Gymnosperms lack:
I. vessels in their xylem
II. sieve tubes and companion cells
III. secondary growth
1. Only I and II
2. Only I and III
3. Only II and III
4. I, II, and III
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Phloem in angiosperms is composed of all the following except:
1. Sieve cells
2. Companion cells
3. Phloem parenchyma
4. Phloem fibers
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The nucleus of companion cells controls the functions of:
1. Sieve cells
2. Sieve tubes
3. Albuminous cells
4. Phloem parenchyma
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Identify the correctly matched pairs:
I: |
Sieve cell |
Food conducting element in gymnosperms |
II: |
Sieve-tube element |
Food conducting element in angiosperms |
III: |
Albuminous cells |
Delivery of substances to sieve-tube element |
IV: |
Companion cell |
Delivery of substances to sieve cells |
1. Only I and II
2. Only III and IV
3. Only I and III
4. Only II and IV
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In the given diagram of phloem in an angiosperm, the structure not seen in most of the monocots is indicated by the letter:
1. A 2. B 3. C 4. D |
Phloem fibers [bast fibers] are:
1. | made up of collenchyma and generally not seen in primary phloem |
2. | made up of collenchyma and generally not seen in secondary phloem |
3. | made up of sclerenchyma and generally not seen in primary phloem |
4. | made up of sclerenchyma and generally not seen in secondary phloem |
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Match each item in Column I with one in Column II and choose your answer from the codes given below:
Phloem components |
Feature |
A. Sieve tube elements |
a. Commercial use as in jute, flax and hemp |
B. Companion cells |
b. Plasmodesmatal connections and storage function |
C. Phloem parenchyma |
c. Maintaining pressure gradient in sieve tubes |
D. Phloem fibers |
d. Perforated end walls |
Codes
A | B | C | D | |
1. | a | b | c | d |
2. | b | a | d | c |
3. | b | d | c | a |
4. | d | c | b | a |
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Which of the following components of the phloem tissue in angiosperms loses protoplasm and becomes dead at maturity?
1. Sieve tube elements | 2. Companion cells |
3. Phloem parenchyma | 4. Phloem fibers |
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Protophloem differs from metaphloem in having:
1. companion cells present
2. dead sieve tube elements
3. narrow sieve tubes
4. lignified phloem fibers
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In their phloem tissue, gymnosperms have:
1. Sieve cells and Companion cells
2. Albuminous cells and Sieve cells
3. Sieve tubes and Companion cells
4. Sieve tubes and Albuminous cells
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