Inside the living plant The key to life on our planet

Why are plants the key to life on our planet Earth needs a constant input of energy to sustain life The sun is this source Plants convert solar energy into sugar so it is usable for all organism This stored sugar is passed through the food chain and life is sustained.

What is a plant? Plants are multi-cellular eukaryotes They have cells with walls made of cellulose. They carry out photosynthesis by using chlorophyll.

Plants need 4 things to live 1.Sunlight: plants convert solar energy into chemical energy in the form of sugar. 2.water and minerals: also involved in making sugar

3. gas exchange: CO 2 in and O 2 out. The Carbon on the CO 2 is used to make an organic sugar C 6 H 12 O Transport of water and nutrients: roots and other structures that take water and minerals to leaves and other cells.

Special plant cells. Leaves are the site of the food making process called photosynthsis Leaves have special cells called stomata and guard cells. Stomata is a tiny pore, found on the underside of a plant leaf and used for gas exchange.

Guard cells are cells on the underside of leaves for controlling gas exchange and water loss. Guard cells occur in pairs and are shaped so that a pore, or stomata, exists between them.

During dry weather, when a plant is in danger of losing water, the guard cells close, cutting down evaporation from the interior of the leaf.

Cross section of a leaf Leaf activity

Section 23-4 Stoma OpenStoma Closed Guard cells Inner cell wall Stoma Guard cells Inner cell wall Guard Cells

When the plant has water, sun, carbon dioxide and minerals, sugars and be made. Sugars are a chemical energy (stored) created from solar energy Solar energy chemical energy This is what photosynthesis is all about

Photosynthesis: Turning light energy from the sun into chemical energy of sugar

Light intro

Key Ideas of photosynthesis Carbon dioxide is converted to glucose (sugar). CO2 is an inorganic form of carbon. Its converted to glucose sugar, an organic form of carbon. Inorganic organic chloroplast Occurs in chloroplast of most plant cells and some single celled organisms.

Organisms come in two forms. 1. Heterotrophic organisms: obtain energy from the food they eat. Cannot use the sun to make food (energy). Name One________________ 2. Autotrophic organism: Can use the sun’s energy to make food (energy).

ATP ATP is the form of energy that is stored in and used by cells. ATP stands for adenosine triphosphate. How many phosphates does it have?____ Energy is released when ATP is converted to ADP or adenosine diphosphate. Can you guess what happened? Tri to di

ATP to ADP means that one phosphate is removed As a result, energy is released. The cell can use this energy for daily activities. ATP is the basic energy source for all cells.

Glucose ATP is used by the cell. They have only enough energy for a few seconds. It’s not very good for storage Glucose is the stored form of energy. It is a form of sugar stored by the body. When cells need more ATP, they break down the glucose molecule in the mitochondria. This is called cellular respiration.

Photosynthesis Photosynthesis is when plants use the energy of the sun to convert water and carbon dioxide into oxygen and high energy carbohydrates (sugars and starches). The equations:

Sunlight reaches earth and hits the plant. Plants absorb the sunlight with pigments such as cholorphyll.

Notice in the equation above that a plant converts 6 molecules of carbon dioxide at a time. How many carbons does the sugar product have? Why? Plants use this sugar that they created to produce complex carbohydrates such as starches.

What is photosynthesis: review

Why does the plant make it’s own sugar? 1. It uses the energy for growth and development. 2. The sugar is usually a starch in which other animal can eat. Through the food chain, the animal indirectly uses the energy of the sun with the plant being the middle man.

Flowers Many plants have flowers for reproduction Flowers not only look and smell pretty but are important in the reproduction process The sweet smell and bright colors attract other organisms to pollinate. Bees and butterflies are examples of pollinators.

Flowers have some basic parts. Most have both male and female organs. A. Pistil: female organ. The pistil usually is located in the center of the flower and is made up of three parts: 1. Stigma: sticky stem-like tube that catches pollen 2. Style: supports the stigma, holds it up high to catch pollen 3. Ovary: contains the female egg cells called ovules.

B. Stamen: The male part of the flower. They usually surround the pistil. The stamen is made up of two parts: 1. anther produces pollen (male reproductive cells). 2. filament holds the anther up.

Fertilization: steps 1.pollen lands on the stigma, 2.a tube grows down the style and enters the ovary. 2. Male reproductive cells travel down the tube and join with the ovule (egg), fertilizing it. 3. The fertilized ovule becomes the seed, and the ovary becomes the fruit. This is how apples are made

Petals: help attract pollinators such as bees, butterflies and bats.

Sepals: tiny green leaf- like parts at the base of the flower. They help to protect the developing bud.

Fruit: the ripened ovary of a plant containing the seeds. How does this happen? After fertilization, the ovary swells and becomes fleshy to protect the developing seeds. fruits help seeds spread Animals do not digest the seed and excrete them in another area The seed will germinate and grow where it is excreted.

Ovary to fruit

The Seed Seeds are made up of a small embryo, a food source and a seed coat. Seed coat protects the seed. The embryo grows into the plant. The food source feeds the embryo until it can undergo photosynthesis.

Seeds are a plant's way of getting from one area to another Usually does this with the help of wind, water or animals. Every seed is a tiny plant embryo with leaves, stems, and root parts. It’s waiting for the right conditions to make it germinate and grow. Water gives it this spark and growth enzymes are activated.

Review questions Most autotrophs store energy in the form of 1. starches 2. carbon dioxide 3. water 4. nucleic acids

7 The largest amount of DNA in a plant cell is contained in (1) a nucleus (2) a chromosome (3) a protein molecule (4) an enzyme molecule

Which part of a molecule provides energy for life processes? (1) carbon atoms (3) chemical bonds (2) oxygen atoms (4) inorganic nitrogen

The dissolved carbon dioxide in a lake is used directly by (1) autotrophs (3) fungi (2) parasites (4) decomposers

How was it discovered?