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

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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how to get sick with fever fast​

Answers

Stay out in the cold for long periods of time as this can make you have a runny nose. You could also drink cold water or and put ice on your forehead to fake a temperature

Answer: Over exhaust your self and stay up for two days no sleep.

Wild diploid wheat has seven chromosomes in its pollen. Discuss the major events that had to occur for tetraploid pasta wheat to have evolved. Describe the genome and fertility of pasta wheat (number and kinds of chromosomes).

Answers

Answer:

Tetraploid wheat evolved by allopolyploidization and subsequent diploid-like behavior due to cytological diploidization

Explanation:

Durum wheat (Triticum durum) or pasta wheat, is a tetraploid wheat species that has 28 chromosomes, i.e., seven pairs in each genome (2n = 4x = 28). Durum wheat was domesticated from wild emmer wheat, which originated by hybridization of two diploid wheat species with 14 chromosomes: Triticum monococcum (genome AA) and one wild progenitor (genome BB). Triticum durum is a typical example of evolution by hybridization and polyploidization, where the resultant tetraploid species has two complete sets of chromosomes. Allopolyploidization is one of the most common types of plant speciation. During meiosis, 28 chromosomes form 14 homologous chromosome pairs, because homologous chromosomes have developed 'restriction of pairing' (i.e., cytological diploidization). The restriction of pairing to fully homologous chromosomes ensures a correct meiotic behavior, which otherwise would be altered due to the high level of homology that still exists among chromosomes from different wheat progenitors.

which is a characteristic of pseudoscience

resistance to change
continually changing
involves a step-by-step method
updated by new technology​

Answers

A. resistance to change

Hope this helps!

Answer:

a

Explanation:

i took the test

What were the ancestors of mitochondria according to the endosymbiotic theory?

20 points

A. Aerobic eukaryotes

B. Aerobic bacteria

C. Anaerobic bacteria

D. Chloroplasts

Answers

Answer:

d is your answer

Explanation:

Ancestors of Mitochondria were aerobic bacteria, according to endosymbiotic theory.

What is endosymbiotic theory ?

According to Lynn Margulis' endosymbiotic theory, mitochondria in eukaryotes are thought to have originated via an endosymbiotic connection with purple photosynthetic bacteria around 1.5 109 years ago. The endosymbiont, which had been captured, was subsequently transformed into a useful organelle bound by two membranes. Supporting data for the endosymbiont theory.

Prokaryotic cells and mitochondria are the same size. The DNA found in mitochondria is structurally identical to bacterial DNA. Similar to bacteria, mitochondria are self-replicating cells divide by binary fission Two membranes enclose mitochondria, and the inner membrane is structurally very similar to that of bacteria.

Therefore, aerobic bacteria are the ancestors of mitochondria.

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The long whip-like structure that helps a cell move and gather food is called a
A. flagella
B. cilia
C. false foot
D. whipper

Answers

Answer:

flagella

Explanation:

It helps the cell move

In humans, earlobes that are suspended (detached) are dominant over those that are attached. If a mother has suspended earlobes (but her mother did not) and the father has attached earlobes, what are the chances that their first child will have attached earlobes?

Answers

Answer:

i would say it is a 50/50chance

Explanation:

NEED HELP RLLY BAD
where are excessive ketones normally seen in a test?
1. blood
2. urine
3. saliva

Answers

I’m pretty sure it’s in normally seen in urine from what I remember or could be blood but its not saliva

The region in a plant that is analogous to animal stem cells, and can develop into various types of tissues and organs, is the ______.

Answers

he root system includes those parts of the plant below ground, such as the roots, tubers, and rhizomes. Plant cells are formed at meristems, and then develop into cell types which are grouped into tissues

Suppose we stock a pond with 100 fish and note that the population doubles in the first year (with no harvesting), but after a number of years, the population stabilizes at what we think must be the carrying capacity of the pond: 2,000 fish. Growth seems to have followed a logistic curve. a. What population size should be maintained to achieve maximum yield, and what would be the maximum sustainable fish yield? b. If the population is maintained at 1,500 fish, what would be the sustainable yield?

Answers

Answer:

Explanation:

From the given information,

The first process is to determine the initial growth rate by using the formula:

[tex]R_o = \dfrac{In(2)}{t_d}[/tex]

where;

The initial growth rate(constant) = [tex]R_o[/tex] ; &

the doubling time = [tex]t_d[/tex] = 1 year

[tex]R_o = \dfrac{In(2)}{1 \ year}[/tex]

[tex]R_o[/tex] = 0.693 / year

Now, we move up to the net stage to find the growth constant by using the formula:

[tex]r = \dfrac{R_o}{(1 - \dfrac{N_o}{K})}[/tex]

where;

[tex]N_o[/tex] = population of fish in the pond = 100

[tex]R_o[/tex]  = The initial growth rate(constant)  = 0.693 /year

K = carrying capacity = 2000

Then;

[tex]r = \dfrac{0.693 \ /year }{(1 - \dfrac{100}{2000})}[/tex]

[tex]r = \dfrac{0.693 \ /year }{(1 - 0.05)}[/tex]

[tex]r = \dfrac{0.693 \ /year }{(0.95)}[/tex]

r = 0.730 / year

a)

Now, the maximum yield can be evaluated by using the expression:

[tex]= \dfrac{rk}{4}[/tex]

[tex]= \dfrac{0.730 \times 2000}{4}[/tex]

= 365 fish per year

Also, the maximum sustainable yield is said to be half of the carrying capacity suppose that the population growth obeys logistic curve;

i.e.

[tex]N' = \dfrac{1}{2} \times 2000[/tex]

N' = 1000 fish

b)

If the population is maintained at 1500 fish;

The sustainable yield can be calculated by using the formula:

The Sustainable yield = [tex]r\times N (1 - \dfrac{N}{K})[/tex]

The Sustainable yield = [tex](0.730/ year ) (1500) (1 - \dfrac{1500}{2000})[/tex]

The Sustainable yield = 1095 × 0.25

The Sustainable yield = 273.75 fish per year

The Sustainable yield ≅ 274 fish per year

Population size should be maintained to achieve maximum yield and Sustainable yield if population is maintained at 1,500 fish are 364.7 , 273.525 fish per year

Sustainable yield:

Given that;

Stock in start = 100 fish

Double in 1 year

Capacity of pond = 2000 fish

Find:

Population size should be maintained to achieve maximum yield

Sustainable yield if population is maintained at 1,500 fish

Computation:

Growth rate = ln₂ / 1

Growth rate = 0.693 per year

With no growth constraint r = [tex]\frac{0.693}{1-\frac{100}{2000} }[/tex]

With no growth constraint r = 0.7294 per year

A. Population size should be maintained to achieve maximum yield = [tex]\frac{0.7294 \times 2000}{4}[/tex]

Population size should be maintained to achieve maximum yield = 364.7 fish per year

B. Sustainable yield if population is maintained at 1,500 fish = [tex][(0.7294))(1500)][1-\frac{1500}{2000} ][/tex]

Sustainable yield if population is maintained at 1,500 fish = 273.525 fish per year

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A teacher asked her students to transcribe a DNA sequence into a complementary RNA strand. She gave the students the following DNA code: AGC TTA GGC. Which student created the correct RNA strand?

Student 1

CUG AAC UUG

Student 2

AGC UUA GGC

Student 3

TCG AAT CCG

Student 4

UCG AAU CCG



Question 4 options:

a.student 3


b.student 2


c.student 1


d.student 4

Answers

Answer:

student 4 bcoz thymine is replaced by uracil in RNA

Answer:Student 4

Explanation:

Need help ASAP 48 points

4 questions and map on top ASAP :)

Answers

We can’t see Figure 6

a metacentric chromosome is one that has a centrally located centomere and chromosome arms with approximately equal length. which of the human chromosomesare metacentric

Answers

Answer:

Human chromosomes 1 and 3

Explanation:

There are four types of chromosomes classified based on the position of their centromere. These chromosomes are metacentric, submetacentric, acrocentric and telocentric. As rightly stated in this question, metacentric chromosome is the chromosome that has a centrally located centomere making the chromosome arms to be approximately of equal length.

The metacentric type of chromosomes are present in humans as viewed using KARYOTYPE (a pictorial display of chromosome arrangement). Based on karyotyping, chromosomes 1 and 3 are METACENTRIC.

Describe the resting state of a neuron.

Answers

A resting neuron is negatively charged

Human protein X is encoded by human gene X. Gene X consists of 4 exons of 200 bp each, interspersed with introns of 1,000 bp each.
An mRNA cap will be found on ____________.
a. the primary transcript
b. the mRNA
c. at least one of the lariats
d. the poly(A) tail.
e. exon 1
f. all exons
g. some introns

Answers

Answer:

a. the primary transcript

Explanation:

The first step in RNAm maturation is the modification of the 5' end of the transcript via the addition of a structure called a cap or 7-methyl guanosine cap. The enzymes responsible for the formation of this cap are recruited to the phosphorylated C-terminal domain after the addition of the first twenty to thirty nucleotides of ARN. The formation of the cap is started by the addition of a GTP molecule oriented inversely to the 5' end nucleotide on RNA. Then methyl groups are added to this G residue and to the ribose forms of one or two nucleotides located on the 5' end. All these reactions take place in the nucleus when the mRNA is found as a primary transcript.

What happens to the actin and myosin during a muscle contraction?

Answers

Answer:

Once the myosin-binding sites are exposed, and if sufficient ATP is present, myosin binds to actin to begin cross-bridge cycling. Then the sarcomere shortens and the muscle contracts. In the absence of calcium, this binding does not occur, so the presence of free calcium is an important regulator of muscle contraction.

these minerals are formed through crystallization of molten materials which statement best describes these two minerals?

the mineral on the left formed from lava
the mineral on the right formed from magma
the mineral on the left has smaller crystals in the middle on the right
the mineral on the left cool more slowly than the mineral on the right ​

Answers

Answer:

The answer is D.

Explanation:

Just took the quiz and got it correct.

The correct statement is that the mineral on the left cool more slowly than the mineral on the right

The crystallization process is simply known as the way through which atoms are arranged to form a material with a crystal structure.

A ways minerals is formed is by:

Crystallization of magma or lava

The minerals that forms igneous rocks often solidify or freeze at different temperatures.

Magma are created underground, in the lower crust or upper mantle, due to the intense heat there.

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From how many stem cells does cell division take place in meiosis?

Answers

Answer:

They probably divide to make EITHER two stem cells, OR two more specialized cells.

Explanation:

Doctors are investigating the case of a patient with defective proteins.

Which organelle is most likely the cause?

A. lysosome
B. cell membrane
C. cytoplasm
D. ribosome

Answers

Answer:

Answer is D

Explanation:

I also took the test as well and got 100% on it

define asexual reproduction help plz​

Answers

Reproduction occurring without the sexual union of male and female gametes. :))

Which statement is evidence that the components of the genetic code are common to all organisms?

A. All animals have the same four nitrogenous bases in common with each other.

B. All eukaryotes have the same four nitrogenous bases in common with each other.

C. All living organisms have the same four nitrogenous bases in common with each other.

D. All prokaryotes have the same four nitrogenous bases in common with each other.

Answers

Answer:

C. All living organisms have the same four nitrogenous bases in common with each other.

Explanation:

Because all living organisms have the same 4 nitrogenous bases in common with each other but different sequences.

Natural _______is a mechanism for the evolution of a population to become better adapted for survival in a specific environment.

Answers

Answer:

natural selection

Explanation:

Which helps in the production of eggs?

testosterone
estrogen
semen
fallopian tube

Answers

Answer:

Semen helps in the production of eggs!

answer:

... semen...

explanation:

i'd be embarrassed to explain that bit

The energy given off by burning fossil fuels can be measured in
A) Joules
B) calories
C) Hertz
D) electronvolts​

Answers

Answer:

A

Explanation:

A

Answer:

A

Explanation:

Joules are used to measure energy

Please select the word from the list that best fits the definition

Brings dry, clear weather

Answers

Answer:

conduction?

Explanation:

Answer:

anticyclone/2nd one down

"Can dogs identify colors?" is an example of a scientific question. "Are dogs better pets than cats?" is not. Use complete sentences to explain the difference between these questions and why only one is scientific. (5 points) Your answer:

Answers

Dongs can Identify color i beleive because they do a lot of things that involve color like finding there toy and looking fir there owner i know they have other senses like scent and hearing and so but I beleive they do indetify color

In which form food is stored in the leaves? Comment

Answers

the answer is starch

Explanation:

food is stored in the leaf in form of starch in plants


Cell _________
is the process by
which cells divide

Answers

Answer:

Cell cycle

Explanation:

Mitosis is a process of nuclear division in eukaryotic cells that occurs when a parent cell devides to produce two identical daughter cells.

Brainly! For the first one to answer! Answer in one paragraph.

Do you solar cells, wind farms, tidal power, hydropower and thermal energy will solve our future energy needs?

Answers

Yes, personally I believe that solar cells, wind farms, tidal power, hydropower and thermal energy will solve future energy needs. The most common energy right now is coal and by burning fossils fuels, we are risking climate change as well as limiting our resources. Supplies won’t last forever especially at the rate we are going. By using sun, wind, and water as sources of energy, we have renewable energy which won’t run out anytime soon. Those energy are low cost and solves pollution issues!

Yes, according to my point of view I strongly believes that solar cells, wind farms, tidal power, hydropower and thermal energy will solve future energy needs.

Which source of energy is common now a days?

The most common energy now a days is coal and by burning fossils fuels, we are risking climate change as well as limiting our resources. Supplies won’t last forever especially at the rate we are going. By using sun, wind, and water as sources of energy, we have renewable energy which would not run out anytime as soon as we required. Those energy charges are low cost and solves pollution issues too.

Heat energy has been transferred from one place to another by three main processes and in convection, heat energy has been carried by the movement of particles of matter. In conduction, heat is transferred by particles vibrating. In radiation, heat is carried directly by electromagnetic waves.

Therefore, Yes, according to my point of view I strongly believes that solar cells, wind farms, tidal power, hydropower and thermal energy will solve future energy needs.

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From a single fertilized ovum undergoing a series of rapid cell divisions, a human infant develops. The embryonic cells become specialized for a variety of functions. Which of these statements best describes how different cell types develop?
A. Each cell type contains only the active parts of the DNA needed for that cell type.
B. Each cell has multiple copies of DNA that are affected in different ways by the environment to change the function of the cell at regular intervals.
C. Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells.
D. Each cell type has only one chromosome containing thr DNA needed for that cell type.

Please help ill give you 5 star and brainliest.

Answers

Answer:

Answer is C

Explanation:

Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes leading to a variety of cells

The statements 'each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells' BEST describes how different cell types develop (Option C).

Epigenetics refers to any change in gene expression that does not involve a change in the nucleotide sequence.

In an organism, all somatic cells are genetically identical, thereby changes in gene expression are due to epigenetic modifications.

These epigenetic modifications include DNA methylation and histone modifications (e.g., histone acetylation, histone methylation, etc).

Enzymes that add specific epigenetic marks such as histone acetyltransferases alter the accessibility of transcription factors to chromatin, thereby activating or repressing gene expression.

In conclusion, the statements 'each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells' BEST describes how different cell types develop (Option C).

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