Enzymes catalyze the many reactions in a cell. there are hundreds of different enzymes in a cell—each with a unique three-dimensional shape. why do cells have so many different enzymes?
In 1980, only 1 to 5% of all staphylococcus aureus isolates were mrsa strains. now 60 to 70% of s. aureus isolates are mrsa strains. what process is the cause of this situation?
Final answer:
The rise in MRSA strains among S. aureus isolates is due to the overuse and misuse of antibiotics, which selects for resistant strains. MRSA, resistant to many antibiotics, poses a significant health risk both in healthcare settings and in the community.
Explanation:
The process that has led to an increase in the percentage of MRSA strains among Staphylococcus aureus isolates from 1 to 5% in 1980 to 60 to 70% now is largely due to the imprudent use of antibiotics. This misuse fosters the expansion of populations of antibiotic-resistant bacterial forms. Methicillin-resistant Staphylococcus aureus (MRSA), which is resistant to multiple commonly used antibiotics such as methicillin, amoxicillin, penicillin, and oxacillin, represents a significant health challenge in various environments. Originally prevalent in healthcare settings, MRSA strains are now also found in the community, affecting younger populations. The development of MRSA is a classic example of bacterial adaptation through the selection pressure exerted by antibiotic use, resulting in strains that are challenging to treat due to their resistance to nearly all available antibiotics.
transcribe the highlighted portion of DNA into mRNA transcription mRNA copies of DNA into RNA using complementary bases
Ans. The correct answer is 'A-U-G-G-C-A.'
Transcription involves synthesis of mRNA molecule from a parent DNA molecule, with the help of RNA polymerase enzyme.
The RNA polymerase adds nucleotides in the growing RNA chain by reading template DNA strand, according to complementary base pairing, i.e., adenine binds with uracil, thymine binds with adenine, and cytosine binds with guanine, and guanine binds with cytosine.
Template DNA strand is : T-A-C-C-G-T
The mRNA strand will be: A-U-G-G-C-A.
Plants use the ____________ to make organic molecules. o₂ is an important product of the ____________ . the light-dependent reactions involve a series of ____________ conversions. an electron carrier called ____________ drives the light-independent reactions. h₂o provides ____________ for the light-dependent reaction
Answer:
1) Sun
2) Photosynthetic process
3) Chemical
4) NADPH
5) Oxygen and Hydrogen electrons
Explanation:
1) Photosynthesis is the process by which plants convert energy from the sun. It is the process that allows plants to create organic molecules that they use as fuel.
2) Specifically, plants use energy from sunlight to react carbon dioxide and water to produce sugar (glucose) and oxygen. Oxygen is also written as O[tex]_{2}[/tex].
3) the light-dependent reactions involve a series of chemical conversions.
Many reactions occur, but the overall chemical reaction for photosynthesis is: 6 CO2 + 6 H2O + light → C6H12O6 + 6 O.
That is Carbon Dioxide + Water + Light is converted to Glucose + Oxygen.
4) an electron carrier called NADPH drives the light-independent reactions. The full meaning of NADPH nicotinamide adenine dinucleotide phosphate hydrogen. NADPH is a produced during the first stage of photosynthesis and is used to catalyse the reactions that take place in the second stage of photosynthesis.
5) In photosynthesis, the light-dependent reaction uses light energy from the sun to split water (photolysis). Water, when broken down creates oxygen, hydrogen, and electrons.
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Photosynthesis converts light energy into chemical energy in plants, producing ATP and NADPH in light-dependent reactions. These energy carriers drive the Calvin cycle in light-independent reactions, creating organic sugar molecules from CO₂. Water provides the electrons needed for the light-dependent reactions.
Explanation:Plants use the process of photosynthesis to make organic molecules. Oxygen (O₂) is an essential product of the light-dependent reactions. These reactions involve a series of energy conversions in which sunlight is absorbed by chlorophyll and that energy is converted into stored chemical energy in the form of ATP and NADPH. An electron carrier called NADPH drives the light-independent reactions, also known as the Calvin cycle. Here, the ATP and NADPH produced in the light-dependent reactions are used to fix CO₂ into organic sugar molecules. Water (H₂O) provides electrons for the light-dependent reactions, with photosystem II initiating photosynthesis through the absorption of a photon
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Two events in space are described below. Event 1: The moon, the sun, and Earth are aligned along a straight line with the moon in the center, and the moon completely covers the sun. Event 2: The moon comes between the sun and Earth and covers only the sun's center, leaving the outer edges to form a ring of fire. Which event or events represent(s) a time any eclipse will be seen on Earth?
Both event one and two (which is C)
The reason for this is because for both examples, the sun, moon, and earth are aligned in some order, causing an eclipse
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Both Event 1 and Event 2 describe the types of eclipses that can be seen from Earth. Both Event 1 (total solar eclipse) and Event 2 (annular solar eclipse) represent times when an eclipse can be seen on Earth.
What is an eclipse?An eclipse is an astronomical event that occurs when one celestial object passes through the shadow of another celestial object. The most common type of eclipse is a solar eclipse, which occurs when the moon passes between the Earth and the sun, blocking the light of the sun and casting a shadow on the Earth.
Event 1 describes a total solar eclipse, which occurs when the moon passes between the sun and Earth and completely covers the sun. This alignment of the moon, sun, and Earth causes a shadow to fall on Earth, and those within the shadow can observe a total solar eclipse.
Event 2 describes an annular solar eclipse, which occurs when the moon passes between the sun and Earth but is farther away from Earth than during a total solar eclipse. As a result, the moon appears smaller in the sky and does not completely cover the sun, leaving a "ring of fire" visible around the edges. Those within the path of the moon's shadow can observe an annular solar eclipse.
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Two continental plates collide and begin to build up a mountain range. Gradually, a species of lizards becomes separated by the mountain range. The members on one side can no longer interact with members on the other side. Due to their separation, the two populations of lizards A. will evolve in exactly the same manner and remain as one species. B. will likely become extinct within one year. C. will begin hunting one another for food. D. will likely evolve into separate species over millions of years.
Two continental plates collide and begin to build up a mountain range. Gradually, a species of lizards becomes separated by the mountain range. The members on one side can no longer interact with members on the other side. Due to their separation, the two populations of lizards D. will likely evolve into separate species over millions of years.
This form of speciation is called allopatric speciation that happens due to the separation of a population of species by a geographical barrier. Due to the barrier the gene flow or the intermixing of the different individuals in the population stops which affects the gene frequencies in the population leading to a gradual drift in the genetic characters.
The use of Chemicals such as formaldehyde and asbestos has decreased because they have been
A biology student is studying ways to grow crops in soils that are high in salts and other dissolved solids. To determine whether corn plants can tolerate salty soil conditions, she grows 50 corn plants in typical garden soil and 50 corn plants in the same garden soil plus 0.01 kilograms of salt. After 6 weeks of growth, the corn plants grown in salty soil were the same mass and height as the corn plants grown in non-salty garden soil. The student concluded that salt had no effect on the growth of corn.
What comment would you make to the student regarding her experimental design and conclusion?
A) The experimental design included both a control and an experimental group. The conclusion is valid.
B) The student should have used more plants in each sample group; the larger the sample size, the more valid the results.
C) The conclusion is not valid. Increasingly high amounts of salt should have been added to more corn plots for comparison.
D) Although the conclusion is valid, next time the student might want to grow corn in plots with different water and temperature conditions as well.
Answer:
The correct answer will be option-C.
Explanation:
The experimental design to test a hypothesis must include all the parameters to be tested. The experimental design should include two types of samples: experimental groups in which the independent variable can be manipulated and the control group in which the variable to be studied must be absent.
In the given experiment the student tried to study the tolerance of the corn plants to salinity. So the amount of salt must be provided in different concentrations in experimental samples. The different amount of salt will help the student to compare the tolerance of corn plants in different concentration and will lessen the errors.
Thus, Option-C is the correct answer.
Nomex and kevlar are polyamides that are unusually tough and flame resistant. what structural feature makes nomex and kevlar different from other polyamides
A client comes to the emergency department reporting symptoms of the flu. when the health history reveals intravenous drug use and multiple sexual partners, acute retroviral syndrome is suspected. a test for the human immunodeficiency virus (hiv) is performed and acute retroviral syndrome is diagnosed. which clinical responses are associated most commonly with this syndrome
How does your nervous system code for the difference in intensity between a gentle tap with a hammer and a hard blow with the hammer?
Final answer:
The nervous system differentiates between a gentle tap and a hard blow by varying the frequency of action potentials fired by neurons, which is interpreted by the brain as different intensities of sensation.
Explanation:
The nervous system codes for the difference in intensity between a gentle tap with a hammer and a hard blow through the frequency of action potential firing by neurons. For instance, when a painful stimulus is applied, such as a hammer hit, it triggers activity in the nervous system, which is detectable through techniques like electroencephalography (EEG). The strength of the stimulus influences the rate of action potentials, providing the nervous system with information about the stimulus's intensity. This process allows us to perceive and differentiate between various intensities of sensory inputs, like distinguishing a gentle tap from a hard blow. Essentially, more intense stimuli lead to a higher frequency of action potentials, which the brain interprets as a stronger sensation.
The cartilage on the ends of wendell's joints is deteriorating. around age 65, he developed bony lumps on the end of the joints on his fingers. recently, he has been experiencing joint pain, swelling, and some loss of flexibility. wendell probably has __________.
Scientists theorize that Australia was once part of a larger mainland area but due to plate tectonics, broke away. According to island theory, scientists can explain ALL BUT one of these occurrences as a result of Australia becoming and staying an island for a very long time. That is
Answer:
The answer is "D"
Explanation:
Island theory suggests that you would see all but a large assortment of plant dispersal mechanisms on a well-established island that was once part of a mainland. The plants no longer need an array of dispersal mechanisms; they breed with like species that are near-by on the island. Also, they have an established niche in that location that has proven successful over the decades; whatever they are doing is working.
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According to island theory, scientists can explain ALL BUT one of these occurrences as a result of Australia becoming and staying an island for a very long time, and that is the presence of marsupials in Australia.
What is island theory?The theory of island biogeography suggests that islands have a limited capacity to support species, and as a result, they tend to have lower species diversity compared to larger land masses. Marsupials, a unique group of mammals characterized by their reproductive strategy of carrying their young in a pouch, are predominantly found in Australia and nearby islands, but not on other continents such as Africa, Europe, or South America.
The presence of marsupials in Australia cannot be explained by the island theory alone, as it would suggest that marsupials would have had to evolve in isolation on the Australian continent, which is unlikely given their close evolutionary relationships with placental mammals found in other parts of the world.
Hence, according to island theory, scientists can explain ALL BUT one of these occurrences as a result of Australia becoming and staying an island for a very long time, and that is the presence of marsupials in Australia.
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What is the correct way to write 1,550,000,000 in scientific notation? 1.55 109 1.55 1010 15.5 108 15.5 109
1.55 x 10^9
Explanation;Scientific notation is a way of writing very large or very small numbers. A number is written in scientific notation when a number between 1 and 10 is multiplied by a power of 10. For example, 1,550,000,000 can be written in scientific notation as 1.55 × 10^9.Sales promotions constitute the interpersonal arm of the promotional mix.
a. True
b. False
A pea plant with round seeds has the genotype rr. if you cross this plant with a wrinkled-seed plant, genotype rr, what is the probability that the offspring will have wrinkled seeds?
Describe problems that humans face because of pollution caused by urbanization and industrialization
Death and illness in a population is bad for the productivity of the system and is a destabilizing force. which theory takes this approach to medicine?
Answer:
Structural functionalism
Explanation:
In sociology, structural-functionalist theory explains the functioning of a society from social actions. That is, how the various actions of individuals make society function more or less stably. From actions arise social roles, from which in turn arise social institutions. Influenced by Durkheim and Radcliffe-Brown, structural-functionalist sociological theory took shape with Talcott Parsons (1902–1979) and Robert K. Merton (1910–2003) in the postwar United States.
Explain how the basic structure of the human respiratory system provides such a large area for gas exchange
Final answer:
The human respiratory system's large surface area for gas exchange is due to the presence of around 300 million alveoli in each lung. The alveoli provide a surface area of approximately 75 m² that facilitates the diffusion process, allowing oxygen to enter the blood and carbon dioxide to be expelled efficiently.
Explanation:
The basic structure of the human respiratory system is designed to maximize gas exchange by providing a large surface area within the lungs. This is primarily achieved through the presence of approximately 300 million alveoli in each lung, which collectively create a surface area of around 75 m². This extensive area is crucial as it increases the amount of gas that can diffuse into and out of the lungs.
Gas exchange occurs via diffusion, which is the movement of molecules from a region of high concentration to one of low concentration. Oxygen-rich air enters the alveoli and diffuses into the blood due to the higher oxygen concentration in the alveoli compared to the oxygen-depleted blood. Conversely, carbon dioxide diffuses from the blood, which has a higher concentration of CO₂, into the alveoli to be expelled from the body. This process is aided by the proximity of capillaries to the alveoli, allowing for rapid exchange of gases with blood.
What carcinogen is known to be produced when high-carbohydrate foods are cooked at high temperatures? acrylamides carrageenan nitrosamines dioxins?
Double fertilization results in the formation of select one:
a. two diploid embryos and a haploid endosperm.
b. one diploid embryo and a triploid endosperm.
c. two diploid embryos.
d. one diploid embryo and a diploid endosperm.
e. two diploid embryos and a diploid seed coat.
The phosphorus cycle differs from the biogeochemical cycles in that
The phosphorus cycle differs from other biogeochemical cycles as it lacks an atmospheric component and exists primarily as phosphate ions without a significant gaseous presence (option a).
The phosphorus cycle is unique among the biogeochemical cycles because it does not have an atmospheric reservoir (option a). Unlike other cycles, such as the nitrogen or carbon cycles, there is no gaseous form of phosphorus that is significantly present in the atmosphere. The cycle primarily involves the movement of phosphates, which enter soil and water ecosystems through the weathering of rocks and can be assimilated by organisms. Phosphorous is a key component in DNA, ATP (the carrier of energy within cells), cell membranes, bones, and teeth. Eventually, some of these phosphates reach the ocean and contribute to marine ecosystems or become part of the sediment. While phosphorus does not cycle through the atmosphere, it does have an oceanic reservoir in the sediment.
Another name for the range of motion of joints is _____. muscle endurance. cardiorespiratory endurance. flexibility. muscle strength.
Being a living example of a tobacco-free lifestyle can __________.
a. prevent others from trying smoking
b. convince friends to stop smoking
c. make others around you more healthy
d. all of the above please select the best answer from the choices provided. a b c d
Answer:
d
Explanation:
Rule out myocardial infarction is considered a ____ diagnosis
Which digestive organ is responsible for digestion and absorption of nutrients in earthworms?
Final answer:
The intestine is the digestive organ in earthworms that is responsible for the digestion and absorption of nutrients.
Explanation:
The digestive organ responsible for digestion and absorption of nutrients in earthworms is the intestine. As the food passes through the earthworm's alimentary canal, it first enters the mouth, moves through the esophagus, and is stored temporarily in the crop. The food then moves into the gizzard, where it is ground up and digestion begins. Following the gizzard, the food reaches the intestine where the digestion and absorption of nutrients occurs. Essentially, as the food travels through the earthworm's intestine, enzymes break it down, and the nutrients are absorbed into the bloodstream to nourish the earthworm. Unabsorbed waste material continues along the alimentary canal to be excreted as feces, also known as castings, through the anus.
Which of the following represents the highest level of DNA organization?
Nucleosome represents the highest level of DNA organization.
What is Nucleosome?
The fundamental repeating subunit of chromatin that is bundled inside the cell's nucleus is called a nucleosome.
In order to fit around six feet of DNA into a nucleus that has a diameter smaller than a human hair in humans, nucleosomes are crucial to the process.
About 150 base pairs of DNA are wrapped around a histone protein core to form a single nucleosome. The nucleosomes constantly fold in on themselves throughout the formation of a chromosome to compact and tighten the packed DNA. In our genomes, nucleosomes perform numerous functions.
Therefore, Nucleosome represents the highest level of DNA organization.
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During normal meiosis, homologous chromosomes pair up and separate so that each gamete receives a copy of every chromosome. Sometimes an error is made during this separation and homologous chromosomes fail to separate. This results in one gamete that has two copies of the chromosome, and another gamete that does not have the chromosome at all. This type of error is known as _______ and usually results in zygotes that either do not develop to term or have severe abnormalities. A. chromosome inversion B. chromosome insertion C. chromosome translocation D. chromosome nondisjunction
Answer: The correct option is D. chromosome nondisjunction.
Nondisjunction is a failure of either of two homologous chromosomes of passing into separate cells during the first meiotic division or the two chromatids of a chromosome are passed to the different cells during second meiotic division or during the mitosis. In other way, when the paired chromosomes fail to disjoin or to separate at the time of cell division, both the chromosomes go to only one daughter cell and none goes to the other. The error in chromosome numbers is caused due to nondisjunction like trisomy in Down’s syndrome and monosomy in Turner’s syndrome.
Which layer of the uterus is the site for implantation of an embryo?
Damage to the ________________ resulted in monkeys being unable to perform a once familiar response, specifically pushing in a lever and then turning it to the left. this result suggests that this brain area is involved in executing well-learned sequences of motor responses.
Damage to the basal ganglia leads to difficulties in carrying out well-learned motor tasks, demonstrating its vital role in movement control and motivation.
Explanation:Damage to the basal ganglia resulted in monkeys being unable to perform a once familiar response, specifically pushing in a lever and then turning it to the left. This result suggests that this brain area is involved in executing well-learned sequences of motor responses. The basal ganglia are interconnected brain areas that play important roles in movement control and posture. When damaged, as seen in certain diseases like Parkinson's, individuals can experience motor impairments and difficulty in executing controlled movements.
The basal ganglia also regulate motivation, which is observed in cases where damage to this area resulted in individuals showing a lack of interest in engaging in activities unless externally stimulated. This behavioral change signifies the crucial role the basal ganglia play not just in movement, but also in driving motivation to perform tasks.