Photosynthesis - PHOTOSYNTHESIS While a Jolly Green Giant...

Info iconThis preview shows pages 1–8. Sign up to view the full content.

View Full Document Right Arrow Icon
PHOTOSYNTHESIS While a Jolly Green Giant serves well as an advertising gimmick, animals rely completely on plants as a source of matter and energy. Without photosynthesis, life would not be as we know it on Planet Earth. Go hug a tree today.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
How do plants convert inorganic reactants to organic products? Photosynthesis, the biochemical process by which plants capture energy from sunlight and store it in carbohydrates, has long attracted attention. By the 1800s, scientists had learned: Three ingredients are needed for photosynthesis: H 2 O, CO 2 There are two products: carbohydrates and O 2 . Water, which comes primarily from the soil, is transported through the roots to the leaves. The CO 2 is taken in from the air through stomata in the leaves. By 1804, scientists had summarized the overall chemical reaction of photosynthesis: CO 2 + H 2 O + light --> sugar + O 2
Background image of page 2
The Two Stages of Photosynthesis: A Preview The light reaction is driven by light energy captured by chlorophyll. It produces ATP and NADPH + H + . The Calvin–Benson cycle does not use light directly. It uses ATP, NADPH + H + , and CO 2 to produce sugars. Photosynthesis occurs in the chloroplasts of green plant cells and consists of many reactions. Photosynthesis can be divided into two pathways: “dark reaction”
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Chloroplast Double membrane Contains chlorophyll Thylakloids (membranes that contain photosynthetic pigments: chlorophyll and carotenoids) Grana – stacks of thylakoids Stroma – fluid around the grana Stoma lamellae – membranes connecting grana Also is a semiautonomous organelle with its own DNA, ribosomes, tRNA; consistent with evolution from endosymbiotic bacteria
Background image of page 4
The light reactions convert solar energy to the chemical energy of ATP and NADPH Light - electromagnetic energy travels in waves Wavelength is the distance between the crests of waves and determines the type of electromagnetic energy Visible light includes the colors of light we can see and includes the wavelengths that drive photosynthesis Gamma rays X-rays UV Infrared Micro- waves Radio waves 10–5 nm 10–3 nm 1 nm 103 nm 106 nm 1 m 106 nm 103 m 380 450 500 550 600 650 700 750 nm Visible light Shorter wavelength Higher energy Longer wavelength Lower energy
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The Interactions of Light and Pigments When a photon and a pigment molecule meet, one of three things happens: The photon may bounce off, pass through,or be absorbed by the molecule. If absorbed, the energy of the photon is acquired by the molecule. The molecule is raised from its ground state to an excited state of higher energy.
Background image of page 6
The Interactions of Light and Pigments Molecules that absorb wavelengths in the visible range are called pigments . When a beam of white light shines on an object,
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Image of page 8
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 25

Photosynthesis - PHOTOSYNTHESIS While a Jolly Green Giant...

This preview shows document pages 1 - 8. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online