Ribosomes attached to its surface for protein synthesis.
C) Ability to process alcohol and drugs.
D) Its location in relation to the Golgi apparatus.
What evidence supports the endosymbiotic theory of mitochondria and chloroplast
origins?
A) Both contain phospholipids similar to eukaryotic cells.
B) Both are surrounded by a single membrane.
C) Both have their own DNA and ribosomes, similar to prokaryotes.
D) Both are synthesized entirely by the nucleus.
1. Explain the role of the endomembrane system in protein synthesis and secretion. Include
the roles of the rough ER, Golgi apparatus, and vesicles.
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2. Compare and contrast the structures and functions of mitochondria and chloroplasts.
Include their roles in energy transformation and evidence for the endosymbiotic theory.
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3. Describe the cytoskeleton's components (microfilaments, microtubules, and intermediate
filaments) and their functions in maintaining cell shape, movement, and internal
organization.
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4. Explain how lysosomes function in intracellular digestion. Provide an example of how
they contribute to immune system processes like pathogen destruction.
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5. Discuss the structural differences between tight junctions, gap junctions, and
desmosomes in animal cells. How do these structures contribute to tissue function?
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What is the primary role of cholesterol in the plasma membrane?
A) Facilitating passive transport of molecules.
B) Acting as an energy source for active transport.
C) Maintaining membrane fluidity across temperature changes.
D) Binding to phospholipids to prevent water entry.
Which component of the plasma membrane contributes to its selective permeability?
A) Cholesterol molecules.
B) Phospholipid bilayer with hydrophobic tails.
C) Peripheral membrane proteins.
D) Glycoproteins on the extracellular surface.
How does facilitated diffusion differ from simple diffusion?
A) Facilitated diffusion requires ATP, while simple diffusion does not.
B) Facilitated diffusion uses transport proteins, while simple diffusion does not.
C) Simple diffusion moves molecules up their concentration gradient.
D) Facilitated diffusion is faster than osmosis.
Which of the following is a function of the sodium-potassium pump?
A) Transporting Na⁺ and K⁺ down their concentration gradients.
B) Establishing an electrochemical gradient.
C) Facilitating bulk transport of ions.
D) Transporting glucose and sodium together.
What type of transport protein is responsible for moving two different molecules in
opposite directions?
A) Uniporter
B) Symporter
C) Antiporter
D) Channel protein
Which type of bulk transport involves the uptake of small liquid molecules into the cell?
A) Phagocytosis
B) Pinocytosis
C) Exocytosis
D) Receptor-mediated endocytosis
In osmosis, water moves from a region of:
A) Higher solute concentration to lower solute concentration.
B) Lower solute concentration to higher solute concentration.
C) Higher water concentration to higher solute concentration.
D) Equal solute concentration to equal water concentration.
Which of the following is an example of secondary active transport?
A) Sodium-potassium pump using ATP.
B) Glucose-sodium symporter utilizing the sodium gradient.
C) Endocytosis of large molecules.
D) Ligand-gated ion channels.
Why is receptor-mediated endocytosis considered highly specific?
A) It only occurs in the presence of ATP.
B) It involves ligand binding to specific receptors.
C) It does not involve vesicle formation.
D) It allows random molecules to enter the cell.
What happens to an animal cell placed in a hypertonic solution?
A) It swells and bursts.
B) It gains water and becomes turgid.
C) It loses water and shrinks.
D) It maintains equilibrium and remains unchanged.
1. Describe the components of the fluid mosaic model of the plasma membrane. Include the
roles of phospholipids, cholesterol, and membrane proteins.
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2. Explain the differences between passive transport, active transport, and bulk transport.
Provide an example for each mechanism.
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3. Discuss the role of the sodium-potassium pump in maintaining membrane potential.
Explain how it is an example of primary active transport.
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4. Define osmosis and describe its effects on cells in isotonic, hypertonic, and hypotonic
solutions. Use specific examples to explain these effects in animal and plant cells.
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5. Explain how receptor-mediated endocytosis works. Include an example of its biological
significance and the consequences of defects in this process.
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Which of the following best describes the First Law of Thermodynamics?
A) Energy can be recycled within a system.
B) Energy can be created or destroyed under certain conditions.
C) Energy can only be transferred or transformed, not created or destroyed.
D) The total entropy of a system always increases.
What is the primary distinction between catabolic and anabolic reactions?
A) Catabolic reactions require energy, while anabolic reactions release energy.
B) Catabolic reactions build complex molecules, while anabolic reactions break them
down.
C) Catabolic reactions release energy, while anabolic reactions consume energy.
D) Catabolic reactions occur only in the presence of oxygen, while anabolic reactions do
not.
Which of the following processes represents an example of an endergonic reaction?
A) Cellular respiration
B) Photosynthesis
C) ATP hydrolysis
D) Diffusion
What is the role of activation energy (Eₐ) in a chemical reaction?
A) It determines the equilibrium of a reaction.
B) It is the energy released during a reaction.
C) It provides the initial energy needed to break bonds in reactants.
D) It prevents reactions from proceeding.
How do enzymes affect the rate of a chemical reaction?
A) By increasing the activation energy required.
B) By decreasing the energy required to form reactants.
C) By lowering the activation energy required for the reaction.
D) By increasing the energy of the products.
Which of the following components is a coenzyme?
A) Zinc
B) Copper
C) Vitamin B6
D) Iron
What occurs during feedback inhibition of an enzyme?
A) The enzyme’s structure is permanently altered by a substrate.
B) The final product of a pathway inhibits an enzyme early in the pathway.
C) A coenzyme binds to an enzyme to enhance its activity.
D) The substrate is converted to an inhibitor by the enzyme.
Which molecule is most directly used as energy currency in cells?
A) Glucose
B) ATP
C) NADH
D) FADH₂
Why does ATP have a high potential energy?
A) Its phosphate groups repel each other due to negative charges.
B) Its sugar group is highly reactive.
C) It has strong bonds between its adenine and ribose.
D) It contains a large amount of thermal energy.
Which of the following best explains the Second Law of Thermodynamics in cellular
processes?
A) Cells convert all energy into usable forms.
B) Energy transformations increase the entropy of the universe.
C) Energy input is unnecessary to maintain organization.
D) Cells do not lose energy as heat.
1. Explain the First and Second Laws of Thermodynamics and how they apply to metabolic
processes in cells. Provide specific examples for each law.
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2. Compare and contrast catabolic and anabolic pathways in metabolism. Use examples like
cellular respiration and photosynthesis to support your explanation.
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3. Describe how enzymes lower the activation energy of a reaction. Include details about the
enzyme-substrate complex, the active site, and the concept of induced fit.
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4. Discuss the structure and function of ATP in cellular energy transfer. How does the
hydrolysis of ATP couple exergonic and endergonic reactions?
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5. Explain the role of feedback inhibition in regulating metabolic pathways. Provide an
example of a biological pathway that uses this form of regulation.
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