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 ?

Answers

Answer 1

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.


Related Questions

A bird flies at 12.5 meters per second. the wind speed is 4.5 meters per second. what is the speed of the bird when it flies with the wind?

Answers

Answer:

17m/s

Explanation:

Given parameters:

Speed of the bird  = 12.5m/s

Speed of the wind  = 4.5m/s

Unknown:

Speed of the bird when it flies with the wind = ?

Solution:

The speed of the bird when it flies with the wind is the sum of the speed of the bird and the speed of the wind.

  Speed of the bird with wind  = 12.5m/s + 4.5m/s  = 17m/s

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

Answers

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.

This part of the respiratory system prevents food from entering your trachea.
A. Mouth
B. Epiglottis
C. Bronchioles
D. Nose

Answers

Answer:

the answer is epiglottis in the respiratory system

in your own, explain why you think that geologists find relative dating useful
i need the answer ASAP

Answers

Answer:

Because they can compare their findings with other geologest and their results.

Explanation:

Which types of mutations in the lac operon stop Escherichia coli from utilizing lactose as a carbon source? a) promoter deletion b) lactose-binding site mutation c) repressor DNA-binding site mutation d) operator deletion

Answers

Answer:

D.) repressor DNA-binding site mutation

Explanation:

lacl prevents the repressor polypeptide is a mutant that prevent operon from binding lactose, and thus will bind to the operator and be non-inducible.. This mutant will represses the lac operon whether lactose is present or not and the lac operon will not be expressed. It is also called“super-supperesor".

The lacI locus – One type of mutant allele of lacI (callled I-) prevents the production of a repressor polypeptide or produces a polypeptide that will not allow to bind to the operator sequence.

This is also a constitutive expresser of the lac operon because absence of repressor binding permits transcription.

Will give brainliest please help me.

Answers

Answer:

It looks like it could be the first one or last. But I'm pretty sure it's the last one.

Which of these mechanisms exerts gene control by suppressing transcription in eukaryotes?

A. Acetylation of histone proteins
B. Methylation of DNA
C. Action of activator proteins

Answers

Sets of transcription factor proteins buying a specific DNA sequences in or near a gene and promote or repress its transcription into RNA. Which i believe its C

Answer:

Its B. Methylation of DNA I just took the test.

Explanation:

Photosynthesis occurs inside of which organelle? a chloroplasts b the cell wall c mitochondria d ribosomes

Answers

Answer/Explanation:

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

A blonde woman uses dye to change her hair color to red;
however, her children WILL NOT INHERIT this red hair color because the
woman does NOT have *
O A) genes for red hair in her skin.
O B) proteins for red hair in her stomach cells.
O C) proteins for red hair in her brain.
D) genes for red hair in her gametes.

Answers

Answer:

D

Explanation:

Answer:

D,  genes for red hair in her gametes.

Explanation:

Because of the genetics. unless a family member or the father has red hair, in any relation (not including dye) then the children will not inherit the hair.


What are the ramifications (pros and cons of introducing a natural predator of cane toads?

Answers

I agree with the other presos

In rigor mortis, muscle tissue becomes locked in position because myosin heads are tightly attached to neighboring actin thin filaments. This lock-up is prevented in living muscle because ordinarily myosin is rapidly displaced from the thin filament by:_________.A. binding of a new molecule of ATP B. hydrolysis of ATP C. release of ADP after ATP hydrolysis D. release of phosphate after ATP hyrdolysis

Answers

Answer:

The correct answer is option A. binding of a new molecule of ATP.

Explanation:

Actin and myosin are complementary filaments present in muscle, actin is thin and myosin is a thick filament, these two filaments are responsible for the movement by muscle contraction and relaxation. Actin and myosin head shows great affinity towards one another.

Myosin heads are tightly attached to neighboring actin thin filaments due to its affinity to actin, however, myosin at other pockets also show a huge affinity for ATP. If myosin is bound to actin the affinity for ATP is changed and if new ATP bounds to the empty pockets it changes the conformation of myosin and prevents lockup or binding of the actin-myosin protein.

Adam's wife is concerned about his recent behavior. He wanders from room to room in their home and often has difficulty finding the front door, yet his vision seems fine. He complains that he feels odd sensations on his skin like bugs landing on him but when he goes to brush them off there are no bugs.

What part of the brain is damaged?

What functions does this part of the brain perform?

Answers

Answer:

La esposa de Adam está preocupada por su comportamiento reciente. Vaga de una habitación a otra en su casa y, a menudo, tiene dificultades para encontrar la puerta principal, pero su visión parece estar bien. Se queja de que siente sensaciones extrañas en su piel como insectos que se posan sobre él, pero cuando va a sacudirlos no hay insectos.

¿Qué parte del cerebro está dañada?

¿Qué funciones realiza esta parte del cerebro?

Explanation:

Adam's wife is concerned about his recent behavior. He wanders from room to room in their home and often has difficulty finding the front door, yet his vision seems fine. He complains that he feels odd sensations on his skin like bugs landing on him but when he goes to brush them off there are no bugs.

What part of the brain is damaged?

What functions does this part of the brain perform?

If a flower is not pollinated what will happen?​

Answers

Answer:

Will die?

Explanation:

We could have a shortage to our food supply

In a typical mammalian cell, what is the average percentage of total cell weight for protein and dna?

Answers

Answer:Protein is evaluated at ≈55% of the cell dry weight, followed by RNA at ≈20%, Lipid at ≈10% and DNA at ≈3% (the rest being polysaccharides, metabolites, ions etc.).

Explanation:

A typical mammalian cell averages 18% protein and 0.25% DNA by weight composition.

According to research, a typical mammalian cell is made up of water, ions, and macromolecules such as proteins, lipids, DNA, RNA, carbohydrates, and some miscellaneous metabolites.

The water component of a typical mammalian cell is about 70%, 18% proteins, 1% inorganic ions, 3% small metabolites, 5% lipids, 0.25% DNA, 1.1% RNA, and 2% polysaccharides.

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The commercial fishing industry uses large nets to capture fish. Often these nets catch many species of organism that are not used by humans. What Change could lessen the negative effect to this practice for the commercial fishing industry?


A. Designing nets that release unwanted species without harming them.

B. Using the net in deeper regions of the ocean where different organisms live.

C. Decreasing the size of the nets, but using more of them.

D. Exploring new and uncharted areas of the ocean where the nets can be used.

Answers

Answer:

A. Designing nets that release unwanted species without harming them.

Explanation:

Over-fishing is a negative human practice that leads to the over-exploitation of aquatic ecosystems (i.e., both marine ecosystems and freshwater ecosystems). In an aquatic ecosystem, the communities of organisms coexist in a delicate balance where they are dependent on each other in the food web, providing stability to the whole ecosystem. Therefore, the over-exploitation of any aquatic species is expected to impact the whole ecosystem, thereby also having a negative impact on other fish populations.

How many O2 molecules are required for to undergo cellular respiration?

Answers

Answer: Cellular Respiration and Photosynthesis In glycolysis, the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate. This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules.

Explanation:

Write a food chain from this food web with six trophic levels..

Answers

What food web? Do you have a pic?

Which of the following types of specialized cells are only found in plants? A:Phloem B:Glandular C: Muscle D: Nerve

Answers

Answer:

pretty sure its d im so sorry if im wrong I greatly apologize

How do healthy cell decide when to divide?​

Answers

Answer:

Cells regulate their division by communicating with each other using chemical signals from special proteins called cyclins. These signals act like switches to tell cells when to start dividing and later when to stop dividing.

A healthy cell decides when to divide by sensing and receiving signals from its surrounding environment.

The cell cycle can be divided into interphase and a mitotic (M) phase.

During the interphase, the cell synthesizes all materials required (i.e., proteins, DNA, etc) to divide during the M phase.

During the cell cycle, a cell modulates its division by communicating with other cells via specific chemical messenger molecules known as cyclins.

Cyclins are proteins that interact with Cyclin-dependent kinases (CDKs)  and thus function as molecular switches that regulate the progression through the cell cycle.

In conclusion, a healthy cell decides when to divide by sensing and receiving signals from its surrounding environment.

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The on in the middle pls

Answers

i
think it’s gonna be false

What are some of the functions of vascular tissue in seedless plants? (Choose all that apply)
provides structural support that allows some lycophytes to grow taller
transports water and minerals
transports food
produces food through photosynthesis

Answers

Answer:

Explanation:

Xylem transports and stores water and water-soluble nutrients in vascular plants.

Phloem is responsible for transporting sugars, proteins, and other organic molecules in plants.

Vascular plants are able to grow higher than other plants due to the rigidity of xylem cells, which support the plant.

Vascular tissues can provide support to the plants and also help in the transport of water, mineral and food. So, the correct options are A, B and C.

What is vascular tissue?

Vascular tissues mainly perform the function of supplying all the parts of the plant with water, minerals and food. there are two kinds of vascular tissues - xylem and phloem.

Xylem is the water-conducting vascular tissue. It conducts water from the roots of the plant to various other parts. In the xylem, the movement of water is unidirectional, which means it only conducts water from bottom to top and sometimes sideways

Phloem is the food-conducting vascular tissue of plants. It conducts water from leaves to other parts of the plant. In phloem, the movement of water is bidirectional, which means it conducts water from both directions. Xylem and phloem lie next to each other in a bundle called a vascular bundle.

Lycophytes are a group of seedless vascular plants which have a unique arrangement of their vascular tissues. In these plants, the lycophytes support the growth of plants.

Therefore, the correct options are A, B and C.

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Which of the following best describes the Earth's crust?

Answers

Answer:“Crust” describes the outermost shell of a terrestrial planet. Earth's crust is generally divided into older, thicker continental crust and younger, denser oceanic crust. The dynamic geology of Earth's crust is informed by plate tectonics. “Crust” describes the outermost shell of a terrestrial planet

Explanation: did the test in 7th grade and got in correct

Answer:

Thinnest under oceans and thickest under continents

how do you think the system used to organized where people live is similar to how your body is organized?​

Answers

The human body is organized at different levels, starting with the cell. Cells are organized into tissues, and tissues form organs. Organs are organized into organ systems such as the skeletal and muscular system

Which statement about a catalyst is correct?
1) A catalyst slows down a chemical reaction.
2) A catalyst speeds up a chemical reaction.
3) A catalyst has no affect on a chemical reaction.

Answers

Answer:

choice 2

Explanation:

because the catalyst reduces the activation energy of the reactants so the reaction then requires lower energy to occur then the reactents reach that energy in shorter time so the reaction takes shorter time .

In the covalent compound HCl, H—Cl, or H:Cl, which element has the greater electronegativity

Answers

Chlorine has a higher electronegativity than hydrogen, but the chlorine atom's attraction for electrons is not sufficient to remove an electron from hydrogen. Consequently, the bonding electrons in hydrogen chloride are shared unequally in a polar covalent bond.

Chlorine has a higher electronegativity than hydrogen, but the chlorine atom's attraction for electrons is not sufficient to remove an electron from hydrogen.

What is electronegativity?

Electronegativity is defined as property of an atom of a particular chemical element which has been a property to attract the shared electrons while formation of chemical bond. Atomic number is the only factor that can affect the electronegativity of an atom.

The subatomic particle which is negatively charged and that has been move freely or bounded is known as electron. Electron is a subatomic particle that contain negative charges and proton is the subatomic particle which contain positive charge. Electron does not contain fix shape and size.

Hydrogen is known as the most lightest known element and hydrogen is present in the form of gas and the atomic number of hydrogen is 1. The burning of hydrogen with oxygen in order to form water.  Atomic number is the only factor that can affect the electronegativity of an atom.

Therefore, Chlorine has a higher electronegativity than hydrogen, but the chlorine atom's attraction for electrons is not sufficient to remove an electron from hydrogen.

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Try reducing the level of fossil fuel percentage increase and decrease deforestation by 1 GT per year. Predict what will happen to the atmospheric carbon levels and record it in your Data Table. Run the simulation to test your hypothesis. Were you correct? Were you surprised by the result? What about your result surprised you?

Answers

Answer: The atmosphere can handle almost 700 billion tons of carbon in it. The carbon levels are increasing due to industrial revolution.

Explanation:

The overload of the emission of carbon in the atmosphere surprised me. The data was recorded and investigated for 2000 to 2100. Different parameters like ocean water and fossil fuel. The fossil fuel when burn contribute to the release of carbon monoxide and carbon dioxide gas. The oceanic water release the decomposed carbon dioxide by calcium carbonate of coral reefs and respiration of aquatic animals.

Explain the characteristics you observed when studying the epithelial types of the Epithelial Tissue from Kidney and Epithelial Tissue from Dermis and Epidermis images.

Answers

Answer: The epithelial tissue is a membranous tissue which has a function of covering.

Explanation:

The cuboidal epithelial tissues are present in the proximal convoluted tubules or PCT these tissues help in absorption of materials present in the filtrate generated in the glomerulus. These includes necessary salts, glucose, amino acids, water, gets selectively reabsorbed.

The stratified squamous epithelium are present in dermal layer of the skin. The dermal layer is the layer which receives the nerve supply of blood and nourishment. The epithelium helps in secretion of sweat and protection against microorganisms.  

If the atomic number of an element is 6 and its mass number is 13, how many neutrons
are
contained in the nucleus?
19
8
7
6

Answers

Answer:

There will be 7 neutrons in a carbon isotope with an atomic mass of 13.

Explanation:

The number of protons in the carbon isotope will be the same as the atomic number, 6, so if we need an atomic mass of 13 there will be 7 neutrons, as 6+7=13.

If the atomic number of an element is 6 and its mass number is 13, there will be 7 neutrons. Therefore, the correct statement is option C.

What is atomic number?

Atomic number is the number of protons found in the nucleus of an atom of a specific chemical element. The atomic number is also equal to the number of electrons orbiting around the nucleus in a neutral atom.

Mass number is the total number of protons and neutrons found in the nucleus of an atom and is represented by the symbol A. The mass number is used to determine the atomic mass of the atom.

The atomic number of an element is the number of protons present in its nucleus, which is 6. The mass number of an element is the total number of protons and neutrons in its nucleus, which is 13. So, the number of neutrons in the nucleus can be calculated by subtraction of the atomic number from the mass number.

The formula is number of neutrons = Mass number - Atomic number.

Therefore, there are 7 neutrons in the nucleus of the given element.

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3. When a single-celled organism splits into 2 new organisms it is called _________________. *

a.fission
b.budding
c.fragmentation
d.sporulatioin

Answers

Answer:

When a single-celled organism splits into 2 new organisms it is called fission.

When a single-celled organism splits into 2 new organisms it is called fission. Therefore, option (A) is correct.

What is binary fission?

In biology, fission is the split of a single organism into two or more pieces, followed by the regeneration of those parts into new, distinct organisms that resemble the original. Cells are often the thing that undergoes fission, although the phrase may also describe how creatures, bodies, populations, or species divide into distinct sections.

Asexual reproduction in bacteria occurs via a mechanism called binary fission. A single organism splits into two separate ones during binary fission. The duplication of organelles in eukaryotes is sometimes referred to as binary fission.

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7. The vessels that transports sugars produced during photosynthesis are______
and the vessels that transport water to the leaf are
called______
8.
______buds help plants to increase in height and_______
buds
helps plants to increase the width of the plant.

Answers

7. Phloem & xylem.
And I’m not sure about 8
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