to finish a two page question regarding biology, kinda ez

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just finish this homework watching a video it's an experiment clip included in the homework page1

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Station B: Observing Photosynthesis: Be sure to watch the video for Station B: https://www.youtube.com/watch?v=7Ye8WA79q0w Use the data collected in the video to answer these questions. Name Lab Section Note: There are two pages to this assignment. 1. As photosynthesis is occurring why does the pH in the vial change? 2. Compare the pH values for vials with plant placed at 5 cm, 10 cm and 30 cm from the light (these are the “light vials”). Which vial had the lowest concentration of CO2 at the last time check? Vial: 3. Why did the amount of CO2 vary in the 5cm vial as compared to the 10 cm vial and the 30 cm vial? 4. The following questions ask you to compare the pH changes in the “no plant” vial to the changes in the light vial at 5 cm at the 40 minute time check (the last time check). a. What was the pH of the “no plant” vial? b. What was the pH of the “light vial” at 5 cm? c. Why was there a difference in pH when comparing these two vials? 5. What was the purpose of the “no plant” vial for this experiment? [Hint: this vial also acted as a “control”, but a control for what.] 8. The following questions ask you to compare the pH changes in the 5 cm vial to the changes in the dark vial (aluminum foil vial). a. What is the pH of the “dark” vial at 5 cm? b. Is there a difference in pH between these two vials? Why or why not c. What was the purpose of the “dark” vial for this experiment? [Hint: this vial acted as a “control”, but a control for what?] 9. Plants produce oxygen as a by-product of photosynthesis, but most plants cannot live in anoxic soils. Anoxic soils form when soils gets compacted and you lose the space between the soil particles. Why can't most plants live in such anoxic conditions? (hint: look at the structure of the cell from the pre-lab) 10. A plant body, such as a redwood tree, is a very large mass of carbon compounds—what is the primary source of the carbon you find in the wood (or even the desk you might be sitting at if it is made of wood)? 11. CO2, although very important for plant growth, is considered one of the major greenhouse gasses. Studies have shown an increase in CO2 can increase plant growth, but that increase in growth is temporary (See Lecture 7, Discussion 2). Why is an increase in plant growth with increasing levels of CO2 only temporary? Another way to think about it: Why can’t plants alone solve our increasing CO2 problem? They use it, don’t they? This content is protected and may not be shared, uploaded, or distributed. Lab 2: Resource Acquisition Goals and Objectives At the end of this laboratory you should be able to: 1. Describe the basic metabolic requirements of eukaryotic organisms. 2. Explain how eukaryotic autotrophs, in particular plants, acquire resources (including oxygen, carbon, nutrients, and water) from the living and nonliving world. 3. Explain how eukaryotic heterotrophs acquire resources (including oxygen, carbon, nutrients, and water) from the living and nonliving world. 4. Describe particular structures used for resource acquisition in plants (including roots, shoots, vascular systems, and leaves) and animals (including teeth, jaws, guts, and vascular systems). 5. Describe the structures associated with resource allocation and storage in plants. 6. Compare and contrast the body plans of single-celled and multicellular autotrophs and heterotrophs in terms of their abilities to acquire resources. 7. Explain the role of autotrophs and heterotrophs within a community. 8. Calculate a surface-area-to-volume ratio and explain what this ratio means. 9. Homework: Station B. Posted under Assignments on Canvas. Watch video for Station B. Note: In Lab 2 normally you would move from station to station and look at the organisms and the information provided in the lab room. Since we can’t do that, we have a video for each station for you to view. Watch the videos for an overview of each station (we tried to keep those brief) and pay attention to the goals of each station that are outlined in this document. We will provide the station notes in a separate pdf. This is a longer lab with a lot of information being presented to you and so you might want to do this in chunks rather than trying to work through this in one sitting. The homework you will turn in will be based on Station B. This will be available on Canvas under Assignments and turned in through the Assignments. We will have a video of Station B showing you what you would have done, and in the video data will be presented that you will use to answer the homework questions. Now on with the lab. In this lab you will explore how organisms collect (acquire) the resources they need to survive, grow, and eventually reproduce. Organisms can alter their size, shape, growth plan, and behavior to acquire new resources. When resources are in short supply, organisms must compete for them. Last week the class collected data on diversity, but today you will collect and use ideas from lab stations posted online. There are two sets of stations—one set on autotrophs (stations A to F) and another set on heterotrophs (stations G to L). Lab 2 Stations A-F: https://www.youtube.com/watch?v=FZ5SVHbNcyk Lab 2 Stations G - L: https://www.youtube.com/watch?v=upfhR17KF2A Lab 2 Station B (Lab Homework) https://www.youtube.com/watch?v=7Ye8WA79q0w This content is protected and may not be shared, uploaded, or distributed. Station A. How Do Photoautotrophs Acquire Energy? Things to Discover What does a photosynthetic pigment do? What photosynthetic pigments exist, other than chlorophyll? Why should one organism have a range of pigments? What kinds of photosynthetic pigments would you expect to see in a coastal alga living at 30 meters? Would you expect to see greater amounts of each photosynthetic pigment in a tropical understory plant living in shaded conditions or in a tropical plant living in bright light? Background Some organisms, called photoautotrophs, convert the energy in sunlight to chemical energy via photosynthesis. That energy is used, along with other elements, to build bodies. Light energy varies in wavelength. Wavelength is measured in nanometers (nm) from peak to peak of a wave, as shown in Figure 2-10. Wavelength determines the color of the light you see. Visible light is made up of several colors or wavelengths. The chart above shows which wavelengths produce each color. What color would you see at a wavelength of 600 nm? Because light occurs at many wavelengths, autotrophs possess pigments that absorb different wavelengths. We refer to these as light-harvesting pigments; the most common one is chlorophyll, which is found in three forms: a, b, and c. Chlorophyll a absorbs light at wavelengths of 430 nm and 670 nm (violet and red light). Because chlorophyll a is absorbing light from both ends of the visible spectrum, the light it reflects appears green. This is why most plants look green to us. There are other pigments, such as carotenes, anthocyanins, phycocyanins, fucoxanthins, and phycoerythrins that specialize on different light wavelengths. Visible light is made up of several colors or wavelengths. The chart above shows which wavelengths produce each color. What color would you see at a wavelength of 600 nm? Because light occurs at many wavelengths, autotrophs possess pigments that absorb different wavelengths. We This content is protected and may not be shared, uploaded, or distributed. refer to these as light-harvesting pigments; the most common one is chlorophyll, which is found in three forms: a, b, and c. Chlorophyll a absorbs light at wavelengths of 430 nm and 670 nm (violet and red light). Because chlorophyll a is absorbing light from both ends of the visible spectrum, the light it reflects appears green. This is why most plants look green to us. There are other pigments, such as carotenes, anthocyanins, phycocyanins, fucoxanthins, and phycoerythrins that specialize on different light wavelengths. A technique called Thin Layer Chromatography (TLC) can be used to separate pigments. We have an image of a TLC plate with separated pigments from a flowering plant and from three major groups of algae. On the TLC plate you will see separate vertical lanes for four kinds of autotrophs: A=Anthophyta-flowering plants C=Chlorophyta-green algae P=Phaeophyta-brown algae R=Rhodophyta-red algae The plate is coated with an adsorbent material. A concentrated pigment extract from each plant is placed at the base of the plate, and the plate is set in a solvent bath. Pigments differ in solubility and in the degree to which they are adsorbed by the coating on the plate. As the TLC plate adsorbs the solvent, pigments are carried up the plate to different points; a band of color marks the place each pigment stops. Notice that the bands differ in color; each color represents a different pigment. Two bands with the same color at the same place on the TLC plate represent the same pigment (see red ovals on TLC plate). Notice that not all bands are present in each organism. Why should different organisms have different pigments? Not all habitats receive the same amount or type of sunlight—imagine the light environments at 30 meters below the surface of the ocean or under the shade of a large canopy-forming tree. Autotrophs must be able to use the wavelengths available in their environment. In the ocean, water filters out certain components of the visible light spectrum; you can see which parts of the spectrum penetrate the ocean in a diagram posted at the station. What did you notice? At the Station Is there enough energy in light to power the solar devices? Shine the light on the photocell to find out. Visible light is made up of several colors or wavelengths that can be absorbed by different pigments. Examine the image of the TLC plate with pigments from a flowering plant and from three major groups of algae. This content is protected and may not be shared, uploaded, or distributed. Station B. Observing Photosynthesis Things to Discover How would you know if photosynthesis was occurring? From what you know about the chemistry of photosynthesis, which dissolved gas(es) are used in photosynthesis and which are produced? How does the amount of light affect photosynthesis? Video for Station B: https://www.youtube.com/watch?v=7Ye8WA79q0w Background At this station we will demonstrate, in a video, that photosynthesis occurs in a freshwater aquatic plant. Freshwater contains dissolved oxygen and carbon dioxide from the surrounding atmosphere. From lecture and the pre-lab, recall the main events that occur during photosynthesis, and ask yourself where the carbon that is made into carbohydrates comes from? What products are released when energy is captured and carbon is fixed? To visualize changing concentrations of gases in the solution around the aquatic plants, we have added an indicator solution. Our indicator changes color depending on the pH of the solution. As dissolved gases are added to, or removed from, the solution surrounding the plant, the pH of the solution will change, and the color of the solution will change accordingly. A pH of 1 results from a strong acid, whereas a pH of 14 results from a strong base. A pH of 7 is neutral. The particular indicator shown in the video is sensitive to changes in pH between 7.6 and 9.2. Nearest the neutral pH (7), the indicator is yellow, but it changes to blue as it approaches a pH of 9.2 (when the solution is more basic). Using a color chart, you can easily determine the pH of the solution. The addition of CO2 to an aqueous solution lowers pH (solution becomes more acidic), whereas removal of CO2 from an aqueous solution raises pH (solution becomes more basic). For those with an interest in chemistry, the states are: – CO + H O ⇔ H CO ⇔ H + HCO + 2 2 2 3 3 When plants photosynthesize, what happens to the amount of carbon in the solution? Does it increase or decrease? In the experiment watch the video where we will place a segment of the living aquatic plant into 3 vials of indicator solution at different distances (5, 10, and 30 cm) from a light source. We will also place a vial with a plant segment covered in foil and a vial containing only indicator solution at 5 cm from a light source. (What is the function of the last two vials?) How and why do you expect pH to change as the vials are exposed to light? This content is protected and may not be shared, uploaded, or distributed. At the Station 1. We will have five vials: 5 cm, 10 cm, 30 cm, dark vial, and no plant vial. 2. We added pH indicator solution to each vial 3. Initial pH is given at the station (7.6). This is our starting point. 4. We will position the vials at the required distance from the light source: 5, 10, and 30 cm. Completely cover the “dark” vial using the aluminum foil provided. We will place both the “dark” vial and the “no plant” vial at 5 cm from the light source. 5. We set the timer for 20 minutes, initially, then check pH. We will then do another check at 40 minutes. All data will be presented in the video. Use those data for the homework. Results After 20 minutes we will: Match the vial solution color to the color guide. Record the pH at home. We will set the timer for another 20 minutes and see what happened. After 40 minutes: We will do the same pH check. Record the data at home. Vial Type Initial pH Light at 5 cm 7.6 Light at 10 cm 7.6 Light at 30 cm 7.6 Dark 7.6 No Plant 7.6 pH at 20 minutes pH at 40 minutes The homework is posted under Assignments on Canvas This content is protected and may not be shared, uploaded, or distributed. Station C. Multicellularity in Autotrophs Things to Discover What are the different ways to be multicellular? What advantages are associated with a multicellular body as compared to a unicellular form? What are the basic plant parts—what is the function of each? Background The first autotrophs were unicellular cyanobacteria. Descendants of these single-celled forms persist today, along with many multicellular autotrophs. What advantages exist for organisms with larger, more complex body plans? One obvious advantage to multicellularity is that parts of the body can be specialized for functions such as photosynthesis or nutrient absorption One simple way to increase body size is have a colonial body plan. Cells divide by mitosis to produce new cells, but all the cells remain attached to each other. In this case there is little or no differentiation among cells, and the individual cells can survive on their own if the colony breaks up. Examine Volvox and decide whether it is a simple colony or one with specialized cells. Another simple way to become larger is to form a filamentous body. This involves repeated divisions along the same plane. You will learn in Station K why neither the colonial nor filamentous plans result in complex organisms. Complex organisms can have a variety of body shapes and specialized parts, and they are formed by true three-dimensionsal growth in which cells can divide in any plane. One important adaptation, especially in plants, is growth in the z-axis—or from the perspective of the plant, towards the sun. The photosynthetic protists (sometimes called algae) illustrate many directions in the evolution of a complex body plan. Classify the algal specimens as colonial, filamentous, or capable of true threedimensional growth. © Chu 2008. Used with permission How Do You Get a Multicellular Body? This content is protected and may not be shared, uploaded, or distributed. Identify these structures on a live plant if you have one © Hamamoto 2008. Used with permission Basic Plant Structure Plants have two basic cell types: those capable of perpetual division (growth) and those that eventually stop growing. The cells that stop growing are derived from the perpetually dividing cells. Once these cells stop growing, they differentiate and become specialized for particular functions (for example, photosynthesis in leaves; absorption in roots). In contrast, the dividing cells remain undifferentiated or totipotent, meaning that their fates have not yet been decided. Groups of these plant cells, called meristems, are functionally equivalent to animal stem cells. They are not evenly distributed throughout plant tissues but instead occur in particular regions, for example, at the growing tip of a plant shoot and at each node in a stem. We will explain these terms and tell you more about meristems shortly, but first you will need to know about the plant body, which is mainly composed of specialized differentiated cells. A multicellular body has the potential for sets of cells to work together on particular functions. Groups of different cells might support the body while other such groups collect nutrients or light. A group of cells specialized for a particular function forms a tissue (for example, animals and plants have epidermal or skin tissues), and an organ is a collection of tissues that work together (a kidney is an animal organ). There are three types of vegetative organs in flowering plants: leaves, stems, and roots. Flowering plants are incredibly diverse. They range in size from the tiny duckweed to tall trees such as maples, and occupy habitats ranging from hot, dry deserts to arctic tundra or oceans and lakes. It is amazing to think that all flowering plants, collectively called angiosperms, are variations of one basic morphology and organ structure. The three basic parts of the plant are divided into two broad categories: shoots include the leaves and stem, and roots are the underground portion. This content is protected and may not be shared, uploaded, or distributed. We recognize certain features typical of each vegetative (nonreproductive) organ: Leaves are typically flat and broad; they are specialized for photosynthesis with a waxy cuticle that protects the inner photosynthetic cells from drying out. Small internal pockets create space for gas exchange and are visible in the leaf cross section in the figure below. Stems are typically long and narrow; they are specialized to transport water and nutrients between the leaves and roots. Stems also display the leaves in positions that maximize light exposure. Stems have nodes, where leaves are attached and lateral shoots may emerge, and regions between nodes, called internodes. A small population of meristematic cells remains at each node as the stem elongates during growth (see below). As the plant grows, hormones can trigger different populations of meristem to become active and differentiate into new stems and leaves. Nodes and internodes are visible in the figure © Hamamoto and Lim 2008. Used with permission Roots are typically long and branched; they are specialized to take up water and nutrients and to transport those materials to the rest of the plant using the central vascular tissue (blood vessels are an animal vascular tissue). A fundamental difference between roots and stems is that roots do not show the node and internode structure. Root tips contain meristematic regions similar to the stem tips, but, of course, roots typically grow downward. As the growing root tip advances, it leaves populations of suppressed meristem cells within the central vascular tissue. If these meristematic cell populations begin to grow outward from the side, they form lateral roots which increase root surface area. Root surface area can be increased to a lesser extent by root hairs; a root hair forms when a single epidermal cell extends outward in a tube. This content is protected and may not be shared, uploaded, or distributed. Vascular Tissue: Plants need some way to move water and nutrients through their bodies. In particular, the products of photosynthesis, which are generated in the leaves, need to be accessible to the rest of the plant. Likewise, water picked up by the roots needs a way to move u ...
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