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

Explain the evolution of altruism.

Answers

Answer:

Altruistic behavior, such as sterile worker ants caring for the offspring of their queen, evolves only between related individuals through what is known as kin selection — or so many evolutionary biologists have thought since the 1960s.

PLS HELP 20 PTS

Write a supported hypothesis of how the body would react if the peripheral nervous system was shut down while the central nervous system continues to function.

Answers

Explanation:

The real magnitude of this challenge can perhaps be best judged by considering the structural and functional complexity of the human brain and the bewildering complexity of human behavior. The human brain is thought to be composed of about a hundred billion (1011) nerve cells and about 10 to 50 times that number of supporting elements or glial cells. Some nerve cells have relatively few connections with other neurons or with such effector organs as muscles or glands, but the great majority receive connections from thousands of other cells and may themselves connect with several hundred other neurons. This means that at a fairly conservative estimate the total number of functional connections (known as synapses) within the human brain is on the order of a hundred trillion (1014). But what is most important is that these connections are not random or indiscriminate:

They constitute the essential "wiring" of the nervous system on which the extraordinarily precise functioning of the brain depends. We owe to the great neuroanatomists of the last century, and especially to Ramón y Cajal, the brilliant insight that cells with basically similar properties are able to produce very different actions because they are connected to each other and to the sensory receptors and effector organs of the body in different ways. One major objective of modern neuroscience is therefore to unravel the patterns of connections within the nervous system—in a word, to map the brain.

What happens when many water molecules come into contact with one another? Explain.

Answers

Answer:

When the oxygen atoms of different water molecules come together, they repel. When the hydrogen atoms of different water molecules come together, they repel.

Hope this helps

Why do you think scientists track the genes of other organisms such as rats or mice in the database? Do you think rat genes are important to human gene research?

Answers

Scientists study and track other animals' genes in an effort to understand how non-human creatures' genes work and operate. They do this to understand genetic risk factors in illnesses in the human population. This comes primarily from research on the genes of mice because mice are incredibly genetically close to humans --- there are literally thousands of genes in mice and rats that are phenomenally similar to humans. Manipulating their genes is extremely simple, such as adding or deleting genes to better understand their bodily functions --- also known as genetic engineering. The majority of mice and rats used in genetic research and medical studies are inbred and genetically similar, which makes the medical trial outcomes more consistent. This helps us find an understanding in whatever it is that we're trying to find. 

Scientists track the genes of other organisms like rats and mice in databases because these organisms share evolutionary similarities with humans, allowing researchers to study biological processes, diseases, and potential treatments that can apply to humans.

Rat genes are important to human gene research due to their similarities and potential for modeling human diseases and drug responses.

Scientists track the genes of various organisms, including rats and mice, in databases because these organisms serve as valuable model systems for studying biological processes, genetics, diseases, and potential treatments that are relevant to humans. Despite the differences in size and appearance, many biological functions and genetic pathways are conserved across species due to evolutionary relationships.

Rats and mice share a significant portion of their genes with humans and have similar anatomical and physiological characteristics. This similarity allows researchers to study fundamental biological mechanisms and disease processes in these animals and extrapolate the findings to humans. By tracking the genes of these organisms in databases, scientists can access a wealth of information about their genetic makeup, which aids in designing experiments and conducting comparative studies.

Rat genes, in particular, are important to human gene research because rats have a similar genomic organization and share many orthologous genes with humans. Rats are used extensively in medical and scientific research as model organisms to study human diseases such as cancer, cardiovascular disorders, diabetes, neurological conditions, and more. Their genetic and physiological similarities enable researchers to mimic disease processes and test potential therapeutic interventions in rats before moving to human clinical trials.

In summary, tracking the genes of organisms like rats and mice in databases is essential for advancing our understanding of genetics, diseases, and treatments that apply to humans. Rat genes are valuable in human gene research due to their evolutionary relationship with humans and their potential for modeling human diseases and drug responses, ultimately contributing to the development of medical treatments and therapies.

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Identify the following by typing (a) for mitosis or (b) for meiosis on the line before the statements: _____ produces 4 unique gametes _____ begins with a somatic cell _____ produces only 2 identical cells _____ has only one nuclear division _____ happens in the testes and ovaries _____ daughter cells are haploid _____ has two nuclear divisions _____ daughter cells are diploid

Answers

Answer:

b - produces 4 unique gametes

a - begins with a somatic cell

a - produces only 2 identical cells

a - has only one nuclear division

b - happens in the testes and ovaries

b - daughter cells are haploid

b - has two nuclear divisions

a - daughter cells are diploid

Explanation:

Mitosis is a kind of cell division that involves the formation of two daughter cells, which are genetically identical and have the same number of chromosomes as their parent cell (diploid). Mitosis occurs in body or somatic cells for repair and multiplication. Mitosis involves only one nuclear division.

Meiosis, on the contrary, involves formation of four daughter cells that are genetically different from the parent cell and have a reduced chromosomal number (by half). Meiosis occurs in reproductive cells like tested or ovaries. Meiosis occurs in two nuclear divisions.

In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon

Answers

Answer:

This question lacks options, options are: A) DNA replication is semiconservative. B) DNA replication is conservative. C) RNA synthesis is conservative. D) DNA replication is not conservative. The correct answer is A.

Explanation:

Watson and Crick proposed the semi-conservative hypothesis (later demonstrated by Meselson and Stahl in 1957), according to which new DNA molecules formed from an old one have an old and a new strand. This replication model assumed that the double helix DNA separates its two strands and each one serves as a template to synthesize a new strand following the complementary rules of nitrogenous bases. This model was called Semiconservative, since the two newly synthesized double helices have an old strand (an old half) and a new strand (a new half).

The process of the formation of new DNA from the older DNA is called replication.

The answer to the following question is semi conversation of DNA.

In the replication, there are two-strand in which one stand is template strand and the other stand is called leading strand. Both the strands act as a template strand and is being copied by the DNA polymerase.

These template strands formed the new DNA and joined it by the DNA ligase to complete it.

Hence, In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. This phenomenon is known as semi-conservation.

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Como es el sistema respiratorio de la vaca?

Answers

Answer:

Explanation:

jjjjjjjjjjjjjjjjjjjjjjjjjjjjjs4r44444

Which statement correctly compares nucleid acids and corbohydrates?

Answers

Answer:

The correct answer is 4) They both contain carbon, but only nucleic acids contain phosphorous.

Explanation:

nucleid acids and corbohydrates both contain carbon, but only nucleic acids contain phosphorous. Nucleic acid and carbohydrates are essential biomolecules, which are important for the survival of life forms. DNA and RNA comprises the nucleic acid, which posses the genetic information of the living organism.

If constructive interference occurs when two waves are cresting, it will decrease the height of the crest.
True
False

Answers

Answer:

True is the answer for your question. Mark me as the brainliest first please.

Explanation:

Answer:

False

Explanation:

I said true because of the other person and it was wrong. Trust me it’s False

Plz help I’ll give you brainliest!!
The California Current is a surface current that carries
water south from polar regions.
Callfornia Current
Which statement best describes how this current affects the climate on
nearby land?
A. It warms the eastern coast of the United States
B. It cools the eastern coast of the United States.
C. It warms the western coast of the United States.
D. It cools the western coast of the United States

Answers

Answer:

D

Explanation:

It's located on the west coast and it's carrying water from the cooler polar regions. It cools the western coast of the US.

Consider the phylogenetic tree of Old World primates.
According to the tree, which primates share the most recent common ancestor with humans?
A. gorillas
B. chimpanzees
C. bonobos and chimpanzees
D. bonobos and gorillas

Answers

Bonobos and chimpanzees.

Answer:  c)  bonobos and chimpanzees

Mr. Lim wants to start a sustainable oil palm plantation. In your opinion, how can Mr.Lim control the rat population that frequently destroy crops?​

Answers

Answer:

hope it helps

Explanation:

He can grow a cat or birds.

He can set up traps.

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thanku

refer the picture for question please

Answers

Answer: P= Nucleus Q= Mitochondria R= Golgi Bodies hope its help you keep smiling be happy stay safe

which organsism transform nitrogen to a form this useful to plants? a. bacteria b.animals c.fungi d.humans

Answers

Answer:

a. bacteria

Explanation:

There are nitrogen-fixing bacteria whose sole purpose is to transform nitrogen into a form which can be used by our friends called the plants.

Answer:

A. Bacteria

Explanation:

Nitrogen-fixing bacteria are capable of transforming it into fixed-nitrogen particles, that are usable by plants

any four different between ecology and ecosystem? please help me to do this.​

Answers

Explanation:

Ecology is the study of the relationship between living organisms and their environment. An ecosystem is a place, such as a rotting log, a forest, or even a schoolyard, where interactions between living and non-living things occur.

Answer:

Ecology is the study of the relationship between living organisms and their environment. An ecosystem is a place, such as a rotting log, a forest, or even a schoolyard, where interactions between living and non-living things occur.

Which type of protein would more likely be able to function as a channel through the plasma membrane

Answers

Answer:

Aquaporins

Explanation:

Aquaporins are the channel proteins that is present in the membrane of the cell which allow water to cross the membrane very quickly. This aquaporins play an important roles in plant cells, red blood cells, and certain parts of the kidney where this protein minimize the amount of water lost as urine. Without this protein, the diffusion of water across the cell membrane is not possible very quickly.

Which of the following types of stars started out on the main sequence with the largest initial mass?

a, b, c, or d?

Answers

Answer:

answer: C

Explanation:

hope it helps thanks❤

In a population of wild bees, a mutation resulted in slightly larger wingspan in some of the bees. This larger wingspan made the bees more efficient in their flights to flowers to collect nectar. Thus, these bees became more successful. This trait was passed on to offspring, and eventually the larger wingspan variety of bee replaced their smaller-winged relatives completely. It could be said that ____ favored the bee with the larger wingspan, and so the ____ evolved

Answers

Answer:

The correct answer is - natural selection, population.

Explanation:

In this case, the wild bees population experienced a mutation which helps in become more eeficient to fight for nector. This bees population is more sucessful to other that didnt recieved mutation and this mutation as it is adavtageous.

Natural selection always favored beneficial traits for the organisms to eveolved in generation therefore, these population is more succesful and replaced the short winged bees.

difference between clarias gariepinus and hetrobranchus bidorsalis?​

Answers

Answer:

The clarias gariepinus or african sharptooth catfish , belongs to the Clariidae family of airbreathing catfishes. They exist in freshwater lakes, rivers, and swamps, as well as man-made environments like oxidation ponds and even urban sewage systems, throughout Africa and the Middle East.

Hetrobranchus bidorsalist, he African catfish, sometimes known as the eel-like fatty fin catfish, is an airbreathing catfish found in Africa. It has a lot in common with the vundu catfish, which is well-known among anglers.

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In interstitial growth of cartilage ______. Multiple choice question. only new cells are produced only new matrix is produced news cells and new matrix are produced

Answers

Answer:

The correct answer is ''news cells and new matrix are produced''

Explanation:

Interstitial growth consists of the production of new layers of cartilage in the inner layer of the perichondrium. This process occurs because chondrocytes meet in the form of small groups, called isogens or cell nests, they are capable of dividing and the cartilaginous matrix is distensible. Daughter cells initially occupy the same gap but as they secrete new intercellular matrix they separate. These daughter cells can divide again, forming so-called isogenic groups, which are frequently found in growing cartilage.

which of the following structures helps our sense of balance​

Answers

Answer:

D answer is correct

Explanation:

semi circular helps our sense of balance

Answer:

eardrum

Explanation:

The ear is a sensory organ that picks up sound waves, allowing us to hear. It is also essential to our sense of balance: the organ of balance (the vestibular system) is found inside the inner ear. It is made up of three semicircular canals and two otolith organs, known as the utricle and the saccule

Someone, please help!

Answers

Answer:

Step 2: The right ventricle pumps the oxygen poor blood to the lungs via pulmonary valve. Step 3: The left atrium receives oxygen -rich blood and pumps it to the left ventricle. Step 4: The left ventricle pumps the oxygen-rich blood via aortic valve, submitting this blood through the entire body.

Explanation:

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what are the limitations of using fossil in evolution theory. Please answer​

Answers

The limitations of using fossil in evolution theory are that fossils are rare and only show changes in bones of animals. In many environments the preservation of fossils is hard creating gaps in fossil records that can make identifying change very hard. And when changes present themselves they can be in many forms, such as changing in the soft tissue, coverage and thickness of hair, and changes in organs, all of which can not be preserved by fossilization.

I’m not sure what kind of answer you need but I hope this is sufficient. Hope this helps. Stay healthy and stay safe! :)

After you eat lunch, nerve cells in your stomach respond to the distension (the stimulus) resulting from the food. This is best described as a mechanism between:

Answers

Answer:

stimulus, control center

Explanation:

The control center is the main nervous system of the brain that is used to carry out different sensory, the motor and integration of data.

The stimulus control is the behavioral control that is described as the situations where behavior is triggered by the presence or the absence of any stimulus. Stimulus is the functional reaction in a tissue or any organ.

In the context, the nerve cells in the stomach responds to the stimulus that results from the foods after eating food is a mechanism between the stimulus and the control center.

Pesticides are: Group of answer choices Always highly toxic to humans All of the listed answers All synthetic chemicals Always the best weapon against insect pests None of the listed answers

Answers

Answer:

Always highly toxic to humans.

Always the best weapon against insect pests

Explanation:

Pesticides are always highly toxic to humans as well as all synthetic chemicals are always the best weapon against insect pests because the chemicals used in these pesticides affect the body structure as well as other mechanism of survival for the insects or pests. The ingredients present in pesticides are highly toxic to humans which leads to the death of human while on the other hand, it is the best weapon used by humans against pest.

What organisms are in the chlorophyta reichenbach phylum

Answers

Answer:

Several species of Chlorophyta live in symbiosis with a diverse range of eukaryotes, including fungi (to form lichens), ciliates, forams, cnidarians and molluscs. i hope this helps

How many taxa or levels exist in the phylogentic?
a)7
b)4
c)6
d) 8​

Answers

D would be the correct answer I think

What concept includes the limiting factors that describe the zonation of flora and fauna along an elevational transect

Answers

Answer:

i dont know

Explanation:

because i have drop biology

Summarize what responsibilities scientist have and why:

Answers

To conduct and communicate scientific information with the public for the benefit of society, with excellence, integrity, respect, fairness, trustworthiness, clarity, and transparency. They play an important role in educating nonscientists about the content and processes of science. In fulfilling these responsibilities scientists must take the time to relate scientific knowledge to society in such a way that members of the public can make an informed decision about the relevance of research.

How does the experiment relate to what you've learned about submersible technology suck as submarines and ROV's?

Answers

Answer:

A submersible technology designed to operate the  submarines underwater.

Explanation:

We have learned about submersible technology suck as submarines and ROV's is that pumping system is used to remove water from the submarines and ROV's in order to make it lighter. A submersible is designed to push water to the surface. When a pressure switch is turned on, the impeller started to spin drawing water into the pump. The water is then pushed through the pump and brought it to the surface. Due to removal of water, the submarines and ROV's become lighter and they will come to the surface of water.

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animales muy sencillos cojmcuerpo bando a Anelidos b Artropodos c nidarios d Equinodermos In the electron transport chain, which structure forms a channel in the inner membrane of the mitochondria and adds phosphate to ADP According to the general equation for conditional probability, if P(A n B) = 3/4 and P(B) = 4/5 what is P ( A|B)?A. 35/36B. 15/16C. 8/9D. 24/25 Over the last several years, the United States has run a ________ in the goods trade balance and a ________ in the services trade balance. QUESTION 8Which of the following occurs during cell division in prokaryotes?Answers pick one:Spindle fiber attachmentDNA replicationHistone productionAll of the aboveNone of the above A man is charged by Congress with a crime. He is arrested and put in jail without trial. What forbidden power has Congress just used? A. Excluding a suspects Miranda rights B. Passing an ex post facto criminal lawC. Illegally issuing a bill of attainder D. Suspending the writ of habeas corpus number of ways you can wear 10 outfits to school each day in a 5 day week The correct answer is? 5Which equation represents the graphed function?40.3)fo(3.2)2.O y=-3x + 3o y = 3x - 3O y= 3x - }1 2 35X5 % -3 -2 -11-2-3O y=x+315 According to the census of 1790, how many enslaved people of African ancestry lived in the colonies? CAN SOMEONE HELP ME AND EXPLAIN ASAP THANKS! 1.Quick change of weight from one foot to the other displacing the supporting foot. 2. The person standing in opposite position across the set. 3.Like the motion on the handle of the clock moving to the left, when facing the center of an imaginary circle. Right shoulder is toward the center when moving forward. 4. Girl to right of Boy and Boy to left of Girl 5. Weight on one foot, swing the free foot in an arch, so that the ball or heel strikes the floor at lowest point of the arch. This may be done forward, sideward, or backward. Chloe has a small dog and a large dog. Each day, the small dog eats 3/4 cup of dog food, and the large dog 2 1/2 cups of dog food. In one week, how much more dog food does the large dog eat than the small dog ?A. 1 3/4 cups B. 8 3/4 cups C. 12 1/4 cups D. 22 3/4 cups writing a letter to your friend on how the party he couldn't attend went On Monday, ALL the Grade 7 students either bought their lunch at the canteen or brought their lunch from home. Given that 20% of the students bought their lunch at the canteen and 116 students brought lunch from home, how many students are in Grade 7? Helpppp and explain :)) 6. What is the relationship between genes and alleles? Consider the following equations and name the property of equality used to solve for the variable.A. x + 3.75 = 7B. 3b = 18C. StartFraction m Over 5 EndFraction = negative 25D. m 4 = 9 A company using the FIFO method had beginning work in process inventory of 10,000 units and completed 75,000 units. They also had 5,000 units in ending work in process inventory. The number of units started and completed equals_________ if AB ={(-1,1),(-1,2),(2,1),(2,2),(3,1),(3,2)}. find AA and BB. i need for exam.