The Ames test involves mutants of Salmonella that __________ the ability to make histidine in the __________ of a suspected mutagenic chemical.

Answers

Answer 1

Answer:

gain; presence

Explanation:

The Ames test is a lab methodology used to determine whether a particular chemical substance can trigger mutations in an organism, which can be used to indicate whether exposure to the target chemical compound is associated with a greater risk of developing cancer. The Ames test can use a strain of Salmonella typhimurium carrying mutations in a key gene that encodes a protein involved in histidine biosynthesis. In consequence, this S. typhimurium strain is considered to be a 'histidine auxotroph' which is unable to synthesize histidine residues. After exposure to the target chemical compound, bacteria are then cultured in a medium lacking histidine. Subsequently, bacteria that regain the ability to synthesize histidine proliferate to form colonies. Finally, the number of these colonies is then compared with the number of mutants in absence of the potential mutagen, enabling thus the determination of the mutagenic potential of the target chemical compound.


Related Questions

How do DNA and RNA differ?

Answers

Answer:

DNA is a long polymer with deoxyriboses and phosphate backbone. Having four different nitrogenous bases: adenine, guanine, cytosine and thymine. RNA is a polymer with a ribose and phosphate backbone. Four different nitrogenous bases: adenine, guanine, cytosine, and uracil.

Answer:

DNA contains the sugar deoxyribose, while RNA contains the sugar ribose. DNA is a double-stranded molecule, while RNA is a single-stranded molecule. DNA is stable under alkaline conditions, while RNA is not stable. DNA and RNA perform different functions in humans.

Explanation:

QUESTION
All the following statements support the theory that similar organisms have a common ancestor except...
CHOICES
a. groups of organisms display similar embryonic development
b. transitional fossils show links between groups of organisms
c. similar DNA patterns occur in closely related organisms
d. organisms sharing a habitat tend to develop similar behaviours

Answers

Answer:

similar DNA patterns occur in closely related organisms

Why are coral reefs important to ocean life? Coral reefs take carbon dioxide out of the water and secrete it into their skeletons. Corals provide an important cleaning function by filtering debris from the water. Corals are an important link in the benthic food chain. Coral reefs provide food, shelter, and breeding grounds for thousands of marine organisms. Coral reefs grow upward to near sea level, providing shallow zones for benthic organisms.

Answers

Coral reefs are important becase they provide an important ecosystem for underwater life, they also not only protect the underwater world but also are safety as well it works as a buffer and it protects are coasts form waves , storms, and floods. Also the coral reefs themselves teem with diverse life thousands can be found in just one reef.

ruth is presenting the feedback model to her class help her complete the statements

Answers

Answer:

Feedback models are tools that provides specific, concise, and clear feedback for a particular thing.

Explanation:

Feedback models are tools that provides specific, concise, and clear feedback for the organization so that an organization can make useful changes which is necessary for the organization growth and development. There is high need of this feedback model which helps us to know about the specific areas where one needs to improve performances in order to work more effectively.

PLLZZZ HELP!!

 Diagram the alternation of generations life cycle of a plant. Put the following terms in order and type arrows (>) between the terms to show which direction the life cycle is going: sporophyte, gametes, gametophyte, spores, meiosis, sporangium. Label which parts are haploid and which parts are diploid. You may also list the terms in numerical order.

Answers

Answer:

i know that gametes and meiosis are both haploid, but i havent heard of the others yet, i cant help you there :/

The fruit of the mistletoe, a parasitic angiosperm, is a one-seeded berry. In members of the genus Viscum, the outside of the seed is viscous (sticky), which permits the seed to adhere to surfaces such as the branches of host plants or the beaks of birds. What should be expected of the fruit if the viscosity of Viscum seeds is primarily an adaptation for dispersal rather than an adaptation for infecting host plant tissues

Answers

Answer:

We should expect that the fruits should grow in population and spread more easily.

Explanation:

Like the relationship between bamboo and pandas, the relationship between the seeds and the beaks of birds should allow the seeds to spread to other areas more easily that would otherwise be a very gradual process if the seeds did not evolve its viscous ability.

When calcium carbonate is heated, it
decomposes into calcium oxide and carbon
dioxide. If 100 g of calcium carbonate are
decomposed, 56 g of calcium oxide is produced.
What would be the mass of the carbon dioxide
given off by the decomposition?
A. 448
B. 110 g
C. 156 g

Answers

Answer:

A. 44 g

Explanation:

First, you need to write a balanced equation:

CaCO₃ -> CaO + CO₂

Then, you need to find the molar mass of CaCO₃:

Ca = 40.078 amu

C = 12.0107 amu

3O = 47.9982 amu

_________________

100.0869 amu

Then, you calculate the moles of CaCO₃:

100 g ÷ 100.0869 amu = 0.9991 moles

In the balanced equation, we can see that the molar ratio of CaCO₃ and CO₂ is 1 : 1, so moles of CaCO₃ = moles of CO₂.

Now you need to find the molar mass of CO₂:

C = 12.0107 amu

2O = 31.9988 amu

________________

44.0095 amu

Finally, you can calculate the mass of CO₂ produced:

0.9991 moles * 44.0095 amu = 43.9698 g = 44 g

describe the stages in the process of selective breeding​

Answers

Answer:

Selective breeding takes place over many generations. These are the main steps for both plants and animals involve:

Decide which characteristics are important enough to select.Choose parents that show these characteristics from a mixed population. They are bred together.Choose the best offspring with the desired characteristics to produce the next generation.Repeat the process continuously over many generations, until all offspring show the desired characteristics.

Hope this answer helps you..!!

.

.

Select this answer as the BRAINLIEST!!

Answer:

I think the answer is Selective breeding takes place over many generations. These are the main steps for both plants and animals involve:

Decide which characteristics are important enough to select.

Choose parents that show these characteristics from a mixed population. They are bred together.

Choose the best offspring with the desired characteristics to produce the next generation.

Repeat the process continuously over many generations, until all offspring show the desired characteristics.

Hope this answer helps you ^^

Describe what makes the Möbius strip different from a strip of paper taped in a circle

Answers

It’s taped in the opposite direction, making a Möbius strip.

A child is suffering from fever but the doctor cannot immediately pinpoint the ailment on the basis of this one symptom. Explain why. Also mention another two such general symptoms.​

Answers

the child can also have sore and or maybe stomach problems. it can be indigestion

so there are various conditions one can go through and this may take time for a doctor to discover or bring to light the medical condition that the person I'd goin thru

Explanation:

please notify me if I'm incorrect

diffrences between pine tree and mango tree​

Answers

well ones a pine tree, and ones a mango tree

Answer:

A:pine tree is also know as Christmas tree

Explanation:

B:mango tree is broad andextremly big

Suppose you run three different paths from A to B. Along which path(s) would your distance traveled be different from your displacement

Answers

The distance is the measurement all around the path whereas displacement is the measurement of how far apart objects/ points are.
Hope this helps, please give me brainliest:)

trong chương trình lớp 7 các em đã học các ngành động vật nào?

Answers

Answer:

what's this can u explain me in hindi pls

Fatty acids are the building blocks of(1 point)


monosaccharides




amino acids




DNA




lipids

Answers

Answer:Lipids
Fatty acids are the building blocks of lipids:)

Fatty acids are the building blocks of lipids

WHAT ARE LIPIDS?

Lipids are one of the four major biological molecules in nature (the other three are proteins, carbohydrates and nucleic acids).

Lipids are organic compounds that are generally characterized by their insolubility in water.

MONOMERS OF LIPIDS:

Lipids, like every other biological molecule, are polymeric compounds i.e. they are made up of smaller monomeric units. The monomers that make up lipids are called FATTY ACIDS.

Therefore, fatty acids are the building blocks of lipids.

Learn more: https://brainly.com/question/18846036

what is meant by photosynthesis​

Answers

Answer:

Photosynthesis is a physio-chemical process by which green plants use light energy to drive the synthesis of organic compounds. It is an enzyme regulated anabolic process.

Explanation:

Answer:

During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. ... This transforms the water into oxygen and the carbon dioxide into glucose. The plant then releases the oxygen back into the air, and stores energy within the glucose molecules.

an experiment is replicable if different scientist can do the experiment and get the same results true or false​

Answers

Answer:

True

Explanation:

if multiple scientist do the same thing that means they are replicating the experiment

The statement "An experiment is replicable if a different scientist can do the experiment and get the same results" is definitely true.

What is a scientific experiment?

A scientific experiment may be defined as a complete set of procedures that are carried out under controlled conditions in order to determine the validity and accuracy of a hypothesis or construct a discovery.

If multiple scientists construct the same hypothesis and perform identical research and received the same results. It implies that they are just replicating the same experiment number of times.

But the only difference is that they understand different things and methodology very closely based on such outcomes. This gives each scientist a sense of special perception based on facts and evidence.

Therefore, the statement "An experiment is replicable if a different scientist can do the experiment and get the same results" is definitely true.

To learn more about Scientific experiments, refer to the link:

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A biochemist discovers several new microorganisms in a sample taken from the bottom of a deep lake in Antarctica. In characterizing one of these organisms, she finds that it cannot survive in an aerobic environment and produces lactic acid as a waste product. What is also likely true about this organism

Answers

Answer:

These organisms can live in anaerobic conditions.

Explanation:

These organisms can live in anaerobic conditions due to death occur in the presence of oxygenated environment or aerobic environment because these organisms are allergic oxygen and open environment. They have to be cultured and colonized in anaerobic condition means without the presence of oxygen so we can say that these organisms lives anaerobically.

What does an Electrocardiogram do?
A. Measures the electrical activity of a heart by measuring the current in the skin above it.
B. Pill that contains 3 grams of electrochemical material that helps keep the electrical current in the heart balanced.
C. Measures how much electrical current can be passed through a heart before it stops beating.
D. Restarts the heart by sending an electrical pulse through it.

Answers

Answer:

It actually measures the electrical activity

Explanation:

They are sticky wires that they put on your arms and chest etc

Electrocardiogram measures how much electrical current can be passed through a heart before it stops beating. The correct option is C.

What is electrocardiogram?

An electrocardiogram is a simple test that can be employed to check the rhythm and electronics activity of your heart. Sensors connected to the skin detect the electrical signals generated by your heart every time it beats.

The electrical signals in the heart are recorded by an electrocardiogram. It's a prevalent and painless test for detecting heart problems and monitoring heart health.

An electrocardiogram, also known as an ECG, is frequently performed in a doctor's office, clinic, or hospital room.

It is a heart electrogram, which is a chart of voltage over time of the electrical activity of the heart recorded with electrodes placed on the skin.

Thus, the correct option is D.

For more details regarding electrocardiogram, visit:

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There is a U-tube in which solutions in two arms A and B are separated by a membrane. Arm A contains glucose with concentration of 0.4 mol per liter and sodium chloride with concentration of 0.5 mol per liter. Arm B contains glucose with concentration of 0.8 mol per liter and sodium chloride with concentration of 0.4 mol per liter.
The solutions in the arms of a U-tube (the figure) are separated at the bottom of the tube by a selectively permeable membrane. The membrane is permeable to sodium chloride but not to glucose. Side A is filled with a solution of 0.4 M glucose and 0.5 M sodium chloride (NaCl), and side B is filled with a solution containing 0.8 M glucose and 0.4 M sodium chloride. Initially, the volume in both arms is the same.

If you examine side A in the figure after three days, the concentrations of glucose and NaCl should be _____________.

Answers

Answer:

0.4 M glucose, 0.45 M NaCl

Explanation:

I hope this helped!

Why is the sequence of amino acids important to the properties of a protein?

It provides structural support; the structure determines the function.
It retains and transmits important biological information.
It stores energy and provides covering to avoid water loss.
It stores energy and provides structural support for cells.

Answers

Answer:

it provides structural support, the structure determines the function

Answer:

it provides structural support, the structure determines the function

Explanation:

took the test and I got it right :) happy learning everyone

wirte 2 slogans on 'need to conserve nature? ​

Answers

Answer:

Tree planting is the safest solution to pollution. Save the earth, save our environment. Don't be cruel, conserve your fuel.

Answer:

Explanation:

1. Save plants, save nature

2. Don't let mother nature become a "once upon time"

Osteoporosis is a disease that affects the bones and leads to an increase in bone fractures. Osteoporosis is most likely
to be affected by which cycle?

Answers

Answer:

osteoporosis is most likely to be affected by phosphorus.

I hope this helps

During starch test why is leaf boiled in ethanol?
A) to kill its Protoplasm
B) to soften it
C) to extract its chlorophyll
D) to retain its starch

Answers

Answer:

think its C cause when you boil it almost loses all its colour

Question 4
What happens to the host cell at the end of the lytic cycle?
the cell breaks open and releases the new viruses
viral DNA combines with host DNA
the host cell divides normally and reproduces viral DNA along with it's own
new viruses are made inside the bacterial cell

Answers

Answer:

In the lytic cycle, a phage acts like a typical virus: it hijacks its host cell and uses the cell's resources to make lots of new phages, causing the cell to lyse (burst) and die in the process.

Explanation:

Hope this helps.

Prior to the industrial revolution in the mid-1800s, a species of moth had light-colored wings speckled with small black spots. This coloration camouflaged the moths resting on the birch trees growing in their native habitat, since birch bark has similar coloring. In the early 1900s, this changed as dark soot produced by industrial pollution coated birch trees such that the trees lost their speckled coloring. Years later, it was observed that the moths of this species had changed from being light and speckled to being solid black. Which is the most plausible reason for this change

Answers

Answer:

The dark colored moths were due to a genetic mutation, and were more than likely present before the Industrial Revolution. Their fitness was low because predators could easily see them on the light-colored trees. They would be eaten before they could reproduce and pass on their genetic mutation. After the trees became darkened by soot, the darker colored moths now had the survival advantage, able to "hide" from predators. The lighter colored moths became more visible to predators, and the advantage shifted. Now, the light colored moths were more visible to predators, were eaten, and didn't have the chance to reproduce. The darker moths with the mutation had the survival advantage, blending in with the soot-covered trees, and were able to reproduce at higher rates, passing the mutation on to later generations.

help with the answer

Answers

Answer:

last answer

Explanation:

epithelial tissue is a network of cells that lines your organs

14. Brainstorm and write at least 3 potential challenges or important points to consider when conducting the described
data collection.


Answers

When conducting an experiment, there are different aspects to consider, such as the question that drives to the reseach, the hypothesis, theoretical framework, variables involved -independent, dependent, and controll-, methodology, study groups, data analisys, among others.    

In the exposed example, Pincky is lacking theoretical framework, defining which are the study groups, methodology to collect data, and a description of data analysis.

---------------------

The scientific method is a research method that consists of systematic observations, measures, experimentation, analysis, and verification of a hypothesis. It is based on two aspects: reproducibility, which is the capability of reproducing the experiment in any other place by any researcher, and refutability, which is the susceptibility to be refused.

When conducting an experiment, you need to consider,

Definition and problem statement. The question for which there is not an answer yet.

Hypothesis formulation. A hypothesis is a scientific conjecture, not verified, that requires corroboration.

Data collection and analysis. This step involves testing the observations.

Results

Verification of hypothesis. This step involves the deriving of the working hypothesis.

Discussion and Conclusion.

Previous knowledge about the study object is always required for a better understandig.  A question the investigator wants to answer. The main goal of the study, which is basically what the investigator wants to find out. The researcher makes a hypothesis to predict what is going to happen. The experiment is to be performed to answer the question. The conclusions through which the hypothesis might be rejected or accepted.

--------------

So in this experiment there must be,

Theoretical framework, such as information about the species, life stage at which they begin chirping, about external factors that might affect it or benefit it, and etcetera.

The goal: To know how temperature affects cricket´s chirping

Hypothesis: Crickets chirp less frequently under cold temperature than under warm temperature.

Variables: Temperature → Independent

                 Chirp frequency → Dependent

                 Water and food supply, light exposure, refuge → Controlled

Study groups: group of crickets exposed to a warmer temperature

                        group of crickets exposed to a colder temperature

Methodology: Individuals analyzed should be in the same development stage, or at least be sexually mature. Two groups of 10 individuals each should be placed under the same conditions, excepting for temperature. One of the groups should be exposed to warmer temperatures and the other one to lower temperatures. Chirps should be recorded for a week.

Data analysis: Using the chirps records, the frequency can be measured for each group. Results should be compared using different statistical analyses.

Results: Results should be clearly exposed, using texts, charts, and graphs.

Discussion and Conclusion: Hypothesis acceptance or rejection. Discussion about the expected results against the observed ones.

-----------------------------

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Jenna's pencil fell off of her desk and she quickly reached down to catch it before it hit the ground. In the process the

Answers

Answer:

The complete question with its options is:

Jenna's pencil fell off of her desk and she quickly reached down to catch it before it hit the ground. In the process, the (1)_____ system first recognized the falling pencil. It sent signals to the (2)______ system, which then moved the components of the(3) _____ system in order to catch the pencil.

Options:

(1) 1. Nervous 2. Muscular 3. Skeletal

(2) 1. Nervous 2. Muscular 3. Skeletal

(3) 1. Skeletal 2. Digestive 3. Nervous

The answer is:

Jenna's pencil fell off of her desk and she quickly reached down to catch it before it hit the ground. In the process, the (1) Nervous system first recognized the falling pencil. It sent signals to the (2) Muscular system, which then moved the components of the(3) Skeletal system in order to catch the pencil.

Explanation:

The nervous system receives the signal that the pencil is falling. In other words, Jenna sees or feels that the pencil falls, so the senses send a signal to the nervous system to produce a response. We call this a stimuli. Once that the nervous system receives and processes the stimuli, it elaborates an answer. The answer is to send a signal to a group of muscles that will move certain bones to make the movement that will catch the pencil. The muscles are from the muscular system, and they are attached to the bones, which are part of the skeletal system. When the muscles contract, they move the bones and make the movement possible.

Hibernation is _______.

Answers

Answer:

PROCESS OF SLEEPING FOR MONTHS .

LIKE BEARS,BATS,ETC

Answer:

the condition or period of an animal or plant spending the Winter in a dormant state.

What is the definition of gene flow?

Answers

Answer:

the transfer of genetic material from one population to another

Explanation:

Gene flow is also known as gene migration. It is the transfer of genetic material from one population to another.
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