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Photosynthesis

Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

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Energy & Life Chemical Energy and ATP a. ATP – energy molecule used by cells (Fig. 8-2) b. Energy is stored in the bonds between phosphate c. When these bonds are broken energy is released c. When these bonds are broken energy is released

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Page 1: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis

Page 2: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Energy & LifePhotosynthesis is the process of capturing and transforming the energy of sunlight into chemical energy. (What type of organisms can make their own food?)

a. Autotrophs – organisms that can make their own food

b. Heterotrophs – organisms that obtain energy from the food they

consume

Page 3: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Energy & LifeChemical Energy and ATP

a. ATP – energy molecule used by cells (Fig. 8-2)

b. Energy is stored in the bonds between phosphate

c. When these bonds are broken energy is released

Page 4: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Energy & Life

Page 5: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Energy & LifeUsing Biochemical Energy

a. Active Transporthttp://www.dnatube.com/video/359/Active-Transport

b. Motor proteins move organelles throughout the cellhttps://www.youtube.com/watch?v=y-uuk4Pr2i8c. Synthesize various molecules

Page 6: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An OverviewI. Understand the

significance of Helmont’s,

Priestley’s, and Ingenhousz’s experiments.

II. 6CO2 + 6H2 O C6 H12 O6 + 6O2

Page 7: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An OverviewIII.Light and Pigments (Fig. 8-5)

A. Wavelength – distance between crests; shorter wavelengths have higher energy than longer wavelengths

Page 8: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An Overviewhttps://www.youtube.com/watch?v=

wJDlxp17rY4

Page 9: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An OverviewIII.Light and Pigments (Fig. 8-5)

B. Photon – a particle of lightC. In photosynthetic organisms,

absorbed energy is used to make chemical energy (glucose)D. Photosynthetic pigment – molecule that absorbs light (color you see is the color being reflected)

1. chlorophyll a - primary pigment; converts light energy to chemical energy

Page 10: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An OverviewIII.Light and Pigments (Fig. 8-5)

D. Photosynthetic pigment (con’t)

1. chlorophyll a - (con’t)a. reflects green lightb. absorbs red & blue

lightc. normally hides other pigments

2. Chlorophyll b – accessory pigment; absorbs light

andtransfers the energy tochlorophyll a

Page 11: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Photosynthesis: An OverviewIII.Light and Pigments (Fig. 8-5)

D. Photosynthetic pigment (con’t)

3. carotenes & xanthophylls –

accessory pigment; colors

can be seen in autumn when

chlorophylls start to break

downE. Absorption spectrum – the different

colors (wavelengths) of lightabsorbed by each pigment

Page 12: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisI. Inside a chloroplast – organelle

in which photosynthesis occurs

Page 13: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisI. Inside a chloroplast

A. Thylakoids – flattened sacs of photosynthetic membranes; pigments and proteins are organized into photosystems in order for light energy to be captured & stored as chemical energyB. grana – stacks of thylakoidsC. stroma – region between grana

Page 14: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisII. Electron Carriers – molecules

that can accept a pair of high-energy electrons and protons and transfer them to another molecule (NADP+)

Page 15: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisThere are two sets of reactions that take

place within the chloroplasts: The light dependent reactions & the Calvin Cycle (also know as the light independent or the dark cycle)

Page 16: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIII.Light Dependent Reactions

A. Takes place only in the presence of lightB. Occurs on membranes of thylakoidsC. Produces high energy compounds that are used in the dark reaction: ATP and NADPHD. Photosystem II

1. pigments absorb light energy and electrons are boosted to a higher energy level

Page 17: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIII.Light Dependent Reactions

D. Photosystem II (con’t)2. lost electrons are

replaced by the splitting of H2O into 2 e- ,2 p+, and O2

a. electrons are picked up by NADP

b. protons (H+) are pumped into inner thylakoid space

Page 18: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIII.Light Dependent Reactions

D. Photosystem II (con’t) c. Flow of hydrogen

ions down their gradient provides the energy necessary to synthesize ATP: ATP is used to

power the Calvin cycle

Page 19: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIII.Light Dependent Reactions

E. Photosystem I1. pigments use energy

from light to re-energize the elctrons from photosystem II

2. produces NADPH which also powers the Calvin Cycle

Page 20: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIII.Light Dependent Reactions

https://www.youtube.com/watch?v=hj_WKgnL6MI

Page 21: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIV.The Calvin Cycle – (light

independent, dark reaction) – uses ATP and NADPH from the light dependent reactions to produce high energy sugars (Fig. 8-11)

A. Takes place with or without the presence of light as long as ATP and NADPH are availableB. Occurs in the stroma chloroplastC. 6CO2 molecules enter the cycle from the atmosphere and combine with 6 five carbon

molecules

Page 22: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisIV.The Calvin Cycle (con’t)

D. The resulting 12 three carbon molecules use the energy from ATP and NADPH to produce 12 high energy three carbon

moleculesE. 2 of these molecules are used to synthesize sugar and other compoundsF. The remaining 10 molecules are used to produce more of the “starting” 6 carbon molecule of the cycle

Page 23: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

The Calvin Cyclehttps://www.youtube.com/watch?v=wJDlxp17rY4

Page 24: Photosynthesis. Energy & Life Photosynthesis is the process of capturing and transforming the energy…

Reactions of PhotosynthesisV. Factors Affecting

PhotosynthesisA. Light intensity – as intensity

increases the rate of photosynthesis increases (up to a point)B. Temperature – photosynthesis occurs rapidly at specific temp.; extreme temps. are damaging to enzymesC. H2O – decrease in water slows rate of photosynthesisD. Minerals – must be present in certain amounts