Plants

Structure and Function

Plants – An Overview

• Have existed on this planet for nearly 400 million years.• Without plants, life on Earth would not exist as we

know it.• Plants provide many great resources to planet Earth,

including sources of food, oxygen, and habitat for other organisms.

• Plants are known as producers, because they make or produce their own food through the process of photosynthesis .

Photosynthesis

• Photosynthesis is shown in the picture and equation given below.

Photosynthesis continued

• Plants are autotrophic or autotrophs, which literally means “self-feeders.”

• A chemical equation is a written series of symbols that contains both reactants (ingredients) and products (end results).

• Photosynthesis is a process that is unique to plants and some protists; without photosynthesis there is no recycling of the oxygen and carbon dioxide in the atmosphere.

Plant Structures and FunctionsSTRUCTURE FUNCTION

RootsStore nutrients; absorb nutrients; support plant

StemsTransport nutrients between leaves and roots

LeavesPrimary site of photosynthesis and transpiration

SeedsPlant embryos (undeveloped “baby” plants)

ChloroplastsOrganelle where photosynthesis takes place

Chlorophyll

Green pigment inside the chloroplasts that facilitates photosynthesis

Plant Structures and FunctionsNutrients

Minerals and water that are absorbed by the plant through the ground or atmosphere

Flower

Produces new plants by developing fruit that contains seeds; this is the sexual organ of the plant

StamenMale part of the flower; contains the pollen (sperm cells)

PistilFemale part of the flower; contains the eggs

PollenPlant sperm cells; male reproductive cell

Egg Female reproductive cell

FruitContains plant seeds; used to attract other organisms to plants to help spread seeds

Plant Structures – Roots, Stems, Leaves

Plant Structures – The Plant Cell

Plant Structures – The Flower

Seeds

• Seeds are undeveloped plants or in simple terms “baby” plants.

• All flowering plants produce seeds. • There are two main types of seeds.• Monocots which have one cotyledon.• Dicots which have two cotyledons.

Seed Structures and Functions STRUCTURE FUNCTIONSeed coat Protects seed from infection

and dehydrationCotyledon Provides energy and

nutrients to begin growingPlumule The part of seed that

eventually grows into the first leaves

Hypocotyl The part of the seed that eventually grows into the stem

Hilum The area where the seed was attached to the ovary wall

Seed Diagram

Review Questions

1. Which observation of a plant supports the inference that photosynthesis can take place?

(1) a strong, sweet smell(2) a dry, rough texture(3) a green color(4) a smooth stem

Review Questions

2. A plant forms new tissue at the tips of its roots and stems. This new tissue growth is a direct result of

(1) circulation (2) coordination (3) cellular respiration (4) cell division

Review Questions

3. Which letter in the diagram represents the stored food that the new plant will use for early development?

(1)A (3)C(2)B (4)D

Review Questions4. Several tomato plants are grown indoors next to a sunny

window. The plants receive water and fertilizer and remain on the window sill. What will most likely happen?

(1) Most of the leaves on the window side will wilt and die.

(2) The roots of the plants will grow upward from the soil.

(3) Water droplets will collect on the leaves facing away from the window.

(4) The stem will bend toward the window.

Review Questions

5. What is the name of the process represented in this diagram that produces the carbon dioxide?

(1) photosynthesis (3) respiration(2) metamorphosis (4) fertilization

Xylem and Phloem

• Xylem- the tubes in a stem of a plant that carry water away from the roots.• Phloem- transports dissolved sugars and

other compounds throughout the plant

Stomata

• Stomata- openings in the outer cell layer of the leaf surface that allows for the exchange of water, carbon dioxide, oxygen and other gases• Guard Cells- cells that open and close

a plant’s stomata by changing their shape.

Vascular vs non vascular