Unit 1: Cellular Organization; Cytoskeleton and Function of Intracellular Organelles - Practice Quiz

1 Which of the following is a universal feature found in all living cells?

2 Which molecule serves as the universal carrier of genetic information in all cells?

3 Which element is the most abundant by mass in living cells (excluding water considerations)?

4 The monomer unit of proteins is the:

5 The widely accepted model describing the structure of the cell membrane is the:

6 The basic structural framework of the cell membrane is formed by:

7 Compartmentalization in eukaryotic cells is mainly achieved by:

8 Which of the following is NOT a component of the cytoskeleton?

9 Microtubules are primarily composed of the protein:

10 The plant cell wall is mainly composed of:

11 Which organelle is considered the control center of the cell?

12 The mitochondrion is best described as the:

13 The main function of the Golgi apparatus is to:

14 Lysosomes are often referred to as the cell's:

15 Which type of endoplasmic reticulum has ribosomes attached to its surface?

16 Peroxisomes are involved in the breakdown of which harmful compound?

17 Which of the following is a type of plastid that stores starch?

18 The large central vacuole in a mature plant cell mainly functions to:

19 The green pigment found in chloroplasts that captures light energy is:

20 Which cytoskeletal structures form the core of cilia and flagella involved in cell movement?

21 All living cells, regardless of their type, share a common set of features. Which combination represents features found universally in every cell?

22 A researcher analyzes the dry weight of a bacterial cell and finds that one class of macromolecule accounts for the largest fraction. Which macromolecule is this most likely to be?

23 During condensation (dehydration) reactions in biosynthesis, monomers are joined into polymers. What is released with each bond formed?

24 The fluid mosaic model describes the plasma membrane. Which experimental observation best supports the 'fluid' aspect of this model?

25 Compartmentalization in eukaryotic cells provides a functional advantage. Which statement best explains this advantage?

26 Three cytoskeletal filament types differ in diameter. Arranged from smallest to largest diameter, the correct order is:

27 Microtubules exhibit structural polarity with a fast-growing plus end and a slow-growing minus end. This polarity arises because:

28 A plant cell and a fungal cell both possess cell walls, but their structural polysaccharides differ. Which pairing is correct?

29 The nuclear envelope is perforated by nuclear pore complexes. What is the primary functional role of these pores?

30 The inner mitochondrial membrane is highly folded into cristae. What is the functional significance of this folding?

31 A secretory protein moves through the Golgi apparatus. In which direction does it travel through the cisternae?

32 Lysosomal hydrolytic enzymes function optimally at acidic pH (~4.5–5.0). What is the protective advantage of this pH requirement for the cell?

33 A cell specialized in steroid hormone synthesis is examined. Which feature would you expect to be most abundant?

34 Peroxisomes contain the enzyme catalase. What is the primary role of catalase in these organelles?

35 Plastids can interconvert depending on cellular needs. A green chloroplast in a potato tuber exposed to darkness may convert into which plastid type used for starch storage?

36 The large central vacuole of a mature plant cell contributes to turgor pressure. What happens to the cell when this vacuole loses water in a hypertonic environment?

37 The light-dependent reactions of photosynthesis occur in a specific chloroplast compartment. Where do these reactions take place?

38 The 'sliding filament' mechanism of muscle contraction depends on an interaction between two cytoskeletal-related proteins. Which motor protein 'walks' along actin filaments to generate force?

39 Cilia and flagella beat using a characteristic internal arrangement of microtubules. What is this arrangement called?

40 Cholesterol is an important component of animal cell membranes. How does it affect membrane fluidity at high temperatures?

41 A researcher performs a FRAP (Fluorescence Recovery After Photobleaching) experiment on a plasma membrane protein and observes that only 60% of the fluorescence recovers after bleaching, with a slow recovery half-time. Which interpretation is most consistent with these data?

42 In the chemiosmotic model, an uncoupler like 2,4-dinitrophenol (DNP) is added to actively respiring mitochondria. What is the predicted effect on oxygen consumption and ATP synthesis?

43 Treadmilling of an actin filament occurs when subunits add to the plus (barbed) end and dissociate from the minus (pointed) end at equal rates. This steady state requires that the free G-actin concentration equals which value?

44 A secretory protein is synthesized but fails to be N-glycosylated in the ER lumen. Assuming the signal sequence is intact, which is the most likely direct cause?

45 In I-cell disease (mucolipidosis II), lysosomal enzymes are secreted extracellularly rather than delivered to lysosomes. The underlying defect is a deficiency in which enzyme?

46 During the light reactions, cyclic electron flow around Photosystem I differs from linear (non-cyclic) flow in that cyclic flow produces:

47 Peroxisomal matrix proteins are imported post-translationally in a folded state, which distinguishes their import from that into the ER and mitochondria. This is enabled primarily by:

48 Nuclear import of a large cargo bearing a classical NLS requires directionality provided by the RanGTP gradient. What maintains high RanGTP in the nucleus and low RanGTP in the cytoplasm?

49 The cisternal maturation model of Golgi transport is best supported by which observation?

50 Microtubule dynamic instability is governed by the state of the GTP cap. Which scenario triggers rapid depolymerization (catastrophe)?

51 A polymer of amino acids linked by peptide bonds and a polymer of nucleotides both grow by condensation reactions. Which statement correctly compares the directionality of their biosynthesis?

52 The near-universality of the genetic code across bacteria, archaea, and eukaryotes is most parsimoniously explained by which conclusion?

53 Gram-positive and Gram-negative bacteria retain crystal violet differently during Gram staining. The mechanistic basis for Gram-positive retention is:

54 The large central vacuole in a mature plant cell is essential for turgor. If a plant cell is placed in a hypertonic solution, which sequence best describes the vacuole's role in the resulting change?

55 Proplastids can differentiate into distinct plastid types depending on tissue and light. Which pairing of plastid type and primary function is correct?

56 Membrane lipid asymmetry is actively maintained. Exposure of phosphatidylserine (PS) on the outer leaflet is a physiologically important signal. What enzyme activity typically maintains PS on the inner leaflet, and what disrupts it during apoptosis?

57 In the sliding filament mechanism of ciliary/flagellar beating, dynein arms attempt to slide adjacent microtubule doublets. Bending (rather than sliding apart) occurs because:

58 The endosymbiotic theory predicts specific features of mitochondrial molecular biology. Which observation is LEAST consistent with a free-living bacterial ancestor?

59 A misfolded protein accumulates in the ER lumen. The unfolded protein response (UPR) is triggered. Which coordinated set of outcomes best represents an adaptive UPR?

60 Intermediate filaments differ fundamentally from actin filaments and microtubules in a way that suits their mechanical role. Which distinction is correct?