Lab Exercises 1-8

calculating weight of media

milliliters (ml) convert to liters (L) so divide 1000, then multiply by the grams (g) listed on the label

measuring water what to use

graduating cylinders, look at meniscus level, if you need 20ml DON’T do two 10ml instead use a 100ml because its less room for error

The label of the bottle directs you to combine 31g of medium in one liter of water. How many grams do you need to make 270ml?

31g x 0.27L = 8.37g of medium

According to a direction on a bottle: “Suspend 24.2g of the powder in 1L of purified water. Stir to mix thoroughly. Heat with frequent agitation and boil for 1 minutes to completely dissolve the powder. Do not overheat.” How much grams of powder do you need to make 350ml of medium?

24.3g x 0.35L = 8.47g of medium

The label on a bottle of medium indicates, “Suspend 17g of the powder in 1L of purified water.” How many grams would you use to make 250 ml of medium?

17g x 0.25L = 4.25g of medium

This medium is a mixture of nutrient agar and sodium chloride NaCl. According to the directions on the NA bottle, “To rehydrate use 23g of powder per one liter.” How many grams would you use to make 300ml of medium, and how much sodium chloride (NaCl) would you add to make it 7% solution of NaCl?

23g x 0.3L = 6.9g of medium; 0.07 × 300 = 21g NaCl

200ml TSA is needed to make a slant (must boil), powder into beaker and then water 200ml, the beaker must be 50% bigger than the fluid

so if it’s 200ml, then 50% is 100 more, making the beaker 300ml or bigger for it to work

what is autoclaving

sterilization using high-pressure steam, use for anything living

TSA is

more nutrient than NA(nutrient agar) so it grows better but it dies sooner