Chapter 4

Plants

Lesson 1 How do leaves help a plant?

Leaves are organs made of cells and tissues Plants make their own food called glucose Leaves contain various tissues. Each tissue

has a particular cells that perform certain roles

Leaves have openings in the bottom to let air in and out

Plants make their own food. They are called PRODUCERS Producers- organisms that make their own

food. Humans are consumers. Consumers- CANNOT make their own

food. Most of a plant’s food is made in its

leaves. The top layer of a leaf is smooth and this

protects the plant. The bottom layer of a leaf looks like a

sponge. It has spaces that air can pass through.

Parts of a Leaf

PhotosynthesisThe process in which plants make sugar

for food Plants perform photosynthesis by using:

Carbon dioxideWaterSunlight

Photosynthesis occurs in the chloroplastsChloroplasts make the plant green

Sunlight provides the cells the energy they need for photosynthesis.

A plant’s roots get the water. The water enters the chloroplasts. Carbon dioxide comes from the atmosphere

(air). Carbon dioxide enters the plant through its

leaves (bottom). Carbon dioxide then enters the chloroplasts. The water and carbon dioxide combined are

used to make sugar. Photosynthesis makes OXYGEN for humans and

animals. Photosynthesis also makes GLUCOSE (sugar) for

plants to grow. This means that plants make glucose (sugar),

their food, during the day. They don’t use all of their food during the day;

they save some for night time.

Cellular respiration- plants use oxygen with food to get the energy they need for growth, repairs, and reproduction

Sugar moves from the leaves to other parts of the plant where it is stored and later provides energy. It also forms cellulose, a chemical that makes up the strong cell walls.

Carbon dioxide + water + sunlight → oxygen + sugar

Lesson 2How do stems and roots help a plant?

Stems- plant organs that hold leaves, flowers, and fruit on a plant

Xylem and phloem tissues are tubes that transport substances within vascular plants

Stems Leaves grow on stems. Stems are plants’ organs (heart,

kidney). Stems help leaves get more sunlight. Stems also hold fruit and flowers on

plants. Some stems have thorns (roses). Thorns are a plant’s protection. A thorn is a sharp point. There are two kinds of stems:

Woody stems (trees and bushes) Non-woody stems (dandelions)

Parts of a Stem Inside a stem there are

tubes that transport (carry) things: Minerals Water Nutrients

There are two types of tubes: Xylem Phloem

XylemTubes that carry AWAY water and

minerals from the roots to the leaves.

The roots take water from the soil.The water has minerals in it that

came from the soil (like fertilizer).Plants use these minerals for

photosynthesis.

PhloemThese are tubes that carry sugar

from the leaves to the rest of the plant.

In trees, the phloem is the innermost layer of the bark.

The bark protects the phloem.

RootsRoots are plant organsThey grow in the groundRoots are strongThey hold the plant in placeRoots also help the plant get

WATER from the ground

Different Kinds of Roots Taproots- a large root that grows

straight down Fibrous root- many roots grow out in all

directions / the roots divide into smaller and smaller roots

Lesson 3 How do plants reproduce?

Parts of a flower: Petals- colorful outer area of the flower Stamen- the male part of the flower (a

single flower may have many stamens) Anthers- tissues at the top of each stamen

(where pollen is located) Filament- holds the anthers

Pistil- the female part of the flower (has a bottle-like shape) Stigma- receives pollen during civilization Ovary- female reproductive organ

Pollination Pollination is the moving of pollen from

the stamen to the pistil But how is this possible if plants don’t

move? Wind, insects (bees), water, birds, and

even bats can move pollen Flowers attract these organisms to come

and eat the flower When they rub against the flower,

stamen cells attach to them

When they go to another flower, they drop the pollen down to the pistil

They join with egg cells in the pistil This is called fertilization (just like how

babies are made) DNA carries information about how a

plants looks and works The sperm cell has half of the male

parent’s DNA The egg has half of the female parent’s

DNA This DNA combined causes new plants

to look similar to their parents

Seeds Parts of a seed:

Seed coat- protects the embryo Embryo- where the new plant is formed Endosperm- surrounds the embryo

A seed has one or two cotyledons. Seeds of plants with one cotyledon are called monocots, while seeds of plants with two cotyledon are called dicots

http://www.brainpop.com/science/diversityoflife/seedplants/

Spreading Seeds Seeds can be spread through a variety

of ways Animals Humans Wind Water

Affects rate of plant growth: DNA Environment

Spores Spores are single plant cells that are not

fertilized like seeds, but can grown into a new plant.

Many plants reproduce asexually, (with only one parent)

Some plants can reproduce both sexually and asexually

There are some plants that are cones that contain seeds. These seeds are moved through wind, birds, insects, etc. and these help spread the seeds.

Monocot & DicotMonocot Dicot

A monocot seed, like corn, has one area of stored food, while a dicot has two areas that are easily split apart such as a bean

A monocot has veins that are parallel, while a dicot’s veins branch out

Most monocots have fibrous root systems. Most dicots have taproot systems.