Biotechnology I G/T
Unit 2
Name ____________________
Dough only
Chips
Chips and nuts
You start with 100Tbs of dough to make cookies for your whole picky family. You will use that one batch of
dough to make 3 different kinds of cookies: plain, chocolate chip, and chocolate chips with nuts. Show units.
Reduce all fractions.
1. Each Cookie is 2.5 Tbs. First you make 10 cookies plain. What volume of dough do you use for plain
cookies? (use Tbs) ________ Then you add chips to the remaining dough and you make 20 cookies with
chocolate chips only. What volume of dough do you use for chocolate chip cookies? (use Tbs) ________
Finally, you add nuts to the last bit of dough and you make 10 cookies with chips and nuts. What volume of
dough do you use for chip and nut cookies? (use Tbs) _________
2. The bag of chips is 10 ounces. There are 300 chips in the bag. How many chips are there per ounce?
3. The bag of nuts is 8 ounces. There are 200 nuts in the bag. How many nuts are there per ounce?
4. You added the whole bag of chocolate chips to the dough after you made the dough only cookies. How
much dough did you add the chips to? _________
What is the concentration of chips per dough? Use chips per Tbs. __________
5. How many chips are there per cookie?
6. How many bags would you need to make 500 chocolate chip cookies?
Biotechnology I G/T
Unit 2
Name ____________________
LB/Amp/Arabinose Worksheet
1. You made up 500 ml of LB agar. You pipetted 12.5 ml into each plate. You made 16 plates of plain LB agar.
How many ml of the original 500 ml was used for plain LB plates?__________ You made 16 plates of LB/Amp
agar. How many ml of the original 500 ml was used for these plates?__________ You made 8 plates of
LB/Amp/Arabinose agar. How many ml of the original 500 ml was used for the LB/Amp/Arabinose
plates?__________
2. Ampicillin is supplied in lyophilized (freeze-dried) form. A 30 mg vial is rehydrated with 3 ml of sterile distilled
water. What is the resulting concentration of ampicillin in this stock solution?
[How many mg/ml?] __________
3. Arabinose is also supplied in lyophilized form. A 600 mg vial is rehydrated with 3 ml of sterile distilled water.
What is the resulting concentration of arabinose in this stock solution? __________ [How many mg/ml?]
4. The contents of the ampicillin vial were added after the first 16 plates were poured. Therefore, the ampicillin was
added to__________ ml of media. [see #1]. The concentration of the ampicillin in the media is
_____mg/_____ml, which can be reduced to __________mg/ml.
5. The contents of the arabinose vial were added after 32 plates were poured. Therefore, the arabinose was added to
__________ml of media [see #1]. The concentration of arabinose in the media is _____mg/_____ml, which can
be reduced to __________mg/ml.
6. Now you know the final concentration of ampicillin and arabinose in the media. Suppose you want to make 1L of
LB/Amp media. How many ml of the stock ampicillin do you need?__________
[Hint: You used 3 ml of
stock ampicillin to make 300 ml of LB/Amp media last time.]
7. Suppose you want to make 1L of LB/Amp/Arabinose media. How many ml of the stock arabinose do you
need?__________ [Hint: You used 3 ml of stock arabinose to make 100 ml of LB/Amp/Arabinose media last
time.]
8. You used up the stock solutions making the first batch of media. Now you have dry ampicillin and arabinose
powders. Suppose you need to make 1L of LB/Amp media. How many grams of ampicillin powder do you need
to weigh out?__________ [see #4 for the desired concentration] How many grams of arabinose powder do you
need to weigh out to make 1L of LB/Amp/Arabinose media?__________ [see #5 for the desired concentration]
9. You need to make 500 ml of LB/Amp and 500 ml of LB/Amp/Ara media. You start with 1L of plain LB media.
How many grams of ampicillin do you need to weigh out?__________ How many grams of
arabinose?__________