1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
jarptica [38.1K]
3 years ago
9

In many states, the legal limit for all bacteria present in pasteurized milk is not to exceed 20,000 CFU/mL. You have been away

on vacation and left an unopened plastic jug of milk in your refrigerator. The "Sell By" date was three days ago. Instead of throwing it out, you decide to test it using your eScience Microbiology Kit. Here are your results for a "countable" plate in your serial dilutions: 186 colonies on a plate where the dilution factor was 1 x 10-4 and the volume that you plated was 1 mL. (20 points)
a. How many bacteria are present in 1 mL of this milk?
b. Is this milk safe to drink by Public Health standards?
Biology
1 answer:
zaharov [31]3 years ago
8 0

Answer:

a. The formula for finding the number of colonies in a given volume is,  

CFU/ml, here CFU is the colony forming units or the number of colonies formed in a volume plated in ml × dilution

The dilution factor given in the question is 1 × 10⁻⁴ and the number of colonies given is 186. Therefore, the number of bacteria present in the given 1 ml of the milk is,  

CFU/ ml = 186 / 1 × 10⁻⁴ = 186 × 10⁴.  

Hence, the concentration of bacteria in the milk is 186 × 10⁴ CFU/ml.  

b) The limit of the bacterial concentration in the pasteurized milk is 20000 CFU/ml, however, it can be seen that the sample of the milk possess more concentration of bacteria than the desired value. Therefore, the milk is not safe to drink by Public Health Standards.  

You might be interested in
Photosynthesis occurs inside of which organelle? a chloroplasts b the cell wall c mitochondria d ribosomes
Delvig [45]

Answer/Explanation:

Chloroplasts are the organelle that uses chlorophyll. Chlorophyll is in the process of photosynthesis.

6 0
3 years ago
Which of these sentences describe sources and preservation of genetic variation? Select all that apply.
madam [21]

The correct sentences are the following:

 A) Antibiotic resistance in bacterial populations is caused by natural selection of bacteria that inherit mutations that make them resistant to the antibiotics.

 C) Crossing-over causes a shuffling of allele combinations during meiosis as the alleles from each parent form new combinations on homologous chromosomes.

 E) When two bacteria are linked during conjugation, the donor cell passes DNA to the recipient cell which causes genetic recombination.

Explanation:

These three options are associated with the generation and preservation of genetic diversity

4 0
3 years ago
What are your thoughts about how the universe formed?
V125BC [204]

 For centuries scientists thought the Universe always existed in a largely unchanged form, run like clockwork thanks to the laws of physics. But a Belgian priest and scientist called George Lemaitre put forward another idea. In 1927, he proposed that the Universe began as a large, pregnant and primeval atom, exploding and sending out the smaller atoms that we see today.

His idea went largely unnoticed. But in 1929 astronomer Edwin Hubble discovered that the Universe isn’t static but is in fact expanding. If so, some scientists reasoned that if you rewound the Universe's life then at some point it should have existed as a tiny, dense point. Critics dismissed this: the celebrated astronomer Fred Hoyle sarcastically called this concept the “Big Bang Theory"

3 0
3 years ago
Read 2 more answers
Summative test in science quarter 1 (pasagot po sa magaling sa science)
lianna [129]

Answer:

sry I just wanted the points I'm in middle school so I don't know this stuff either but can you give free brainlyest I'm soo close to my next rank I'd really appreciate it if you would

7 0
3 years ago
Dengue fever is an infectious disease of humans that is caused by a virus. There are four main viral strains, and an individual
Yuri [45]

Answer:

12

Explanation:

Suppose the four different strains are P, Q, R, S. Thus, the first infection can be from any of the four strains and it occurs in 4 ways.

Since an individual cannot be infected again with the strain from which he/she is been previously infected;

Then, at the second time;

The possible number of strain to be infected with = 4-1 = 3 ways

Thus; the number of possible different levels of severity can be viewed by forming two lettered word  P, Q, R, and S without repetition which is:

= 4 × 3

 = 12

7 0
3 years ago
Other questions:
  • Which tends to increase the size of a population
    6·2 answers
  • please help me If a heterozygous dominant tall pea plant is crossed with a short pea plant, what is the expected phenotypic rati
    15·1 answer
  • The video describes a coevolutionary arms race between the Plasmodium parasite and its human hosts.
    14·1 answer
  • This epithelial tissue has many cell layers. It forms the outer layer of the skin. True or False
    6·2 answers
  • A scientist claimed that hemophilia is caused by a functional deficiency in Factor VIII. The evidence in the passage that would
    12·1 answer
  • What is the most basic unit of life? A. tissue B. organ C. cell D. organ system
    13·2 answers
  • Muscular dystrophy affects the functioning of skeletal muscle. As this disease advances, it can impair the contraction of the di
    14·1 answer
  • What are two reactants needed for cellular respiration?
    12·2 answers
  • 2. Energy is released from an ATP molecule for cellular processes when it ___
    13·1 answer
  • I need help plssss help me out I mark you brainliest
    5·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!