Chapter 11 Section 1. Taking in Raw Materials To grow you need: –Food –Oxygen Used to release...
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Transcript of Chapter 11 Section 1. Taking in Raw Materials To grow you need: –Food –Oxygen Used to release...
Chapter 11
Section 1
Taking in Raw Materials
• To grow you need:– Food
– Oxygen• Used to release energy from food that you eat• Carbon dioxide and water are produced as wastes
that are removed when we exhale
– What does a plant need to grow?
Plants Need Food Too
Movement of Materials in Plants
• Plants make their own food using water, carbon dioxide, and inorganic chemicals in the soil
• They produce wastes when they make food
Movement of Materials in Plants
• Most water is taken in through the roots
• Leaves are where gas exchange occurs– Most water taken in leaves through the plant
leaves– Carbon dioxide, oxygen, and water vapor
enter and exit through the openings in the leaves
Leaf Structure and Function
• Outer cell layer is the epidermis– Cuticle prevents the
leaf from drying out– Sunlight reaches cells
inside the leaf through the epidermis
– Contains stomata• Guard cells open and
close
Leaf Structure and Function
• Stomata– More than 90% of water plants take in is lost through
the stomata– Usually open during the day to take in raw materials
to make food– Close during the day if too much water is being lost
• Guard Cells– As water moves into the guard cells they swell and
bend causing the stomata to open– As water is lost they deflate and close the stomata
Leaf Structure and Function
• Spongy cell layer– Has open spaces– Carbon dioxide and water vapor fill in the
empty spaces
• Palisade cell layer– Chloroplasts have chlorophyll here– Most of the food is made here
Leaf Structure and Function
Leaf Structure and Function
Chloroplasts and Plant Pigments
• Chloroplasts are green because they contain the green pigment chlorophyll
• Leaves are green because the color green is reflected
• The other colors of the visible spectrum are absorbed by the chlorophyll
• In the fall some chlorophyll breaks down and other colors are visible
Chloroplasts and Plant Pigments
Food-Making Process
• Photosynthesis:– Process in which chlorophyll traps light
energy and sugar is produced– Only occurs in cells with chloroplasts
Light-Dependent Reactions
• Light-Dependent Reactions need light to occur– Chlorophyll traps light – Light causes water to split into oxygen and
hydrogen– Oxygen leaves the plant – Hydrogen is used in the reactions that don’t
require light
Light-Dependent Reactions
Light-Independent Reactions
• Light-Independent Reactions do not require light– Carbon dioxide is used – Light that was trapped earlier combines with
carbon dioxide to make sugar• 1 important sugar made is glucose
Light-Dependent and Independent Reactions
Light-Independent Reactions
• Glucose is the main source of food for plants – Excess is stored as other sugars and starches
in the plant– When you eat carrots, beets, potatoes, or
onions you are eating stored sugar and starches
Importance of Photosynthesis
• 1: Produces food
• 2: Release Oxygen and take in carbon dioxide
Breakdown of Food
• Cellular respiration: – Series of chemical reactions that breaks down
food molecules and releases energy
Cellular Respiration
• 1st: Sugar molecules are broken down
• 2nd: Smaller molecules enter mitochondria
• 3rd: Oxygen breaks down the molecules into water and carbon dioxide– Releases energy
Importance of Cellular Respiration
• Food contains energy but not in a form most cells can use
• Cellular respiration allows food to change into an energy form all cells can use
• Plants use the energy to transport sugar and to open and close the stomata
Comparing Photosynthesis and Cellular Respiration
Comparing Photosynthesis and Cellular Respiration
• Photosynthesis:– Combines carbon dioxide and water by using
light energy– End products are glucose and oxygen – Energy is stored in food– Occurs only in cells that have chlorophyll
Comparing Photosynthesis and Cellular Respiration
• Cellular Respiration:– Combines oxygen and food– Releases the energy in chemical bonds in
food– End products are energy, carbon dioxide, and
water– Has to have a mitochondria