Respiration in plants
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- Which process is closely connected to breathing in organisms?
a) Photosynthesis
b) Cellular respiration ✔
c) Transpiration
d) Fermentation - Where does the energy required for everyday activities come from?
a) Sunlight directly
b) Oxidation of food molecules ✔
c) Water
d) Soil nutrients - Which organisms can make their own food using photosynthesis?
a) Animals
b) Green plants and cyanobacteria ✔
c) Fungi
d) All microbes - Which molecule stores the chemical energy captured during photosynthesis in plants?
a) Proteins
b) Lipids
c) Carbohydrates like glucose, sucrose, and starch ✔
d) Nucleic acids - Which part of a green plant can perform photosynthesis?
a) All cells
b) Cells with chloroplasts, usually in outer layers ✔
c) Roots only
d) Stem only - What type of organisms are animals based on how they obtain food?
a) Autotrophs
b) Heterotrophs ✔
c) Saprophytes
d) Photosynthetic - How do saprophytes like fungi obtain their food?
a) By photosynthesis
b) By eating other animals
c) From dead and decaying matter ✔
d) From sunlight - Which process breaks down food inside cells to release energy?
a) Photosynthesis
b) Cellular respiration ✔
c) Fermentation
d) Transpiration - Where does photosynthesis occur in eukaryotic cells?
a) Cytoplasm
b) Chloroplasts ✔
c) Mitochondria
d) Nucleus - Where does the breakdown of complex food molecules for energy take place?
a) Chloroplasts
b) Cytoplasm and mitochondria ✔
c) Ribosomes
d) Golgi apparatus - What is the process of breaking C–C bonds in food molecules to release energy called?
a) Fermentation
b) Respiration ✔
c) Photosynthesis
d) Glycolysis - What are the substances used in respiration called?
a) Enzymes
b) Nutrients
c) Respiratory substrates ✔
d) ATP molecules - Which macromolecule is most commonly used to release energy in cells?
a) Carbohydrates ✔
b) Proteins
c) Fats
d) Nucleic acids - How is energy released inside the cell during respiration?
a) All at once
b) Slowly in small steps controlled by enzymes ✔
c) By heat only
d) By sunlight - Which molecule stores the energy released from food in a usable form?
a) Glucose
b) ATP ✔
c) DNA
d) RNA - Why is ATP called the energy currency of the cell?
a) Because it is money inside the cell
b) Because it stores energy and releases it when needed ✔
c) Because it makes food
d) Because it absorbs sunlight - What happens to the remaining carbon skeletons produced during respiration?
a) They are excreted as waste
b) They are used to build other important molecules in the cell ✔
c) They form ATP directly
d) They form water
- Do plants need oxygen for respiration?
a) No, they do not require oxygen
b) Yes, plants need oxygen for respiration ✔
c) Only roots need oxygen
d) Only during flowering - Which gases do plants release and absorb during respiration?
a) Release O₂, absorb CO₂
b) Release CO₂, absorb O₂ ✔
c) Release N₂, absorb O₂
d) Release CO₂, absorb CO₂ - Through which structures do plants perform gas exchange?
a) Lungs and alveoli
b) Stomata and lenticels ✔
c) Chloroplasts and mitochondria
d) Roots only - Why don’t plants need special respiratory organs like animals?
a) Because their cells do not respire
b) Each part of the plant handles its own gas exchange ✔
c) They absorb oxygen from soil only
d) They do not need oxygen at all - Why is gas exchange in plants slower than in animals?
a) Plants have fewer cells
b) Roots, stems, and leaves respire much more slowly ✔
c) Plants perform photosynthesis only
d) Plant cells are dead - Which plant cells produce oxygen during photosynthesis?
a) Root cells
b) Leaf cells ✔
c) Stem cells
d) Bark cells - Why can gases easily reach almost all living cells in a plant?
a) Because plant cells are highly permeable
b) Almost all cells are near the surface ✔
c) Because plants have lungs
d) Because they use xylem for oxygen - What is the role of lenticels in stems and roots?
a) Store water
b) Allow gas exchange ✔
c) Photosynthesize
d) Transport food - Which type of cells in stems and roots do not require oxygen?
a) Parenchyma cells
b) Lenticel cells
c) Dead inner cells ✔
d) Epidermal cells - What is the main product when glucose is completely broken down?
a) Oxygen
b) Carbon dioxide, water, and energy ✔
c) ATP only
d) Lactic acid - Why does a plant break glucose in small steps instead of completely at once?
a) To produce more CO₂
b) To prevent energy from being lost as heat and store it as ATP ✔
c) To make chlorophyll
d) To store oxygen - Which molecule stores energy in cells during respiration?
a) CO₂
b) Glucose
c) ATP ✔
d) Water - What is the process where glucose is broken down without using oxygen called?
a) Respiration
b) Photosynthesis
c) Glycolysis ✔
d) Fermentation - Organisms that can live with or without oxygen are called:
a) Obligate anaerobes
b) Facultative anaerobes ✔
c) Autotrophs
d) Heterotrophs - Organisms that cannot survive in the presence of oxygen are called:
a) Facultative anaerobes
b) Obligate anaerobes ✔
c) Aerobes
d) Autotrophs
- What does the word ‘glycolysis’ mean?
a) Sugar formation
b) Sugar splitting ✔
c) Energy production
d) Oxygen use - Which pathway is glycolysis also called?
a) Krebs cycle
b) EMP pathway ✔
c) Calvin cycle
d) Electron transport chain - Where does glycolysis take place in the cell?
a) Nucleus
b) Cytoplasm ✔
c) Mitochondria
d) Chloroplast - Which organisms rely solely on glycolysis for respiration?
a) Aerobic organisms
b) Anaerobic organisms ✔
c) Plants only
d) Animals only - Into how many molecules is glucose broken during glycolysis?
a) One
b) Two ✔
c) Three
d) Four - Which enzyme breaks sucrose into glucose and fructose?
a) Hexokinase
b) Invertase ✔
c) Phosphofructokinase
d) NAD⁺ - Which enzyme converts glucose to glucose-6-phosphate?
a) Hexokinase ✔
b) Invertase
c) Lactase
d) NAD⁺ - Which compound is formed after fructose-6-phosphate is phosphorylated?
a) Glucose-1-phosphate
b) Fructose-1,6-bisphosphate ✔
c) Pyruvic acid
d) Glyceraldehyde-3-phosphate - During glycolysis, when is NAD⁺ converted into NADH + H⁺?
a) When glucose becomes glucose-6-phosphate
b) When PGAL is converted to 1,3-bisphosphoglyceric acid ✔
c) When PEP becomes pyruvic acid
d) When fructose-6-phosphate becomes fructose-1,6-bisphosphate - What is the net gain of ATP molecules per glucose molecule in glycolysis?
a) 1
b) 2 ✔
c) 4
d) 6 - Which molecule is the end product of glycolysis?
a) Glucose
b) Pyruvic acid ✔
c) Fructose
d) ATP - Which process occurs in the absence of oxygen after glycolysis?
a) Krebs cycle
b) Fermentation ✔
c) Electron transport chain
d) Calvin cycle - Which organisms perform lactic acid fermentation?
a) Animals and some bacteria ✔
b) Only plants
c) Yeast only
d) All aerobic organisms - Which organisms perform alcoholic fermentation?
a) Yeast and some unicellular fungi ✔
b) Humans
c) Plants only
d) Obligate aerobes - Which type of respiration fully breaks down glucose into CO₂ and H₂O?
a) Anaerobic respiration
b) Aerobic respiration ✔
c) Glycolysis
d) Fermentation - Which cycle is included in aerobic respiration after glycolysis?
a) Calvin cycle
b) Krebs cycle ✔
c) EMP pathway
d) Glycolysis
- Fermentation occurs under which condition?
a) Aerobic ✔
b) Anaerobic ✔
c) High oxygen
d) Low glucose - In yeast, pyruvic acid is converted into which products during fermentation?
a) Lactic acid only
b) Ethanol and carbon dioxide ✔
c) Glucose and oxygen
d) Water and ATP - Which enzymes facilitate alcoholic fermentation in yeast?
a) Hexokinase and invertase
b) Pyruvic acid decarboxylase and alcohol dehydrogenase ✔
c) Lactate dehydrogenase only
d) NAD⁺ reductase and ATPase - Which enzyme catalyzes lactic acid formation in muscle cells?
a) Alcohol dehydrogenase
b) Lactate dehydrogenase ✔
c) Pyruvic acid decarboxylase
d) Hexokinase - Why is NADH + H⁺ important in fermentation?
a) It acts as a substrate
b) It gets oxidized back to NAD⁺ to continue glycolysis ✔
c) It produces oxygen
d) It makes ethanol - Approximately what percentage of glucose energy is released during fermentation?
a) 100%
b) 50%
c) Less than 7% ✔
d) 25% - What happens if alcohol concentration exceeds 13% during fermentation in yeast?
a) Yeast grows faster
b) Yeast dies ✔
c) More ATP is produced
d) Glucose is fully oxidized - Why is fermentation less efficient than aerobic respiration?
a) It occurs in mitochondria
b) It does not completely break down glucose ✔
c) It uses oxygen
d) It produces too much ATP - Where does aerobic respiration take place in eukaryotic cells?
a) Cytoplasm
b) Nucleus
c) Mitochondria ✔
d) Ribosomes - Which is the primary mode of respiration in higher organisms?
a) Fermentation
b) Glycolysis
c) Aerobic respiration ✔
d) Alcoholic fermentation - What are the end products of aerobic respiration?
a) Ethanol and CO₂
b) Lactic acid
c) CO₂, H₂O, and energy ✔
d) Pyruvic acid only - Why is aerobic respiration more efficient than fermentation?
a) It uses less oxygen
b) It completely oxidizes glucose and produces more ATP ✔
c) It occurs in the cytoplasm
d) It produces alcohol
- Where does aerobic respiration occur in eukaryotic cells?
a) Cytoplasm
b) Nucleus
c) Mitochondria ✔
d) Ribosomes - What is the product of glycolysis that enters the mitochondria for aerobic respiration?
a) Glucose
b) Pyruvate ✔
c) Acetyl CoA
d) Lactic acid - During aerobic respiration, pyruvate undergoes complete oxidation to produce how many molecules of CO₂ per pyruvate?
a) 1
b) 2
c) 3 ✔
d) 6 - Which enzyme complex catalyzes the conversion of pyruvate to acetyl CoA?
a) Hexokinase
b) Pyruvate dehydrogenase ✔
c) Lactate dehydrogenase
d) Alcohol dehydrogenase - Which coenzymes are required by pyruvate dehydrogenase for oxidative decarboxylation?
a) NAD⁺ and FAD
b) NAD⁺ and Coenzyme A ✔
c) ATP and NADH
d) CoA and FADH₂ - What are the products of pyruvate conversion to acetyl CoA?
a) Acetyl CoA, CO₂, NADH, and H⁺ ✔
b) Lactic acid and ATP
c) Ethanol and CO₂
d) Glucose-6-phosphate - How many NADH molecules are generated from the metabolism of two pyruvate molecules from one glucose?
a) 1
b) 2 ✔
c) 4
d) 6 - Which cycle does acetyl CoA enter for further breakdown and energy production?
a) Glycolysis
b) Calvin cycle
c) Krebs cycle (TCA cycle) ✔
d) Fermentation - Who first described the Krebs cycle?
a) Gustav Embden
b) Hans Krebs ✔
c) Otto Meyerhof
d) J. Parnas - Which molecules are produced in the Krebs cycle for ATP synthesis?
a) NADH, FADH₂, and ATP ✔
b) Glucose and NAD⁺
c) Lactic acid and ethanol
d) Oxygen and water - Where does electron transport and ATP synthesis take place during aerobic respiration?
a) Mitochondrial matrix
b) Inner mitochondrial membrane ✔
c) Cytoplasm
d) Nuclear membrane - The complete oxidation of pyruvate releases hydrogen atoms that are ultimately transferred to which molecule?
a) CO₂
b) O₂ ✔
c) ATP
d) FAD
- Which molecule combines with an acetyl group to start the TCA cycle?
a) Citric acid
b) Oxaloacetic acid (OAA) ✔
c) Succinyl-CoA
d) α-Ketoglutaric acid - Which enzyme catalyzes the formation of citric acid from acetyl-CoA and OAA?
a) Citrate synthase ✔
b) Isocitrate dehydrogenase
c) Succinate dehydrogenase
d) Pyruvate dehydrogenase - During the TCA cycle, citric acid is first converted into which molecule?
a) α-Ketoglutaric acid
b) Isocitrate ✔
c) Succinyl-CoA
d) Oxaloacetic acid - How many molecules of CO₂ are removed per acetyl-CoA during the TCA cycle?
a) 1
b) 2 ✔
c) 3
d) 4 - Which step of the TCA cycle involves substrate-level phosphorylation to produce GTP?
a) Conversion of α-Ketoglutarate to succinyl-CoA
b) Conversion of succinyl-CoA to oxaloacetic acid ✔
c) Conversion of citric acid to isocitrate
d) Conversion of isocitrate to α-Ketoglutarate - How many molecules of NADH are formed per glucose molecule in the TCA cycle?
a) 2
b) 4
c) 6
d) 8 ✔ - How many molecules of FADH₂ are produced per glucose molecule in the TCA cycle?
a) 1
b) 2 ✔
c) 3
d) 4 - How many ATP molecules are directly produced per glucose molecule in the TCA cycle?
a) 1
b) 2 ✔
c) 4
d) 6 - At the end of the TCA cycle, why is this stage considered part of respiration even though oxygen has not been used yet?
a) Because ATP is formed ✔
b) Because CO₂ is released
c) Because NADH + H⁺ and FADH₂ are made for the next step
d) Both a and c ✔ - What must the cell do to keep the TCA cycle running continuously?
a) Convert NADH + H⁺ back to NAD⁺ and FADH₂ back to FAD ✔
b) Convert ATP back to ADP
c) Remove CO₂ immediately
d) Increase glucose intake
- Where is the Electron Transport System (ETS) located in eukaryotic cells?
a) Cytoplasm
b) Mitochondrial matrix
c) Inner mitochondrial membrane ✔
d) Outer mitochondrial membrane - Which molecule acts as the first electron acceptor from NADH in the ETS?
a) Ubiquinone
b) NADH dehydrogenase (complex I) ✔
c) Cytochrome c
d) ATP synthase - Ubiquinone receives electrons from which complexes?
a) Complex I only
b) Complex II only
c) Complex I and II ✔
d) Complex III only - Which protein carries electrons from the cytochrome bc₁ complex (complex III) to complex IV?
a) NADH dehydrogenase
b) Ubiquinone
c) Cytochrome c ✔
d) ATP synthase - What is the final electron acceptor in aerobic respiration?
a) NAD⁺
b) FAD
c) Oxygen (O₂) ✔
d) Water (H₂O) - How many ATP molecules are approximately produced from one NADH in oxidative phosphorylation?
a) 1
b) 2
c) 3 ✔
d) 4 - How many ATP molecules are approximately produced from one FADH₂ in oxidative phosphorylation?
a) 1
b) 2 ✔
c) 3
d) 4 - Which complex in ETS is directly responsible for ATP synthesis?
a) Complex I
b) Complex III
c) Complex IV
d) ATP synthase (complex V) ✔ - In ATP synthase, the F₀ part serves which function?
a) Site for ATP synthesis
b) Proton channel ✔
c) Electron transfer
d) Oxygen binding - How many protons are required to synthesize one molecule of ATP?
a) 2
b) 3
c) 4 ✔
d) 5 - Why is oxidative phosphorylation named so?
a) Because oxygen directly forms ATP
b) Because ATP is formed during oxidation-reduction reactions ✔
c) Because phosphorylation happens in the cytoplasm
d) Because NADH is directly converted to ATP
- What is the theoretical total ATP yield from the complete aerobic respiration of one glucose molecule?
a) 2 ATP
b) 36 ATP
c) 38 ATP ✔
d) 40 ATP - Which of the following is an assumption made during the theoretical calculation of ATP yield?
a) All pathways work independently
b) NADH from glycolysis enters mitochondria and is used in oxidative phosphorylation ✔
c) Some substances are used to make other compounds
d) Multiple substrates enter and leave the pathway - Why is the actual ATP yield in cells often lower than the theoretical maximum?
a) All reactions occur in strict order
b) Substances can enter or leave pathways, and ATP is used as needed ✔
c) Only glycolysis occurs
d) Glucose is not broken down - How much ATP is generated from one glucose molecule in fermentation?
a) 2 ATP ✔
b) 4 ATP
c) 36 ATP
d) 38 ATP - Why does aerobic respiration produce more ATP than fermentation?
a) Glucose is only partially broken down in aerobic respiration
b) Glucose is fully broken down to CO₂ and H₂O in aerobic respiration ✔
c) NADH is not regenerated in aerobic respiration
d) Oxygen is not used in aerobic respiration - Which statement is true about NADH in fermentation vs aerobic respiration?
a) NADH is regenerated faster in fermentation
b) NADH is regenerated faster in aerobic respiration ✔
c) NADH is not regenerated in either process
d) NADH is not involved in ATP production - Which of the following is a key difference between fermentation and aerobic respiration?
a) Both produce the same amount of ATP
b) Fermentation requires oxygen, aerobic respiration does not
c) Fermentation partially breaks down glucose, aerobic respiration fully breaks it down ✔
d) Both occur in mitochondria
- Which of the following is the most commonly used substrate for respiration?
a) Proteins
b) Fats
c) Glucose ✔
d) Amino acids - Before other carbohydrates are used in respiration, they are usually converted into:
a) Fructose
b) Sucrose
c) Glucose ✔
d) Glycerol - Fatty acids enter the respiratory pathway after being converted into:
a) Pyruvate
b) Acetyl CoA ✔
c) PGAL
d) NADH - Glycerol from fats enters the respiratory pathway as:
a) Pyruvate
b) Acetyl CoA
c) PGAL (phosphoglyceraldehyde) ✔
d) Oxaloacetate - Proteins enter the respiratory pathway after:
a) Hydrolysis and phosphorylation
b) Deamination ✔
c) Oxidative decarboxylation
d) Reduction - Respiration is primarily considered a:
a) Anabolic pathway
b) Catabolic pathway ✔
c) Amphibolic pathway
d) Photosynthetic pathway - Why is the respiratory pathway called an amphibolic pathway?
a) It only breaks down molecules
b) It only builds molecules
c) It helps in both breakdown (catabolism) and synthesis (anabolism) of molecules ✔
d) It occurs only in amphibians - Which of the following can be synthesized from intermediates of the respiratory pathway?
a) Fatty acids ✔
b) Chlorophyll
c) DNA only
d) Starch only - Acetyl CoA is a key intermediate because:
a) It is only used in glycolysis
b) It participates in both breakdown and synthesis of biomolecules ✔
c) It is produced only from proteins
d) It is not involved in energy production
- Respiratory quotient (RQ) is defined as:
a) Volume of O₂ consumed / volume of CO₂ produced
b) Volume of CO₂ produced / volume of O₂ consumed ✔
c) Volume of O₂ consumed × volume of CO₂ produced
d) Volume of CO₂ produced × volume of O₂ consumed - The formula to calculate RQ is:
a) RQ = volume of O₂ consumed / volume of CO₂ produced
b) RQ = volume of CO₂ produced / volume of O₂ consumed ✔
c) RQ = CO₂ × O₂
d) RQ = O₂ – CO₂ - When glucose is completely oxidized, the RQ value is:
a) 0.7
b) 0.8
c) 0.9
d) 1 ✔ - Which respiratory substrate gives an RQ ≈ 0.7?
a) Carbohydrates
b) Fats ✔
c) Proteins
d) Both carbohydrates and fats - If proteins are used as the respiratory substrate, the approximate RQ value is:
a) 0.7
b) 0.8
c) 0.9 ✔
d) 1 - Why is RQ less than 1 for fats?
a) Fats release more CO₂ than O₂
b) Fats release less CO₂ than O₂ ✔
c) Fats release equal CO₂ and O₂
d) Fats do not require O₂ - Which of the following statements is true about respiratory substrates in living organisms?
a) Only carbohydrates are used
b) Only fats are used
c) Only proteins are used
d) A mixture of carbohydrates, fats, and proteins is usually used ✔ - Tripalmitin (C₅₁H₉₈O₆) oxidation produces CO₂ and H₂O. Its RQ is approximately:
a) 1
b) 0.9
c) 0.7 ✔
d) 0.5 - For a substrate with RQ = 1, the volumes of CO₂ produced and O₂ consumed are:
a) Equal ✔
b) CO₂ less than O₂
c) CO₂ more than O₂
d) Zero - Why are pure fats or proteins rarely used alone in living organisms?
a) They cannot be oxidized
b) Organisms always prefer carbohydrates
c) Real organisms use a mixture of substrates for energy ✔
d) They produce no energy
- Plants exchange gases through:
a) Lungs
b) Gills
c) Stomata and lenticels ✔
d) Trachea - Most living cells in plants can exchange gases easily because:
a) They have lungs
b) They are close to air ✔
c) They use circulatory system
d) They do not respire - The process of breaking C–C bonds in large organic molecules to release energy is called:
a) Photosynthesis
b) Fermentation
c) Cellular respiration ✔
d) Transpiration - The most preferred substrate for respiration in plants and animals is:
a) Fat
b) Protein
c) Glucose ✔
d) Nucleic acids - Where does glycolysis occur in the cell?
a) Mitochondrial matrix
b) Chloroplast
c) Cytoplasm ✔
d) Nucleus - In the absence of oxygen, pyruvic acid may be converted into:
a) Acetyl CoA
b) Alcohol or lactic acid ✔
c) Citric acid
d) ATP directly - Fermentation occurs in which conditions?
a) Aerobic
b) Anaerobic ✔
c) Only in animals
d) Only in mitochondria - During aerobic respiration in eukaryotes, pyruvic acid is converted into:
a) Lactic acid
b) Acetyl CoA ✔
c) Ethanol
d) Glucose - The process of ATP production using the Electron Transport System and oxygen as the final electron acceptor is called:
a) Substrate-level phosphorylation
b) Oxidative phosphorylation ✔
c) Photophosphorylation
d) Fermentation - The respiratory pathway is called an amphibolic pathway because:
a) It only breaks down molecules
b) It only builds molecules
c) It involves both catabolism and anabolism ✔
d) It occurs only in amphibians
Perfect bhai! Chalo mai MCQs 131–200 ready kar deta hoon, isi detail aur high-yield NEET level ke concepts se. Maine inko logical sequence me rakha hai: glycolysis, fermentation, aerobic respiration, TCA cycle, ETS, ATP yield, respiratory substrates, RQ, and amphibolic pathway.
MCQs 131–150: Glycolysis & Pyruvate Fates
- Glycolysis is called the EMP pathway after scientists:
a) Hans Krebs
b) Embden, Meyerhof, Parnas ✔
c) Louis Pasteur
d) Van Helmont - Glycolysis occurs in:
a) Mitochondrial matrix
b) Cytoplasm ✔
c) Chloroplast
d) Nucleus - The end product of glycolysis is:
a) Acetyl CoA
b) Pyruvic acid ✔
c) Lactic acid
d) Glucose-6-phosphate - How many ATP molecules are used in glycolysis initially?
a) 0
b) 1
c) 2 ✔
d) 4 - How many ATP molecules are produced in glycolysis per glucose?
a) 2
b) 4 ✔
c) 6
d) 38 - Net ATP gain from glycolysis per glucose molecule:
a) 1
b) 2 ✔
c) 4
d) 38 - NADH produced during glycolysis per glucose molecule:
a) 1
b) 2 ✔
c) 3
d) 4 - In glycolysis, glucose is first converted into:
a) Fructose-6-phosphate ✔
b) Pyruvate
c) Acetyl CoA
d) Citrate - The splitting of fructose-1,6-bisphosphate produces:
a) Two molecules of PGAL ✔
b) Two molecules of acetyl CoA
c) Two molecules of glucose
d) Two molecules of citrate - PGAL (glyceraldehyde-3-phosphate) is oxidized to form:
a) NAD⁺
b) BPGA ✔
c) Acetyl CoA
d) Citric acid - NADH is produced in glycolysis when:
a) PGAL is converted to BPGA ✔
b) Glucose is converted to glucose-6-phosphate
c) Fructose-6-phosphate is converted to F-1,6-bisphosphate
d) PEP is converted to pyruvate - Phosphoenolpyruvate (PEP) is converted into pyruvate, producing:
a) NADH
b) ATP ✔
c) FADH₂
d) CO₂ - Total ATP produced directly (substrate-level) in glycolysis:
a) 2 ✔
b) 4
c) 36
d) 38 - Glycolysis can occur in:
a) Only aerobic cells
b) Only anaerobic cells
c) Both aerobic and anaerobic cells ✔
d) Only plant cells - Glycolysis of one glucose produces two pyruvate molecules. True or False?
a) True ✔
b) False - The enzyme that converts glucose into glucose-6-phosphate:
a) Hexokinase ✔
b) Lactate dehydrogenase
c) Pyruvate decarboxylase
d) Citrate synthase - Sucrose can enter glycolysis after being split into:
a) Glucose and galactose
b) Glucose and fructose ✔
c) Glucose and maltose
d) Fructose and galactose - The enzyme invertase breaks:
a) Sucrose into glucose and fructose ✔
b) Glucose into pyruvate
c) Lactose into glucose and galactose
d) Starch into maltose - Facultative anaerobes can survive:
a) Only without oxygen
b) Only with oxygen
c) With or without oxygen ✔
d) Only in high CO₂ - Obligate anaerobes:
a) Need oxygen
b) Cannot survive in oxygen ✔
c) Can survive with or without oxygen
d) Only use aerobic respiration
MCQs 151–170: Fermentation & Anaerobic Respiration
- Fermentation occurs in the absence of:
a) Carbon dioxide
b) Oxygen ✔
c) Nitrogen
d) ATP - Alcoholic fermentation occurs in:
a) Yeast ✔
b) Muscle cells
c) Bacteria only
d) All plant cells - Pyruvic acid in yeast is converted into:
a) Lactic acid
b) Ethanol and CO₂ ✔
c) Acetyl CoA
d) Glucose - The enzymes involved in alcoholic fermentation:
a) Lactate dehydrogenase
b) Pyruvate decarboxylase and alcohol dehydrogenase ✔
c) Hexokinase
d) Citrate synthase - Lactic acid fermentation occurs in:
a) Muscle cells under intense activity ✔
b) Yeast
c) Chloroplasts
d) Mitochondria - Lactic acid fermentation uses NADH + H⁺ to:
a) Make ATP directly
b) Reoxidise NADH to NAD⁺ ✔
c) Produce CO₂
d) Split glucose - Energy yield from fermentation per glucose molecule:
a) 2 ATP ✔
b) 36–38 ATP
c) 4 ATP
d) 0 ATP - Alcohol tolerance of yeast:
a) Up to 5%
b) Up to 13% ✔
c) Up to 25%
d) Up to 50% - Which by-product can be harmful in high concentration during fermentation?
a) Water
b) CO₂
c) Alcohol or acids ✔
d) Oxygen - Aerobic respiration yields more energy than fermentation because:
a) Glucose is fully broken down ✔
b) Oxygen is not used
c) Only pyruvate is made
d) Less NADH is formed - Aerobic respiration occurs in:
a) Cytoplasm only
b) Mitochondria ✔
c) Chloroplasts
d) Nucleus - In aerobic respiration, pyruvate is converted into:
a) Lactate
b) Acetyl CoA ✔
c) Ethanol
d) Glucose - Acetyl CoA formation requires coenzymes:
a) NAD⁺ and CoA ✔
b) FAD and NADH
c) ATP and GTP
d) NADP⁺ and CoA - Oxidation of pyruvate produces:
a) ATP directly
b) NADH + H⁺ and CO₂ ✔
c) FADH₂
d) Lactate - Number of NADH molecules per glucose after pyruvate oxidation:
a) 1
b) 2 ✔
c) 3
d) 4 - Krebs cycle also called:
a) Calvin cycle
b) TCA cycle ✔
c) EMP pathway
d) Fermentation cycle - Citrate synthase catalyzes:
a) Formation of oxaloacetate
b) Formation of citric acid from acetyl CoA and OAA ✔
c) Conversion of pyruvate to acetyl CoA
d) NADH oxidation - ATP produced directly in TCA cycle per glucose:
a) 2 ✔
b) 4
c) 36
d) 38 - NADH molecules produced per glucose in TCA cycle:
a) 6
b) 8 ✔
c) 10
d) 12 - FADH₂ molecules produced per glucose in TCA cycle:
a) 1
b) 2 ✔
c) 3
d) 4
