You dilute an unknown sample of bacteria to 1 x 10-6 and plate out 10 onto a Petri dish. The next day you count 64 colonies. The number of viable bacteria in the original sample was:___________. a. 6.4x105 cells/ul b. 6.4x 106 cells/ul c. 6.4 x 107 cells/ul d. 6.4 x 108 cells/ul
Answer:
b
Explanation:
The correct answer would be 6.4 x [tex]10^6[/tex] cells/ul.
For 1 x 10-6 dilution, the plating factor is [tex]10^6[/tex]. To find the number of bacteria in the original sample, the plating factor is multiplied by the colony count per ul.
Number of viable bacteria = plating factor x colony count/ul
Since 10 ul gives 64 colonies. 1 ul will give:
64/10 = 6.4 colonies.
Therefore, the viable bacteria in the original sample = 6.4 x [tex]10^6[/tex] cells/ul
The correct option is b.
The process by which a modified stem or root of a parent plant grows offspring that remain attached is called(1 point)
A. vegetative reproduction.
B. fragmentation.
C. binary fission.
D. tuber reproduction.
Answer:
C
Explanation:
The process by which a modified stem or root of a parent plant grows offspring that remain attached is called vegetative reproduction.
Please select the word from the list that best fits the definition
process in which liquid turns to vapor
Answer:
i think its vapporization
Answer:
evaporation
Explanation:
its the process in which water gets heated up to a point where it turns into steam or vapor
the girl was observing a slide o
f muscle under microscope identified the muscle of striated on the basis of
Answer:
muscles carry lines, the texture is often different by that of tissue that is visible to the eye.
Explanation:
If one strand of DNA has the base sequence TTCCGGAA The complementary strand has which of the following sequence?
Answer:
If a DNA strand has the base sequence TTCCGGAA the complementary strand has the sequence AAGGCCTT.
Explanation:
A DNA molecule is constructed from sequences of its four nitrogenous bases: adenine, thymine, guanine and cytosine. Since DNA is made up of two strands, the sequence of nitrogenous bases of one strand is complementary to the other .
The complementarity of the bases is a characteristic of the nitrogenous bases in the nucleic acids to combine with their complementary base, which is the same as saying that purines complement with pyramidines.
Adenine is combined with Thymine A=T Cytosine is complemented with Guanina C≡GIn this way, given a sequence on a DNA strand :
T-T-C-C-G-G-A-A
The complementary strand will have this sequence:
A-A-G-G-C-C-T-T
There is a healthy bacterial culture growing in the exponential phase . A technician wants to make a growth curve by making cell counts over the day . She plans to take the samples every 30 minutes during the day , hold the samples at room temperature , and then process all samples together at the end of the day .
A) what is the problem with her plan?
B)can she do anything to improve the accuracy of her results ?
A) WHAT IS THE PROBLEM WITH HER PLAN?
Binary fission is one of the asexual process by which most bacteria reproduce, the binary fission brings about a doubling of the number in bacterial cells that are viable.
Generation time is that time that it will require for a cell population to divide and double, it is also known as doubling time. This Generation time varies among distinct organisms and also varies among culture conditions.
Take for instance,a fast growing bacterium that is under an ideal culture conditions has a doubling time of 20minutes and for the bacteria that is grown in a condition that is not so ideal,may have a doubling time of hours.
The major challenge/ problem with her plan is that as she takes the bacterial sample every 30minutes, and then hold the sample till the last sampling is done in the day,those bacterial cells that are collected in the initial intervals will then get divided and further gives a result that is false.
However,if those bacteria that are collected aren't stored in a culture environment that is standard,the bacterial cells may die off and thus will further bring about a false result.
2) CAN SHE DO ANYTHING TO IMPROVE THE ACCURACY OF HER RESULT?
Solution for rectifying the error in her plan;
She can go ahead and add 50-100 μl of formaldehyde to all the culture suspensions that she has and has taken every 30minutes.
As the formaldehyde will fix the bacterial cells,The optical density present in all those aliquots can then be retrieved/taken at the end of the day.
Looking at it alternatively, aliquot 1ml of the culture suspension at an interval of every 30 minutes,and then take the optical density that is OD at a wavelength of 600nm making use of spectrophotometer until the reason you get becomes static.
In which state of matter do the particles move independently of one another?
A.amorphous solid
B.Gas
C.Crystalline solid
D.Liquid
Answer:
I Think Gas
The gaseous state has very loose and unorganized structuring of particles, making them have little attraction and move independently.
CAN SOMEONE HELP!!!!!
Answer:
B and i think D
Explanation:
How do plants contribute to the water cycle?
Answer:
Plants absorb water from the soil. The water moves from the roots through the stems to the leaves. Once water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapor in the air. This process of evaporation through plant leaves is called transpiration.
I really hope this helps!
Plants contribute to the water cycle in several ways through Transpiration, evaporation, Precipitation: and infiltration.
How do we explain?Plants take in water through their roots and transport it up to their leaves. As water evaporates from the leaves, it creates a force that pulls more water up from the roots through a process called transpiration, and it is a major way that water moves through the atmosphere.
Water from plants and soil also evaporates into the atmosphere. This process is called evaporation, and it is another important way that water moves through the water cycle.
When water vapor in the atmosphere cools, it condenses and falls back to Earth as precipitation. This can be in the form of rain, snow, sleet, or hail.
Learn more about water cycle at:
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What effect does studying with music have on student test scores hypothesis?
Answer:
It helps them to focus
Explanation:
some people focus better when listening to music
Answer:
For some students it can help and for some it cant
Explanation:
Which of the following is a biotic factor?
Α. Starfish
B. Salt
C. Sea water
D. Sand
Answer:
It would be Α. Starfish
Which carbon footprint solution does this picture try to reinforce?
a.
Recycling
c.
Using solar power
b.
Driving less
d.
Only using the washer for a full load pzzzzzz help
Answer:
Ig b
Explanation:
it usually means it's a bike only lane, but since it's not an option I would go with b
Answer:
b. Driving less
Explanation:
This photo demonstrates driving less as a carbon footprint solution because riding your bicycle not only provides a wonderful cardiovascular workout but also emits less Carbon Dioxide into the air than a car does.
Please solve this lab reportJohn had a science fair project that he needed to do. He wanted to test the effects that organic and chemical fertilizers had on plant growth. John predicted that the organic fertilizer would make the plants grow taller. He used three pots, three of the same type of seed, soil, organic fertilizer, chemical fertilizer, water, and a ruler. John put soil in the pots. He added chemical fertilizer to the first pot, organic fertilizer in the second pot, and no fertilizer in the third pot. He then planted one seed in each pot. John had to water the pots daily. He also checked for growth and took measurements for a period of 10 days. He measured the height of the plants. FIll out this templatePractice Writing a Lab Report Instructions: Use the lab example given to complete the Practice Writing a Lab Report activity. Please fill in this lab report with the appropriate information and data. Title: Include your name, instructor’s name, and the name of the lab Objecti
Answer:
This question is incomplete; the complete part is: what are the independent, dependent, and controlled variables?
Independent variable: ORGANIC AND CHEMICAL FERTILIZERS
Dependent variable: HEIGHT OF PLANT
Controlled variable: Same type of seed, water
Explanation:
Independent variable is the variable that is changed or manipulated by the experimenter. In this question, John wanted to test the effects that organic and chemical fertilizers had on plant growth. Hence, the independent variable is the ORGANIC AND CHEMICAL FERTILIZERS used.
Dependent variable is the variable that responds to changes made to the independent variable. The dependent variable is the variable that is measured in an experiment. In this case, the HEIGHT OF PLANTS MEASURED is the dependent variable.
Controlled variable or Constant is the variable that is kept unchanged throughout the experiment in order not to influence the experimental result or outcome. In this case, the controlled variable is the SAME TYPE OF SEED USED, WATER.
A marble has a mass of 11.8 g. It has a volume of 3.7 cm3. What is the density of the marbl
Answer:
11.8/3.7= 3.1891891892
Explanation:
Divide 11.8 by 3.7 and instead of putting all of the numbers, just put 3.18
Which is an example of radiation?
A melting snowman sweats drop of water under a bright sun.
A smiling man roasts marshmallows over a wood fire.
A cook stirs vegetables in a frying pan over a gas burner.
Three pairs of bare feet and lower legs walk across black pavement.
Answer:
A: melting snowman sweats drop of water under a bright sun
Answer:
The correct answer is A.
A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have the normal number of digits (five fingers on each hand and five toes on each foot.) The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits?a. 9/16.
b. 3/4.
c. 1/16.
d. 1/2.
e. 1/8.
Answer:
The correct answer is - option D. 1/2
Explanation:
Extra digits on hands and feet mean an individual has six fingers in each hand and feet, this is known as polydactyly. Polydactyly shows an autosomal dominant type of inheritance pattern.
In this case, the mother is normal so she must be recessive alleles and the first daughter is normal so the father must have a recessive allele which means he is heterozygous.
Cross:
Man = Dd
Woman = dd
Their children :
D d
d Dd dd
d Dd dd
Probability of polydactyl child = 2/4 or 1/2 or 50%
This illustration shows a kind of animal that is a free-living organism.
What is the common name of the group that contains this organism?
flatworms
tapeworms
cnidarians
annelids
Answer:
Gotta picture? That would help... Cause it says there's an illustration or something... But either way I just looked it up and found an illustration and the illustration showed a wormy lookin' thing and that wormy lookin' thing look like a flat worm. So I'ma say A. Flat worm. Tall me if I'm wrong! Thanks!
Answer:
Answer. This illustration shows a kind of animal that is a free-living organism. Phylum ( Platyhelminthes ) term is the common name of this organism. The phylum is either free-living or parasitic
Explanation:
PLSS HELP ,, - - - A group of students were testing different insulators. They used three metal cans, one wrapped with bubble wrap, a second with a paper towel, and third unwrapped. Equal amounts of hot water were poured into each can and the temperature was noted at definite time intervals. The data is shown in the table.
From the data what can you conclude which is the best insulator?
Aluminum can wrapped with paper towel
Just the aluminum can
Aluminum can wrapped with bubble wrap
Answer:
Without the table, I can't be 100% certain, but I'm sure that your answer is C). It would only make sense, considering the fact that if bubble wrap is being used, you've put 2 layers of plastic and one layer of trapped air between the can and the hand of those who hold it, thus reducing the amount of thermal energy transfer.
A population of rabbits has individuals with fur coloring that ranges from white to brown. The population lives in a temperate deciduous forest where the summers are mild and average about 50 degrees Fahrenheit. The winters are often below freezing.
If warmer temperatures last longer into the fall and the average temperature in the winter is getting warmer, what do you expect to happen to the population?
A) The percentage of the population with brown fur will decrease.
B) The percentage of the population with white fur will decrease.
C) The percentage will increase in size, but the color percentages will remain unchanged.
D) The percentage will decrease in size, but the color percentages will remain unchanged.
Answer:
The answer is B.
Explanation:
If warmer temperatures last longer there will be no need for the white fur
if today's first high tide is at 7:00 AM, what time will today's next high tide be? Please do not troll. . . . I have already asked this question like 7 times already and got no answer, except foolishness. Please. :(
What controls when a cell divides?
Answer:
A variety of genes are involved in the control of cell growth and division. Tight regulation of this process ensures that a dividing cell's DNA is copied properly, any errors in the DNA are repaired, and each daughter cell receives a full set of chromosomes.
Explanation: hope this helps love
Answer:
A variety of genes are involved in the control of cell growth and division. Tight regulation of this process ensures that a dividing cell's DNA is copied properly, any errors in the DNA are repaired, and each daughter cell receives a full set of chromosomes.
Explanation:
What functions share the animal tissues and the plant tissue
Answer:
hope it's help you...............
How does heat affect enzymes?
Answer:
Temperature
Explanation:
Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction. However, extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working. pH: Each enzyme has an optimum pH range. Extreme pH values can cause enzymes to denature.
_ can cause drain pipes to become to become clogged. A. Hydrotropism B. Thigmotropism
Answer:
b
Explanation:
Answer:
I think B
Explanation:
Hope this helps
A structure that looks the same and does the same job but was not present in a common ancestor is termed:______.
Answer:
The correct answer is - analogous.
Explanation:
Analogous structures or organs are the structures with the same look which is developed to perform the same job and not present because inherited by a common ancestor.
These structures are present in unrelated organisms and look the same from outside and perform the same action for example wings of bat and birds look and perform the same action but not inherited from a common ancestor.
When an oxygen atom forms an ion, it gains two electrons.
What is the electrical charge of the oxygen ion?
2
1
O +1
O + 2
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O+2Is cellulose a monosaccharide, disaccharide, or polysaccharide.
Answer:
Monosaccharide.
Explanation:
The major component in the rigid cell walls in plants is cellulose and is a linear polysaccharide polymer with many glucose monosaccharide units. This is the storage form of glucose in animals and humans which is analogous to the starch in plants.
Answer:
It is a polysaccharide
Explanation:
Please mark me as Branliest!!
Robert Hooke discovered cells in the 18th century.
true or false
Answer:
False it is in the 17th century (1665)
Explanation:
He named the little blocks after cells (little rooms)
help me w this pls would mean a lot
Answer D
Explanation: All the previews could cause it
name six harmful substance in food production
Answer:
Expired food and drugs; expired food and drinks that has stayed beyond the appropriate time
Impure water; impure water is dirty water that is not fit for the body system
Unripe fruits; fruits that is not yet due for...
Infested food
Poorly cooked food
Cigarette
Explanation: