BIO lab practical – Flashcards
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Electron transport in chloroplast What is the purpose of DPIP in this experiment?
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The purpose of the DPIP was to act as an electron acceptor
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What molecules supply the electrons to the electron transport chain?
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Water molecules
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Which test tubes were the controls for this experiment? What did they control for?
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Test Tube 1: control for DPIP; only contained the solution and distilled water. Test tube 2: was wrapped in foil so it controlled the regulation of light entering the tube.
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What happened when DCMU and ammonia were added?
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ATP synthesis was inhibited by DCMU and ammonia acted as an uncoupler of electron transport.
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DPIP result
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blue in oxidized form colorless in reduced form
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Rate of photosynthesis Why are plant leaves most often green?
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chlorophyll
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Where do light reactions occur in the plant?
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thykaloid
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Where does the oxygen come from during photosynthesis
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Oxygen used in photosynthesis comes from the atmosphere.
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Do plants have mitochondria?
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Yes
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Uptake of carbon dioxide Why does the solution change to a yellow color after you blow on it?
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It reacts with water to become carbonic acid
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After the lamp is turned on, what did the solution changed to? Why?
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Pink, the plant is using up the carbon and the light starts the reaction.
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Temperature effect on yeast CO2 production: Why did the water level in the CO2 collection tube move downward?
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As carbon dioxide is produced the water level in the collection tube is displaced.
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Explain which respirometer in this experiment was the negative control.
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The tubes without the sugar are the controls.
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If ethanol fermentation is used in the process of making bread, how come you don't get drunk eating bread?
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Because any alcohol that would have been produced would evaporate once you cook the bread.
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Oxygen consumption during germination: Which seed variety had the highest O2 consumption and which had the lowest?
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The germinating seeds had the highest oxygen consumption and the glass beads had the least.
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Why was it necessary to add KOH?
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Because the KOH absorbed the carbon dioxide that was released from the seeds in order to make oxygen the only gas in the reaction.
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Why did the water move in the pipet?
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The more oxygen the seeds consumed, the more water will move in the pipet.
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Fly anesthesia: How long did it take for the flies to be anesthetized?
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4 to 10 minutes
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How long did it take the flies to be reawaken?
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a few seconds
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Enzyme specificity What was the control in this experiment?
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Test tube six: contained water and no enzyme
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Why does catalase bubble?
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The oxygen in the reaction of hydrogen peroxide causes it to bubble
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Why does urease reaction change pH?
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Because urease converts urea (an acid) to ammonia (a base)
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What would happen if you increased the enzyme concentration?
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It would speed up the reaction as long as nothing else is limiting.
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What would happen if you increase the substrate concentration?
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It would speed up the reaction but it would eventually slow down once it reached its peak.
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What would happen if another substance competed for the enzyme active site?
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the reaction would slow down
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Temperature effect on amylase What was the optimum temperature for amylase activity?
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37 degrees celsius
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Was the activity of amylase consistent between the Iodine and Benedict's test?
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No, the iodine test had much more enzymatic activity.
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Why did the enzyme activity differ at 0 and 70 degrees celsius?
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Because it became denatured which resulted in its inactivity
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As temperature increases, enzymatic activity increases up to a certain point beyond which enzymatic activity decreases.
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As temperature increases, enzymatic activity increases up until a certain point. Once it goes beyond the optimum temperatur the enzymatic activity begins to decrease as it become denatured.
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pH effect on amylase How is the activity of amylase affected by low pH.
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Having either a extremely low or high pH causes the loss of activity. Structure of the enzyme is compromised.
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What was the optimum pH for amylase
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7
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Pepsin hydrolyzes proteins in the stomach. The pH in the stomach is 2, and the optimum pH for pepsin is 2. What do you think would happen to the activity of pepsin when it reaches the small intestine, where the pH is 8? Explain why.
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I believe that the activity will begin to decrease as the pH increases due to the pepsin being denatured.
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pepsin result
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measures the breakdown of pork rind
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lysozyme test
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measures cloudy to clear
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alkaline phosphatase
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positive result yields yellow color
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Benedicts reagent
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green/blue -> red/orange: positive for glucose
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biuret test
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violet color is a positive test for the presence of proteins
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DNA test
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intensity of the blue color determines the concentration of DNA
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Iodine
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blue/black: positive for starch yellow/brown: negative for starch
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What is the three dimensional shape and size of Lactobacillus?
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The lactobacillus appeared to come in various sizes of puffy, cloud looking circles.
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How did methylene blue help improve your visualization of Lactobacillus?
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The methylene blue helped provide a darker contrast in order to determine the shape and size of lactobacillus.
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What is the three dimensional shape and size of Elodea
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The three dimensional shape of elodea was similar to very tiny green polka dot type circles clustered together.
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Where are the chloroplasts located in the Elodea cell and why?
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The chloroplasts are located within the cell wall because it is intended to provide support and protection to the organelles.
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Is cytoplasmic streaming in all of the cells in the same direction?
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The cytoplasmic streaming in the cells is in different directions.
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How did the methylene blue help improve your vision of the onion cells?
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The methylene blue helped by enhancing the cells so that we could observe more details.
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Why are there no chloroplasts in the onion preparation?
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There are no chloroplasts in the onion preparation because photosynthesis takes place in the stems that grow off the onion, not in the actual onion itself. So there is no need for chloroplasts.
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Why did the onion cells plasmolyze when immersed in a hypertonic solution?
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The onion cells plasmolyzed because they lost water in the solution, which eventually made them appeared to be shruken in the stain.
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What is the function of amyloplasts?
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amyloplasts are responsible for the synthesis and storage of starch
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Is a fungi more like a plant or an animal?
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Fungi is more like an animal because the cell walls contain chitin, which is only found in animals. Fungi are also not photosynthetic and must feed like animals.
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How do the size of a human epithelial cell compare to the bacteria and elodea cells that you examined earlier?
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Compared to the bacteria and elodea cells, the cheek cells are a tad bit larger but much less numerous than the two.
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Why do Elodea and onion cells have more consistent shapes than human epithelial cells?
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Elodea and onion cells both contain cell walls, something that the human cheek cells did not have.
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What else do you see on this slide preparation other than cheek cells?
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I observed that within the cheek cells there were small dots which may have been the nucleus.
