All Free Biology MCQs with Answers
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19844 questions · page 609 of 1985
6081. Which of the following is NOT a difference that would allow one to distinguish between a prokaryotic and a eukaryotic cell? Presence of absence of the nucleus Presence or absence of the cell wall Membrane bound versus no membrane bound organelles
- A. I only
- B. II only
- C. III only
- D. I and II only
- E. I, II and III
Explanation: Eukaryotic cells have nucleus and membrane-bound organelles, which is not the property of prokaryotes.The cell wall is not a distinguishing feature between prokaryotes or eukaryotes.
Correct answer: II only6082. All of following are common molecules in membrane of all type of cells except:
- A. Globular protein
- B. Cholesterol
- C. Traces of carbohydrates
- D. Phospholipid
Explanation: Globular proteins, polysaccharides and phospholipids are present in both prokaryotic and eukaryotic cell membranes while cholesterol is present only in eukaryotic cell membrane.
Correct answer: Cholesterol6083. Hydrophobic portion of plasma membrane is present in/at:
- A. Towards extracellular matrix
- B. Towards cytoplasm
- C. Inner core of plasma membrane
- D. Towards the cytoskeleton
Explanation: The outside of plasma membrane is surrounded by water molecules. The hydrophobic portions will be present away from water moelcules i.e., towards the inner core of plasma membrane. (Hydrophobic means water-repelling)
Correct answer: Inner core of plasma membrane6084. Which of the following describes the fluid mosaic model of plasma membrane structure?
- A. Phospholipid monolayer with embedded proteins
- B. Phospholipid bilayer with embedded proteins
- C. Triglyceride bilayer with embedded proteins
- D. Triglyceride monolayer with embedded proteins
Explanation: The model proposes that the membrane is a phospholipids bilayer in which protein molecules are either partially or wholly embedded.
Correct answer: Phospholipid bilayer with embedded proteins6085. In plasma membrane, carbohydrates combine with the lipids and proteins to form glycolipids and glycoproteins and are oriented:
- A. Towards inside
- B. Towards outside
- C. Towards inside and outside
- D. Randomly distributed
Explanation: Glycolipids and glycoproteins are oriented towards the outer surface of plasma membrane and form glycocalyx and act as receptors.
Correct answer: Towards outside6086. Which of the following acts as a receptor site on plasma membrane?
- A. Head of phospholipid molecules
- B. Cholesterol molecules
- C. Tail of phospholipid molecules
- D. Integrins
Explanation: Integrins are receptors present on glycoproteins in the plasma membranes of cells. They are multisubunit transmembrane proteins. They have large extracellular domains, consisting of individually structured subdomains covalently linked by flexible linkers.
Correct answer: Integrins6087. A function that is related to smooth endoplasmic reticulum:
- A. Calcium storage
- B. Steroid synthesis
- C. Enzyme synthesis
- D. A and b
Explanation: Calcium storage and steroid synthesis is the function of SER, while enzyme synthesis is the function of RER. Mechanical support is, however, related to both StR and RER.
Correct answer: A and b6088. Which of the following function is performed by both types of endoplasmic reticulum?
- A. Protein synthesis
- B. Mechanical support
- C. Muscle contraction
- D. Detoxification of harmful drugs
Explanation: Role in detoxification of drugs is the function of SER while protein synthesis is the function of RER. Mechanical support, however, is the function of both RER and SER.
Correct answer: Mechanical support6089. 40S is the smaller ribosomal subunit associated with:
- A. E. coli
- B. C. botulinum
- C. Yeast
- D. T. pallidum
Explanation: E. coli. C. botulinum and T. pallidum are prokaryotic organisms having 30S smaller ribosomal subunit while yeast is eukaryotic organism having 40S smaller ribosomal subunit.
Correct answer: Yeast6090. Ribosomes are associated with all of the following organelles except:
- A. Mitochondria
- B. Nucleus
- C. Golgi apparatus
- D. Chloroplast
Explanation: Mitochondria and chloroplast have 70 ribosomes while nucleus has subunits of ribosomes synthesized in the darkly stained area, called nucleolus. Golgi apparatus, however, does not have any ribosome.
Correct answer: Golgi apparatus