Biology: Biochemistry and Plant Physiology
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Biological Molecules, Biochemistry, and Metabolism
SubtopicBiological Molecules, Biochemistry, and Metabolism under Biology: Biochemistry and Plant Physiology for Grade 8 IB.
Preview questions (no answers)
- 1.
The energy stored in glucose is originally derived from:
A.The soil
B.Water
C.Sunlight
D.The air
- 2.
Which sugar is often found in fruit?
A.Lactose
B.Fructose
C.Maltose
D.Starch
- 3.
What is the function of the waxy cuticle on a leaf?
A.To absorb sunlight
B.To reduce water loss
C.To store glucose
D.To perform respiration
- 4.
What do we call the process of breaking down large food molecules into smaller, soluble ones?
A.Respiration
B.Photosynthesis
C.Digestion
D.Circulation
- 5.
In biochemistry, what is a 'coenzyme'?
A.A non-protein organic molecule that helps an enzyme function
B.An enzyme that works only in the nucleus
C.An inhibitor that stops an enzyme from working
D.The product of an enzyme-controlled reaction
- 6.
Root hair cells are specialized for the absorption of water and minerals. What is their main structural adaptation?
A.They contain many chloroplasts for photosynthesis
B.They have a large surface area for increased absorption
C.They are thick and woody for support
D.They have no cell wall to allow water to enter easily
- 7.
Which of the following describes an 'exergonic' metabolic reaction?
A.A reaction that requires an input of energy to proceed
B.A reaction that releases energy to the surroundings
C.A reaction that only occurs in the presence of light
D.A reaction that synthesizes large molecules from small ones
- 8.
In the structural formula of a fatty acid, what defines it as 'unsaturated'?
A.It lacks a carboxyl group at the end of the chain.
B.It contains at least one double bond between carbon atoms in the hydrocarbon chain.
C.It has the maximum number of hydrogen atoms possible.
D.It is soluble in water due to high oxygen content.
- 9.
What is the effect of a very high concentration of substrate on the rate of an enzyme-catalyzed reaction?
A.The rate will increase infinitely as more substrate is added.
B.The rate will decrease because the substrate molecules will block each other.
C.The rate will reach a plateau () because all enzyme active sites are saturated.
D.The enzyme will denature due to the high osmotic pressure of the substrate.
- 10.
Which of the following molecules contains nitrogen?
A.Glucose
B.Triglyceride
C.Amino acid
D.Amylopectin
Download the worksheet for Biology: Biochemistry and Plant Physiology - Biological Molecules, Biochemistry, and Metabolism to practice offline. It includes additional chapter-level practice questions.
Enzymes as Biological Catalysts and Factors Affecting Enzyme Activity
SubtopicEnzymes as Biological Catalysts and Factors Affecting Enzyme Activity under Biology: Biochemistry and Plant Physiology for Grade 8 IB.
Preview questions (no answers)
- 1.
Can an enzyme that breaks down proteins also break down starch?
A.Yes, enzymes are universal
B.No, because the active site shape is specific to proteins
C.Yes, if the temperature is high enough
D.No, because starch is not a molecule
- 2.
What would happen to a plant if all its enzymes stopped working?
A.It would grow faster
B.It would produce more fruit
C.It would die because vital chemical reactions would stop
D.It would turn blue
- 3.
What type of bonds hold the long chains of amino acids together in an enzyme?
A.Ionic bonds
B.Peptide bonds
C.Hydrogen bonds
D.Metallic bonds
- 4.
Which gas is produced when the enzyme Catalase breaks down Hydrogen Peroxide?
A.Carbon dioxide
B.Nitrogen
C.Oxygen
D.Hydrogen
- 5.
Which of the following describes the effect of a competitive inhibitor on an enzyme?
A.It binds to the substrate and destroys it.
B.It binds to the active site, preventing the substrate from entering.
C.It increases the speed of the enzyme by providing energy.
D.It changes the enzyme into a different type of protein.
- 6.
Which statement about the temperature and enzymes is FALSE?
A.Low temperature decreases the rate of molecular movement.
B.High temperature can break the bonds holding the enzyme's shape.
C.All enzymes have the same optimum temperature of .
D.Enzymes in bacteria living in hot springs have high optimum temperatures.
- 7.
Lactase is an enzyme used to produce lactose-free milk. What is its substrate?
A.Glucose
B.Lactose
C.Galactose
D.Protein
- 8.
Which of the following describes an extracellular enzyme?
A.DNA polymerase working inside the nucleus.
B.Digestive enzymes, such as pepsin, secreted into the lumen of the gut.
C.ATP synthase located on the inner mitochondrial membrane.
D.Rubisco located in the stroma of the chloroplast.
- 9.
Why does a very high concentration of salt (salinity) often inhibit enzyme activity?
A.Salt molecules are too large and block the active site.
B.The ions interfere with the ionic bonds that stabilize the enzyme's tertiary structure.
C.Salt increases the boiling point of water, denaturing the enzyme.
D.Salt converts the enzyme into a carbohydrate.
- 10.
Which statement best describes the concept of 'Metabolic Pathways'?
A.A single enzyme converts one substrate into a final product in one step.
B.A series of linked chemical reactions, each catalyzed by a specific enzyme.
C.The path oxygen takes through a plant during respiration.
D.The sequence of amino acids in a protein.
Download the worksheet for Biology: Biochemistry and Plant Physiology - Enzymes as Biological Catalysts and Factors Affecting Enzyme Activity to practice offline. It includes additional chapter-level practice questions.
Aerobic and Anaerobic Respiration (Glycolysis, Krebs Cycle, Electron Transport, and ATP)
SubtopicAerobic and Anaerobic Respiration (Glycolysis, Krebs Cycle, Electron Transport, and ATP) under Biology: Biochemistry and Plant Physiology for Grade 8 IB.
Preview questions (no answers)
- 1.
The flow of energy through living systems involves several transformations. Based on the flowchart, what specific form of energy is stored in the chemical bonds of organic molecules before it is converted into usable ATP during respiration?
A.Radiant energy
B.Kinetic energy
C.Chemical energy
D.Thermal energy
- 2.
ATP is the primary molecule used by cells to store and transfer energy. According to the structural diagram below, what is the name of the 5-carbon sugar, labeled 'S', that connects the nitrogen base to the phosphate groups?
A.Glucose
B.Ribose
C.Deoxyribose
D.Sucrose
- 3.
During cellular respiration, cells do not capture all the energy from glucose in the form of ATP. According to the diagram, what is the byproduct labeled 'Energy X' that is released into the surroundings and helps maintain body temperature in many animals?
A.Heat energy
B.Light energy
C.Electrical energy
D.Nuclear energy
- 4.
What is the correct order of the three stages of aerobic respiration?
A.Krebs Cycle -> Glycolysis -> Electron Transport
B.Glycolysis -> Krebs Cycle -> Electron Transport
C.Electron Transport -> Glycolysis -> Krebs Cycle
D.Glycolysis -> Electron Transport -> Krebs Cycle
- 5.
What is the final product of the Electron Transport Chain besides ATP?
A.Glucose
B.Carbon dioxide
C.Water
D.Pyruvate
- 6.
How does the amount of energy released from one molecule of glucose compare between aerobic and anaerobic respiration?
A.Aerobic releases significantly more energy
B.Anaerobic releases significantly more energy
C.They release the exact same amount
D.It depends on the temperature of the cell
- 7.
In aerobic respiration, which process uses the high-energy electrons from NADH?
A.Glycolysis
B.The Krebs Cycle
C.The Electron Transport Chain
D.Alcoholic Fermentation
- 8.
Which molecule acts as the starting point for the Krebs cycle by reacting with oxaloacetate?
A.Pyruvate
B.Glucose
C.Acetyl-CoA
D.Lactic acid
- 9.
How many 'turns' of the Krebs cycle are required to process the derivatives of one glucose molecule?
A.One
B.Two
C.Three
D.Four
- 10.
During the conversion of pyruvate to lactate in muscle cells, what happens to ?
A.It is synthesized from
B.It is oxidized to
C.It is used to produce ATP directly
D.It is converted into
Download the worksheet for Biology: Biochemistry and Plant Physiology - Aerobic and Anaerobic Respiration (Glycolysis, Krebs Cycle, Electron Transport, and ATP) to practice offline. It includes additional chapter-level practice questions.
Photosynthesis (Light-Dependent Reactions, Calvin Cycle, Leaf Structure, and Limiting Factors)
SubtopicPhotosynthesis (Light-Dependent Reactions, Calvin Cycle, Leaf Structure, and Limiting Factors) under Biology: Biochemistry and Plant Physiology for Grade 8 IB.
Preview questions (no answers)
- 1.
Which gas is needed for the Calvin cycle to produce sugar?
A.Hydrogen
B.Carbon Dioxide
C.Oxygen
D.Nitrogen
- 2.
Which of these best describes the role of enzymes in photosynthesis?
A.They are used up as fuel
B.They speed up the chemical reactions
C.They provide the light energy
D.They are turned into glucose
- 3.
Which of the following is a reactant in the photosynthesis process?
A.Oxygen
B.Glucose
C.Water
D.Starch
- 4.
What is the name of the process by which water moves into the roots of a plant?
A.Active transport
B.Osmosis
C.Photosynthesis
D.Respiration
- 5.
Plants growing in the shaded understory of a rainforest often have much broader leaves compared to plants in open, sunny environments. Based on the concept of limiting factors, how does this structural adaptation support the process of photosynthesis?
A.It provides a larger internal area for the storage of excess glucose as starch molecules.
B.It helps to reflect excess light and prevents the chloroplast enzymes from denaturing.
C.It increases the surface area available to capture solar energy in low-light conditions.
D.It allows the plant to absorb more water directly from the humid atmosphere through the epidermis.
- 6.
In a chloroplast, where is the chlorophyll actually located?
A.Floating freely in the stroma
B.Embedded in the thylakoid membranes
C.In the outer membrane of the chloroplast
D.In the nucleus of the cell
- 7.
Which of the following is NOT required for the light-independent reactions to occur (assuming the light-dependent reactions have already happened)?
A.ATP
B.NADPH
C.Carbon dioxide
D.Direct sunlight
- 8.
In the chemical equation for photosynthesis (), which reactant is reduced?
A.Water
B.Carbon dioxide
C.Glucose
D.Oxygen
- 9.
What is the primary function of the thylakoid membrane's large surface area?
A.To store starch grains.
B.To provide space for many photosystems and electron carriers.
C.To allow for the storage of .
D.To protect the stroma from light.
- 10.
Which of the following describes the movement of sucrose out of the leaf?
A.Diffusion through the stomata.
B.Active transport into the phloem.
C.Mass flow through the xylem.
D.Osmosis through the epidermis.
Download the worksheet for Biology: Biochemistry and Plant Physiology - Photosynthesis (Light-Dependent Reactions, Calvin Cycle, Leaf Structure, and Limiting Factors) to practice offline. It includes additional chapter-level practice questions.
Plant Transport (Transpiration and Translocation)
SubtopicPlant Transport (Transpiration and Translocation) under Biology: Biochemistry and Plant Physiology for Grade 8 IB.
Preview questions (no answers)
- 1.
In a potometer experiment, why is the shoot cut under water?
A.To keep the leaves clean
B.To prevent air bubbles from entering the xylem
C.To wash away the soil
D.To speed up photosynthesis
- 2.
What is the primary role of the vascular bundle?
A.To protect the plant from sunlight
B.To transport materials and provide support
C.To produce seeds
D.To absorb oxygen from the air
- 3.
Which environmental condition would cause the highest rate of transpiration?
A.Cold, humid, and still air
B.Warm, dry, and windy air
C.Warm, humid, and still air
D.Cold, dry, and still air
- 4.
The loss of water vapor from the leaves creates a vacuum-like effect. This is called:
A.Tension
B.Pushing
C.Gravity
D.Compression
- 5.
Which of the following would NOT be considered a 'sink' for sucrose in a growing plant?
A.A developing fruit
B.A mature, photosynthesizing leaf
C.A growing root tip
D.An expanding flower bud
- 6.
What is the primary direction of transport in the xylem?
A.From leaves to roots
B.From roots to leaves
C.From stems to the atmosphere only
D.In any direction depending on the plant's needs
- 7.
Why do plants wilt on a very hot, dry day?
A.The rate of photosynthesis exceeds the rate of respiration
B.The rate of transpiration exceeds the rate of water uptake
C.The phloem becomes blocked by sugar
D.The roots stop absorbing water to save energy
- 8.
Compare the concentrations of sucrose at the source and the sink. Which is correct?
A.Source: High concentration; Sink: Low concentration.
B.Source: Low concentration; Sink: High concentration.
C.Source: High concentration; Sink: High concentration.
D.Source: Low concentration; Sink: Low concentration.
- 9.
What would happen to the rate of translocation if a plant's leaves were treated with a chemical that inhibits the enzyme 'proton-ATPase'?
A.It would increase as protons would move more freely.
B.It would decrease or stop because the proton gradient needed for sucrose co-transport would disappear.
C.It would remain the same because sucrose loading is a passive process.
D.It would cause the plant to switch to transporting glucose instead of sucrose.
- 10.
What is the function of the 'bundle sheath' in a leaf?
A.To produce sugars via photosynthesis.
B.To protect the vascular tissue (xylem and phloem) and regulate the movement of substances into and out of them.
C.To open and close the stomata.
D.To absorb sunlight for the mesophyll cells.
Download the worksheet for Biology: Biochemistry and Plant Physiology - Plant Transport (Transpiration and Translocation) to practice offline. It includes additional chapter-level practice questions.