Photosynthesis

Chapter 11

What is Photosynthesis?

• Definition:– Photo light– Synthesis putting together

• Photosynthesis is a process that converts carbon dioxide and water into glucose and oxygen using the energy from sunlight.

Ingredients of Photosynthesis

• Following are the ingredients– Water– Carbon Dioxide– Light– Chlorophyll

• Water is taken in through the roots of the plant

• Water is then transported to the leaves by the tubes inside the plant that carry water to the stems W

ater

• Carbon dioxide animals breathe out from the air

• Plants absorb carbon dioxide from the small pores on the leaves

Car

bo

n D

ioxi

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• There are two sources of light– Natural light Sun– Artificial light Light containing red

and blue rays

• Light is used to break down the water in the plant into – Hydrogen which combines with

carbon dioxide to create the food for the plants and ultimately food for animals as well

– Oxygen (a by-product) which the plant gives off and animals use to breathe

Lig

ht

• Incandescent light is not particularly good for plants– As it gives off too much heat at a close

proximity and often need to be placed too far from the plant to do any real good.

• The process of photosynthesis happens in the chloroplast, which contain a green pigment called the chlorophyll.

• Chlorophyll is the most important ingredient of photosynthesis – Because it captures the light from the

Sun and converts carbon dioxide and water into glucose and oxygen.

Ch

loro

ph

yll

• In short, Chlorophyll is the magic compound that can grab that sunlight and start the whole process

Respiration in Plants

• All living organisms need oxygen to live.

• Even though plants lack respiratory system like animals, they need oxygen in order to stay alive. – They absorb oxygen from the air and expel

carbon dioxide

• During the day Photosynthesis is the dominant process in leaves– Carbon dioxide is absorbed to make

glucose

• At night Due to absence of sunlight, photosynthesis does not occur. Instead, the process of respiration occurs– Oxygen is absorbed and carbon dioxide is

given off

No light Bright lightDim light

- Plants produce CO2

- Plants produce O2

- Plants produce both O2 and CO2

• All parts of the plant respire, – Leaves, Stem, Roots and even the Flowers

• The roots of a plant also need oxygen which they obtain from the air spaces in the soil. – If you give too much water to a plant in a

pot you could kill the roots by drowning them!

Carnivorous Plants

• Carnivorous plants rely on animal prey for sustenance.

• Have the most bizarre adaptations to low-nutrient environments.

• Have features to attract, trap, kill, and digest prey, and absorb nutrients. – Various invertebrates– Small frogs– Small fish– Small mammals

• Because insects are one of the most common prey items for most carnivorous plants, they are sometimes called insectivorous plants.

• The most common habitat for these plants is where nutrient concentrations are low.

Traps work in a variety of ways.

• Pitfall traps of pitcher plants are leaves folded into deep, slippery pools filled with digestive enzymes.

•Flypaper (or sticky or adhesive traps) of sundews and butterworts are leaves covered in stalked glands that exude sticky mucilage.

• Snap traps (or steel traps) of the Venus flytrap and waterwheel plant are hinged leaves that snap shut when trigger hairs are touched.

• Suction traps, unique to bladderworts, are highly modified leaves in the shape of a bladder with a hinged door lined with trigger hairs.

Pitfall Traps

Pitcher Plant

Cobra Lily

Snap Traps

Venus Flytrap

Water Wheel

Flypaper

Sundew

Suction Traps

Bladderwort

Highly Sensitive Plants

Mimosa Plant