BIO-1407 Lecture 15 Chapter 35

Which adaptation would you most expect to find in a maize (corn) plant growing in loose, moist soil?

• Buttress roots
• Pneumatophores
• Prop roots
• Storage roots

Answer explanation

Prop roots provide additional support for plants like maize, especially in loose, moist soils where stability is needed. They grow from the stem above ground.

Tags

NGSS.MS-LS2-1

You examine an unknown plant and find it has a fibrous root system with many roots of similar diameter, and leaves with parallel veins. What can you infer about this plant?

• It is a eudicot
• It is a woody perennial
• It is a gymnosperm
• It is a monocot

Answer explanation

Monocots typically have fibrous root systems and leaves with parallel veins (e.g., grasses, palms). Eudicots generally have taproots and branching veins.

A botanist cuts the apical bud from a young plant’s shoot. Which outcome is most likely, and why?

• The plant will stop growing
• The plant will form more storage roots
• Axillary buds will grow into branches due to reduced apical dominance
• The plant will develop a thicker cuticle

Answer explanation

Removing the apical bud eliminates apical dominance, allowing axillary buds to grow into branches. Apical dominance keeps axillary buds dormant under normal conditions.

A botanist finds cells with large vacuoles and thin walls packed with plastids in a potato tuber. What cell type are these?

• Sclerenchyma
• Parenchyma
• Guard cells
• Collenchyma

Answer explanation

Parenchyma cells are thin-walled, large, and filled with plastids for food storage, especially common in potato tubers and other storage organs.

Why are companion cells necessary for the function of sieve-tube elements in phloem?

• They produce chlorophyll for photosynthesis
• They increase the thickness of sieve-tube cell walls
• They conduct water transport
• They provide metabolic support, sharing nucleus and ribosomes

Answer explanation

Companion cells help sieve-tube elements (which lack many organelles) by sharing their nucleus and ribosomes, enabling efficient transport of sugars.

If a mutation prevented the death of sclerenchyma cell protoplasts after cell wall thickening, what effect would this have?

• The plant’s structural support would be compromised
• The plant’s nuts and seed coats would be softer
• The plant would have less efficient water transport
• The plant would lack flexible support

Answer explanation

Sclerenchyma cells, after thickening their walls, die to form hard structures (e.g., nutshells, seed coats). If they did not die, these structures would not harden properly.

Tags

NGSS.HS-LS3-2

What is the main function of the cuticle found on plant epidermis?

• Facilitating gas exchange
• Increasing water absorption
• Transporting minerals
• Reducing water loss

Answer explanation

The cuticle is a waxy coating on the epidermis that helps reduce water loss from the plant’s surface.

In a cross-section of a eudicot stem, which tissue would you expect to find arranged in a ring?

• Mesophyll
• Dermal tissue
• Ground tissue
• Vascular bundles

Answer explanation

In most eudicot stems, vascular bundles (containing xylem and phloem) are arranged in a ring just inside the epidermis.

Which zone of the root tip is responsible for cell division?

• Zone of cell division
• Zone of differentiation
• Apical meristem only
• Zone of elongation

Answer explanation

The zone of cell division is located behind the root cap and contains the apical meristem, where new cells are produced.

Tags

NGSS.HS-LS1-4

Design an experiment to distinguish between primary and secondary growth in woody stems. What would be a key observation?

• Counting annual rings in cross-section
• Measuring leaf size
• Weighing the plant’s roots
• Observing stomata density

Answer explanation

Secondary growth adds girth to stems via the vascular cambium, producing annual rings visible in cross-sections. Counting these rings distinguishes secondary growth from primary growth, which only lengthens stems.