Chapter 4

Lesson 1

Photosynthesis

The process that plants and some other organisms use to make sugar for .

Sunlight supplies the energy needed for photosynthesis.

food

Lesson 1 How do leaves help a plant?

Leaves are made of cells and tissues.

Plants make their food and most of the plant's food is made in its leaves.

The outside layer of the leaf is called the . Like our skin.

organs

own

epidermis

Photosynthesis

Plant cells use cellular respiration just like our cells. They use with food to get the energy they need for growth, repairs, and reproduction.

is the process that plants and some other organisms use to make sugar for food.

Photosynthesis occurs in the . Chloroplasts are in plant cells but not in animal cells.

Carbon dioxide + +sunlight= + sugar

http://m.youtube.com/watch?v=LgYPeeABoUs

photosynthesis

chloroplasts

water oxygen

http://studyjams.scholastic.com/studyjams/jams/science/plants/

photosynthesis.htm

Plant cells don't always use the sugar immediately. They some to use at night.

For long-term storage, plants join many sugars to form a chemical called .

Thousands of sugars combine in plants to form . This chemical makes up the strong cell walls of the plant.

store

starch

cellulose

Review

What is the outside of a leaf called?

Write down the process of photosynthesis.

What is sugar that is stored for a long time called?

What is one way plants are different from animals?

What makes plants green?

Where does photosynthesis take place?

Xylem

tubes that carry materials from the roots to the leaves.

Xylem carry water and minerals from the roots to the rest of the plant.

Phloem

tubes that carry sugar away from the leaves.

Phloem carry sugar to other parts of the plant.

Lesson 2 How do stems and roots help

a plant? Stems like leaves are plant . Stems hold leaves, fruits, and flowers on the plant.

Xylem and Phloem are special tissues inside some plants.

They are found in the roots, stems, and leaves. Not all plants have these tubes, but those that do are called plants.

Xylem - tubes that carry materials from the to the leaves.

Phloem - tubes that carry sugar from the leaves.

Dead phloem in trees make up the . And it protects the phloem behind it.

organs

vascular

roots

away

bark

http://m.youtube.com/

watch?v=HD8L83LOy4k

Roots

Roots are another plant .

Roots are strong and hold the plant in place as it grows.

Different kinds of roots 1) - large root that grows straight down. May store food for the plant. 2) root - many roots grow out in all directions. Divide many times into smaller and smaller roots. http://studyjams.scholastic.com/

studyjams/jams/science/plants/roots-stems.htm

organ

taproot

Fibrous

Functions of Roots

1) Anchor a plant

2) food

3) Absorb water from soil

Minerals or nutrients are dissolved in water that enters the .

With energy from photosynthesis, these materials are used in important ways in the plant's growth, maintenance, and reproduction.

store

roots

Review

Name the tree types of plant organs that we have talked about so far?

Xylem carries water and nutrients to where?

Phloem carries water and nutrients to where?

What are the functions of roots?

Name the two different types of root systems.

Pollen

a grainy, often yellow powder, made at the top of each stamen.

The bee carried the pollen from one flower to another flower.

Pollination

moving pollen from the stamen to the pistil.

Pollination can involve the stamen and pistil of the same plant or of two plants.

embryo

new plant.

An embryo has structures called seed leaves or cotyledons.

How Plants Reproduce - parts of the flower

Petals

stamen - part of the flower, pollen is made at the top of each stamen.

Pollen is a grainy, often yellow powder.

- female part of the flower, may have more than one.

Flowers with only one of these parts are called flowers.

Flowers with both parts are perfect flowers.

A flower is a flower made of many flowers.

male

pistil

imperfect

composite

http://studyjams.scholastic.com/studyjams/jams/science/plants/

flowers.htm

Reproduction

Plants must reproduce or they would die and become extinct.

When plants reproduce they make a new plant that looks like their parent.

is the information that is passed on to make the next generation. It contains the information for making flowers, leaves, and every part of the plant.

There are 2 types of reproduction

Sexual reproduction - the passing of DNA from parents to their offspring.

Asexual reproduction - is the passing of DNA from parent.

DNA

Steps in Reproduction

Pollination-moving pollen from the to the pistil.

Pollination can happen many ways.

3 ways Pollination Occurs 1) Insects and animals. 2) 3) Water

stamen

Fertilization

Once occurs a tube grows from the pollen down to the egg cells in the bottom of the pistil.

Special cells called sperm cells travel down the tube and join the egg cell.

This joining of cells and combining of is called fertilization. First step in the life of a new plant.

pollination

DNA

Combining DNA

Each egg or sperm has only of the amount of DNA found in other cells.

When an egg and sperm join, they make one whole set of DNA.

The egg grows and divides many times.

Every cell of the new plant will have the same set of DNA.

Sometimes the other parts of the flower grow around the seeds to be a ,

The offspring will be pretty much like the parents but may have a few differences. Ex. When pollen from a plant with red flowers pollinates a plant with white flowers the offspring may be a plant with flowers.

http://m.youtube.com/watch?v=dPk_V1KkMuU

half

fruit

pink

Seed and fruit formation.

Parts of a seed.

Seed coat - covering (protects the embryo-new plant also guards a stash of stored food called endosperm.

Embryo - has seed leaves or cotyledons. Seeds that have one cotyledon are called . Seeds with two cotyledons are called .

Endosperm. http://studyjams.scholastic.com/studyjams/jams/science/plants/

angiosperms.htm

monocotsdicots

Seed dispersal

may spread seeds or the seed may just start to grow where it falls off a tree or has been carried by wind.

Once the seed is moved from the parent plant the embryo will stay inside the seed until the temperature, , and other outside conditions are right. Then it will . Then the process repeats.

Animals

moisturesprout

Review

What is the female & male part of the flower called ?

Where do you find the pollen on a flower?

What is pollination?

What are 3 ways seeds can be dispersed/spread?

How Do Plants Grow? Starting to Grow

Different plants grow in different ways.

A plant's growth depends on its DNA and its .

When conditions are right sprouting will occur (sometimes called )

Roots will grow out of the seed downward and a tiny stem will grow upward.

If the conditions aren't right it will not start to grow.

Different plants have different needs.

environment

germination

DNA and Growth

Plants have many different shapes: tall and skinny, short and fat, etc.

How fast a plant grows is due partly to the environment and partly to the .

Ex. A fast growing yucca plant grew about 4 meters (13 ft) in only two weeks!

DNA

DNA and Growth

On conifer trees new branches grow at the top. The branches on the bottom were the first to form. That is why they are the longest. This is how they get their shape.

Even if conditions are perfect, plants will grow at different rates because of .

cone

DNA

Tropisms

Plants often change in the directions they grow to get what they need. Ex. Turning towards the sun or roots growing towards the water.

are ways that plants change their direction of growth in response to the environment.

often occur when the environment changes the amount that cells grow. If one side of the stem grows faster or larger than the other side, the stem will bend.

There are different reasons why some cells grow larger or faster than others. One reason is the amount of hormone.

Growth is a kind of chemical that effects plant growth. These chemicals cause more cells to grow.

Plants make their own growth hormone.

Tropisms

Tropisms

growth

hormone

3 Types of Tropisms

- is the growth of a plant or plant part because of the pull of gravity. Can happen stems and roots

- is a plant's reaction to a source of light.

- is a plant's growth in response to touching an object. Ex. Stems of vines will often grow around posts, fences, and trellises. Helps support the vine so it can get light. Roots may grow away from rocks and hard soil.

Gravitropism

Phototropism

Thigmotropism

Review

Name 2 things that affect the way plants grow?

What is tropism?

Name the three types of tropisms.

What is it called when a plant starts to grow?