The operon model of the regulation of gene expression in bacteria was proposed by _____. the operon model of the regulation of gene expression in bacteria was proposed by _____. watson and crick franklin darwin jacob and monod mendel
Answers
Discovery
The operon model (Lac operon) of the regulation of gene expression in bacteria was proposed by Jacob and Monod and hey got noble prize in 1965 in Physiology and Medicine for this discovery.
Definition
“Operons are cluster of coregulated bacterial genes which regulate other genes responsible for protein synthesis”
Explanation
Operons were first studied in the bacterium E.coli, and they involve the enzyme of lactose metabolism and tryptophan biosynthesis.
Structure of Operon
Operon is generally composed of three basic DNA components:
1. Promotor:
It is a nucleotide sequence which is recognized by RNA polymerase and initiate transcription.
2. Operator:
It is a segment of DNA that is present between the promotor and other genes to be transcribed. In presence of repressor, RNA polymerase is physically obstructed and cannot transcribe the genes. In the absence of repressor, operator is active and start transcription of other proteins.
3. Structural genes:
These genes are responsible for synthesis of targeted proteins under the influence of operator.
Example of operon model:
In bacteria two operon model have been extensively studied, these are:
a. Lac Operon, and
b. Tryptophan operon
The operon model of the regulation of gene expression in bacteria was proposed by François Jacob and Jacques Monod. They discovered that related genes in bacteria are organized into blocks called operons, which are controlled by a single promoter. An example of this is the lac operon in E. coli, which controls the expression of genes related to lactose metabolism.
Explanation:The operon model of the regulation of gene expression in bacteria was proposed by the French scientists François Jacob and Jacques Monod. These scientists demonstrated the organization of bacterial genes into operons, through their studies on the lac operon of E. coli. They proposed that structural proteins with related functions are usually encoded together within the genome in a block called an operon, and are transcribed together under the control of a single promoter, resulting in the formation of a polycistronic transcript.
For example, in E. coli, all of the structural genes that encode enzymes needed to use lactose as an energy source lie next to each other in the lactose (or lac) operon. This operon contains a promoter sequence to which the RNA polymerase binds to begin transcription. Between the promoter and the three genes is a region called the operator; the presence or absence of lactose determines whether a protein, known as a repressor, binds to this operator and prevents RNA polymerase from binding to the promoter. As such, the lac operon is a model for gene regulation in prokaryotic cells.
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Related Questions
Many biologists argue that the euglenoids should be classified as an animal-like protist rather than a plantlike protist
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Euglenoids are a group of unicellular organisms with both animal-like and plant-like traits, leading to classification challenges. Taxonomy and phylogeny based on molecular genetics and genome analysis have led to a restructuring of the kingdom Protista into multiple monophyletic supergroups, taking into account convergent evolution.
The question addresses the classification of euglenoids, which are unicellular organisms with both animal-like and plant-like characteristics. This classification ambiguity arises because euglenoids exhibit mobility and some are heterotrophic, which are traits associated with animals, leading zoologists to sometimes refer to them as 'Euglenozoa'. On the other hand, some euglenoids are capable of photosynthesis, a plant-like trait, causing botanists to call them 'Euglenophyta'. The taxonomy and phylogeny of euglenoids, and protists in general, have been reshaped with the advent of molecular genetics and genome analysis. These analyses have revealed deep evolutionary branches within the domain Eukaryota, dividing it into several monophyletic supergroups. The classification continues to evolve as new genetic information is discovered, making clear that morphologically similar protists may not necessarily share a recent common ancestor—a concept known as convergent evolution.
When Carter first moved into his neighborhood, he noticed hundreds of frogs on the roads after a rain storm. Lately, Carter has seen less than four or five frogs on his five-minute drive through the neighborhood. Which of the recent events is a reasonable conclusion based on Carter's observations? A drought has impacted the population size of the frogs. A new housing development has led to extinction of the frogs. The beginning of the winter has created temperatures too cold for the frogs. Increasingly warm temperatures have dried the skin of the frogs leading to death.
Answers
Answer: A drought has impacted the population size of the frogs.
Explanation:
The frogs are the amphibians who require both water and terrestrial habitats to survive and reproduce. The rainwater accumulates over the terrestrial regions can provide an ideal environment for the survival of the frogs.
According to the given situation, Carter noticed hundreds of frogs on the road after rain storm as the road environment was suitable for the survival of the frogs. But later on he observed less than four or five frogs. This may be because of the fact that the road might not be left with water which could be probably due to drought (a drought is a condition where a region does not receive appropriate amounts of rainfall which leads to the dry and hot environment).
Which two factors are mostly responsible for recent rapid globalization?
Answers
Advances in transportation and communication, alongside reduced trade barriers, have been key factors contributing to rapid globalization.
Advances in transportation and communication have significantly reduced the costs of moving goods globally, particularly with the development of shipping containerization in 1956. This innovation lowered transportation costs by up to 90% and facilitated the movement of goods worldwide. Secondly, the reduction of trade barriers between countries has played a crucial role in the rapid globalization process, making it easier for goods and services to flow across borders.
Medical transcription is the process of transforming medical descriptions of healthcare services into numeric or alphanumeric codes
a. True
b. False
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What is structural adaptation
Answers
Answer:
physical changes in an organism in order to survive in a given environment
Explanation:
edmentum
The Clean Air Act would be a reason for the Environmental Protection Agency (EPA) to regulate car emissions. Please select the best answer from the choices provided T F
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The EPA is an independent agency formed for environmental protection. Hence the statement The Clean Air Act would be a reason for the Environmental Protection Agency (EPA) to regulate car emissions is true.
Car emissions are very harmful for all the living organisms in an environment.
What does the order of DNA bases have to do with the traits of an individual?
Answers
Due to increasing concentrations of ddt as one moves up the food chain, cormorants and mergansers have about ______ times as much ddt residue as the background concentration in the water.
Answers
Toxins will be accumulated in the higher level pyramid, this phenomenon is called biomagnification. The rate of biomagnification from water to producer approximately 1000 times, while the rate for every level above producer around 10 times. Assuming the bird is a tertiary consumer, the rate would be 1000* 10^3= 10^6= 1 million times
Biomagnification leads to a 400-fold increase in the concentration of DDT in birds like cormorants and mergansers compared to the background concentration in the water.
The question addresses the phenomenon of biomagnification, which refers to the increasing concentration of a substance, such as DDT, in the tissues of organisms at successive levels in a food chain. This process occurs because DDT is not metabolized or excreted efficiently by organisms, and therefore accumulates in their bodies, particularly in fat tissue. As smaller organisms that contain DDT are eaten by larger ones, the concentration increases.
Hence, apex predators and birds like cormorants and mergansers, which are higher up on the food chain, can have concentrations of DDT that are significantly higher than the background concentration in the water. In the case of birds feeding on fish that have accumulated DDT, it has been documented that they can have a 400-fold increase in the concentration of DDT.
Explain in a complete sentence why it is important for scientists to share information with one another.
Answers
Which term best describes traits that are found on the x chromosome but not on the y chromosome?
Answers
Final answer:
X-linked traits are determined by genes on the X chromosome and are not present on the Y chromosome, leading to different inheritance patterns in males and females.
Explanation:
The term that best describes traits that are found on the X chromosome but not on the Y chromosome is X-linked traits. These traits are controlled by genes that are located only on the X chromosome. In human females, who have two X chromosomes (XX), these traits have a higher likelihood of being expressed. In contrast, human males, who have only one X chromosome paired with a Y chromosome (XY), can express these traits if the gene is present on their single X chromosome, leading to distinctive patterns of inheritance for X-linked traits.
X-linked traits can have significant implications for the expression of certain conditions, such as color blindness and hemophilia, which are more commonly observed in males due to the presence of only one X chromosome. The absence of a corresponding gene on the Y chromosome means that if a male inherits an X-linked recessive trait, he will express that trait since there's no dominant allele on the Y chromosome to mask the effect of the recessive allele on the X chromosome.
What is the advantage of having muscles that run at different angles in the stomach?
Answers
The stomach has three layers of smooth muscle fibers run in three different angles. These layers are critical in giving the stomach the capability to mix, well, ingested food as it is mixed with enzymes and hydrochloric acid. This is important because smoothe muscles can only contract in one direction hence the layers give multidirectional movements of the stomach hence goof mixing and better digestion.
How might damaged alveoli affect the oxygen level in the blood?
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In the myplate icon, which category is shown as a separate food group?
Answers
A wedge-capped capuchin is a species of South American monkeys. They live in groups that typically have one male and several females. Sometimes young males live in a group too in order to help take care of the young. Most groups have a dominant female that often displays aggression toward other females and young males in the group. Which best describes the group behavior of these monkeys? territorial imperative social hierarchy migratory hibernating
Answers
Answer:
The correct answer would be the social hierarchy.
Explanation:
A basic aspect of social organization that is decided by display behavior or fighting and leads to a ranking system or order of place of the animals in a group is known as social hierarchy.
Dominance type of social hierarchies often decided best or early access to mating, social interactions, or food within animal groups.
Wedge-capped capuchin monkeys show this type of social hierarchy in their pack or group where dominant females display aggression towards other young males and females.
Thus, the correct answer is the social hierarchy.
which kind of tumor grows in only one part of the body?
a. malignant
b. somatic
c. benign
d. signal
Answers
Here is your answer:
The proper answer to this question is option C "benign".
Reason:
The only tumor out of the options that grows in one part of the body would be the benign.
Also...
Benign is not cancer, because cancer can usually spread through the body but benign only stays in one part of the body. They could be dangerous if it forms in your brain but its not often.
Therefore the answer is option C!
If you need anymore help feel free to ask me!
Hope this helps!
~Nonportrit
All cells come from preexisting cells. a cell divides its dna in a process known as ____________ and its cytoplasmic contents in a process known as ____________ , producing two new daughter cells while all life begins as a single cell, the human body is not just one cell type. cells that can divide without becoming a specific cell type (i.e. skin cells) are known as ____________ . when stem cells undergo mitosis and divide, they produce two cells. one cell remains a stem cell and the other is a partially specialized cell known as a ____________ cell. cells undergo a process of specialization or determination called ____________ to become neurons, muscle cells, or skin cells. stem cells are the source of all different cell types.
Answers
All cells come from preexisting cells. A cell divides its DNA in a process known as mitosis and its cytoplasmic contents in a process known as cytokinesis, producing two new daughter cells while all life begins as a single cell, the human body is not just one cell type. Cells that can divide without becoming a specific cell type (i.e. skin cells) are known as stem cells. When stem cells undergo mitosis and divide, they produce two cells. One cell remains a stem cell and the other is a partially specialized cell known as a progenitor cell. Cells undergo a process of specialization or determination called differentiation to become neurons, muscle cells, or skin cells. Stem cells are the source of all different cell types.
Myod promotes muscle cell development by __________.
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Weather conditions would be LEAST likely to affect supply in
A.farming
B. fishing
C. technology
D. transportation
Answers
since the technology production (or supply) isnt affected by the weather
Answer:
c
Explanation:
TECHNOLOGY, weather can only affect supply if the components got damaged.
How can white blood cells tell the difference between body cells and pathogens?
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What is the primary function of the calvin cycle of photosynthesis?
Answers
Calvin cycle also known as dark reaction. It occurs in stroma of chloroplast. Its main function is to fix CO₂ into glucose molecule with the help of ATP and NADH₂.
The Calvin cycle is a crucial part of photosynthesis that converts atmospheric carbon dioxide into carbohydrates using ATP and NADPH, thereby storing energy from sunlight in a form that the plant can use for growth.
Explanation:The primary function of the Calvin cycle in photosynthesis is to convert carbon dioxide from the atmosphere into carbohydrates. This process, also known as carbon fixation, occurs in the stroma of the chloroplasts. During the Calvin cycle, an enzyme called RuBisCO facilitates the reaction between carbon dioxide and a compound called ribulose bisphosphate (RuBP). This reaction in combination with the energy and reducing power of ATP and NADPH results in the creation of Glyceraldehyde-3-phosphate (GA3P) molecules, thereby storing the energy from photosynthesis for the plant's use.
The Calvin cycle can be divided into three stages: fixation, reduction, and regeneration. With ATP and NADPH produced through light-dependent reactions of photosynthesis, CO2 is transformed into carbohydrates in a process that involves regeneration of RuBP. In summary, the Calvin cycle provides a method for plants to convert sunlight energy into chemical energy, which is stored in carbohydrate molecules and used for plant growth.
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Which male accessory structure is inferior to the urinary bladder and surrounds the superior portion of the male urethra?
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The prostate is a gland of the male reproductive system and is responsible for producing an alkaline fluid which constitutes the 30% of the volume of the semen. The main hormone that regulates the prostate is testosterone.
Enzymes are proteins that act as _____ for biological reactions.
Answers
The answer is catalysts. Catalysts speed up the rate of a reaction without getting consumed in the process. Catalysts, in this case, enzymes act by reducing the activation energy or changing the reaction mechanism (such as foregoing some transition states). A popular enzyme is a carbonic anhydrase that catalyzes the formation of carbonic acid in the blood plasma (from carbon dioxide and water), a critical function in regulating blood pH.
Enzymes work specifically to speed up the rate of the chemical reactions that occur inside a cell. They are needed for vital life functions. They aid in digestion and metabolism, They are so important that if one enzyme is missing or defective, the effects would be devastating.
In low-nitrogen conditions UCYN-A participates ina mutualistic symbiotic relationship with other organisms in the microbial mat. predict the most likley typre of symbiotic relationship between UCYN-A and the other organisms in the microbial mat if nitrogen becomes readily available from another source. provide reasoning to support your prediction
Answers
Answer:
There are three distinct kinds of symbiotic associations, that is, commensalism, mutualism, and parasitism. In the given case, that is, when nitrogen becomes readily accessible from another source the UCYN-A will be in a parasitic relationship with other species and will be the obtaining food from them, as this species will not be able to perform the process of photosynthesis in order to generate its own food.
In the parasitic association, one organism, that is, the parasite feeds off of another organism, which is considered as the host, harming it and probably resulting in its death. The parasite thrives on or in the body of the host.
a. True
b. False: skinfold measurements can be used to estimate body fat percentage based on the assumption that the amount of subcutaneous fat is proportional to the total amount of body fat.
Answers
is true
Skinfold measurements can accurately estimate a person's body fat percentage by assuming the amount of subcutaneous fat (under the skin) is proportional to the total body fat. Calipers measure skinfold thickness at several body locations, and these measurements are used in equations to estimate body fat.
Explanation:The statement is indeed true. Skinfold measurements are widely used to estimate a person's body fat percentage. This technique assumes that the amount of fat stored subcutaneously, or directly under the skin, reflects the total amount of body fat. These measurements aid in the calculation of body fat composition, which is crucial in determining individual health status or fitness level. Special calipers are used to measure the thickness of the skinfolds at specific sites on the body. These values are then inputted into an equation to estimate body fat percentage.
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Which part of the gastrointestinal tract does gastric bypass surgery block off?
Answers
During Gastric Surgery, when food is eaten it enters a "new" or "different" stomach, then travels downward into the Jejunum bypassing (skipping) the upper part of the patients intestine. This action, decreases the amount of calories allowed into the body.
Hope this helps you!
~DL
Answer:
A colostomy is made by connecting the colon to the outside of the abdomen, bypassing the lower gastrointestinal tract.
A colectomy is a surgery that removes or excises a portion of the colon.
Explanation:
Name 4 ways the human body protects itself
Answers
Immune system memory - information about the pathogens encountered during an illness is stored in immune cells and is used to quickly destroy those pathogens if they become present in the body again (basis for vaccines)
Metabolic adjustments - during severe infections or trauma, the body lowers the consumption of nutrients thus lowering the chances of introducing unwanted microorganisms or toxins into the bloodstream
Blood-Brain barrier - filters out larger molecules - effetively preventing many microorganisms from entering the brain
Sneezing, runny nose, sweat, high fever, vomitting - creates unfavorable microenvironment and expels decomposed (fully or partially) and active pathogens( bacteria, viruses, fungi)
Hope this helps you! :)
Cartilage, found in the ears and nose, is a rubbery type of _____ tissue. studysoup.com
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Answer: The correct answer is Connective
In garden peas, tall is dominant to short. if two heterozygous tall plants are crossed, what proportion of the tall progeny will be homozygous dominant?
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If both parents are heterozygous tall then their genotypes would be both Tt, one capital and one lower case. In a Punnet it would look like this:
T t
T TT Tt
t Tt tt
Homozygous dominant means that the genotype should be TT. If you look at the punnet square, 1 out of the 4 is TT. This means that 25% will be omozygous dominant.
An example of antagonistic hormones controlling homeostasis is _____. an example of antagonistic hormones controlling homeostasis is _____. epinephrine and norepinephrine in fight-or-flight responses thyroxine and parathyroid hormone in calcium balance progestins and estrogens in sexual differentiation insulin and glucagon in glucose metabolism
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Producers rely on ____________ to create chemical energy and consumers rely on ____________ to release chemical energy.
Answers
B. Plants