Topic 5: On the wild side 17. Describe how to investigate the effects of temperature on the development of organisms (eg seedling growth rate, brine shrimp hatch rates). Procedure You will need: • Brine shrimp egg cysts • 2g sea salt for each treatment • 100cm³ de-chlorinated water for each treatment • 40cm³ beakers (one for each temperature to be tested) • Water baths or incubators (one for each temperature to be investigated) • Stirring rod • Magnifying glass • Pair of forceps • Fine glass pipette • Bright light Experiment: 1. Decide on a range of temperatures from 5°C to 35°C to be tested. 2.
Diffusion Across a Plasma Membrane In order to demonstrate the way in which semipermeable membranes work, an experiment replicating the digestive system of a caterpillar was preformed. To simulate a semipermeable membrane dialysis tubing was used. It is capable of demonstrating the way in which a semipermeable membrane will allow only molecules under a certain size to pass through it. First, to simulate the crop of the caterpillar, a small beaker was filled with four pipettes worth of cooked starch as well as four pipettes worth of alpha amylase solution and stirred. The cooked starch acts as the food, which the caterpillar would eat, and the alpha amylase, which is a digestive enzyme common in saliva, is stirred with it to simulate the chewing and mixing of food and saliva which constitutes the first step in the digestive system.
The starch is used to replicate the starch intake from the plants the caterpillar ingests. Since sugars are insoluble, plants convert them to starches to store them. In the first setup, where no amylase is present, there is no passage of starch from the inside of the tubing to the beaker, however, the Lugols is demonstrated to be a small enough molecule to travel across the membrane, demonstrated by the color change of the inside of the tubing from a cloudy white to a dark blue, a sign of reaction between the Lugol and starch. Once the caterpillar eats the starches, the digestive enzyme amylase breaks down the starch into the original, insoluble sugar. The sugar molecule is now small enough to travel across the membrane to the less concentrated area.
If a substance contains proteins then when Biuret reagent is added the substance will change Easter egg colors (lavender, yellow, and green). Materials: 8 test tubes Test tube rack Test tube holder Glass stirring rod Sharpie marker Hot water bath Iodine solution Brown paper bag Biuret Reagent Benedicts solution 20 ml each: 1. Honey solution 2. Egg white and water solution 3. Gelatin and water solution 4.
The streak plate technique is done to isolate a colony formed by a single cell from a mixture containing millions of cells. The streak plate technique was also used to obtain pure cultures of the bacteria using a trypticase soy agar (TSA) plate and was incubated at 37 ̊ for 48 hours. Secondly a Gram stain was performed as directed from exercise 6in the lab manual (Kleyn 37) and was found to be Gram negative Rods. The Gram stain is important to do because it reveals the morphology of the organism and the arrangement of the cells; if an organism appears purple under a microscope then it is said to be Gram positive, and if it
Lab Report for Experiment #9 Caloric Content of Foods Purpose: (copy from lab; 1 point) • To measure the energy content of various food items, and • To become familiar with energy units like calories and joules Describe any changes to the procedure here in detail here: For example: I weighed the marshmallow directly without the holder. Or I used the following food instead: The food items that I used for this experiment were mini marshmallow, a peanut, and small potato chip. Observations: Keep notes on any observations you make while working on this experiment, copy them into the space below. Be detailed. The mini marshmallow burned very quickly, but did not burn all the way.
If you do not write down everything, you will have to try to think back and remember what you have eaten for entire day; make sure you include the full 24 hours. Try to pick a typical day. If you are going to a party or have to fast for a lab test, pick a different day. • Go to the U.S. Department of Agriculture health food and fitness page: https://www.supertracker.usda.gov/ or copy and paste this address into your web browser. • Click on: FOOD
If the ability to perceive sweetness is stronger, then the salivary amylase activity will be greater, indicated by a lighter color change in the starch and iodine solution. For this experiment, we first gently chewed a saltine for three minutes, rating our sweetness perception from 0-5 on a chart at each sixty-second interval (0 least sweet; 5 sweetest). We then classified the class into three categories: non-tasters (1-2), moderate tasters (3), and tasters (4-5). We recorded the data. Next, we put starch solution and a couple drops of iodine into a reaction tube, and recorded the color.
Eating ¼-cup of red-skimmed peanuts w/your meal provides the same amount of antioxidants. Rose hip powder blocks fat buildup – enjoying 1 T. of this sweet, fruity ‘n slightly tart powder (mix it into smoothies, yogurt or other food) helps block the fat storage that triggers high blood sugar ‘n insulin resistance. Rose hip powder inhibits fat formation in the liver. TIPS: if u prefer, dissolve the powder in a cup of boiling water ‘n drink it as a tea. Fish protects your heart – people who eat at least (3) three fish meals weekly have more heart-healthy HDL cholesterol levels in their blood than less frequent fish eaters.
Wilson English 101 (Extra Credit) How to Grow an Avocado Tree: Have you ever eaten an avocado and wished you could do something with the enormous seed? Well, you can; with a little luck and a little skill, you can grow an attractive house plant from it. Caring for an avocado is not complicated, provided you follow a few simple rules. Wash the seed in tepid water, removing all the pulp. Suspend the seed with the broad end pointing down in a water-filled glass or jar by driving three toothpicks into the sides for support.