BIOL 1208 Lecture : Bio 1208 Notes

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azuremammoth471

15 Mar 2019

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She will give you two wavelengths- change it to the number she gives you by the knob on top. Data should be at zero- change it to the zero by the first knob on the front. Put in blank and change the second knob on front of machine to 100 at transmittance. Once it is at 100, take out the blank, and put in the solution and change to absorbance, and the write down the number it reads when it"s stable. When you change the wavelengths, you must blank it again if the wavelength remains the same you do not. Mechanical pipet 100-1000 reads the same and a 0. Pasteur pipet is small like the transfer pipet but glass as opposed to plastic.

Related Questions

yeast population dynamics

Procedure

1. Work in pairs on this lab, so 12 tubes per pair of students. And share a tube rack with one other pair of students

2. Turn on your spectrophotometer. It needs at least 15 minutes to warm up to give you good readings.

3. Add 5 mL of yeast extract solution (YECM) to each of 12 tubes. (The yeast extract provides vitamins and amino acids for yeast growth and will be the same for all cultures). The tubes should be labeled with your initials, treatment, and tube number. Tape or Parafilm down the lids of 3 tubes, and label them âCONTROLâ.

Do not touch the insides of the tubes or lids! Try to keep these as sterile as possible!!

4. Add 50 mL live yeast culture to each of the remaining 9 tubes.

5. Add the varying volumes of sugar and/or ethanol using Table 1 below.

6. Use Parafilm to close the tops of each tube, making sure the Parafilm is tight and no air can get in, and label each tube with the following:

Amount of sugar added (mL) Amount of ethanol added (mL)

Name of your group Tube number

Table 1: setup yeast tubes (remember, 1 mL = 1000 mL)
Tube number	Yeast culture medium? (5 mL)	Live yeast culture? (50 mL)	Sugar added (mL)	Ethanol added (mL)
1 â control	YES	NO	0	0
2 â control	YES	NO	0	0
3 - control	YES	NO	0	0
4	YES	YES	0	0
5	YES	YES	0.25	0
6	YES	YES	0.5	0
7	YES	YES	0	0.25
8	YES	YES	0.25	0.25
9	YES	YES	0.5	0.25
10	YES	YES	0	0.5
11	YES	YES	0.25	0.5
12	YES	YES	0.5	0.5

Procedure for measuring absorbance (in absorbance units, or AU)

7. Calibrate the spectrophotometer:

Turn on the spectrophotometer and let it warm up for 15 minutes. You will get erroneous results if you donât let it warm up first.

Be sure the spectrophotometer is set to read at the wavelength of 550 nm

With no tube in the spectrophotometer and the lid closed, use the left-hand knob to adjust the reading to 0% Transmittance/push zero button to calibrate

Insert a CONTROL tube (making sure it is clear, without bacterial contamination which would make it cloudy), and use the right-hand knob to readjust the spectrophotometer to 100% Transmittance.

When reading the absorbance, be sure to line up the needle on the spec with its reflection.

8. Immediately before reading any tube, vortex the tube so that the spinning column reaches the bottom of the tube for several seconds. This is critical! The yeast cells are heavy and will tend to sink to the bottom of the tube, so you must vortex the tubes to resuspend them: otherwise, your spectrophotometer readings will be erroneously low. If the vortex is not enough to suspend the pellet of yeast cells at the base of the tube, take a piece of Parafilm and cover the top of the tube, then cover this with your thumb and shake the tube vigorously. The pellet should dislodge and the yeast cells should be easily resuspended after doing this. Use a Kimwipe to wipe down the outside of each tube, to remove fingerprints and other smudges that could affect the absorbance reading. (COULD BE A POTENTIAL ERROR)

9. Record the absorbance (in absorbance units, AU) for the tube on your data sheet.

10. Repeat steps 5 and 6 for every tube.

11. Leave the spectrophotometer turned on for the next user.

Figures you should include are:

Average absorbance vs. time for the no ethanol (0 mL) treatment

Average absorbance vs. time for the 0.25 mL ethanol treatment

Average absorbance vs. time for the 0.50 mL ethanol treatment

Sugar added vs. average carrying capacity (K). Use different symbols to denote each of the three alcohol concentrations

A. After a limit, the increasing concentration of sugar decreases the carrying capacity and growth rate. This is because at higher sugar concentrations, the medium becomes hypertonic and the yeast cells loss water towards the medium.With increasing concentration of the ethanol, the carrying capacity and the growth rate decreases. Why does this happen?

B. Is there any interaction between the effects of adding sugar and alcohol on yeast?

C. why do some cultures not reach K?

D. What are the potential sources of error and assumptions made in this experiment?

E. What do these results mean in a more general (non-yeast) context?

greenporcupine374

As you may recall in the work of Triplett (1898), the presence of others in a bicycle race was found to enhance individual performance. This is called social facilitation (Williams, Harkins, & Karau, 2007). At times, however, the presence of others can detract from individual performance, which is termed social inhibition (Crisp & Turner, 2007). Similarly, social loafing can occur when an individualâs performance within a group decreases due to his or her reliance on others in the group (Crisp & Turner, 2007).

For this Discussion, review the media program, Week 5: The Virtual Office. Focus on the characters in the media and determine which characters displayed social facilitation, social inhibition, and social loafing.

With these thoughts in mind:

Post by Day 3 a description of the characters in the media program demonstrating social loafing, social inhibition, and social facilitation. Explain how you identified them. Then, select one of the characters and, using the current literature, explain two ways you might mitigate their behavior.

Media Program

(Onscreen Text: The employees at the United Cardboard Company often work individually on projects, but as with most environments, they are occasionally asked to participate in group projects. One such group is about to meet right now to plan a presentation for the Board of Directors. Observe the conversation and reactions of various group members to determine which group members exhibit signs of the following: Social Loafing, Social Inhibition, and Social Facilitation.)

(Interior of an office. Ken stands at the front of the conference room.)

KEN: OK, I guess we might as well all get started. As we all know, the big man has requested the five of us to get together and write and conceptualize a presentation to the board on our new packaging system. Maybe we can start by going around and throwing out some initial ideas.

KATHY: Sounds good to me. I think a PowerPoint presentation would do the job well.

GAVIN: I agree. We could follow it up with a physical demonstration of how the packaging looks and folds-- maybe a video of the larger pieces that won't fit into the boardroom.

KEN: Sounds perfect to me. Amanda, Brian, what do you guys think?

BRIAN: Yeah, what you guys said sounds fine.

(Amanda thinks, âI donât know what to say!â)

KEN: Amanda?

AMANDA: I don't know. I didn't really get much chance to think about this. We only found out we needed to do this together three days ago.

KEN: OK, no worries. Let's focus on the PowerPoint idea. I've been doing a lot of them lately, so I'm happy to take the lead on the design aspect. What do you guys think we should all incorporate into the slides?

GAVIN: I think we should start with where we got the idea for this new packaging -- the company that designed it and the different sizes that it comes in.

KATHY: We should follow that with a graph comparing the old prices to the new ones to illustrate how much we'll be saving over time. Amanda, didn't you have most of that information collected at some point?

(Amanda thinks, âOh no! What if I deleted that?)

AMANDA: I don't know, maybe, it's been so long. I didn't think I'd need it again for a group project like this.

(Gavin thinks, âI wonder whatâs gotten into her. Sheâs not usually this tense.â)

KEN: That's OK, Amanda, I'm sure we can easily dig it up again. Brian, do you have any other ideas for the PowerPoint slides?

BRIAN: Nah, I think what you guys mentioned sounds right.

(Kathy thinks, âWow. Way to contribute Brian.â)

KEN: OK then, Kathy and Gavin why don't you send me all of the info and I'll write it up and make the slides. Amanda, don't worry about the cost saving document, I'm sure I can dig it up from my old emails and put it into that slide too.

AMANDA: Are you sure? I'm happy to look. I mean I'm sure I have it somewhere. (Kathy thinks, âShe really needs to get it together. Why is she so nervous?â) At least I think I have it somewhere. You won't tell the Board of Directors if I lost it, will you?

KEN: Of course not, we're in it together. So as I was saying, I'll write up and prepare all the PowerPoint slides. Then we can start our presentation with reading and explaining each slide. Then, what?

KATHY: Well, and then I think we should show them the packaging live, and the quick deconstructing techniques.

KEN: Great idea. You and Amanda can demonstrate the folding, while I narrate what you're doing.

(Amanda thinks, âIs he doing too much of the work? And what if I drop everything while heâs talking?â)

GAVIN: And after you all demonstrate the smaller packaging, we could show a quick video of how the really big ones function down at the warehouse. Brian, would you be able to go film that quickly one of these days?

BRIAN: I don't really have any experience with video cameras or anything like that, so...

(Gavin thinks, âI should have seen that one coming.â)

KEN: That's OK. My wife actually just got me this great little camera for our anniversary. It takes great videos. So I can just run down to the warehouse, get some footage, then put it together on this new editing software I just downloaded. Maybe add a little music. It's going to be really slick!

KATHY: Are you sure, I wouldn't mind doing that too.

KEN: Oh no, it's fine. I love this kind of stuff; just leave it to me. But I suppose that's enough planning. Now it's time to get to work and make the presentation a knock out. Go team!

DNA EXTRACTION LAB

Objective

The purpose of this lab is to extract DNA from the nuclei of an onion, cup of strawberries or a banana.

Introduction

In every eukaryotic cell there are long strings of DNA. The DNA encodes for every protein needed by the organism. The DNA can be millions and millions of bases long. When the DNA is in the nucleus, it is tightly coiled around a set of proteins called the histones. When DNA is released from the nucleus by detergent, it can become long and stringy. In this lab we are going to be extracting the DNA from the nuclei of onions and wrapping the DNA around a glass rod.

Materials

Straw or Coffee Stirrer

2-plastic water bottles (single serving disposable)

Ice

Rubbing Alcohol

Liquid soap (laundry detergent) DawnR works best

Coffee filter

Water- distilled

Onion, Cup of Strawberries, or Banana

Table salt

Procedure

1. First place a bottle of rubbing alcohol on ice to chill.

2. Then make the following detergent/salt solution:

Mix together (1/8 cup) 20 mL of liquid soap, (2-tsp) 20 grams of salt, and (1 1/8 cup) 180 mL of distilled water. When you are finished making the solution, put it on ice to chill for at least 10 minutes.

3. Cut an onion in half and chop it up either in the blender, or with a knife. If using strawberries chop them up to small pieces. If using the banana smash it up in a cup.

4. Add (half) 100 mL of the detergent/salt solution to the chopped onion, strawberries, or banana. Continue crushing the onion, the onion needs to be pulverized.

5. Let the slurry sit for 5 minutes on ice.

6. Cut the top 1/3 from the water bottle and flip it over onto the lower cut portion. Use the top as a funnel and the lower portion to catch the solution as it filters through.

7. Place a coffee filter in the top funnel. Pour the slurry through and capture the filtered solution below.

8. Once all of the slurry is in the beaker slightly tilt the beaker and slowly pour down the side of the beaker an equal volume of ice cold rubbing alcohol. This will form two distinct layers. A white stringy material will form at the interface of the two layers.

* Do not mix the alcohol and the slurry.

8. Carefully insert a glass stir rod in the center of the beaker, being cautious not to touch the sides.

9. Now, twist the stir rod in a clockwise direction (like twirling spaghetti) and you should see a white stringy material collecting onto the rod.

This white stringy material is DNA. Keep twisting until you acquire the maximum amount of DNA.

* If you do not collect any DNA on the stir rod then use a piece of sandpaper to rough up the end of the stir rod and try again.

Questions

What did you observe?

Were you able to isolate DNA?

What did it look like?

BIOL 1208 Lecture : Bio 1208 Notes

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