Biology Exam1 chapter 9

Biology Exam1 chapter 9 - Chapter 9: Photosynthesis:...

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Chapter 9: Photosynthesis: Capturing Energy Photosynthesis: sequence of events by which light energy is converted into the stored chemical ene rgy of organic molecules - Sustains plants and other photosynthetic organisms but also indirectly supports most nonphotosynthetic organisms Photosynthetic organisms covert CO2 into billions of tons of organic molecules - These molecules are building blocks of cells and source of chemical energy that fuels the metabolic reactions that sustain almost all life Pg. 192: Light Electromagnetic spectrum: continuous range of radiation Wavelength: distance from one wave peak to the next o (shortest wavelengths) Gamma rays, x-rays, UV rays, visible, infrared, microwaves, TV and radio waves (longest wavelengths) Photons: small particles that compose light Ground state: condition in which all its electrons are in normal, lowest energy levels Pg. 193: Chloroplasts Green pigment in leaves is only in the chloroplasts (thylakoids) Chloroplasts lie inside the mesophyll Chloroplast Structure: enclosed by outer and inner membranes - Inner membrane encloses fluid filled region called the stroma o Stroma: contains most of the enzymes required to produce carbohydrate molecules - Thylakoids: flat, disk like sacs that interconnect to form a system of membranes within the stroma - Thylakoid lumen: fluid filled space enclosed by the thylakoid membrane - Grana: stacks of thylakoid sacs Chlorophyll is found in the thylakoid membrane o Chlorophyll: main pigment of photosynthesis that absorbs light primarily in the blue and red regions of the visible spectrum – not green o Molecule has two parts: complex ring and side chain o Chlorophyll a: most important type, a pigment that initiates the light dependent reactions of photosynthesis o Chlorophyll b: accessory pigment that also participates in photosynthesis but instead of the methyl group (CH3) as in a, it has a terminal carbonyl group (CHO) – the difference shifts the wavelengths of light absorbed and reflected by it, making it appear yellowgreen o Carotenoids: yellow and orange, absorb different wavelengths of light than chlorophyll which expands the spectrum of light that provides energy for photosynthesis Chlorophyll is the main photosynthetic pigment o Spectrophotometer: measures the relative abilities of different pigments to absorb different wavelengths of lights o Absorption spectrum: plot of pigment’s absorption of light of different wavelengths o Action spectrum: graph of the relative effectiveness of different wavelengths of light to get one measure rate of photosynthesis at each wavelength for leaf cells or tissues to monochromatic light Bacteria go to oxygen experiment Pg. 196: Overview of photosynthesis Cell uses light energy captured by chlorophyll to power the synthesis of carbohydrates
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REDOX: carbon is reduced and oxygen is oxidized Photosynthesis is split into two parts: light dependent reactions (in thylakoids) and carbon fixation reactions (in stroma)
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Biology Exam1 chapter 9 - Chapter 9: Photosynthesis:...

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