Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut.

Name: Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut.
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Description: Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut.

Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut butter sandwich with jelly beans stuck in it. When releasing energy from ATP a chemical reaction occurs that changes ATP to ADP. What is the difference between ATP and ADP? The functions of a cell membrane include signal transduction, transport of molecules, and enzymatic reactions. These functions are all carried out by the proteins or the lipids in the membrane? T/F ATP synthase is an enzyme in the inner membrane of a mitochondrion. It makes/synthesizes ATP as chlorine ions flow through it. a. b. c.

Quiz 5 C6H12O6 (Glucose) + 6O2  6CO2 + 6H2O + Energy (ATP)
6. Cells undergo cellular respiration to make a form of energy that the cell can use. This energy is released from cellular respiration in the form of ATP DNA Light Oxygen T/F The overall equation for cellular respiration is: C6H12O6 (Glucose) + 6O2  6CO2 + 6H2O + Energy (ATP) 8. Does fermentation or respiration produce more ATP? Humans get their energy from the carbon dioxide they inhale. Will fermentation occur in the presence of sufficient oxygen? Quiz 5

AN OVERVIEW OF PHOTOSYNTHESIS
Copyright © 2009 Pearson Education, Inc.

7.1 Autotrophs are the producers of the biosphere
Autotrophs are living things that are able to make their own food without using organic molecules derived from any other living thing Autotrophs that use the energy of light to produce organic molecules are called photoautotrophs Most plants, algae and other protists, and some prokaryotes are photoautotrophs Chemoautotrophs- synthesize all necessary organic compounds from heat methane and sulfur, live in hostile environment like deep sea vents Copyright © 2009 Pearson Education, Inc.

Examples of photosynthetic organisms: leaves from higher plants by colonies of photosynthetic purple bacteria (left) and cyanobacteria (right). Note the different colors Why all the different colors? Shouldn’t they all be green because they have green chloroplasts? "The World & I" (March 1998, pg ) Vermaas Copyright © 2009 Pearson Education, Inc.

Structure of chloroplast – location of photosynthetic reactionse
Leaf cross section Vein Mesophyll Structure of chloroplast – location of photosynthetic reactionse Stomata CO2 O2 Chloroplast Mesophyll cell Outer membrane Thylakoid Intermembrane space 5 µm Figure 10.3 Zooming in on the location of photosynthesis in a plant Stroma Granum Thylakoid space Inner membrane 1 µm

The ability to photosynthesize is directly related to the structure of chloroplasts Chloroplasts are organelles consisting of photosynthetic pigments, enzymes, and other molecules grouped together in membranes These photosynthetic pigments are called chlorophylls and carotenoids Copyright © 2009 Pearson Education, Inc.

7.2 Photosynthesis occurs in chloroplasts in plant cells
Chloroplasts are the major sites of photosynthesis in green plants Chlorophyll, an important light absorbing pigment in chloroplasts, is responsible for the green color of plants Energy for photosynthesis is provided by light, which is absorbed by pigments (primarily chlorophylls and carotenoids) Chlorophylls absorb blue and red light and carotenoids absorb blue-green light Green and yellow light are not effectively absorbed by photosynthetic pigments in plants; therefore, light of these colors is either reflected by leaves or passes through the leaves This is why plants are green Copyright © 2009 Pearson Education, Inc.

What would happen if put a plant in red light. Blue light. Green light
What would happen if put a plant in red light? Blue light? Green light? Which would grow the best or undergo photosynthesis more easily?

Light - further explanation

White light and light from the sun contain all colors of the visible spectrum mixed together
You can separate all of these wavelengths so you can see them with a prism

Objects appear to be certain colors because of interactions with light
Because some wavelengths are being absorbed and some are not – transmitted to our eye where we perceive them

Photosynthetic Pigments: The Light Receptors
Pigments are substances that absorb visible light Different pigments absorb different wavelengths Wavelengths that are not absorbed are reflected or transmitted Leaves appear green because chlorophyll reflects and transmits green light Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

Light Reflected light Chloroplast Absorbed Granum light Transmitted
Fig. 10-7 Light Reflected light Chloroplast Figure 10.7 Why leaves are green: interaction of light with chloroplasts Absorbed light Granum Transmitted light

In short Plants use all kinds of light but the yellow/green light
The best light is actually red or blue

7.6 Reflection and absorbtion
Other photosynthetic organisms, such as cyanobacteria (formerly known as blue-green algae) and red algae, have additional pigments (called phycobilins or bacteriochlorophyll) that absorb and reflect other colors of the spectrum Which colors are being absorbed and reflected by the purple colonies? The orange colonies? "The World & I" (March 1998, pg ) Vermaas Copyright © 2009 Pearson Education, Inc.

So we know light is important for plants.
What else? C02 and H20 C02 and H20 are brought to the plant through: Stomata are tiny pores in the leaf that allow carbon dioxide to enter and oxygen to exit Veins in the leaf deliver water absorbed by roots Copyright © 2009 Pearson Education, Inc.

This gives us the left hand side of the equation for photosynthesis
Light energy 6 CO2 + 6 H2O Carbon dioxide Water Photosynthesis Common sense: All plants need to be watered and placed in a lighted area. The only other element they need is access to is CO2 Copyright © 2009 Pearson Education, Inc.

Just like respiration, photosynthesis is a redox reaction
This implies the transfer of electrons between the reactants and the products of the photosynthetic equation Much like in respiration the electron is passed along in a manner like a bucket brigade The electron originates with water Let’s break water down Oxygen H+ H20 e-

7.4 Photosynthesis is a redox process, as is cellular respiration
Photosynthesis, like respiration, is a redox (oxidation-reduction) process Water molecules are split apart by oxidation, which means that they lose electrons along with hydrogen ions (H+) Then CO2 is reduced to sugar as electrons and hydrogen ions are added to it Compare to respiration Copyright © 2009 Pearson Education, Inc.

7.4 Photosynthesis is a redox process, as is cellular respiration
In photosynthesis, electrons gain energy by being boosted up an energy hill Light energy captured by chlorophyll molecules provides the boost of energy for the electrons As a result, light energy from the sun is converted to chemical energy, which is stored in the chemical bonds of sugar molecules Copyright © 2009 Pearson Education, Inc.

The complete equation Common sense:
Light energy 6 CO2 + 6 H2O C6H12O6 + 6 O2 Carbon dioxide Water Glucose Oxygen gas Photosynthesis Common sense: All plants need to be watered and placed in a lighted area. The only other element they need is access to is CO2 CO2 receives the H+ and e- to make glucose This leaves oxygen gas behind Copyright © 2009 Pearson Education, Inc.

Actually, photosynthesis occurs in two metabolic stages
Light reactions and the Calvin cycle

THE LIGHT REACTIONS: CONVERTING SOLAR ENERGY TO CHEMICAL ENERGY

Light reaction in a nutshell
In the light reactions, light energy is converted in the thylakoid membranes to chemical energy and O2 Water is split to provide the O2 as well as electrons H+ ions reduce NADP+ to NADPH, which is an electron carrier similar to NADH NADPH is temporarily stored and then shuttled into the Calvin cycle where it is used to make sugar Finally, the light reactions generate ATP Copyright © 2009 Pearson Education, Inc.

Light Reactions What goes in . . .

NADPH, ATP, and O2 are the products of the light reactions
What goes in . . . What comes out . . . NADPH and ATP are sent to the Calvin Cycle where they are converted to ADP and NADP+ ADP and NADP+ then return to re-enter the light reactions and start the process again.

7.6 Visible radiation drives the light reactions
Sunlight contains energy called electromagnetic energy or radiation Visible light is only a small part of the electromagnetic spectrum, the full range of electromagnetic wavelengths Electromagnetic energy travels in waves, and the wavelength is the distance between the crests of two adjacent waves Copyright © 2009 Pearson Education, Inc.

7.7 Photosystems capture solar power
The energy released could be lost as heat or light, but rather it is conserved as it is passed from one molecule to another molecule Copyright © 2009 Pearson Education, Inc.

e– Excited state Heat Photon Photon (fluorescence) Ground state
Figure 7.7A Light-excited chlorophyll molecule that releases a photon of red light. Ground state Chlorophyll molecule

7.7 Photosystems capture solar power
The energy is passed from molecule to molecule within the photosystem Finally it reaches the reaction center where a primary electron acceptor accepts these electrons and consequently becomes reduced This solar-powered transfer of an electron from the reaction center pigment to the primary electron acceptor is the first step of the light reactions Copyright © 2009 Pearson Education, Inc.

7.8 Two photosystems connected by an electron transport chain generate ATP and NADPH
During the light reactions, light energy is transformed into the chemical energy of ATP and NADPH To accomplish this, electrons removed from water pass from photosystem II to photosystem I and are accepted by NADP+ The bridge between photosystems II and I is an electron transport chain that provides energy for the synthesis of ATP Copyright © 2009 Pearson Education, Inc.

7.9 Chemiosmosis powers ATP synthesis in the light reactions
Interestingly, chemiosmosis is the mechanism that not only is involved in oxidative phosphorylation in mitochondria but also generates ATP in chloroplasts ATP is generated because the electron transport chain produces a concentration gradient of hydrogen ions across a membrane Copyright © 2009 Pearson Education, Inc.

ATP NADPH Mill makes ATP Photosystem II Photosystem I e– e– e– e– e–
Energy from light causes electron to jump to a higher energy state 6 5 Electron is donated to NADP+ e– ATP 3 e– Electron transport chain produces H+ gradient and ATP e– 2 Energy from light causes electron to jump to a higher energy state NADPH e– 4 e– Light absorbed by another chlorophyll e– 1 Mill makes ATP Photon Light absorbed by chlorophyll e– Photon Photosystem II Photosystem I

Can humans be as smart as plants?
Plants take light energy and convert it to chemical energy If humans could harness the sun like plants do, there is enough solar power reaching the earth to provide all of our energy needs 10,000 times over. "The total power needs of the humans on Earth is approximately 16 terawatts." (A terawatt is a trillion watts.) "In the year 2020 it is expected to grow to 20 terawatts. The sunshine on the solid part of the Earth is 120,000 terawatts. From this perspective, energy from the sun is virtually unlimited." Eicke Weber, director of the Fraunhofer Institute for Solar Energy Systems, in Freiburg, Germany Copyright © 2009 Pearson Education, Inc.

How to harness the sun “There are two main ways to harness it. The first is to produce steam, with a field of flat, computer-guided mirrors, called heliostats, that focus sunlight on a receiver on top of an enormous "power tower." The second way is to convert sunlight directly into electricity with photovoltaic (PV) panels made of semiconductors such as silicon.” How do photovoltaic panels work? -National Geographic. Plugging into the Sun. September 2009.

How is this similar to light reactions in chloroplast?

Future advancements People are trying to make conductors and emitters of electrons into a paint that you could put onto your house Right now solar panels are expensive and only 10-20% efficient – moving to make them more efficient 40%) but still inexpensive Make it storable to use at night or cloudy days

Now back to photosynthesis
We are not done yet ATP is the end goal in respiration, but glucose is the end goal in photosynthesis Copyright © 2009 Pearson Education, Inc.

The complete equation Common sense:
Light energy 6 CO2 + 6 H2O C6H12O6 + 6 O2 Carbon dioxide Water Glucose Oxygen gas Photosynthesis Common sense: All plants need to be watered and placed in a lighted area. The only other element they need is access to is CO2 CO2 recieves the H+ and e- to make glucose This leaves oxygen gas behind Copyright © 2009 Pearson Education, Inc.

ATP NADPH Mill makes ATP Photosystem II Photosystem I e– e– e– e– e–
Energy from light causes electron to jump to a higher energy state 6 5 Electron is donated to NADP+ e– ATP 3 e– Electron transport chain produces H+ gradient and ATP e– 2 Energy from light causes electron to jump to a higher energy state NADPH e– 4 e– Light absorbed by another chlorophyll e– 1 Mill makes ATP Photon Light absorbed by chlorophyll e– Photon Photosystem II Photosystem I Note: water is split to replenish e- supply

ATP is the end goal in respiration, but glucose is the end goal in photosynthesis
What goes in . . . What comes out . . . NADPH and ATP are sent to the Calvin Cycle where they are converted to ADP and NADP+ ADP and NADP+ then return to re-enter the light reactions and start the process again.

THE CALVIN CYCLE: CONVERTING CO2 TO SUGARS

7.10 ATP and NADPH power sugar synthesis in the Calvin cycle
The Calvin cycle makes sugar within a chloroplast To produce sugar, the necessary ingredients are atmospheric CO2, ATP, and NADPH, which were generated in the light reactions Using these three ingredients, an energy-rich, three-carbon sugar called glyceraldehyde-3-phosphate (G3P) is produced A plant cell may then use G3P to make glucose and other organic molecules Copyright © 2009 Pearson Education, Inc.

CYCLE CO2 ATP NADPH Input CALVIN Output: G3P G3P Cellular
Figure 7.10A An overview of the Calvin cycle. G3P Cellular Respiration (50%) Cellulose 2 G3P make 1 glucose Output: G3P Glucose Starch Other organic compounds

7.11 Review: Photosynthesis uses light energy, CO2, and H2O to make food molecules
The chloroplast, which integrates the two stages of photosynthesis, makes sugar from CO2 All but a few microscopic organisms depend on the food-making machinery of photosynthesis Plants make more food than they actually need and stockpile it as starch in roots, tubers, and fruits Although photosynthesizers produce sugar for self-consumption, their sugar is a source for virtually all other organisms on Earth. Copyright © 2009 Pearson Education, Inc.

H2O CO2 Chloroplast Light NADP+ ADP + P RuBP CALVIN CYCLE Electron
Photosystem II RuBP CALVIN CYCLE Electron transport chains 3-PGA (in stroma) Thylakoid membranes Photosystem I ATP Stroma NADPH Figure 7.11 A summary of the chemical processes of photosynthesis. G3P Cellular respiration Cellulose Starch O2 Sugars Other organic compounds LIGHT REACTIONS CALVIN CYCLE

Photosynthesis stores energy into sugars and respiration will release that energy
CO2 ATP NADPH Plants undergo photosynthesis and respiration Input CALVIN CYCLE Figure 7.10A An overview of the Calvin cycle. G3P Cellular Respiration (50%) Cellulose 2 G3P make 1 glucose Output: G3P Glucose Starch Other organic compounds

Antioxidants fighting ROS (reactive oxygen species)
ROS form as a natural byproduct of cellular respiration Are deployed to kill invading microorganisms About 0.1-2% of electrons passing through the electron transport oxygen is instead prematurely and incompletely reduced to give the superoxide radical(O2-) and not water Copyright © 2009 Pearson Education, Inc.

Protein complex of electron carriers H+ H+ Electron carrier H+ H+ ATP synthase Intermembrane space Inner mitochondrial membrane FADH2 FAD Electron flow NADH NAD+ 2  1 O2 + 2 H+ H+ Mitochondrial matrix H+ ADP + P ATP H+ H2O H+ Electron Transport Chain Chemiosmosis If too much damage is caused to its mitochondria by ROS, a cell will kill itself Copyright © 2009 Pearson Education, Inc.

ROS are ions or molecules that that are highly reactive due to the presence of unpaired valence shell electrons. ROS form as a natural byproduct of cellular respiration. Can damage cells.

Tentative negative effects of oxidative damage Limiting lifespan – more ROS has been proven to cause worms to age prematurely Cancer Brain diseases (stroke, Alzheimer's, Parkinson’s) Heart disease In order for your body to fight these negative effects, it needs antioxidants

What are antioxidants? Where are they found?
One class of antioxidants are carotenoids found in fruits and vegetables Photosynthetic pigments – these are the pigments we have been talking about in this chapter Remember? They absorb light to excite electrons

What are antioxidants? Where are they found?
In general, processed foods contain fewer antioxidants than fresh and uncooked foods, since the preparation processes may expose the food to oxygen and use up the antioxidant potentail of the food

Eat your fruits and vegetables Good sources of antioxidants People who do have a lower risk of heart disease and some neurological diseases Some evidence that particular types of vegetables, and fruits in general, probably protect against a number of cancers These observations suggest that antioxidants might help prevent these conditions

Antioxidant supplements
However, a large analysis of 68 reliable antioxidant supplementation experiments involving a total of 232,606 individuals concluded that consuming additional beta-carotene from supplements is unlikely to be beneficial, may even be harmful Health food companies now sell formulations of antioxidants as dietary supplements and these are widely used These supplements may include specific antioxidant chemicals, Resveratrol (from grape seeds) "ACES" products that contain beta carotene (provitamin A), vitamin C, vitamin E and Selenium,

Take home message Although some levels of antioxidant vitamins and minerals in the diet are required for good health, there is considerable doubt as to whether antioxidant supplementation is beneficial, and if so, which antioxidant(s) are beneficial and in what amounts?

Global Warming

7.13 CONNECTION: Photosynthesis moderates global warming
The greenhouse effect results from solar energy warming our planet Gases in the atmosphere (often called greenhouse gases), including CO2, reflect heat back to Earth, keeping the planet warm and supporting life However, as we increase the level of greenhouse gases, Earth’s temperature rises above normal, initiating problems Copyright © 2009 Pearson Education, Inc.

Some heat energy escapes into space Sunlight Atmosphere Radiant heat
trapped by CO2 and other gases Global temperatures have flatlined since 2001 despite rising greenhouse gas concentrations, and a heat surplus that should have cranked up the planetary thermostat.

Carbon Dioxide Levels in the Atmosphere
Carbon Dioxide Levels in the Atmosphere Keeling, C.D. and T.P. Whorf Atmospheric CO2 records from sites in the SIO air sampling network. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A. This graph shows the levels of CO2 in the atmosphere measured at Hawaii’s Mauna Loa Observatory over the last 40+ years—the longest measurement of its kind..

Interpreting Data Here’s a magnified view of 5 years of data on CO2 levels. What do you think is the most likely cause for the cycles you see in this data? The differing amounts of CO2 produced by plant during daylight and night hours. Volcanic emissions Seasonal differences in CO2 uptake by photosynthesizers. Answer: 3

Answer Here’s a magnified view of 5 years of data on CO2 levels. What do you think is the most likely cause for the cycles you see in this data? Seasonal differences in CO2 uptake by photosynthesizers.

Interpreting Data The data indicates that carbon dioxide levels are rising. Answer: 2

Strongly A B C D E Strongly
Biology and Society This graph shows a correlation between Global surface temperature and atmospheric carbon dioxide. The temperature increase and the carbon dioxide increases are real—but direct correlation is difficult to prove. The U.S. has not signed the international Kyoto agreement that sets aggressive goals to reduce carbon dioxide emissions. Do you think we should have direct evidence before taking aggressive action? Disagree Agree Strongly A B C D E Strongly

Strongly A B C D E Strongly
Biology and Society This graph shows a correlation between Global surface temperature and atmospheric carbon dioxide. The temperature increase and the carbon dioxide increases are real—but direct correlation is difficult to prove. The U.S. has not signed the international Kyoto agreement that sets aggressive goals to reduce carbon dioxide emissions. Do you think we had better start right now to curb carbon dioxide emissions? Disagree Agree Strongly A B C D E Strongly

Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut.

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Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut.

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Presentation on theme: "Quiz 5 Which figure depicts an animal cell placed in a solution hypotonic to the cell? T/F The fluid mosaic model describes the cell membrane like a peanut."— Presentation transcript:

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