Chapter 8, Photosynthesis

True or False? Cells contain a large amount of ATP to carry out all of their life functions.

False. ATP seems like, because it only holds a relatively small amount of energy, that the cell would need many ATP molecules to power all of its life functions. However, this is not the case at all. Most cells have a very small amount of ATP, probably enough to last maybe a few seconds of activity. This is because even though ATP is great at transferring energy, it cannot store a large amount of energy for a long period of time. A single molecule of glucose, which is a sugar, stores more than 90 times the enenrgy required to add a phosphate group to ADP to turn it into ATP. Instead of storing large amounts of energy, cells can just regenerate ATP from ADP when it is needed by using energy in foods like glucose.

Which one comes first: a. Light Independent Reactions b. Light Dependent Reactions

First comes the Light-Dependent Reactions, and second comes the Light-Independent Reactions.

Name a couple ways that plants are still able to carry out photosynthesis under extreme conditions.

In order to conserve water, most plants that live in really bright, hot conditions (ones that live in places like the tropics) close the small openings in their leaves that usually take in carbon dioxide. This keeps the plants from drying out, but at the same time, CO2 in the leaves sinks to very low levels. When this happens to plants, photosynthesis can slow down or even stop. However, some plants have adapted to these conditions so that they can still use photosynthesis and carry out its processes. There are two majr groups of these specializd plants: C4 Plants and CAM plants. They both have what are known as "biochemical" adaptions that minimize water loss while still allowing photosynthesis to take place in the intense sunlight. -C4 Photosynthesis: C4 plants have a specialized chemical pathway that lets them capture even really low levels of carbon dioxide to pass through the light-independent reactions (calvin cycle). The name C4 plant comes from the fact that the first compound formed in this pathway contains 4 carbon atoms. This pathway allows photosynthesis to keep working under intense light and high temperatures, but it really requires extra energy in the form of ATP in order to work. C4 organisms include: important crop plants like corn, sugar cane, and sorghum. -CAM plants: Other plants that are super adapted to dry climates use a different method to keep their CO2 (carbon dioxide) while minimizing water loss at the same time. These include members of the family Crassulaceae. -Becasue carbon dioxide becomes incoperated into organic acids during the process of photosynthesis, the process is called Crassulacean Acid Metabolism, or CAM. CAM plants admit air into their leaves only when it is nighttime. In the darkness, when it is cooler outside, CO2 is mixed and combined with existing molecules to produce organic acids, and this produces organic acids, whoch trap carbon within the leaves. During the daytime, when leaves are super tightly sealed up to prevent losing water, the compounds that, in the nighttime, trapped carbon in the leaves, now release the carbon dioxide, which allows carbodyhrates to be produced using photosynthesis. CAM organisms include pineapple trees, many desert cacti, and ice plants, which are often planted near freeways along the west coast to make sure that brush fires don't happen as well as erosion.

True or False? Cells are not "born with a supply of ATP".

True, cells intact are NOT born with a ready supply of ATP. They must produce it. The ATP comes from the chemical compounds known as food. Organisms that obtain food by consuming other living things are called heterotrophs, whereas organsisms that can make their own food are called autotrophs. Some heterotrophs, who eat other organisms for survival, obtain food from plants by indirectly feeding upon plant-eating animals. For example, a cheetah may eat an antelope, but the antelope was a primary consumer that fed on grass. Because the cheetah ate the antelope which ate the grass, the cheetah is in fact recieving food from plants indirectly. Other heterotrophs obtain food by abrsorbing nutrents from decomposing organsisms in the environment. An example of these kinds of heterotrophs are mushrooms, which excrete gastric enzymes that allow them to externally digest their food and then absorb it into their cells. Originally, the energy in nearly all food molecules comes from the sun. Plants, algae, and a few types of bacteria are able to use light energy from the sun to produce food for themselves. These types of organsisms are called autotrophs, because they can make their own food. Nearly all life on Earth depends on autotrophs to capture the energy of sunlight and store it in the molecules that create the food we eat. *THE PROCESS BY WHICH AUTOTROPHS USE THE ENERGY OF SUNLIGHT TO PRODUCE HIGH-ENERGY CARBODYDRATES (SUGARS AND STARCHES) THAT CAN BE USED AS FOOD IS CALLED PHOTOSYNTHESIS!!!* In the process of photosynthesis, plants convert energy from the sun (sunlight) into chemical energy stored in the bonds of carbohydrates (sugars and starches).

Label the parts of the chloroplast shown.

a. Outer membrane of the chloroplast b. Granum (plural: grana)--> a granum is a stack of thylakoids, and all of the grana are interconnected throughout the chloroplast. c. Inner membrane of the chloroplast d. Thylakoid space (space within the thylakoid membrane where chlorophyll, carotene, and other pigments are held). e. Thylakoid membrane f. Stroma (space outside of the grana within the chloroplast).

What do cells generally use energy for?

-Building new molecules -Contracting muscles -Carrying out active transport Without the ability to *obtain* and *use* energy, live would not exist.

Describe light and the visible light spectrum in enough detail to understand the process of photosynthesis.

-Energy from the sun travels to Earth in the form of light. -Sunlight is seen by the eyes as what is known as "white" light, however, it is actually just a mixture of all different wavelengths (colors). -Many wavelengths are visible to our eyes. They make up the visible light spectrum. -Colors on the visible light spectrum include: red, orange, yellow, green, blue, purple, indigo, and violet.

Give four forms in which energy can come.

-Light -Heat -Electricity -Chemical compounds Energy can come in chemical compounds because bonds between atoms and molecules can be broken or reformed that allow energy to be lost or gained in a substance. For instance: When a candle is lit, the wax of the candle melts. The melting wax soaks into the candle's wick, and it burns, causing the candle to maintain its flame over a long period of time. As the wax burns, chemical bonds between hydrogen and carbon atoms in the wax and broken. Later, new bonds are formed between hydrogen, carbon, and oxygen, which will then result in CO2 and H2O (carbon dioxide and water). These new bonds are at a lower state of energy than the orgiginal chemical bonds between the carbon and hydrogen in the wax. This is because energy was lost from the light and heat of the candle's flame as it was burning.

What is so special about chlorophyll that allows photosynthesis to occur correctly?

-Light is a form of energy, so any compound that is able to absorb light is also absorbing energy when doing so. -Chlorophyll is a pigment that absorbs visible light very well (it absorbs the blue and red ends of the visible light specrum very well, but not the green, which is why plants are green- the leaves reflect the green light instead of absorbing it). -When chlorophyll absorbs the visible light a large amount of the light energy is transferred directly to electrons in the chlorophyll molecule itself. -By raising the energy levels of the electrons in the chlorophyll, the light energy can produce a steady supply of high-energy electrons. These high energy electrons are what makes photosynthesis work.

What are chloroplasts, and what do they have to do with photosynthesis?

-Plants and other photosynthetic eukaryotes use photosynthesis. It takes place inside organelles known as chloroplasts. Chloroplasts contain a lot of saclike photosynthetic membranes known as thykaloids. Thykaloids are interconnected and placed in stacks called grana (singular: granum). Pigments like chlorophyll are located inside of these thykaloid membranes. The fluid portion of the chloroplasts, outside of the thykaloids, is known as the stroma. *Remember that chloroplasts have an inner membrane and an outer membrane, and that the inside of a thylakoid is an area called the "thylakoid space".

What are pigments and how do they have to do with photosynthesis?

-Plants are able to gather energy that comes from the sun with pigments, which are light-absorbing molecules. -Photosynthetic organisms (organisms that use photosynthesis) capture energy from the sun (sunlight) using pigments. -The main pigment in plants is cloryphyll, but there are two types of cloryphyll. There is cloryphill a and b, and they both absorb light really well in the blue-violet and red regions of the visible light spectrum. However, chlorophyll doesn't absorb green light very well. -Since leaves reflect green light instead of absorbing it, plants look green. Plants also have red and organge pigments (ex: carotene) that absorb light in other regions of the visible spectrum. However, since there is so much green chlorophyll (chlorophylls a and b), the accessory pigment colors are not seen. However, later in the year, temperatures drop and the chlorophyll molecules are the first to break down. This leaves the beautiful orange, yellow, and red colors of fall to come through and show up on the leaves.

What are high-energy electron (also called electron) carriers?

-The high energy electrons- that are produced when the chlorophyll (pigment) absorbs light from the sun and the energy is transferred directly to the pigment molecules themselves- are really reactive and unstable. Thus, they need a special high-energy electron carrier to hold them. -Think of a high-energy electron as a hot potato that comes straight from the oven. Obviously, Ravi Masa the cook does not want to move the hot potato straight out of the oven with his bare hands. He needs and oven mitt to cary the hot potato. In a chemical, molecular sense, the oven mitt is the high-energy electron carrier. -A high-energy electron carrier is a compound that can accept two (a pair) of high energy electrons and transfer them, along with most of their energy, to another molecule. -You might be wondering- what compounds are high-energy electron carriers? One of the carrier molecules is a compound called NADP+ (nicotinamide adenine dinucleotide phosphate). The name might seem super complicated, but really, its job is super simple. -NADP+ is responsible for accepting and holding a pair (2) of high-energy electrons, along with a single (1) hydrogen ion (H+ ion). When NADP+ accepts and holds the high-energy electrons and the hydrogen ion, it becomes NADPH. This conversion and change from NADP+ to NADPH is one way in which some energy from the sunlight can be trapped in chemcial form. -Once the NADP+ becomes NADPH, it can carry the electrons and the hydrogen that were produced when the light was absorbed in chlorophyll to chemical reactions in other places within the cell.

Describe the light-dependent reactions in detail.

BACKGROUND AND GENERAL INFORMATION -The light dependent reactions require direct sunlight to take place in the cell. They explain why plants need a direct source of light to grow. -The light-dependent reactions use energy from sunlight to produce oxygen and convert ADP and NADP+ into the energy carriers ATP and NADPH. -Light-dependent reactions take place in the thylakoids of chloroplasts. -Remember that thylakoids are saclike membranes that contain clusters of chlorophyll and proteins called photosystems. -The photosystems are surrounded by accessory pigments, and they are super essential to the light-dependent reaction process. Photosystems absorb sunlight and then create high-energy electrons that are then passed to a series of electron carriers embedded in the thylakoid membrane. PHOTOSYSTEM II -Light-dependent reacitons begin when pigments in photosystem II absorb sunlight. Photosystem II was discovered after photosystem I, even though it comes first. This is why it is labeled II and not I. Remember that photosystems I and II are located in the thylakoid membrane. -When light energy is absorbed by the pigments found in photosystem II, electrons in the pigment molecules gain a substantial amount of energy, making them high-energy electrons. These high-energy electrons are then passed to the electron transport chain. -An electron transport chain is a series of electron carrier proteins that move high energy electrons during reactions that produce ATP. -As more and more light continues to shine, more and more high-energy electrons are being removed from the chlorophyll and being transferred to electron transport chains. This DOES NOT mean that chlorophyll will eventually run out of electrons. Instead, the thylakoid membrane contains a system that provides new electrons to the chlorophyll to replace the ones lost. -These new electrons come from water molecules (H2O). -Enzymes on the inner surface of the thylakoid break up each water molecule into 2 electrons, 2 H+ ions (hydrogen ions), and 1 oxygen atom. - The 2 electrons are meant to replace the high-energy electrons that were lost to the electron transport chain. -As the plants keep removing electrons from the water molecules, oxygen is left behind and is released into the air. This is how humans and millions of other life forms get most of their air from the atmosphere. In turn, we breath out carbon dioxide as a result of cellular respiration, and this supplies one of the reactants for the light-independent reactions of photosynthesis. Thus, we rely on plants, and plants rely on us for reactants of our necessary chemical reactions. -The hydrogen ions that are left behind when water is broken apart are released inside the thylakoid. (in the thylakoid space). ELECTRON TRANSPORT CHAIN -What happens to electrons as they move down the electron transport chain? -Energy from the electrons is used by the proteins in the chain to help pump hydrogen (H+) ions from the stroma into the thylakoid space. These hydrogen ions are pumped into the thylakoid space, and at the end of the electron transport chain, the electrons themselves pass into a second photosystem called photosystem I. PHOTOSYSTEM I -Because some energy has been used to pump H+ ions across the thylakoid membrane into the thylakoid space, electrons don't contain as much energy as they used to when they reach photosystem I. Pigments in photosystem I use light energy to reenergize the "tired" electrons. Then, there is anther short electron transport chain. After this, at the end, NADP+ molecules in the stroma (outside of the thylakoid membrane) pick up two high energy electrons each and one hydgrogen (H+) ion each, at the outer surface of the thylakoid membrane, and they become NADPH because of this. Then, the NADPH becomes super important during the light-independent reactions of photosynthesis. WHAT HAPPENS TO THE HYDROGENS THAT WERE PUMPED INTO THE THYLAKOID SPACE DURING THE FIRST ELECTRON TRANSPORT CHAIN AFTER PHOTOSYSTEM II? WHAT ABOUT THE HYDROGEN IONS THAT WERE LEFT BEHIND IN THE THYLAKOID SPACE AFTER THE SPLITTING OF WATER TO REPLACE ELECTRONS LOST TO THE FIRST ELECTRON TRANSPORT CHAIN? -In photosystem II, hydrogen ions started getting accumulated in the thylakoid space by two ways. 1. Some were left behind from the splitting of water to make up for lost electrons to the electron transport chain. 2. Other hydrogen ions were "pumped" in from the stroma during the first electron transport chain. -The buildup of hydrgoen ions inside the thylakoid space makes the stroma (outside the thylakoids) *negatively* charged in relation to the space within the thylakoids. You can remember the charges of the stroma in relation to the thylakoid space by thinking of hydrogens. You know that there is an accumulation of hydrogens wihtin the thylakoid space, and Hydrogens are represented by H+. The H+ shows (with the addition) sign that they are positively charged. Thus, wouldn't having an accumulation of them inside the thylakoid space make the thylakoid space positively charged overall in relation to the stroma? That makes logical sense. -So because the stroma is negatively charged in relation to the thylakoid space, the *gradient* in charge (difference in the charge across the membrane and the concentration of H+ ions across the membranes) provides the energy to create ATP from ADP. -H+ (Hydrogen ions) cannot pass across the thylakoid membrane directly. The thylakoid membrane instead carries an enzyme (protein) called ATP synthase that spans the expanse of the membrane and allows the hydrogen ions to pass through it. -Powered by the gradient between the stroma and the inside of the thylakoid, the H+ (hydrogen) ions are able to pass through the ATP synthase and force it to rotate, almost like a water turbine being spun. As the ATP synthase rotates, it binds ADP (floating around) to another phpsphate group (remember that ADP only has two phosphate groups, but when a third one is added, it is able to store more energy and become ATP). Now that a third phosphate group is added to ADP, it becomes ATP. This proces of adding another phosphate group to ADP to create ATP is called chemiosis. It enables light-dependent electrons transport to produce not only NADH, but ATP as well.

What are some factors that affect photosynthesis?

-There are multiple factors that influence the rate of photosynthes. These include: *light intensity, temperature, and availability of water*. -The reactions of photosynthesis are able to happen because enzymes help carry out the reactions. The enzymes need to live in environments with temperatures between ) degrees celcius and 35 degrees celcius. Any temperatures above or below the necessary temps may denature the enzymes, which could either stop them from working at all or slow down their rate. Usually at very low temps, photosynthesis will stop entirely. This is why you are not going to see palm trees in Antartica. It just doesn't allow photosynthesis to occur with all of the cold temperatures in that area. -Intensity pf light also affects the rate pf photosynthesis in a plant. High light intensity increases the rate of photosynthesis, since the pigments will be able to energize their electrons much faster with more light to absorb from the sun. After the light intensity reaches a certain level, though, the plant reaches its max. rate of photosy. -Water is also extremely important for photosynthesis. Shortage of water could slow or completely halt photosynthetic processes in the plant. Water loss can also damage plant tossues. To deal with these dangers, plants such as desert plants and conifers (plants that produce cones, like pine trees that produce pine cones) that live in dry conditions will usually have leaves with a waxy coating known as cutin. This reduces water loss. they also have biochemical adaptations that make photosynthesis more efficient under certain conditions, like a dry, arid environment. These next types of plants will be explained below.

How do cells utilize the biochemical energy that comes from ATP?

1. Cells use ATP to carry out active transport. Cell membranes usually contain sodium-potassium pumps, which are proteins in the membrane of the cell that pump sodium ions (Na+) out of the cell and pump potassium ions (K+) into the cell. ATP is what provides the enery to keep the pump working, maintaining the balance of ions on either side of the membrane. 2. ATP powers movement of both the individual cells and the parts of the body/tissue that are made up of cells. It provides the energy for motor proteins (think of motor neurons) that allows muscles to contract and powers the movement of cilia and flagella on cells. 3. ATP powers the synthesis of proteins within the cells (protein production) 4. ATP powers the response to chemical signals at the surface of the cell (recognized by carbohydrate cell receptors). 5. The energy from ATP can be used to produce light as well. In the night sky, whenever you see the blink of a light on the end of a firefly, the light is created by an enzyme that is powered by adenosine triphosphate.

What is ADP, and how can the difference between ATP and ADP be compared to the brightness of light emitted by a flashlight?

ADP is short for Adenosine Diphosphate, and it looks almost identical to ATP, except instead of having three phosphate groups on the right side of the ribose molecule, it only has two. This difference is essential to the method in which cells are able to store energy. When a cell has extra energy available, it wants to store it for later use. To do this, it adds on another phosphate group to ADP molecules, producing ATP and storing a little bit more energy than ADP would. This does NOT mean that ADP does not have any energy at all. It has some, but ATP has more. The difference between ATP and ADP can be compared to the light of a flashlight. ADP is like a rechargable battery almost, because it is not fully charged until another phosphate group is added to it to change it to ATP. When a phosphate group is added to an ADP molecule, ATP is created, ADP contains some energy, but not as much as ATP. Because of this, ADP is almost like a partially charged battery in a flashlight that only emits a small glow of light. However, when the battery is recharged, this can be compared to ATP, which produces a strong ray of light. The recharging of the battery is similar to the cell's adding of a phosphate group to the ADP molecule to make ATP.

Define ATP, its structure, and its basic, general function.

ATP is one of the most important compounds that cells use to store and release energy. ATP stands for adenosine trophosphate, and it is made up of three major sections. In the middle is a 5-carbon sugar called ribose. You can remember which part is the ribose because it forms a 5-sided "ring" in the center of the compound. On the right are three phosphate groups all lined up horizontally, and on the left is adenine. The 3 phosphate groups are often alled the most important section of the ATP compound, because they are very important to the method used by ATP to store and release energy. ATP is the basic energy source used by every type of cell, whether it be a plant OR animal cell.

What is the simple definition of energy?

Energy is the ability to do work. Almost every activity in modern society requires energy and depends upon it. Ex: When a car runs out of fuel (the chemical energy located in gasoline), it will stop running because its engine will not be able to function. Ex: When lights do not have access to electrical energy, they cannot turn on.

Describe the light-independent reactions of photosynthesis in detail.

OVERVIEW OF THE CALVIN CYCLE/BACKGROUND INFORMATION -The ATP and NADPH produced by the light-dependent reactions of photosynthesis contain a huge amount of chemical energy, but tgey simply are not stable enough to hold that energy for more than a few minutes. During the light-independent reactions, also called the Calvin Cycle, plants use the energy stored in ATP and NADPH to build high energy carbohydrate compounds that can be stored for a much longer period of time. -During the light-independent reactons, the basic overview is that ATP and NADPH from the light-dependent reactions are used to produce high-energy sugars. -The Calvin Cycle is named after the American scientist Melvin Calvubm who came up with all the details of this complicated and interesting cycle. Each set of reactions will be explained below, but remember that Mrs. Peloquin, in the past, has only had the class remember what goes in and what comes out of the Calvin Cycle. CARBON DIOXIDE ENTERS THE CYCLE -First, carbon dioxide must enter the Calvin cycle. The light-independent reactions are what make carbon dioxide one of the reactants of photosynthesis, along with the reactant of water used in the light-dependent reactions in photosynthesis. Carbon dioxide molecules will enter the Calvin Cycle (light independent reactions) from the atmosphere. The CO2 is breathed out by all of the animal life on earth, enabling a symbiotic relationship between life on earth (animals) and plant life on earth (autotrophs). -Once the CO2 has entered the chloroplast of the cell, an enzyme in the stroma of the chloroplast combines the molecules of carbon dioxide with 5-carbon compounds that are already present within the organelle. -The combination of the 5-carbon compounds with the molecules of carbon dioxide creates 3-carbon compounds that will continue on in the cycle. For every 6 carbon dioxide molecules that enter the cycle, a complete total of 12 3-carbon compounds are produced when the 6 CO2 molecules combine with 5-carbon compounds already present within the chloroplast. -Other enzymes within the chloroplast then convert these 3-carbon compounds into higher energy forms in the rest of the cycle. The energy for all of these conversions and combinations comes from the ATP and high-energy electrons from NADPH- both of these ingredients coming as the products of the light-dependent reactions of photosynthesis. SUGAR PRODUCTION IN THE CALVIN CYCLE -When the Calvin Cycle reaches mid-cycle, two of the twelve 3-carbon compounds that were produced are removed from the cycle. This is a super important step because these two 3-carbon compounds are goint to become the building blocks that the plant uses to produce sugars, lipids, amino acids, and other important compounds. -The remaining 10 3-carbon compounds are then converted back into six 5-carbon compound molecules. These molecules combine with six-new carbon dioxide molecules to begin the next cycle. In an essence, the 5-carbon compound molecules that combined with the 6 carbon dioxide molecules at the beginning of the cycle originally came from the end of the last Calvin Cycle (this is why it is called a "cycle"). -Now that all of the Calvin Cycle has happened, here is a quick overview of what came in and what came out: ~6 molecules of carbon dioxide from the atmosphere were used to produce a single 6-carbon sugar molecule (this came from two of the twelve three-carbon compound molecules removed from the Calvin Cycle in the middle if the process). The energy for these reactions that made all of this possible is supplied by compounds that were produced in the light-dependent reactions, like ATP and NADPH. -The plant will use the sugars produced by the Calvin Cycle to meet all of its energy needs and build macromolecules needed for growth and development, like lipids, proteins, and complex carbs such as cellulose (cellulose makes up most plant material). When other organisms eat plants, they can use the energy stored in the compounds created by photosynthesis. This is why producers are at the bottom of the food pyramid/chain. Because they make their own energy, organisms that rely on other organisms for energy can use autotrophs (plants, mostly) for energy. Autotrophs that use photosynthesis form the base of all energy for other organisms, so photosynthesis is one of the most important bioloical processes on Earth.

Describe the Light-Independent Reactions generally.

Plants absorb carbon dioxide from the atmosphere and complete photosynthesis by producing carbon-containing sugars and other carbohydrates. During the light-independent reactions, ATP and NADPH molecules produced by the light-dependent reactions are used to produce high-energy sugars from CO2 (Carbon Dioxide). -No light is needed to power the light-independent reactions, as you can tell from the name. The light-independent reactions do not take place in the thylakoids like the light-dependent reactions; instead, they take place in the stroma, which is the area outside of the thylakoid membranes.

How does the cell release energy from ATP? What makes adding and releasing energy so great for the cell?

The cell can release stored energy in ATP by breaking the chemical bonds between the second and third phosphate groups. A cell is able to add and subtract the phosphate groups as needed, which is a great way of storing and releasing the energy when needed. The storing and releasing of energy is so great for cells because the ability to change ATP into ADP is unique and useful. It makes ATP exceptionally useful as a basic energy source for all cells.

The first process in the light dependent reactions of photosynthesis is: a. light absorption b. electron transport c. oxygen production d. ATP formation

The correct answer is A, light absorption. This is where the plants get the energy they need to start converting water and CO2 into complex sugars.

Which of the following is used by cells to store and release the energy needed to power cellular processes? a. DNA b. ATP c. H2O d. CO2

The correct answer is B, ATP. ATP is responsible for enabling plants to store and release the energy needed to power the reactions that make up photosynthesis. When a phosphate group is added to ADP, ATP is created, which stores more energy. When a phosphate group is taken away from ATP to make ADP once again, energy is released. This release and store of energy are what allow photosynthesis to take place.

Which substance from the light-dependent reactions of photosynthesis is a source of energy for the Calvin Cycle? a. ADP b. NADPH c. H2O d. Pyruvic Acid

The correct answer is B, NADPH. This is created in the light-dependent reactions at the end of the second electron transport chain when high energy electrons are accepted by NADP+ molecules outside of the thylakoid membrane. Thus, it is needed as a reactant for the light-independent reactions of photosythesis.

Which of the following are autotrophs? a. deer b. plants c. leopards d. mushrooms

The correct answer is B, plants. Plants are autotrophs, meaning they make their own food. Think of an "auto"mated register, in which a person buying grocery items scans and pays for the items him/herself instead of having the cash register people do it for you. Just like you would scan the items and buy the food yourslef, plants carry out photosynthesis to create glucose molecules and other complex sugars themselves as well.

CAM plants are specialized to survive under what conditions that would harm most other types of plants? a. Low temperatures b. Excess water c. Hot, dry conditions d. Long day lengths

The correct answer is C, hot dry conditions.

ATP synthase in the thylakoid membrane makes ATP, utilizing the energy of highly concentrated: a. Chlorophyll d. electrons c. hydrogen ions d. NADPH

The correct answer is C, hydrogen ions, which are accumulated in the thylakoid through both the splitting of water molecules inside the thylakoid to make up for missing electrons in the electron transport chain, and the pumping of hydrogen ions into the thylakoid membrane during the first electron transport chain.The gradient between the thylakoid space and the stroma, stroma being negatively charged, is what gives the energy fro the H+ ions to go through the ATP synthase.

When a candle burns, energy is released in the form of: a. Carbon dioxide and water b. The chemical substance ATP c. Light and heat d. Electricity and motion

The correct answer is C, light and heat. When a candle is burned, the wax soaks into the wick and is burned away. This causes the bonds between the wax molecules to break and reform themselves, thus losing energy in the form of light and heat.

The leaves of a plant appear green because chlorophyll: a. Reflects blue light b. Absorbs blue light c. Reflects green light d. absorbs green light

The correct answer is C, reflects green light. Chlorophyll is a pigment inside the thylakoid membranes of a chloroplast that absorbs light energy very well in the blue and red ends of the visible light spectrum, but not the middle of the spectrum like the greens and light yellows. Thus, since it reflects these colors. These are the wavelengths that hit our eyes and allow our eyes to see the color green for leaves.

In addition to light and chlorophyll, photosynthesis requires: a. Water and oxygen b. Water and sugars c. Oxygen and carbon dioxide d. Water and carbon dioxide

The correct answer is D, water and carbon dioxide. Those are the two reactants of photosynthesis, not counting light energy from the sun.

Describe the Light Dependent Reactions generally.

The light dependent reactions are the first set of reactions that occurs during the process of photosynthesis. The light-dependent reactions require the direct involvement of light and light-absorbing pigments such as chlorophyll and carotene. -The light dependent reactions use energy from sunlight to produce energy rich compounds such as ATP. The light dependent reactions happen in the thylakoids- specifically, in the thylakoid membranes- of the chloroplast. Remember the reactants of photosynthesis, which are water and carbon dioxide? Well, the light-dependent reactions require water to work. Water is required in these reactions as a source of electrons and hydrogen ions. Oxygen is released from these reactions as a *byproduct*. -The light dependent reactions explain why plants need light to grow.

The light-independent reactions of photosynthesis are also known as the: a. Calvin cycle b. Sugar cycle c. Carbon cycle d. ATP cycle

The light independent reactions of photosynthesis are also known as the Calvin Cycle, which is why answer A, Calvin Cycle, is correct.

Give an overview of photosynthesis + include chemical formulas.

There are multiple steps in the process of photosynthesis, but the general sequence and process is the following sentence: Photosynthesis uses the energy of sunlight to convert water and carbon dioxide (reactancts) into high-energy sugars and oxygen (products). Plants can then use the sugars to make complex carbohydrates like starches, and to provide energy for the synthesis (creation) of other compounds like proteins and lipids. -Photosynthesis usually produces 6-carbon sugars (C6-H12-O6) as the final product. Below is a chemical formula depicting the overview of photosynthesis. 6 CO2+6 H2O--> C6-H12-O6+ 6 O2 AKA: 6 carbon dioxide molecules+ 6 water molecules ---------> (light) 6 sugar molecules + 6 oxygen molecules.