Plant Biology: Leaf Structure and Functions

Questions and Answers

What is a petiole?

The skin of the leaf

The leaf tip

The leaf stalk (correct)

The large center vein

What is the midrib?

The large center vein

What is a blade in relation to a leaf?

The large, flat part of the leaf

What do veins do in a leaf?

They are the structural framework Signup and view all the answers

What is the margin of a leaf?

The edge of the leaf Signup and view all the answers

What is the apex of a leaf?

The leaf tip Signup and view all the answers

What is the upper epidermis?

The skin of the leaf that prevents moisture loss Signup and view all the answers

What is the lower epidermis?

A protective layer with stomata and guard cells Signup and view all the answers

What are stomates?

Small openings under the leaf for breathing or transpiration Signup and view all the answers

What function do guard cells serve?

Regulate the opening and closing of stomates Signup and view all the answers

What are chloroplasts responsible for?

Contain chlorophyll and are necessary for photosynthesis Signup and view all the answers

What is photosynthesis?

The process by which plants convert sunlight into food Signup and view all the answers

What is respiration in plants?

Converts sugars and starches into energy Signup and view all the answers

What is transpiration?

The release of water vapor from the leaves Signup and view all the answers

What does sessile mean in botany?

Leaves without a petiole Signup and view all the answers

What are bracts?

Modified leaves Signup and view all the answers

What are needles and scales?

Modified leaves Signup and view all the answers

What does glabrous mean?

Smooth non-hairy feel Signup and view all the answers

What does pubescent mean?

Hairy feel Signup and view all the answers

What are lenticels?

Breathing pores found on stems and branches Signup and view all the answers

What do bud scale scars indicate?

Where terminal buds have been located Signup and view all the answers

What is a terminal bud?

A bud on the end of the stem Signup and view all the answers

What is an axillary bud?

The bud located at the axil of the leaf Signup and view all the answers

What are lateral buds?

Buds on the side of the stem Signup and view all the answers

What is xylem?

The tissue that transports water and nutrients Signup and view all the answers

What is phloem?

The tissue that transports food down from leaves to roots Signup and view all the answers

What is cambium?

A thin, green, actively growing tissue Signup and view all the answers

What is bark?

Old inactive phloem Signup and view all the answers

What is heartwood?

Old inactive xylem Signup and view all the answers

What is sapwood?

New active xylem Signup and view all the answers

What are cotyledons?

Seed leaves Signup and view all the answers

What are monocots?

Plants with vascular bundles containing both xylem and phloem Signup and view all the answers

What are dicots?

Plants with a phloem layer and a xylem layer separated by cambium Signup and view all the answers

What is the function of the stem?

Translocation Signup and view all the answers

What is a root cap?

Where new cells are produced at the tip of the root Signup and view all the answers

What do root hairs do?

Absorb moisture and minerals Signup and view all the answers

What are fibrous roots?

Many branched shallow roots that are easy to transplant Signup and view all the answers

What are tap roots?

Long roots with few branched ones that are difficult to transplant Signup and view all the answers

What are the functions of roots?

Storage Signup and view all the answers

What are sepals?

The green parts that protect the flower bud Signup and view all the answers

What are petals?

Leaves modified to attract insects for pollination Signup and view all the answers

What are stamens?

The male flower parts Signup and view all the answers

What is an anther?

The sac-like structure containing pollen Signup and view all the answers

What is a filament?

The short stalk that holds up the anther Signup and view all the answers

What is a pistil?

The female parts of the flower Signup and view all the answers

What is the stigma?

The sticky part on top of the style where pollen lands Signup and view all the answers

What is the style?

The part that holds up the stigma and connects it to the ovary Signup and view all the answers

What happens to the ovary if it is fertilized?

It becomes a fruit Signup and view all the answers

What are ovules?

The eggs or female sex cells Signup and view all the answers

What are the functions of a flower?

Produces fruit to nourish and protect seeds Signup and view all the answers

Complete flowers have only male parts.

False Signup and view all the answers

Incomplete flowers have either male or female parts.

True Signup and view all the answers

What is fertilization?

When pollen travels down the style joining the sperm and ovule Signup and view all the answers

What is pollination?

The transfer of pollen from the anther to the stigma Signup and view all the answers

What is cross-pollination?

The transfer of pollen from the stamen of one flower to the stigma of another plant Signup and view all the answers

What is self-pollination?

The transfer of pollen to the stigma of a flower on the same plant Signup and view all the answers

What is a corolla?

All auxiliary parts of the flower excluding reproductive organs Signup and view all the answers

What is a calyx?

The external usually green or leafy part of a flower Signup and view all the answers

What is a receptacle?

The enlarged tip of a stem on which a flower is born Signup and view all the answers

What is the role of fruit?

To serve as protection for the seeds Signup and view all the answers

What is the juvenile stage of a fruit?

To help with seed dispersal Signup and view all the answers

Study Notes

Leaf Structure and Functions

Petiole: Connects the leaf to the stem; known as the leaf stalk.
Midrib: Central vein of the leaf providing support and transportation.
Blade: Flat part of the leaf responsible for capturing sunlight.
Veins: Supportive framework within the leaf, aiding in transport.
Margin: Edge of the leaf, influencing overall leaf shape and health.
Apex: The tip of the leaf, which can vary in shape and size.

Epidermis and Gas Exchange

Upper Epidermis: Protective skin layer that minimizes moisture loss.
Lower Epidermis: Contains stomata and guard cells; protects and facilitates gas exchange.
Stomates: Tiny openings for gas exchange; crucial for respiration and transpiration.
Guard Cells: Regulate the opening and closing of stomates, controlling gas flow.

Photosynthesis and Respiratory Processes

Chloroplasts: Green organelles containing chlorophyll; essential for photosynthesis.
Photosynthesis: Process converting sunlight, carbon dioxide, and water into food.
Respiration: Metabolic process converting sugars into energy for plant functions.
Transpiration: Loss of water vapor from leaves; aids in cooling and nutrient transport.

Leaf Variations and Structures

Sessile: Leaves without a petiole; Example: zinnia.
Bracts: Modified leaves often associated with flowers; Example: poinsettia.
Needles and Scales: Types of modified leaves found in certain plants; Example: pine trees.
Glabrous: Smooth, hairless leaves; Example: southern magnolia.
Pubescent: Hairy leaves; Example: African violet.

Stem and Bud Structures

Lenticels: Breathing pores on stems and branches for gas exchange.
Bud Scale Scars: Indicators of past terminal bud locations on stems.
Terminal Bud: Located at the end of the stem; responsible for growth.
Axillary Bud: Bud found in the axil of a leaf; potential for new growth.
Lateral Buds: Buds located along the sides of the stem.

Vascular Tissues in Plants

Xylem: Tissue transporting water and nutrients from roots upwards.
Phloem: Tissue responsible for distributing food from leaves to roots.
Cambium: Actively growing tissue between bark and wood, producing new cells.
Bark: Composed of old, inactive phloem.
Heartwood: Old, inactive xylem located at the center of the stem.
Sapwood: Newly formed, active xylem, recognizable by its light color.

Seed and Flower Structures

Cotyledons: First leaves produced by seed plant embryos; known as seed leaves.
Monocots: Plants with one seed leaf and vascular bundles containing xylem and phloem; Examples include grasses and corn.
Dicots: Plants with two seed leaves and distinct vascular arrangements; Examples include many vegetables and trees.

Roots and Their Functions

Root Cap: Protective structure at root tip, facilitating new cell growth.
Root Hairs: Tiny extensions that enhance the absorption of water and nutrients.
Fibrous Roots: Shallow, branched roots; easy to transplant.
Tap Roots: Long, deep roots; harder to transplant but provide stability.
Functions of Roots: Provide anchorage, absorb nutrients, store food, and facilitate asexual reproduction.

Flower Anatomy and Pollination

Sepals: Green, protective components covering the flower bud.
Petals: Modified leaves that attract pollinators; primarily for visual appeal.
Stamens: Male reproductive parts of the flower.
Anther: Part of the stamen that contains pollen.
Filament: Stalk supporting the anther.

Pistil and Fertilization

Pistil: Female reproductive structures of the flower.
Stigma: Sticky surface for pollen capture, located at the top of the style.
Style: Connects stigma to the ovary, allowing pollen transfer.
Ovary: Enlarged base of the pistil; if fertilized, develops into fruit.
Ovules: Female sex cells that may become seeds.

Pollination and Fertilization Processes

Functions of Flowers: Attract insects for pollination, produce seeds for reproduction, generate fruit to protect and nourish seeds.
Complete Flower: Contains both male and female reproductive structures.
Incomplete Flower: Lacks either male or female parts.
Fertilization: Pollen travels through style to fertilize ovules.
Pollination: Transfer of pollen from anther to stigma.
Cross-Pollination: Pollen transfer between different flowers; enhances genetic diversity.
Self-Pollination: Pollen transfer within the same flower; less genetic variation.

Flower Parts and Seed Dispersal

Corolla: Collective term for all petals in a flower.
Calyx: All sepals of a flower, typically protective and green.
Receptacle: Enlarged tip of the stem where the flower grows.
Fruit: Protects seeds and aids in their dispersal.
Juvenile: Refers to functions of fruit related to seed dispersal.

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Description

Explore the intricate structures of leaves and understand their vital functions in plants. This quiz covers the petiole, midrib, blade, and more, emphasizing their roles in photosynthesis and gas exchange. Test your knowledge of leaf anatomy and processes essential for plant survival.