Wood Anatomy Practice Questions
20 free Wood Anatomy practice questions for the NCERT Biology. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
In a mature woody stem, sapwood is best described as:
- A The central, non-functional dead xylem region
- B The outer, lighter-colored functional xylem
- C The region where the vascular cambium is active
- D The outermost bark layer of the mature stem
Correct answer: The outer, lighter-colored functional xylem
Sapwood is the outer region of secondary xylem that actively conducts water and minerals. It appears lighter in color compared to heartwood.
Heartwood differs from sapwood mainly because heartwood:
- A Conducts water and minerals efficiently
- B Contains living, metabolically active xylem cells
- C Is darker and non-functional in conduction
- D Is produced continuously by the vascular cambium
Correct answer: Is darker and non-functional in conduction
Heartwood consists of dead xylem elements that no longer conduct water. It appears darker due to deposition of substances like tannins and resins.
Which of the following functions is primarily associated with sapwood?
- A Mechanical support only
- B Food storage
- C Water and mineral conduction
- D Protection against pathogens
Correct answer: Water and mineral conduction
Sapwood contains active xylem vessels and tracheids. These elements are responsible for upward transport of water and minerals.
Heartwood is formed due to:
- A Activity of cork cambium in the outer bark
- B Death and blockage of older xylem elements
- C Secondary growth and expansion of phloem tissue
- D Formation of annual rings in the outer wood
Correct answer: Death and blockage of older xylem elements
As xylem ages, older vessels get blocked by deposits and lose conducting ability. This transformation leads to the formation of heartwood.
Which substance is commonly deposited in heartwood, giving it a dark color?
- A Cellulose and lignin
- B Chlorophyll and carotene
- C Tannins and resins
- D Starch and proteins
Correct answer: Tannins and resins
Heartwood accumulates tannins, resins, oils, and gums. These substances impart a darker color and increase durability.
Which statement regarding sapwood is correct?
- A It is dead tissue
- B It provides mechanical strength
- C It is physiologically active
- D It cannot turn into heartwood
Correct answer: It is physiologically active
Sapwood is physiologically active and involved in conduction. With age, it gradually gets converted into heartwood.
Which part of wood provides greater resistance to insect attack?
- A Bark
- B Sapwood
- C Heartwood
- D Phloem tissue
Correct answer: Heartwood
Heartwood contains toxic substances like tannins and resins. These make it more resistant to insects and decay.
The presence of tyloses is commonly associated with:
- A Primary xylem
- B Sapwood vessels only
- C Heartwood vessels
- D Phloem fibers and rays
Correct answer: Heartwood vessels
Tyloses are balloon-like outgrowths that block xylem vessels. They are typically found in heartwood, preventing water conduction.
Which of the following best explains why heartwood does not conduct water?
- A Absence of vessels and tracheids
- B Vessels filled with deposits
- C Lack of lignin in cell walls
- D Presence of active cambium layers
Correct answer: Vessels filled with deposits
In heartwood, xylem vessels become blocked by deposits like resins and gums. This prevents further water conduction.
Sapwood can be distinguished from heartwood by its:
- A Position near the center
- B Darker coloration
- C Ability to conduct sap
- D Presence of cork cells
Correct answer: Ability to conduct sap
Sapwood actively conducts water and minerals. Heartwood lacks this conducting ability.
Which tissue is directly responsible for converting sapwood into heartwood?
- A Cork cambium
- B Vascular cambium
- C Medullary rays
- D Secondary phloem
Correct answer: Medullary rays
Medullary rays help in lateral transport and deposition of substances into older xylem. This contributes to heartwood formation.
The mechanical strength of wood is mainly due to:
- A Sapwood tissue alone
- B Heartwood tissue alone
- C Both sapwood and heartwood
- D Phloem, bark, and cork layers combined
Correct answer: Both sapwood and heartwood
Both sapwood and heartwood consist of lignified xylem elements. Together, they provide mechanical support to the plant.
Which type of wood is more suitable for making durable furniture?
- A Sapwood
- B Primary xylem
- C Heartwood
- D Secondary phloem
Correct answer: Heartwood
Heartwood is harder, darker, and more resistant to decay. These properties make it suitable for furniture and construction.
Sapwood is sometimes referred to as:
- A Duramen
- B Alburnum
- C Periderm
- D Phellem
Correct answer: Alburnum
Sapwood is also known as alburnum. Heartwood, in contrast, is called duramen.
Which of the following statements about heartwood is incorrect?
- A It lacks living cells
- B It conducts water actively
- C It is darker than sapwood
- D It provides mechanical support to the stem
Correct answer: It conducts water actively
Heartwood does not participate in water conduction. Its main roles are mechanical support and protection.
The conversion of sapwood to heartwood occurs due to:
- A Secondary growth in phloem
- B Ageing of inner xylem cells
- C Increase in cambial activity
- D Primary growth of stem
Correct answer: Ageing of inner xylem cells
As xylem elements age, their conducting function is lost. This ageing process converts sapwood into heartwood.
Which of the following is a functional difference between sapwood and heartwood?
- A Both conduct water
- B Only sapwood conducts water
- C Only heartwood conducts water
- D Neither conducts water
Correct answer: Only sapwood conducts water
Sapwood actively conducts water and minerals. Heartwood has lost this conducting function.
In a transverse section of an old tree trunk, heartwood is found:
- A Just beneath the outer bark
- B At the center of the stem
- C Within the active cambial zone
- D Outside the phloem layer
Correct answer: At the center of the stem
Heartwood occupies the central region of a mature woody stem. Sapwood surrounds it towards the periphery.
Which property of heartwood increases its commercial value?
- A High water content
- B Soft texture
- C Resistance to decay
- D Presence of living cells
Correct answer: Resistance to decay
Heartwood is resistant to fungal and insect attack due to chemical deposits. This increases its durability and commercial value.
Overall, sapwood and heartwood together mainly contribute to:
- A Photosynthesis
- B Secondary growth in thickness
- C Water transport and structural support
- D Protection of the stem against transpiration and drought stress
Correct answer: Water transport and structural support
Sapwood ensures conduction of water, while heartwood provides strength and durability. Together, they support the structure and function of woody plants.