Answer:
d. Wings were used in a flapping motion to help climb up steep inclined slopes such as trees
Explanation:
According to Top-down ( arboreal ) theory, feathered bird/dinosaur were tree dwelling species. They leaped in between trees to catch prey or avoid predators. They evolved flight mechanism to be able to glide better. According to Bottom-up ( terrestrial ) theory, feathered bird/ dinosaur were ground dwelling species. They used feathers to be able to sprint better and maintain balance while doing so. They also got lift with the help of feathers before running.
Both of these theories either considered origin of flight as a mechanism formed from tree dwelling species or by ground dwelling species. WAIR theory or Wing Assisted Incline Running theory had components from both of them. According to it, birds could run along steep or inclined slopes using wings, so they neither had to be completely tree dwelling or completely ground dwelling. Wings propelled them up the slopes and also conserved their energy.
Enzymes are important in cell's chemical reaction. Describe what a enzyme's role in chemical reactions is and explain what an enzyme does. The following key words may help you structure your response: active site, enzyme-substrate complex, and activation energy. Please try to use...
Answer:
Enzymes are proteins that allow certain chemical reactions to take place much quicker than the reactions would occur on their own.
Explanation:
Enzymes function as catalysts, which means that they speed up the rate at which metabolic processes and reactions occur in living organisms.
Answer:
Enzymes are proteins that catalyze chemical reactions that occur in living things. They accelerate the speed of reactions, which contributes to metabolism. Without enzymes, many reactions would be extremely slow.
Explanation:
Each enzyme is specific to a type of reaction. That is, they only act on a given compound and always perform the same type of reaction. The compound on which the enzyme acts is generally referred to as substrate. The great enzyme-substrate specificity is related to the three-dimensional form of both.
The enzyme binds to a substrate molecule in a specific region called a binding site. For this, both the enzyme and the substrate undergo conformation change for the socket.
They fit perfectly like keys in locks. We call this behavior the Key-Lock Theory.
Which of the following is a scientific statement?
A. A shark can jump as high as a low flying helicopter as shown in pictures on the internet.
B. Dinosaurs were killed off by a great flood as described in the Bible.
C. Unicorns used to exist because there are paintings of them from years ago.
D. According to DNA comparisons, humans share a common ancestor with chimpanzees.
E. Dogs are smarter than cats because it's easier to train them.
The correct answer is D. According to DNA comparisons, humans share a common ancestor with chimpanzees.
Explanation
A scientific statement is a statement made based on scientific evidence, that is, a scientific statement is the result of several tests focused on testing a hypothesis or proposal. These scientific statements can be developed in different areas of knowledge such as science, biology, physics, mathematics, geometry, among others. they are also predominant in the exact sciences because in the human sciences it is complicated to establish scientific statements because human behavior does not obey exact laws. According to this definition, option D. is the correct answer because it refers to DNA tests between humans and chimpanzees and therefore this is based on scientific evidence and tests.
The people who "discovered" the structure of the DNA molecule are:
a. Lewis &Clark
b. Schleiden & Schwann
c. Henderson & Hasselbeck
d. Watson & Crick
Answer:
Watson & Crick
Explanation:
DNA is present as the genetic material of all the living organism. The DNA contains of the nitrogenous bases, pentose sugar and the phosphate group.
The X ray structure of the DNA was given by Franklin. The structure of the DNA molecule and its properties was fully explained by the Watson and crick. They explains the polarity, base pairing and the arrangement of the DNA structure.
Thus, the correct answer is option (d).
James Watson and Francis Crick discovered the structure of the DNA molecule in 1953. They proposed the double helix model of DNA, which has proven to be crucial in the field of genetic engineering. The correct answer to the student's question is 'd. Watson & Crick'.
Explanation:The DNA molecule was discovered byJames Watson and Francis Crick.
In 1953, they proposed the double helix model of DNA. Their discovery was extremely important because it showed how genetic information is passed from one generation to another. This laid the groundwork for a whole new area of scientific research known as genetic engineering.
The answer to the question is: d. Watson & Crick.
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The plasma half-life of a hormone is inversely related to its metabolic clearance rate (MCR).
a. True
b. False
Answer:
True
Explanation:
The plasma half-life of a hormone is inversely related to its metabolic clearance rate (MCR) is true Statement.
Half life of a hormones is the life after which a hormone looses its half of pharmacological and physiological life whereas metabolic clearance rate is the volume of biological units cleared completely of drug metabolites as measured in unit time.
Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?
a. The species became separated by convergent evolution.
b. The climates of the two regions are similar.
c. India is in the process of separating from the rest of Asia.
d. India was a separate continent until 45 million years ago.
Answer:
The correct answer is option d. "India was a separate continent until 45 million years ago".
Explanation:
135 million years ago, Pangea was a single continent that became separated into Laurasia in the north and Gondwana in the south. India was part of Gondwana along with Australia, South America, Antarctica and Africa. However, as a result of tectonic activity India got separated from Gondwana. This period of time at which India was a separated continent is the factor that most likely explains why animals and plants in India differ greatly from species in nearby southeast Asia. At being a separated continent, India's plants and animals go through an independent evolutionary process which made them very different an unique from nearby species.
The difference in species between India and Southeast Asia is due to India being a separate continent until about 45 million years ago, leading to the evolution of distinct species through geographic isolation.
Explanation:The most likely cause for the difference in animal and plant species between India and Southeast Asia is related to geographic isolation. Historically, India was indeed a separate continent until about 45 million years ago; this prolonged separation has allowed for the evolution of distinct species in India that differ from those in nearby Southeast Asia. This concept is fundamental to our understanding of biogeography and evolutionary theory, showcasing how geographic barriers can lead to speciation.
Regions such as Australia and India, which have been physically separated from other land masses for millions of years, are home to many endemic species — species that are found nowhere else on Earth. This is a result of species evolving in relative isolation, without the influence of gene flow from outside their geographic area, leading to unique biological diversity in these separated regions. Thus, the distinct animal and plant life in India compared to Southeast Asia can be attributed to the historical separation of India as a land mass.
Charles Darwin observed this phenomenon during his scientific expeditions, noting that geographically isolated areas with similar climates often had 'utterly dissimilar' flora and fauna, further providing evidence for speciation through geographic isolation.
Glycolyis occurs ________________
a. photosynthesis
b. aerobic respiration only
c. both aerobic and anaerobic respiration
d. anaerobic respiration only
Answer:
Both aerobic and anaerobic respiration.
Explanation:
Glycolysis may be defined as the process of break down of glucose molecules for the formation pf ATP with the help of enzymes and chemical factors. Glycolysis occurs in the cytosol of the organism.
Glycolysis may occur in the presence of organism known as aerobic respiration. The glycolysis can occur in the absence of oxygen as well known as anaerobic respiration. The steps involved up to the formation of pyruvate molecule from the glucose is same in case of aerobic and anaerobic respiration.
Thus, the correct answer is option (c).
There are chemical signals that call on non-infected cells to help fight a virus. Which are they?
A. Complement proteins
B. Macrophages
C. B cells
D. Interferons
E. Natural killer cells
Answer:
D. Interferons
Explanation:
Interferons are the chemical signals (secretary proteins) responsible for activating non-infected cells so that they could fight a virus. In case of a viral infection, a cell infected by virus release interferons to let neighboring cells know the presence of a virus so that they could enhance their anti viral defense.
Interferons are of 3 types:
1) Interferon α
2) Interferon β
3) Interferon γ
Interferon α & β are secreted by white blood cells while interferon γ is mainly synthesized by natural killer cells.
Natural selection changes allele frequencies because some ______ survive and reproduce better than others.
a. alleles
b. loci
c. species
d. individuals
Answer:
The correct answer is option D. Individuals.
Explanation:
Natural selection is the process in which some individuals adapt traits or trends according to the environment changes in order to service and reproduce more. These trends are pass from one generation to another generation.
Natural selection is the first time described by Charles darwin.
Thus, the correct answer is option-
d. individuals
Some individuals survive and can reproduce better compared to others.
Natural selection is a method of selection of the organisms that have adapted to the change in their environment and can survive and reproduce in the variation.
What survives and adapts to natural selection?Individuals having better traits and attribute over others can survive and even can continue the generation of the species as they have adapted to the frequency change of the allele.
The alleles are the alternative gene form for a particular trait and characteristic and are located on the chromosome of the organism as they get passed from generation over generation.
Loci or the locus is a specific point where the allele for a specific trait lies on the chromosome. Species is the classification level of the taxonomy and includes organisms having major similar traits.
Therefore, option d is correct.
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A pea plant heterozygous for plant height, pod shape, and flower color was selfed. The progeny consisted of 272 tall, inflated pods, purple flowers; 92 tall, inflated, white flowers; 88 tall, flat pods, purple; 93 dwarf, inflated, purple; 35 tall, flat, white; 31 dwarf, inflated, white; 29 dwarf, flat, purple; 11 dwarf, flat, white. Which alleles are dominant in this cross?
Answer:
Tall , Inflated and Purple are dominant
Explanation:
The given phenotypical count is as follows -
Tall, inflated pods, purple flowers- [tex]272[/tex]
Tall, inflated, white flowers - [tex]92[/tex]
Tall, flat pods, purple - [tex]88[/tex]
Dwarf, inflated, purple- [tex]93[/tex]
Tall, flat, white - [tex]35[/tex]
Dwarf, inflated, white- [tex]31[/tex]
Dwarf, flat, purple- [tex]29[/tex]
Dwarf, flat, white- [tex]11[/tex]
Total number of species
[tex]272+92+88+93+35+31+29+11\\= 651[/tex]
Let Trepresents tall allele and t represent dwarf allele , P represents allele for purple flower and p represents allele for white flower , I represents alleles for inflated flower and i represents allele for
Phenotypical ratio
Tall, inflated pods, purple flowers- TTIIPP
Tall, inflated, white flowers - TTIIpp
Tall, flat pods, purple - TTiiPP
Dwarf, inflated, purple- ttIIPP
Tall, flat, white - TTiipp
Dwarf, inflated, white- ttIIpp
Dwarf, flat, purple- ttiiPP
Dwarf, flat, white- ttiipp
Hence, Tall , Inflated and Purple are dominant allele
The dominant alleles in this cross are tall, inflated, and purple.
Explanation:In this cross, the dominant alleles can be determined by analyzing the traits that appear in the offspring. By looking at the progeny, we can see that tall plants, inflated pods, and purple flowers are the most common traits. Therefore, the dominant alleles for plant height, pod shape, and flower color are tall, inflated, and purple respectively.
No two people are genetically identical, except for identical twins. The main source of genetic variation among humans is
a. new mutations that occurred in the preceding generation.
b. genetic drift.
c. the reshuffling of alleles in sexual reproduction.
d. environmental effects.
Answer:
c. the reshuffling of alleles in sexual reproduction.
Explanation:
During gametogenesis, meiosis occurs in reproductive cells. As a result, haploid gametes are produced. During meiosis, a process called ‘crossing over’ occurs in the pachytene stage of prophase I of meiosis. During crossing the chromosome segments are exchanged between non-sister chromatids of homologous chromosomes. Exchange of chromosome segment creates a new combination of genes or genetic recombination and produces hybrids. Thus, genetic variation occurs in all sexually reproducing organisms due to crossing over.
While many non-avian dinosaurs achieved gigantic sizes, the Sauropods were the true giants of the Mesozoic. in fact, the largest terrestrial vertebrates to ever live are members of this clade. However, it is not easy to estimate how large an animal was from just a fossil skeleton. Which of these is a method by which dinosaur body size is estimated?
a. Paleontologists measure the length of the legs from the hip to the foot and using a 2/3's power relationship convert that to a mass
b. Paleontologists use Archimedes principle and dunk the entire skeleton of a Sauropod into a pool of water and measure the water displacement
c. Paleontologists make scaie models with estimates of muscle mass, density and skin morphology and then estimate the volume of the model and scale it up
d. a and b
e. a and c
Answer:
The correct answer is option d. "a and b".
Explanation:
Plenty of methods had been developed to estimate the body size of dinosaurs such as the gigantic Sauropods. One of the first estimations that paleontologists used was the Archimedes principle, consisting in dunking the entire skeleton of a Sauropod into a pool of water and measure the water displacement or more precisely small dinosaur models. However this method requires the preservation of almost the entire skeleton. A more used and useful method is to measure the length of the legs from the hip to the foot and using a 2/3's power relationship convert that to a mass. This method is more used since it only requires a couple of leg bones, which are often well preserved.
Which of the following observations helped Darwin shape his concept of descent with modification?
a. Species diversity declines farther from the equator.
b. Fewer species live on islands than on the nearest continents.
c. Birds live on islands located farther from the mainland than the birds’ maximum nonstop flight distance.
d. South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
Answer:
The correct answer will be option-D.
Explanation:
Darwin is best known for his theory of evolution which he proposes after collecting the specimens of plants and animals on his voyage.
He observed the similarity and differences of the morphological pattern as well as the species present in the area. On the basis of his conclusions, he suggested that organism get traits from their parents and species to change over time also called descent with modification.
One of the evidence that supported his concept is that he observed plant species in South America and found that these species closely resembled the species of the tropical regions of South America rather than species of the temperate region of Europe as the habitat was same.
Thus, option-D is the correct answer.
Option D- South American temperate plants being more similar to tropical plants in South America than to temperate plants of Europe- helped shape Darwin's concept of Descent with Modification. This observation suggested organisms from a common geographical location were likely descendants of a common ancestor, supporting biography and the theory of evolution.
Explanation:The observations that helped Charles Darwin shape his concept of Descent with modification, primarily pertain to the geographical distribution of species, also known as biogeography. Several of the options you provided contain elements of this concept. However, the option which most explicitly illustrates this is:
d. South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
This observation supported Darwin's argument that geographic proximity is a better predictor of relationships between species than similarity in environment. This suggests that these species likely originated from a common ancestor and then evolved differently due to different environmental pressures - a phenomenon central to the concept of Descent with modification.
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Breathing is more difficult in higher altitudes because the
a. air weighs less
b. partial pressure of atmospheric oxygen is lower
c. partial pressure of atmospheric carbon dioxide is higher
d. partial pressure of atmospheric nitrogen is lower
e. partial pressure of atmospheric oxygen is higher
Answer:
Option (b).
Explanation:
Breathing may be defined as the inhalation of oxygen and exhalation of carbon dioxide. The breathing depends on the various internal and external factors.
The partial pressure of oxygen is directly proportional to the breathing and the inhalation of oxygen in the body. The altitude contains lower atmospheric pressure and the partial pressure o the oxygen decreases at high altitude. The decrease in the partial pressure of the oxygen reduces the affinity of oxygen with hemoglobin and thus an individual feels difficulty in breathing.
Thus, the correct answer is option (b).
Which of the following serves as reservoir hosts for all three of the pathogens that cause salmonellosis, influenza, and toxoplasmosis?
a. cats
b. reptiles
c. birds
d. mice
e. cattle
Answer: Birds option c is correct.
Explanation: Birds represents an example of natural reservoir host for the three zoonotic pathogens. For example poultry for salmonellosis and influenza from which house cats, humans and birds of prey can be infected. In the case of Toxoplasma gondii pigeons represent a better example of reservoir host.
Explain the reasoning establishing that a sequence of three nucleotides (a triplet codon) is the basic unit of the code relating DNA to protein.
Answer:
A sequence of three nucleotide called triplet codon is the basic unit of the code relating DNA to protein because we have four nucleotide which can code for 20 amino acids. So if we take a doublet code it can code for only 16 combination (4²=16) which is not sufficient for 20 amino acids.
But when we take a triplet code it can code for 64(4³=64) combination which is sufficient to code 20 amino acids found in human body. So this was the reason for scientist to establish three nucleotide code for a single amino acids. Later it was found that genetic code is universal and in every organism it is same for a particular amino acid.
suppose you want to set up an experiment to test the hypothesis that electromagnetic fields cause CCD, and you have 6 hives to work with. Which of these is the best experimental setup?
A. 6 hives exposed to high levels of EMF
B. 5 hives exposed to high levels of EMF and 1 hive with no EMF exposure
C. 3 hives exposed to high levels of EMF and 3 hives with no EMF exposure
D. 2 hives exposed to low EMF levels, 2 hives exposed to medium EMF. levels, and 2 hives to high EMF levels
The best experimental setup to test the hypothesis that EMF causes CCD would be to have 3 hives exposed to high levels of EMF (experimental group) and 3 hives with no EMF exposure (control group). This setup allows for comparison and contrast between the two groups, thus enhancing the accuracy and validity of the test results.
Explanation:The best experimental setup for testing your hypothesis that electromagnetic fields (EMF) cause Colony Collapse Disorder (CCD) in bees would be option C. 3 hives exposed to high levels of EMF and 3 hives with no EMF exposure. This arrangement allows for a control group (the hives with no EMF exposure), and an experimental group (the hives exposed to high levels of EMF).
The control group is necessary to compare and contrast with the experimental group, further enhancing the accuracy and validity of your results.
A good experiment requires a comparison between test subjects (the EMF exposed hives) and control subjects (the hives with no exposure), from which you can draw conclusions.
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In analyzing the number of different bases in a DNA sample, which result would be consistent with the base-pairing rules?
a. A = G
b. A + G = C + T
c. A + T = G + C
d. A = C
Answer:
b. A + G = C + T
Explanation:
Chargaff's rule states that a DNA molecule has the same amount of pyrimidines (T and C) as purines (A and G).
In the DNA, A pairs with T and G pairs with C. For that reason, the number of A bases has to be the same as the number of T bases, and the number of G has to be the same as the number of C.
Using the DNA base-pairing rules, the equation A + G = C + T would be consistent as the total number of purines (A and G) equals the total number of pyrimidines (C and T).
Explanation:Within DNA, the base-pairing rules state that adenine (A) pairs with thymine (T), and guanine (G) pairs with cytosine (C). Based on these rules, the equation A + G = C + T would be consistent as the total number of purines (A and G) equals the total number of pyrimidines (C and T). The other options are incorrect because A does not equal G or C, and the sum of A and T does not necessarily equal the sum of G and C.
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In writing On the Origin of Species, Darwin synthesized ideas from other publications, as well as observations he made while voyaging on the H.M.S. Beagle and afterward at home. The publications referenced in the first half of the time line all had a strong influence on Darwin. Which publication provided Darwin the insight that changes to the Earth can happen gradually over millions of years? Principles of Geology Philosophie zoologique Systema Naturae Essay on the Principles of Population
Answer:
Principles of Geology
Explanation:
J. Henslow gifted Darwin the first volume of Principles of Geology, written by Charles Lyell. The book explains about the old age of the earth. Accordingly, the slow rate of several geological processes suggests that the earth is very old.
Darwin read the book as the ship was crossing the Atlantic and learned about geological processes occurring over the millions of years. For example, he learned that the earth's surface was not formed by some catastrophic event.
In his book, Lyell explained the slow and gradual geological processes like erosion gave rise to the vast landscapes present on the earth's surface.
Darwin compared the time taken by geological processes to form the earth's surface and reasoned if these millions of years were enough to support the evolution of species.
What are the potential benefits, if any, and the side effects of each of the following supplements: steriods, diuretics, creatine, stimulants, boron, and vanadium.
Answer:
Steroids are prescribed to treat the condition of inadequate testosterone production, to treat the injury, and to initiate puberty. Some of the potential side effects of steroids are that in males it can cause reduction in sperm count, and shrinkage of testicles. While in women, it can cause the growth of body hair and can reduce the size of breasts.
In both males and females, steroids can cause liver and kidney damage, acne, heart issue, and psychological issues.
Diuretics help to reduce the amount of fluid in the blood vessels, which further helps to lower the blood pressure. Some of the side effects of diuretics are fatigue, muscle cramps, irregular heartbeat, dehydration, and even death.
Creatine assists in making muscles to produce more ATP and delay muscle fatigue. Some of the side effects are stomach and muscle cramps, diarrhea, nausea, weight gain, and water retention.
Stimulants help to reduce fatigue, better alertness and suppress appetite. Some of the side effects are nervousness, irritability, increased blood pressure, insomnia, hallucinations, and heart attack.
Boron is used in the treatment of osteoarthritis, enhances the levels of testosterone, and for better muscle coordination and better-thinking skills. Some of the side effects of boron are diarrhea, dermatitis, discoloration of feces, vomiting, nausea, and upper abdominal pain.
Vanadium is used to treat low blood sugar, diabetes, heart issue, high cholesterol, water retention, syphilis, and better athletic performance in weight training, and even prevents cancer. However, it can cause some side effects like green tongue, and diarrhea.
There are various supplements each with potential benefits and side effects. Steroids increase muscle mass but can cause health problems; diuretics remove waters and salts in bodies but can dehydrate; creatine increases strength and muscle mass but can lead to stomach discomfort; stimulants enhance focus and reduce fatigue but can increase heart rate; Boron could boost testosterone levels but high doses are toxic; Vanadium could improve athletic performance, but could damage kidneys.
Explanation:Several types of supplements are used for different purposes, each with potential benefits and side effects.
Steroids, synthetic forms of the male hormone testosterone, can help build muscle mass, however, their side effects can include infertility, aggressive behavior, cardiovascular disease, and brain cancer.Diuretics increase the amount of water and salt expelled from the body as urine. While this can aid rapid weight loss, it can also lead to dehydration, kidney problems, and electrolyte imbalances.Creatine is used to improve strength and lean muscle mass. It's generally safe but can cause side effects like stomach discomfort, muscle cramping, and dehydration with excessive use.Stimulants, like caffeine, can improve focus and reduce fatigue, but may lead to increased heart rate, hypertension, and insomnia.Boron is thought to boost testosterone levels, however, research is limited and high doses can lead to poisoning symptoms, including vomiting, inflammation, and digestive discomfort.Lastly, Vanadium may improve athletic performance and bodybuilding but it's not well studied, and can potentially cause kidney damage in high doses.
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What term is used to describe the relationship of the DNA strands to each other?
a. parallel
b. antiparallel
c. congruent
d. non-congruent
e. recumbent
Answer:
The correct answer will be option-B.
Explanation:
Deoxyribose nucleic acid or DNA is the genetic material of the organism which is made up of nucleotide monomer. The structure of DNA is made up of two strands of nucleotides coiled in a helical structure thus providing a double-helical shape to the structure.
Each nucleotide of a strand is composed of a five-carbon sugar, phosphate group and nitrogenous bases. These molecules are arranged in anti-parallel fashion in DNA which provides the polarity to the DNA strand. One strand is read from the 5' to 3' direction whereas another form 3'to 5' direction.
Thus, Option-B is the correct answer.
Vinblastine is a standard chemotherapeutic drug used to treat cancer. Because it interferes with the assembly of microtubules, its effectiveness must be related to
a. disruption of mitotic spindle formation.
b. suppression of cyclin production.
c. myosin denaturation and inhibition of cleavage furrow formation.
d. inhibition of DNA synthesis
Answer:
a. disruption of mitotic spindle formation.
Explanation:
Vinblastine is a chemotherapeutic drug which is used to restrict cancer cell proliferation. During metaphase, it binds to microtubular proteins which play a very important role in mitotic spindle formation. If spindles will not form then during anaphase, the sister chromatids will not separate and mitosis will not take place. This is how hyper-proliferative cancerous cells are controlled from dividing and cancer is treated using this drug.
Describe the key features of the Watson-Crick model for DNA structure.
Answer:
Watson and Crick proposed the double helical model of DNA.
Explanation:
- This model says that DNA exist as double helix. It has two polynucelotide strands running in opposite direction i.e the strands are anti-parallel.
- Each polynucleotide strand is made up of several nucleotide liknked together by phophodiester bonds.
- The two strands are not coiled upon each other but the double strand is coiled upon itself around a common axis like the spiral stair case. Here base pairs forms the stairs and backbone of two strands form railing. Back bone contains sugar and phosphate.
- The base pairing is specific, adenine always pairs with thymine and guanine always pairs with cytosine. Thus if we see any base pair, it consists of one purine and one pyrimidine.
- The two strands of DNA thus show complementary base pairing.
- The strands are held together because of hydrogen bonding between the bases in opposite strand.
- One full helical turn involves ten base pairs and the base pairs are stacked 3.4 A apart.
- This form is called as B-form of DNA.
Why do scientists think that new genes arise by duplication of an original gene and divergence by mutation?
Answer:
Explanation:
This is because of the fact that genomes of the organisms exhibit gene families and superfamilies. These contain genes that typically encode for proteins with similar aminoacid sequences, the proteins form by these aminoacids perform related functions. In this way the genes and their functions are duplicated among the gene families. This duplication of genes prevents the divergence from mutation.
The system of slavery began to replace indentured servitude because
Africans began to arrive in the colonies.
indentured servants began demanding higher “freedom dues.”
the need for a steady supply of low-cost labor increased.
Answer:
the need for a steady supply of low-cost labor increased
Explanation:
In the beginning (18th century) before slavery, indentured servitude was a way for poor Euopeans to pay their way for the costly voyage across the Atlantic to the New Colonies. Their contract terms were fixed in which they worked for their landowners or shippers until their debt was paid. As more and more of these indentured servitude served their contracts and became free, they also increased the demand for labor as they became landowners. The need for labor increased and the cost of indentured servants also increased.
White landowners, especially in early Virginia, turned to Africa for servitude. With time, using race to undermine Africans, greed for profits by landowners resulted in slavery and enactment of Slave Law in 1641.
Slavery began to replace indentured servitude due to the need for a consistent, cheap labor force in the American colonies. The arrival of Africans and the demands for freedom dues by indentured servants added challenges, leading to colonists to shift towards slavery.
Explanation:The system of slavery began to replace indentured servitude primarily due to socioeconomic reasons during the colonial period. Indentured servitude often led to social mobility and advancement once a servant's contract had ended, which created an inconsistent labor source for colonists. Colonists required a consistent, cheap workforce to cultivate profitable cash crops such as tobacco and cotton.
The arrival of Africans provided a new source of cheap labor. By classifying these individuals as property, colonists created an unchanging workforce. In addition to this, the demand for “freedom dues” from former indentured servants was hard to maintain. Furthermore, the economic need for a steady supply of low-cost labor due to the expanding plantation economy was a driving factor.
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DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that
a. humans and chimpanzees share a relatively recent common ancestor.
b. humans evolved from chimpanzees.
c. chimpanzees evolved from humans.
d. convergent evolution led to the DNA similarities.
Answer:a. humans and chimpanzees share a relatively recent common ancestor.
Explanation:
Humans and chimpanzees are not evolved from one another, but both have a common ancestors. Humans share a common ape ancestor with chimpanzees who is expected to live 6-8 million years ago. The humans and chimpanzees have been evolved differently from this ancestor.
The most likely explanation for this result is that humans and chimpanzees share a relatively recent common ancestor.
What is the common ancestor of humans?Scientists tend to believe that our common ancestor with the chimpanzee lived between 9 and 7 million years ago. Sahelantropus tchadensis is the closest hominin to this date that we know of.
With this information, we can conclude that the most likely explanation for this result is that humans and chimpanzees share a relatively recent common ancestor.
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Most cells cannot harness heat to perform work because
a. heat does not involve a transfer of energy.
b. cells do not have much thermal energy; they are relatively cool.
c. temperature is usually uniform throughout a cell.
d. heat can never be used to do work.
Answer:
Temperature is usually uniform throughout a cell (Ans. C)
Explanation:
Heat or thermal energy is a kinetic energy. That is connected with the random movements present in the atoms. Temperature is usually uniform throughout the cell so the most cell can not harness heat to perform work.
Heat is a type of energy which is transfer from one body to another body due to the temperature difference.
It can only perform work if it is transferred from one source which is warmer to a body which is cooler. The temperature in living organisms is usually kept very constant due to the process of homeostasis.
Most cells cannot harness heat to do work because temperatures within the cell are typically uniform, so there's no heat gradient for work to be conducted. Heat tends to be lost instead.
Explanation:Most cells are not able to harness heat to perform work because heat energy is often dissipated as waste during biochemical reactions. The correct option is c. The temperature is usually uniform throughout a cell. This means that there isn't a high temperature gradient in the cell, which would be needed in order for heat to be used for work. For heat to be harnessed and used for work, there must be a temperature difference because work is done when heat flows from a hotter area to a cooler one. Without a temperature gradient, heat energy cannot be used to perform work within a cell and is instead lost to the surrounding environment.
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Simply, transcription is a copy of __________
a. proteins from mRNA
b. mRNA from DNA
c. proteins from DNA
d. mRNA from proteins
Answer:
b. mRNA from DNA
Explanation:
Transcription is the process of synthesis of RNA using a DNA template strand. The process of transcription occurs inside the nucleus in eukaryotes as their DNA is present in the nucleus.
The process includes unwinding of DNA double helix to expose the DNA template strand. The enzyme RNA polymerase binds to the specific start sites on the DNA template strand and starts making its RNA copy.
The newly formed RNA undergoes modification in eukaryotes before serving as a template for protein synthesis. However, in prokaryotes, the process of transcription and translation can occur simultaneously.
A functional group on an amino acid that is polar and can become negatively charged: ___________
Answer:
Carboxylic acid.
Explanation:
Amino acids are made up of the amine group, carboxyl group, hydrogen and R hydrophobic chain. Amino acids are the monomers of the protein and they are coded by the particular codons.
Amino acids contains both the amino group and the carboxyl group. The carboxylic group is a polar group and becomes negative charged when the pH of the solution is greater than the pKa value of the amino acids.
Thus, the answer is carboxylic acid.
Relate how Mendel's experimental approach Is similar to the process of modem scientific inquiry.
Answer:
Explanation:
A modern scientific inquiry system uses the scientific method to understand and explain the natural phenomenon.
The scientific theory involves various steps which begin with making an observation , asking questions, doing background research and proposing a hypothesis. The hypothesis is tested through experiments which prove or disproves the hypothesis which when established form laws and theory.
The Mendel followed the same approach unaware of the scientific method and performed experiments to answer the scientific question of how traits are controlled and passed on in generations. He analysed the conclusions which were proved after his death by other scientists and framed the biological laws called Mendel's law of inheritance.
Thus, Mendel's inquiries followed the same steps of the scientific method.
Which method is used to construct large, recombinant vectors when polylinker restriction enzymes are not useful?
a. recombineering
b. FISH
c. gene libraries
d. YACs
e. hybridization
Answer:
The correct answer will be option-A.
Explanation:
Recombineering is a molecular technique based on the recombination mechanism of DNA which is also known as recombination-mediated genetic engineering.
This method is used mainly in bacterial genetics to generate conditional mouse knockout target vector and modifying DNA in Bacterial artificial chromosome.
Since it does not use older methods like restriction enzymes and DNA ligases to combine DNA, therefore, option-A is the correct answer.