Leaf Anatomy Quiz
Questions: 16 · 10 minutes
1. What is the primary function of the waxy cuticle covering many leaves?
Opening and closing each stoma
Transporting sugars from the leaf to the roots
Creating air spaces for internal gas movement
Reducing uncontrolled water loss from the leaf surface
2. In a typical broad leaf, which tissue contains tightly packed, chloroplast-rich cells specialized for absorbing light?
Lower epidermis
Spongy mesophyll
Palisade mesophyll
Phloem
3. The upper epidermis of many leaves is thin and transparent. How does this feature support photosynthesis?
It pumps sugar directly into palisade cells
It replaces the cuticle during dry conditions
It converts xylem into phloem near the surface
It allows light to pass to chloroplast-rich tissue beneath it
4. Carbon dioxide enters an open stoma. Which route best describes how it then reaches photosynthetic cells?
It flows through xylem vessels and enters the upper epidermis
It diffuses through internal air spaces to mesophyll cells
It moves through phloem and then crosses the cuticle
It travels along the petiole and exits through leaf veins
5. Which term refers to the broad, flattened portion of a typical leaf?
Blade, or lamina
Stipule
Petiole
Node
6. A student moves inward from the upper surface of a typical dorsiventral leaf. After crossing the cuticle and upper epidermis, which tissue is usually encountered next?
Petiole cortex
Lower epidermis
Palisade mesophyll
Root endodermis
7. A green-and-white leaf is exposed to light, but the white areas contain little or no chlorophyll. Which result is most likely?
The white areas absorb more carbon dioxide because they lack veins
The green areas carry out more photosynthesis than the white areas
The white areas transport more water because they lack chloroplasts
The green areas lose their epidermis as photosynthesis increases
8. Which sequence best describes the movement of water involved in transpiration within a leaf?
Xylem supplies water, water evaporates from moist cell surfaces, and vapor diffuses out through stomata
Stomata absorb water vapor, which condenses inside xylem vessels
Mesophyll produces water, which flows through phloem to the epidermis
Phloem brings water to guard cells, which pump it through the cuticle
9. Which vascular tissue delivers water and dissolved mineral ions into a leaf?
Epidermis
Phloem
Mesophyll
Xylem
10. After sugars are produced in the mesophyll, which tissue carries much of this material to other parts of the plant?
Xylem
Upper epidermis
Cuticle
Phloem
11. What is the usual structural role of a petiole?
It surrounds each stoma and controls its opening
It forms the photosynthetic tissue inside the blade
It connects the leaf blade to the stem and contains vascular tissue
It creates the waxy layer over epidermal cells
12. Which cells directly control the opening and closing of a stoma?
Palisade mesophyll cells
Guard cells
Xylem vessel cells
Epidermal hairs
13. Why are large air spaces common within spongy mesophyll tissue?
They store concentrated sugar before it enters the veins
They allow gases to diffuse among stomata and photosynthetic cells
They prevent light from reaching chloroplasts
They form rigid tubes that draw water up from the roots
14. During water shortage, guard cells lose turgor and a leaf's stomata narrow. What is the most immediate benefit to the plant?
Less water vapor escapes through the stomata
More carbon dioxide enters the leaf
Phloem transport changes into xylem transport
The cuticle begins producing sugars
15. A coating seals most stomata on the lower surface of a leaf. Which process is most directly restricted first?
Water transport through the petiole's xylem
Sugar transport through the phloem
Gas exchange between internal leaf spaces and the atmosphere
Light absorption by chlorophyll molecules
16. Two otherwise similar leaves differ mainly in cuticle thickness. The leaf with the thicker cuticle would generally be better able to do what?
Limit evaporation from exposed epidermal surfaces
Increase direct sugar loading through stomata
Replace xylem transport with diffusion
Create more chlorophyll in vascular tissue