Unit 3: Plant Bioactives, Single Cell Culture and Germplasm Preservation - Practice Quiz

1 Single cell culture in plants involves the growth and multiplication of:

2 Which enzyme is commonly used to isolate single cells by degrading the middle lamella between plant cells?

3 Which method uses a very thin layer of medium in a dish to culture single cells?

4 Single cells obtained after enzymatic removal of the cell wall are called:

5 The technique in which single cells are grown on a layer of nurse cells is known as:

6 Single cell culture is especially useful for producing:

7 Which of the following is an important application of single cell culture?

8 Single cell culture helps study the process of __ at the individual cell level.

9 Single cells that can develop into complete plants demonstrate the property of:

10 Secondary metabolites in plants are mainly produced using:

11 The addition of a compound that stimulates increased production of a secondary metabolite is called:

12 Which cultured organ system is often used to produce secondary metabolites due to genetic stability?

13 Large-scale culturing of plant cells for metabolite production is typically carried out in a:

14 Many plant secondary metabolites are commercially important as:

15 Which anticancer secondary metabolite is obtained from Taxus species?

16 Plant bioactives are commonly used in the food industry as natural:

17 A cryoprotectant is a substance used to:

18 Which of the following is a commonly used cryoprotectant?

19 Cryopreservation of plant germplasm is generally carried out in liquid nitrogen at approximately:

20 Which storage method is considered best for long-term preservation of plant germplasm?

21 A researcher wants to isolate single cells from intact leaf mesophyll tissue without using enzymes. Which technique is most appropriate?

22 In the feeder layer technique for culturing single cells at low density, what is the primary role of the feeder layer?

23 The Bergmann cell plating technique is primarily used to:

24 Which culture method keeps a single cell in a very small volume of medium in a microchamber, allowing continuous microscopic observation of its division?

25 Single cell cloning is valuable in plant biotechnology mainly because it allows:

26 In a mutant selection program, single cells are grown on medium containing a selective agent (e.g., an amino acid analogue). The surviving colonies are most likely:

27 Which application relies on the totipotency demonstrated by single plant cells?

28 In cell suspension cultures, a two-stage (growth and production) strategy is often used because:

29 Adding a precursor such as phenylalanine to a culture producing rosmarinic acid is an example of:

30 Treating a cell culture with a fungal cell-wall extract to boost alkaloid production is called:

31 Why are hairy root cultures (via Agrobacterium rhizogenes) often preferred for producing certain secondary metabolites?

32 Cell immobilization in calcium alginate beads benefits secondary metabolite production mainly by:

33 Which pairing of a plant secondary metabolite with its commercial use is correct?

34 Shikonin, produced commercially from Lithospermum cell cultures, is valued mainly as a:

35 A pharmaceutical company chooses cell culture rather than field cultivation to obtain a bioactive alkaloid. Which is the strongest justification?

36 DMSO and glycerol are commonly used cryoprotectants because they:

37 Which statement best distinguishes a penetrating from a non-penetrating cryoprotectant?

38 In the vitrification method of cryopreservation, cells are protected because:

39 Cryopreserved plant material is typically stored in liquid nitrogen. The corresponding temperature is approximately:

40 For short/medium-term in vitro conservation, growth is slowed by reduced temperature and osmotic agents. Which addition most directly slows growth osmotically?

41 In the Bergmann cell plating technique, a single cell suspension is mixed with molten agar medium and poured into a Petri dish. If the plating efficiency is defined as the ratio of colonies formed to cells plated, and a researcher plates cells and obtains 1600 colonies, what is the plating efficiency, and what does a low value primarily indicate?

42 A researcher wants to culture a single isolated cell without diluting the conditioning factors it secretes. Which technique best achieves cell growth at effectively 'high density' for the individual cell while keeping it physically isolated?

43 Single cell cloning is exploited to isolate somaclonal variants. Which statement most accurately describes why single-cell-derived clones are preferred over shoot-tip derived plants for capturing novel variation?

44 In a two-stage batch culture for secondary metabolite production, cells are first grown in a growth medium then transferred to a production medium. Why is this two-stage strategy often necessary?

45 Elicitation is used to boost secondary metabolite yield. A biotic elicitor such as a fungal cell wall fragment (e.g., chitosan) primarily enhances metabolite production by:

46 In-situ product removal (ISPR) using adsorbent resins or a second organic phase is applied during metabolite production mainly to overcome which limitation?

47 Shikonin was the first plant secondary metabolite commercially produced via cell suspension culture. Which combination of factors made this economically viable compared to other metabolites?

48 Hairy root cultures induced by Agrobacterium rhizogenes are often superior to cell suspension cultures for producing certain alkaloids because they:

49 Cryoprotectants are classified as penetrating and non-penetrating. DMSO (penetrating) and sucrose (non-penetrating) are often combined. What is the principal complementary mechanism of this combination?

50 During vitrification-based cryopreservation, a highly concentrated cryoprotectant mixture (e.g., PVS2) is applied. The primary goal of vitrification is to:

51 Excessively high DMSO concentrations or prolonged exposure at room temperature before freezing can be detrimental because DMSO:

52 In the classical two-step (slow) freezing protocol, samples are cooled at a controlled rate (e.g., ) to about before plunging into liquid nitrogen. The controlled slow cooling step is critical because it:

53 Rapid, uncontrolled warming (thawing) after cryopreservation is generally recommended for slow-frozen plant cells to prevent:

54 Encapsulation-dehydration is a cryopreservation technique where explants are encased in alginate beads. The key advantage of this approach over direct vitrification is that it:

55 For medium-term germplasm storage, growth is slowed rather than stopped. Which combination of methods is most consistent with achieving reduced-growth in-vitro storage?

56 A key limitation of reduced-growth (medium-term) storage compared to cryopreservation is that:

57 'Recalcitrant' seeds (e.g., many tropical species) cannot be conserved in conventional seed banks. The main reason and the recommended long-term alternative are:

58 Liquid nitrogen storage at is considered ideal for long-term germplasm conservation primarily because at this temperature:

59 Protoplast fusion followed by single-cell culture is used for somatic hybridization. If a fusion produces a heterokaryon that later loses chromosomes from one parent during culture, the resulting product is best described as a:

60 Precursor feeding is a strategy to enhance secondary metabolite yield. For it to be effective, the fed precursor must: