A sample from a stock of a bacterial colony in liquid media was diluted by a factor of 106, and 2 ml of this dilution was spread on a Petri dish of solidified media. 56 colonies were observed. What was the concentration of bacteria of the initial stock?

Answers

Answer 1

Answer:

28 × 10⁶ colonies/ml

Explanation:

Let C be the concentration of bacterial in the initial stock. When it is diluted by a factor of 10⁶, the new concentration is C' = C/10⁶.

When 2 ml of this concentration is spread on a Petri dish of solidified media, 56 colonies were produced. The number of colonies, n after spreading the 2 ml of C' is C' × 2 ml = 2C' = 2C/10⁶.

So, n = 2C/10⁶.

Since the number of colonies after spreading on a Petri dish of solidified media is 56, n = 56 colonies.

So, 2C/10⁶ = 56

Making C subject of the formula, we have

C = 56 × 10⁶/2

C = 28 × 10⁶ colonies/ml

So, the initial concentration of bacteria is 28 × 10⁶ colonies/ml


Related Questions

explain why in the morning plant leaves are moisten​

Answers

Answer:-

It occurs when there is active absorption of water by roots and transpiration is low i.e. moist and humid conditions. Therefore, guttation generally occurs in the early morning because transpiration is less at that time but water is actively absorbed by the roots.

In crude oil affect eggs and larvae of fish and increase mortality.
O a.
Hydrocarbon
O b.
PAH
O c.
liquid petroleum

Answers

Answer:

its c liquid petroleum 100% surr

Explica con tus palabras el proceso de la formacion de orina

Answers

Answer:

Answer to the following question is as follows;

Explanation:

The kidneys filtration undesirable chemicals from the bloodstream and expel them through urine. Urine is formed in three stages: glomerular filtration, re - absorption, and secretion. These procedures guarantee that the bodies natural waste and surplus water are eliminated.

water can act as either a(n)__or a​

Answers

Explanation:

Water can act as an acid and a base. As an acid, water donates H+, the hydrogen ion. As a base, water donates OH-, the hydroxide ion

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Which of the following describes a parasite
1 a bear that kills and eats fish?
2 a worm that lives inside a bear.
3 a dish that is killed and eaten.
4 a bear that has worms in its gut

Answers

Answer:

2

Explanation:

A parasite is an organism that feeds on the intestine of living organiy

The correct answer would be a worm that lives inside a bear! A parasite is something that lives inside a host and is receiving its food from the host — this being the bear! Safe learning :)

Sucrose and monosodium glutamate (MSG) are added to a salad dressing made of vinegar and oil. If the mixture is then shaken, it will eventually separate into two phases. After this phase separation, where will most of the sucrose and MSG be located?
a. Both will concentrate in the vinegar.
b. Both will concentrate in the oil.
c. Both will concentrate at the interface between the two phases.
d. Sucrose will concentrate in the oil, and MSG will concentrate in the vinegar.
e. Sucrose will concentrate in the vinegar, and MSG will concentrate in the oil.

Answers

Answer:

both will concentrate in the vinegar layer because both are polar and Hbond with vinegar (an acid)

Explanation:

What were the three large, flightless birds with similar features found on different continents, Australia, Africa, and South America?

Answers

Answer:

Rhea from south america

Emu from Australia

ostrich in Africa

The ribosomes’s primary function in both prokaryotic cells and eukaryotic cells is to
A. Build proteins according to the cell’s DNA instruction
B. Create RNA
C. Replicate DNA and RNA
D. Produce amino acids to be used to make tissues

_________ is required so that group of cells called tissues may have different function.
A. Cell interaction
B. Cell differentiation
C. Cell Proliferation
D. Cell Movement

Answers

Answer:

first A then B

Explanation:

The ribosomes's primary function in both the prokaryotic cells and the eukaryotic cells is to build proteins according to the cell's DNA instruction. Cell differentiation is required so that groups of cells called tissues may have different function. Thus, the correct options for 1 and 2 are A and B, respectively.

What are Ribosomes?

A ribosome is the cellular machinery which is responsible for the production of proteins in a cell. There are many ribosomes in each cell, each of these ribosomes are made up of two subunits- one large and one small subunit. These two subunits lock around the messenger RNA (mRNA) and then travel along the length of the messenger RNA molecule by reading each of the three-letter codons in the mRNA molecule.

Cell differentiation is the process which is required so that the group of cells called as tissues may have different functions. Cell differentiation results into formation of different cells and organs in the body.

Therefore, the correct options for 1 and 2 are A and B, respectively.

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To determine whether eating sweet snacks (e.g. candy) causes more weight gain than eating oily snacks (e.g. potato chips), you feed two different groups of mice 1g of either candy or potato chips each day for seven days, and you compare the starting weight of each group with the final weight after the week.

Identify the following elements of your snack experiment:

a. iIndependent variable:
b. Dependent variable:
c. Control treatment(s):
d. Experimental treatment(s)
e. Standardized variables:

Answers

Answer:

a. the independent variable is the type of food you are giving the mice.

b. the dependent variable is the final weight of each group of mice.

c. the control is the amount of food you give to the mice.

d. the experimental treatment is what you are doing (which is feeding the mice two types of food to see which one causes more weight gain).

e. the standardized variable is the amount of time you are feeding the mice for (seven days for both groups)

Explanation:

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If a diglyceride is formed, how many water molecules are involved?

a.
One.

b.
It depends upon the length of the fatty acids involved.

c.
Two.

d.
Three.

e.
None.

Answers

Answer:

b.

It depends upon the length of the fatty acids involved

In a certain breed of dog, the alleles B and b determine black and brown coats respectively. However, the allele Q of a gene on a separate chromosome is epistatic to the B and b color alleles resulting in a gray coat (q has no effect on color). If animals of genotype B/b ; Q/q are intercrossed, what phenotypic ratio is expected in the progeny

Answers

Answer:

12 gray , 3 black, 1 brown

Explanation:

If Q allele of a gene on a separate chromosomes is epistatic to the B (black) and b (brown) color alleles, in cross between two animals with genotypes BbQq produces 12 gray coat color, 3 black coat color and 1 brown coat color animals.

                                        BbQq      x      BbQq

                                   Gray coat        Gray coat

                   BQ                  Bq                 bQ                 bq

   BQ    BBQQ(gray)  BBQq(gray)   BbQQ(gray)   BbQq(gray)

   Bq     BBQq(gray)   BBqq(Black)  BbQq(gray)   Bbqq(Black)

   bQ     BbQQ(gray)  BbQq(gray)   bbQQ(gray)   bbQq(gray)

   bq     BbQq(Gray)   Bbqq(Black)  bbQq(gray)    bbqq(brown)

So the phenotypic ratio is  Gray : Black : Brown

                                        =      12  :      3   :      1

In carbon dioxide (CO2), there are two oxygen atoms for each carbon atom. Each oxygen atom forms a double bond with carbon, so the molecule contains two sets of double bonds.

Two sets of double bonds means that the total number of electrons being shared in the molecule is

two.
four.
six.
eight.

Answers

Answer:

the total number of being shared is six

Answer:

C.

Explanation:

What's is biosynthesis

Answers

The answer is:

Biosynthesis is a process in which substrates are converted to more complex products with inf living organisms or cells.

In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form macromolecules. This process often consists of metabolic pathways.

Answer:

the part of an organism close to the flesh and the cells

Explanation:

Biosynthesis is a multi-step, enzyme-catalyzed process where substrates are converted into more complex products in living organisms. In biosynthesis, simple compounds are modified, converted into other compounds, or joined together to form micro molecules. This process often consists of metabolic pathways.

Match the type of evidence for evolution with the correct example

Answers

Vestigial structures: 1st box

Homologous structures: Last box

DNA sequence data: 2nd box

Analogous structures: 3rd box

Which of the following does NOT relate to water?
A. Dehydration damages cells.
B. 70% of the human body.
C. Controls negative feedback mechanisms.
D. Contains and moves ions in and out of cells.

Answers

The answer should be D. Contains and moves ions in and out of cells

The following that does not relate to water is it contains and moves ions in and out of cells. The correct option is D.

What is water?

Water is a chemical compound made up of hydrogen and oxygen. It is a necessary part of life. As our body is made up of 90% of water, and without water, organisms would not survive.

The transport of ions and molecules in and out of the cell is done by the cytoplasm filling in the cell.

Thus, the correct option is D. Contains and moves ions in and out of cells.

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The MN blood group in humans is under the control of a pair of co-dominant alleles, M (we will call the frequency of M, p) and N (we will call the frequency of N, q). In a group of 556 individuals, the following numbers of individuals are found for each of the genotypes:

167 MM
280 MN
109 NN

Required:
a. What is the frequency of each allele?
b. What is the value of the Chi-square statistic test to find if in this particular case the genotypic frequencies conform to the Hardy-Weinberg distribution.
c. What is the probability associated with you chi square statistic calculated above?

Answers

Answer:

do you know some people have golden blood

Basidia within a basidiocarp are obvious for mushrooms, but this may not be as obvious for other examples that you have observed. For each of the examples of basidiomycetes that you have observed, speculate about the location of structures analogous to the basidia observed in mushrooms. Think about the formation of spores by meiosis.

a. bird's-nest fungi
b. common puffballs
c. earthstar puffball
d. shelf fungi
e. corn smut

Answers

Answer:

Birds nest fungi: Basidicarp, a cup shaped with several lenticular bodies appear as bird's nest with eggs. The eggs are called the peridioles and the nest serves release the eggs onto the twigs or branches and spores are liberated .

common puffball: The young fruit body is covered with whitish spines that become mark of scar after maturity.

Earth star puff balls: The fruiting body is in the shape of an egg, it has an outer part that separates away from the inner basidiocarp and splits into several rays which curve backwards and resembles a star.

shelf fungi: The fruiting body develops on the tree trunks and termed conk which are tough and leathery often plate-like growing out of the tree trunks.  

corn smut: The diploid teliospores germinate and undergo meiosis to result in four haploid basidiospores.

A biologist discovered a new animal. Upon studying its embryonic development, she observed radial cleavage with the blastopore developing into an anus. This animal was categorized as a parazoan. pseudocoelomate. deuterostome. protostome. radiata.

Answers

Answer:

The correct answer is ''deuterostome''.

Explanation:

Deuterostomes are a superphylum of animals in which the anus is formed in or near the blastopore area in the developing embryo, and the mouth is secondarily formed elsewhere. The oral apparatus that these adult animals enjoy does not come from the embryo's blastopore. Instead it is a new formation. They enter the Bilateria classification, where species that enjoy bilateral symmetry are incorporated. In deuterostomes, the primary phases of division occur in parallel to the axis between the tips. That is, the segmentation they have is radial when the embryo is in state 1 with four cells.

Which statement about the genetic code is false?
A. There is no punctuation or spacing between codons.
B. Codons are composed of sets of three nucleotides.
C. Every amino acid is specified by a single codon.
D. The genetic code is almost universal, but not quite.

Answers

————C————

Step by step explaintion:
trust me i’m right lol

The statement 'every amino acid is specified by a single codon' about the genetic code is FALSE (Option C).

The genetic code refers to the process by which the heritable information is passed from the DNA sequence to RNA during transcription, and then from RNA to protein during translation.

The genetic code is said to be redundant because there are amino acids that can be encoded by more than one codon.

For example, the amino acid leucine can be specified by four different codons (CUU, CUC, CUA, and CUG).

In conclusion, the statement 'every amino acid is specified by a single codon' about the genetic code is FALSE (Option C).

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which of the specific classification is the specific organism found

Answers

Answer:

Species are as specific as you can get. It is the lowest and most strict level of classification of living things. The main criterion for an organism to be placed in a particular species is the ability to breed with other organisms of that same species.

explain how the various specialiesed cells are modified to Cary out to their function 20mark​

Answers

Sperm cell; has acrosome containing lytic enzymes; that digest the egg membranes for penetration during fertilization; has a long tail; containing numerous mitochondria; to generate maximum energy for propulsion/swimming in the vaginal fluid after ejaculation; Red blood cells; are flattened, circular/spherical biconcave in shape; to increase the surface area for packaging of haemoglobin; has haemoglobin; that combines with respiratory gases; for transport to and from body tissues; White blood cells; are amoeboid in shape hence able to change shape; to engulf pathogens through phagocytosis; lymphocytes produce antibodies to fight pathogens; Nerve cell; has extensions/dentrites; to receive and send information for sensation; Ciliated epithelial cells; have cilia for propulsion of mucus that traps dust and micro-organisms in the respiratory tract; Muscle cells; elongated, striated and contractile; to bring about movement; Plant cells: Guard cells; bean-shaped; to regulate the size of the stomata allowing gaseous exchange; and control water loss; has chloroplasts with chlorophyll; for photosynthesis; Root hair cell; elongated; thin-walled; with dense cytoplasm for absorption of water and mineral salts; Epidermal cell; thin; for protection of inner tissues from mechanical and micro-organism attack; Palisade cell; contains numerous chloroplasts with chlorophyll; for photosynthesis; elongated; to increase surface area for trapping maximum amounts of light energy; Meristematic cell; thinwalled; with dense cytoplasm; for primary and secondary growth

describe why heart failure is so often referred as "congestive" heart failure ?

Answers

Answer:

Heart failure — sometimes known as congestive heart failure — occurs when the heart muscle doesn't pump blood as well as it should. When this happens, blood often backs up and fluid can build up in the lungs, causing shortness of breath.

Explanation:

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Which is a compound that allows plants to get nitrogen from the nitrogen cycle?

Answers

Answer:

Plants can use ammonia as a nitrogen source. After ammonium fixation, the ammonia and ammonium that is formed will be transferred further, during the nitrification process. Aerobic bacteria use oxygen to convert these compounds.

A DNA fragment is introduced into the lacZ gene of a plasmid, which also contains an ampicillin resistance gene. What is the appearance of bacteria transformed with this plasmid if they are spread on plates containing ampicillin and X-gal

Answers

Answer: White colonies that are resistant to ampicillin.

Explanation:

The lac operon is an operon required for the metabolism of lactose in enteric bacteria such as Escherichia coli . It has three structural genes, a promoter, an operator and a regulator, all regulated by the availability of glucose and lactose. The lac repressor, a protein, senses lactose and blocks transcription of this operon. It acts as a repressor when lactose is present. A catabolite-activating protein (CAP), on the other hand, acts as a glucose sensor. The bacterium should express the lac operon only when lactose is available and glucose is not available. Thus, genes can always be transcribed, except when the Lac repressor protein is bound to the operon region, for which it has a high affinity (i.e. in the absence of lactose), where the Lac repressor protein maintains its high affinity for the operon region, preventing RNA polymerase from transcribing the structural genes. Thus, the system remains closed with consequent energy savings for the bacterium. In the presence of lactose, it binds to the Lac repressor protein and generates a conformational change that decreases its affinity for the operator region. Thus, the operator region is left free, RNA polymerase can freely transcribe the structural genes and the synthesized β-galactosidase (an enzyme) can degrade lactose to glucose plus galactose for energy.  

Thus, the lac z gene encodes the enzyme β-galactosidase, which catalyzes the hydrolysis reaction of lactose to glucose and galactose. In gene cloning experiments, a compound called X-gal is used as an indicator of cells expressing the β-galactosidase enzyme. X-gal is hydrolyzed by the enzyme to galactose and another compound that is oxidized giving an insoluble blue compound. Thus, if X-gal and a β-galactosidase inducer are dissolved in the medium of a culture plate where the transformed bacteria is found, colonies grown on the plate that possess a functional lac z gene (either because they were not transformed by the plasmid, or if they were but the plasmid does not have the cloned fragment or gene that disrupts the lac z gene) can be clearly distinguished by their blue coloration. If they have another gene inserted interrupting the lac z gene, they will not be able to produce the enzyme that degrades X-gal, resulting in white colonies since X-gal is not degraded giving that characteristic blue color.

The white, non-transforming colonies are eliminated by adding an antibiotic to the medium for which the plasmid provides resistance (in this case ampicillin), so that we can select the recombinant colonies that carry the vector with our sequence, simply by their color.

So, if bacteria are transformed with a plasmid (with ampicillin resistance) cloned with a gene that interrupts the lac z gene, the bacteria will be white because they do not synthesize the enzyme that degrades X-gal and will be resistant to ampicillin.

Wheres the cell membrane located?

Answers

Answer:

in cells the cell membrain is located in the middel but this can vary in diffrent cells Explanation:

In the middle of the cell :)

Bacteria break down the nitrates and release oxygen. True or false? Short answer

Answers

Answer:

True

Short Answer-Denitrifying bacteria transform nitrate in extremely wet soils and swampy grounds where there is very little oxygen, i.e. the conditions are anaerobic. The bacteria get the oxygen they need for respiration from the breakdown of nitrates.

Explanation:

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Is the word ‘Autotroph’ rightly used to describe animals based on nutrition? Justify

Answers

Answer:

Autotrophs are the producers in the food chain, meaning they create their own nutrients and energy

Answer: I don't think that they are known as 'Autotroph'

Explanation: Encyclopedic entry. An autotroph is an organism that can produce its own food using light, water, carbon dioxide, or other chemicals. Because autotrophs produce their own food, they are sometimes called producers.

In the garden pea, yellow cotyledon color is dominant to green, and inflated pod shape is dominant to the constricted form. When both of these traits were considered jointly in self-fertilized dihybrids, the progeny appeared in the following numbers : 193 green, inflated : 184 yellow, constricted : 556 yellow, inflated : 61 green, constricted. Test the data for independent assortment

Answers

Answer:

IT was shown that observations of 60 : 40 produced a significant chi-square at the 5% level when uncorrected for continuity. Apply the Yates correction for continuity and retest the data.

Select the logical fallacy used in this statement: If we ban semiautomatic weapons, it won't stop until handguns and rifles are banned as well, and then the criminals will have all the guns.

Select one:
a.
Slippery Slope
b.
Ad Populum
c.
Ad Hominem
d.
There is no fallacy in this statement

Answers

Answer:

A- Slippery Slope

Explanation:

A slippery slope fallacy is when someone claims, without proper evidence, that an action will lead to an often catastrophic consequence via a series of events.

Here, the statement claims that if semi-automatics are banned, so will handguns and rifles, however, doesn't provide any evidence that this is the case.

The mass of the Sun is 1.99 × 1030 kg. Jupiter is 7.79 × 108 km away from the Sun and has a mass of 1.90 × 1027 kg. The gravitational force between the Sun and Jupiter to three significant figures is × 1023 N.

Answers

Answer:

4.16

Explanation:

edge2021

Answer:

4.16

Explanation:

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