Answer: Cellulose
Explanation:
In plant the cell wall is mainly composed of strong fiber made of carbohydrates polymer known as cellulose.
It is the major component of cotton fiber, wood and other plants. It also helps in paper production.
This substance helps in the protection of the plants from outer environment, also provides strength and rigidity to the plants.
Hence, the correct answer is cellulose.
Q:- In dogs, the Mexican hairless phenotype never breeds true. When Mexican hairless are interbred the offspring are 2/3 hairless and 1/3 normal. It is also observed that some deformed puppies are born dead. Propose a genetic explanation for these observatios.
Explanation:
The problem says that the hairless phenotype never breeds true. That means that it's not the result of a homozygous genotype (H₁H₁ or H₂H₂), so it is caused by the heterozygous genotype (H₁H₂).
The expected offspring from the cross between two Mexican hairless would be:
P H₁H₂ x H₁H₂F1 1/4 H₁H₁, 2/4 H₁H₂ and 1/4 H₂H₂.And the expected phenotypic ratio 3:1. However, the observed offspring shows a 2:1 ratio. What's happening?
If the observed phenotypic ratio in the offspring of a monohybrid cross (a single gene with two alleles) is 2:1, we can suspect that one of the genotypes is lethal in homozygosis and therefore does not appear in the progeny (the puppies are born dead).
If we proposed that the H₂ allele is lethal in homozygosis, then:
The H₁H₁ genotype would cause normal puppies --> 1The H₁H₂ genotype would cause hairless puppies --> 2The H₂H₂ is lethal and causes the death of puppies --> 0The phenotypic ratios change to 2:1, as observed in the experiment.
While there are a number of characteristics that vary between monotremes and marsupials, there is one characteristic that links them together. What is it?
a. they both have nipples for sucking
b. they both have a single opening for reproduction, excretion and defecation
c. they both gave birth to underdeveloped young
d. they both have members that retain the primitive reptile-gait
Answer:
c. they both gave birth to underdeveloped young
Explanation:
a. they both have nipples for sucking: this is a characteristic that monotremes don't have. They produce milk but babies are fed through skin openings.
b. they both have a single opening for reproduction, excretion and defecation: marsupials have a separate genital tract.
d. they both have members that retain the primitive reptile-gait: Monotremes, like reptiles, have a single cloaca. Marsupials don´t.
Both groups will finished their development inside a mothers sack.
Which of the following is not a characteristic of cancer cells?
A. They have a coarse chromatin.
B. They have a single small nucleus.
C. They have multiple nuclei.
D. They have a small amount of cytoplasm.
E. They have large and multiple nucleoli.
Answer:
B. They have a single small nucleus.
Explanation:
The presence of large nucleus is a characteristic feature of cells that frequently undergo cell division. Cancer cells are characterized by uncontrolled continuous cell division even when the new cells are not required by the body.
This leads to the formation of benign or metastatic tumors. To undergo continuous cell division, the cancer cells have a large nucleus. The nucleus of the cancer cells is mostly hyperchromatic and distinct due to higher nuclear to cytoplasmic ratio. It allows these cells to exhibit the uncontrolled cell division.
At the beginning of the Cenozoic, the distribution of continents changed from that seen throughout most of the Mesozoic. Which of these best describes the new distribution of continents?
a. a single land mass that allowed for easy moevement of animals between continents
b. individual land masses that are moving towards the poles
c. most of the land masses are located near the equator
d. the continents were already in the positions that we have in the current time.
Answer:
b. individual land masses that are moving towards the poles
Explanation:
The Mesozoic started with the Triassic period, 251.9 million years ago, after a mass extinction that wiped out most of life on Earth. At this moment, all the continents were part of a continuous landmass called Pangaea. By the Late Jurassic, the continents started to drift towards the poles. Africa and South America stay move from the southern hemisfere towards the Equator, Antartica and Australia move towards the south pole. It is during this time that we have two continents: Laurasia in the north, comprised of Europe, North America, Russia, China, and parts of Central Asia; and Gondwana, comprised of South America, Africa, Australia, India and Antarctica.
Towards the end of the Mesozoic, Laurasia and Gondwana also start to split. Laurasia breaks up and still occupies the Northern hemisphere, but pieces of broken Gondwana drifted north, such as South America, Africa and India. Of these, Africa collided with Europe and originated the Italian peninsula, the Iberian peninsula, and the Balkan region. The collision of India with China, Tibet and Russia prompted the beginning of the formation of the Himalaya.
By the beginning of the Cenozoic, Laurasia and Gondwana had split into several individual landmasses, most of them in the Northern Hemisphere.
The motor cortex is part of the ________.
a. cerebrum
b. cerebellum
c. spinal cord
d. medulla oblongata
The correct answer is A. Cerebrum
Explanation:
The motor cortex is an area of the cerebral cortex (outer layer of the cerebrum in the brain), this area is the one responsible for movements especially voluntary ones and including the movement of different parts of the body such as the limbs, the jaw, the tongue, the eyeballs, the neck, etc. Additionally, due to the complexity of the motor cortex, this is divided into three areas located in the same zone that include the primary motor cortex, the supplementary motor area, and the premotor cortex. According to this, it can be concluded the motor cortex is part of the cerebrum as it is located in the cerebral cortex which is part of it (cerebrum).
Answer:
The answer is A. cerebrum.
Hope this helps... Good luck.
How is photosynthesis similar in C4 plants and CAM plants?
a. In both cases, only photosystem I is used.
b. Both types of plants make sugar without the Calvin cycle.
c. In both cases, rubisco is not used to fix carbon initially.
d. Both types of plants make most of their sugar in the dark.
Answer:
In both cases, rubisco is not used to fix carbon initially (Ans C)
Explanation:
Photosynthesis is similar in C4 plants and CAM plants because they separate the light and dark reactions to reduce photorespiration. Plants which lives in dry and hot condition may be C4 plants and CAM plants have an alternative method of carbon fixation.
In C4 plants carbon dioxide is taken into the leaves through the stomata present in leaves but is converted to a 4 carbon molecule, then this molecule can be pumped to the deeper layer present on the leaves for the Calvin cycle to occur away from the presence of the oxygen.
CAM plants take in carbon dioxide at night time and convert them to other carbon molecules which can be stored in the vacuole. During the day time, CAM plants shut their stomata and instead utilize the carbon which was brought at night to reduce water loss and photorespiration.
During photorespiration plants shut their stomata and reduce the intake of CO2 and reduce water loss, with a limited amount of CO2, rubisco uses oxygen instead of CO2 in the dark reaction. (which is present in both C4 and CAM plants)
The key similarity between C4 and CAM plants is their mechanism of concentrating and fixing carbon dioxide prior to its entry into the Calvin cycle. C4 plants perform this process spatially across different cell types, while CAM plants perform it temporally, fixing carbon dioxide at night and performing the Calvin cycle during the day.
Explanation:Photosynthesis is similar in C4 plants and CAM plants notably in one key aspect, both use a specialized method to concentrate and fix carbon dioxide prior to its entry into the Calvin cycle. However, these processes are arranged slightly differently in each type of plant.
In a C4 plant, the carbon dioxide is initially fixed in the mesophyll cells to form a four-carbon compound (hence the name C4). This embraces the enzyme PEP carboxylase, which has a strong affinity for carbon dioxide and can function effectively even when its concentrations are low. This compound is then translocated to the bundle-sheath cells where the carbon dioxide is released and then enters the Calvin cycle.
In CAM plants (Crassulacean Acid Metabolism plants), the process is temporally divided. The plant fixes carbon dioxide into a four-carbon compound, similar to a C4 plant, but this occurs during the night when the stomata are open to reduce water loss. During the day, when the stomata are closed, the carbon dioxide is released from the four-carbon compound and enters the Calvin cycle. Hence, the processes revolve around the diurnal cycle to conserve water.
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Which of the following statements describes the most likely selective pressure behind the evolution of feathers?
a. Feathers assisted with the ability to climb into trees
b. Feathers were used to help direct turning while in flight
c. Feathers were used as part of a social display
d. Feathers were used to collect food from burrows
e. Feathers were used to help reduce water loss
Answer:
c. Feathers were used as part of a social display
Explanation:
There are many speculations about the origin of feathers, some researchers believe that they emerged as a specific function, others defend the idea of the emergence of feathers from a social display.
The social display may have been one of the factors for the origin of the feathers, since in addition to the conquest of the female, animals thus selected would gain more conducive conditions for survival, such as better regulation of body temperature. But social display alone could not have forced the emergence of more complex feathers, since in many cases sexual characters usually occur only in males and not in females, or less apparent in females.
The appearance of penaceous appendages in theropods may be linked to the evolution of a high metabolic rate, which provides an improvement in locomotor skills as well as distinct behavior and visual communication. The development of penaceous appendages may also have played an important role in regards competition and radiation success of maniraptor theropods and their descendants of active flight in the Jurassic. Therefore, the theory is believed that external factors (natural selection) along with social display could have propitiated the origin of feathers.
In a particular population of mice, certain individuals display a phenotype called "short tail," which is inherited as a dominant trait. Some individuals display a recessive trait called "dilute," which affects coat color. Which of these traits would be easier to eliminate from the population by selective breeding? Why?
Answer:
The "short tail" dominant allele is easier to eliminate by selective breeding.
Explanation:
The only way for a recessive allele to be expressed (be visible) is when it appears as recessive homozygotic. These means the organisms need to have 2 copies of the gene. Selective breeding is based on the characteristics that one can see, so if the organism shows the "dilute" phenotype you can keep reproducing this individuals and get rid of the dominant allele.
On the other hand if you have a population with the dominant phenotype, you discard all the ones that have a recessive trait and you breed the dominant phenotype you could still get individuals with the recessive phenotype and individuals that express the dominant phenotype but are heterozygous.
Adaptive radiations can be a direct consequence of three of the following four factors. Select the exception.
a. vacant ecological niches
b. genetic drift
c. colonization of an isolated region that contains suitable habitat and few competitor species
d. evolutionary innovation
Answer:
The correct answer is option b, that is, genetic drift.
Explanation:
Adaptive radiation refers to a procedure that exists in enhancing the diversity of life in the course of evolution. Various groups of species develop adaptive compositions to get adapt to the new surroundings and perform new ecological functions.
These give rise to many new species that get amended with various new ecological habitats. The adaptive radiation occupies the vacant ecological niches. It results in the development of new and diversified characteristics within the species that take place in the niches with appropriate habitat. Evolutionary innovation is also a direct outcome of the adaptive radiation.
Genetic drift is not a direct outcome of adaptive radiation, it refers to a process, which takes place in small populations, and because of certain chance incidences, the allele frequencies of populations modify with time.
In this condition, either some of the individuals become distinguished from the main population and turn into new species or a huge population suddenly gets diminished to a small population, and therefore, modification in allelic frequency takes place.
Genetic drift is the exception among the given factors as it doesn't directly cause adaptive radiation, which is often triggered by vacant ecological niches, colonization of isolated regions, and evolutionary innovations.
Explanation:Adaptive radiations occur when a species rapidly diversifies to fill various ecological niches. Factors contributing to adaptive radiation include vacant ecological niches, colonization of an isolated region with suitable habitat and few competitor species, and evolutionary innovations that allow exploiting different resources or environments. Among the options provided, genetic drift is the exception as it's a random change in allele frequencies that by itself does not cause adaptive radiation, although it might play a role in the divergence of populations over time.
Examples of Adaptive Radiation
Examples include the Hawaiian honeycreepers and Darwin's finches, where a founder species radiated into multiple species each adapted to different niches within isolated geographical locations like island archipelagos.
What do structures B and C have in common?
Both B and C epresent the muscularis externa, the outermost layer of smooth muscle found in most hollow organs of the digestive tract. This layer contracts and relaxes to propel food along the digestive system.
: B and C are major blood vessels supplying the respective sections of the digestive tract. Adequate blood flow is crucial for nutrient absorption and transport. They could also represent lymphatic vessels involved in draining fluids and immune cells from the digestive tract. The lymphatic system plays a vital role in fighting infection and absorbing dietary fats.
B and C could be labeled as nerves or ganglia, representing the autonomic nervous system branches controlling digestive functions like muscle movement and secretion of digestive juices.
What feature is unique to Yersinia pestis when compared to other Yersinia species?
A- Motile
B- Capsule
C- Spore forming
D- Can grow in the presence of oxygen
Answer:
B-Capsule
Explanation:
Bacteria from Yersinia genus don't develop capsules, but Yersinia pestis has the exception. Y.pestis develops a similar structure to a capsule.
Other options are true for Y.pestis and all Yersina genus. Despite the fact that someones can lose their motility in a stage of their life cycle, these bacteria are motile. Also, they are facultative anaerobic organisms and they don´t form spores.
Ultimately, the oxygen necessary for cellular respiration come from
a. Waste products of photosynthesis.
b. Water vapor
c. Carbon dioxide
d. glucose
Answer: Option A
Explanation:
Plants intake the carbon dioxide that is present in the atmosphere. They absorb it and along with water and other materials in the presence of sunlight is converted into chemical energy.
This chemical energy is glucose and the by-product that is released by splitting of water into oxygen and hydrogen ions is released into the environment.
This oxygen is required for the process of cellular respiration.
Using Chargaff's Rules, which of the following satements about genomic base content is TRUE?
a. Senior citizens have higher genomic AT content in their brains than 21 year olds.
b. Malnutrition has no significant effect on the genomic base pair content of a person's muscles.
c. Since GC base pairs are more stable than AT, Alaskans typically have slightly higher genomic GC contents than Floridians.
d. Human racial differences are reflected in increased genomic GC contertin native Americans as compared to Africans.
e. The genomic AT content in human lung tissue is equal to the AT content in shark gills
Answer:
The correct answer is option b. "Malnutrition has no significant effect on the genomic base pair content of a person's muscles".
Explanation:
Chargaff's Rules state that the content of nucleotides in the cells have a 1:1 ratio of pyrimidine and purine bases and the composition of DNA varies from one species to another but not within the same specie. Therefore according to Chargaff's Rules malnutrition has no significant effect on the genomic base pair content of a person's muscles, since no variation of the genomic base pair content should occur within the same person or specie.
Explain why the value of the recombination frequency between any two genes is limited to 50%.
Answer:
Explanation:
During meiosis, each chromosome has 2 chromatids. When homologous chromosomes pair they form a tetrad (2 chromosomes, 4 chromatids).
Crossing over can happen between 2 out of the 4 chromatids, and as a result, only half of the resulting gametes (at most) can be recombinant. The other 2 gametes will be parental.
Distinguish the different structural forms of DNA from one another.
Answer:
The major structural forms of DNA are A- DNA, B-DNA, and Z-DNA.
There are several differences among the 3 DNAs in their helix turn, number of nucleotides, distance between the base pairs, etc.
Explanation:
DNA is a double-stranded helix. These are the twisted ladders where base pairs are attached by hydrogen bonds. There are 3 major forms of DNA such as A - DNA, B- DNA, and Z - DNA. They are different from each other by their helix type, diameter or complete turn, and distance between the 2 base pairs.
A - DNA: This type of DNA was discovered by Rosalind Franklin. It was discovered by the X-ray diffraction method. Its helixes are right-handed. The helixes are shorter than the B - DNA. The diameter of the helix is 2.55nm. The distance between the base pair/rise is 0.29nm. The number of base pairs per complete turn is 11.
B - DNA: This is the common type of DNA structure. This is the Watson and Crick model of DNA. The helix is right-handed and the diameter is 2.37nm. The distance of a complete turn is 3.4nm. The rise per base pair or the distance between 2 base pairs in B-DNA is 0.34nm. The number of base pairs per complete turn of the helix is 10 nucleotides.
Z -DNA: It is the left-handed DNA. This type of DNA was discovered by Robert Wells and colleagues. This DNA is in a zig-zag form. So it is called Z-DNA. It is long and thin than other DNA. The distance per turn is 4.5 nm. and rise per base pair is 0.37 nm. The number of base pairs per complete turn is 12 nucleotides. The minor groove is deep.
If the B-DNA is compressed it becomes the A-DNA and if the B-DNA is expanded it turns into a Z- DNA.
Food irradiation requires a nuclear reactor, which produces radioactive waste.
a. True
b. False
Answer:
b. False
Explanation:
Food irradiation is a process of exposing the food packaging stuff to the ionization process by the use of X Rays, gamma rays, and electronic beans. This energy can be directly transmitted without the direct contact of the source i.e radiation capable of freeing the elections. This technology is used to improve food quality and safety by extending the shelf line. This technology is permitted to bout 50 countries with 5 lakh metric tons of foods manually processed. These techniques make the food more productive and reduce the impact of radioactivity and chemical reactions. Destruction of pathogens and changes that take place in shipping industries. The radiation cause changes are much higher than the doses used during irradiation these results lead to the conclusion that there is no significant risk from radiolytic products.An albino corn snake is crossed with a normal-colored corn snake. The offspring are all normal-colored. When these first- generation progeny snakes are crossed among themselves, they produce 32 normal-colored snakes and 10 albino snakes. a. How do you know that only a single gene is responsible for the color differences between these snakes? b. Which of these phenotypes is controlled by the dominant allele? c. A normal-colored female snake is involved in a test-cross. This cross produces 10 normal-colored and 11 albino offspring. What are the genotypes of the parents and the offspring?
a. We can infer that only one gene is responsible for the only two phenotypes of snakes due to the 3: 1 Mendelian ratio. If there were other genes involved, the ratio would be different.
b. The normal-colored
c. To have raised an albino half offspring, these individuals received a recessive gene from both father and mother. And the other half of normal individuals received at least one dominant gene. Since the statement says that the female snake is a normal phenotype, we know that it has a dominant and a recessive gene. The male snake can only be recessive homozygous to generate offspring half and half. If he was heterozygous for the disease, the offspring would have a 3: 1 ratio.
Here you can see the cross and the genotype of each individual:
A x a
a Aa aa
a Aa aa
The recent loss of biodiversity on Earth stems from ___________
a. destruction of habitat
b. consumption by humans
c. effects of introduced species
d. global climate change
e. all of these factors contributed to the recent loss of biodiversity
Answer: Option E
Explanation:
The loss of biodiversity can be defined as the loss of beneficial plants and animals that is found in the environment.
The destruction of habitat of animals, hunting, introduction of invasive species has led to the loss of biodiversity in case of animals and plants.
The global climate change has also resulted in the loss of species, the increased consumption of plants, animals and many more sources has led to loss of biodiversity.
Hence, all of the given parameter encourages loss of biodiversity.
Answer:
The Correct answer is E
Explanation:
Causes of the Loss of Biodiversity
According to most sources, the major direct source of loss of Biodiversity are such as:
There are five main sources of loss of Biodiversity
Habitat alteration Invasive speciesOverharvestingPollutionAnd, Climate change is now considering as the fifth reason behind the loss of Biodiversity.
What is hypersensitivity? Allergies? Autoimmune disorders?
Answer:
Hypersensitivity is also known as intolerance which is defines as an unwanted reactions due to changes or interference with immune system for example allergies and autoimmunity. Hypersensitivity is the reaction of immune system that can be harmful and weakens once body.
Allergy is kind of hypersensitive reaction which is having fast response within few minutes rather than hours or days. In the case of allergies free antigens cross link with IgE on mast cells and basophils and releases vasoactive biomolecules. Few example of Allergies are anaphylaxis and asthma.
Autoimmune disorders are also a kind of hypersensitive reaction which occurs when body's immune system attacks own body cells mistakenly. few examples are Type 1 diabetes, Rheumatoid arthritis (RA), and Multiple sclerosis.
Translate the following mRNA: 5'AUGGCGAACUGCGAGUGA3'
a. Ser-Glu-Arg-Gin-Ala-Val
b. Met-Ala-Gin-Arg-Glu-Ser
c. Val-Ala-GIn-Arg-Glu-Ser
d. Met-Ala -Asn-Cys-Glu
Answer:
Option (d).
Explanation:
Genetic code may be defined as the triplet code of the nucleotides that are heritable in nature. The mRNA molecule contains the group of codons that codes for the particular amino acids by the process of translation.
The amino acids are specified by the specific codons. Here, AUG codes for methionine and also acts as the initiator codon. GCG codes for Alanine. AAC codes for Asparagine, Cysteine is coded by UGC and GAG codes for glutamic acid. UGA is a stop codon and result in the termination.Hence, the translated mRNA is Met-Ala -Asn-Cys-Glu.
Thus, the correct answer is option (d).
Where does the energy in food come from?
A. Proteins, carbohydrates, or fats
B. ATP
C. Food, by itself, doesn't contain energy, but the digestive system creates it.
D. The chemical bonds holding the food molecules together
E. Combining water with any sort of food creates energy.
Answer:
A. Proteins, Carbohydrates, or fats
Explanation:
There are essential nutrients for life in which we can include carbohydrates, fats, proteins, minerals, vitamins, fiber, and water. The main nutrients we use for energy are carbohydrates, fats, and proteins. This is because they contain calories in them and the calories are what our body needs to create energy.
Our bodies, like a car, need fuel to function. The fuel we need comes from food. The food has energy stored in it so whenever we eat food, that stored energy is transferred to us. This food act as fuel for the cells in our body so they can carry all the metabolic processes and give us the energy to move, run, think, talk, digest and all of the biological processes we need to survive.
The circulatory system delivers oxygen and nutrients to the cells and transports wastes away from cells.
a. True
b. False
Answer:
True.
Explanation:
Circulatory system may be defined as the network of the various blood vessels that helps in the transportation of materials inside the body. Circulatory system is also known as cardiovascular system.
The main function of the circulatory system is to delivers the oxygen to each and every cell of the body. The nutrients are transported into the cells via blood and waste materials are transported away from the body. This system is also important to provide immunity to the body.
Thus, the correct answer is option (a).
Nitrogen and carbon are more abundant in proteins than sulfur. Why did Hershey and Chase use radioactive sulfur instead of nitrogen and carbon to label the protein portion of their bacteriophages in their experiments to determine whether parental protein or parental DNA is necessary for progeny phage production?
Answer:
Hershey and Chase experiment confirms that DNA is the genetic material of the living organism, not the RNA or protein. They also got a noble prize for this discovery.
Hershey and Chase use the radioactive sulfur to label the proteins and distinguish them from the DNA because DNA do not contain sulfur. The radioactive label phosphorus was used to label the DNA as phosphorus is specific to DNA as they wants to know exactly the genetic material. They do not use the radioactive carbon and nitrogen because both carbon and nitrogen are present in DNA and RNA. This labeling may produce confused result as it label both DNA as well as protein. The result o radioactive phosphorus and sulfur determines that DNA is the genetic material of the organism.
Radioactive sulfur and phosphorus were used to distinctly label T2 bacteriophage proteins and DNA, leading to the discovery that DNA is the genetic material in Chase and Hershey's 1952 experiments.
Explanation:In the groundbreaking Hershey-Chase experiments, radioactive sulfur (³⁵S) and radioactive phosphorus (³²P) were used to label proteins and DNA, respectively, in T2 bacteriophages. They chose radioactive sulfur to label the protein because sulfur is present in some amino acids (methionine and cysteine) that comprise proteins, but is not a component of nucleic acids.
Conversely, they used radioactive phosphorus to label the DNA because phosphorus is a key component of the DNA molecule but is not found in the amino acid structure of proteins. The conclusive experiment demonstrated that radioactivity from the labeled DNA, not the protein, was present inside the bacterial cells infected by the phages, thereby identifying DNA as the genetic material responsible for inheritance.
Mammalian evolution began with the evolution of the first synapsids. What is the defining synapomorphy of synapsis?
a. the possession of the amniotic egg
b. a single temporal fenestra
c. the dentary squamosal joint
d. respiration with a diaphragm
e. endothermic metabolism
Answer:
b. a single temporal fenestra
Explanation:
Synapsids have a temporary fossa in the lower part of the temporal bone. These reptiles mamiferoides only have a single inferior temporal fenestra.
The synapsids were the first amniots to diversify and appeared in the middle of the Carboniferous. These first synapses were characterized by the presence of a single temporary fenestra behind each orbit, through which the mandibular muscles pass.
Which of the following are useful traits of cloning vectors?
a. an antibitioc resistance gene on the plasmid for selection of cells containing the plasmid
b. a site that contains unique, clustered restriction enzyme sequences for cloning foreign DNA
c. a high copy number plasmid so that large amounts of DNA can be obtained
d. alpha complementation to determine if the foreign DNA was inserted into the cloning site
e. all of the above are useful traits
Answer:
The correct answer is option - e. all of the above are useful traits.
Explanation:
A cloning vector is a small segment of DNA that can be established stably in an individual organism and able to internalize a foreign DNA for cloning purposes. The cloning vector could be taken from different organisms such as plasmid of a bacterium, or DNA from a virus. A cloning vector must possess some characteristics -
The cloning vector must be self-replicating ability in the host cells, it should be small in size with restriction site for the restriction endonuclease enzymes in it. The replication character of the vector should not interfere with the internalized DNA fragment. The presence of marker genes in the vector is also a property that is helpful in identifying of recombinant cells.
Thus, the correct answer is option - e. all of the above are useful traits.
The aging process is thought to be initiated at the cellular level. Among the changes that can occur after a certain number of cell divisions is the loss of a cell’s ability to respond to growth factors and other signals. Much research into aging is aimed at understanding such losses, with the ultimate goal of extending the human life span. Not everyone, however, agrees that this is a desirable goal. If life expectancy were greatly increased, what might be the social and ecological consequences?
Answer:
Enhancement in the life expectancy of humans can exhibit certain unwanted outcomes that could affect the quality of life. Some of the probable social and ecological outcomes due to an increase in life expectancy are:
Social: Greater life expectancy would signify that the age of employment would get extended. As an outcome, the older individuals would hold the seats for a longer duration, leaving only some seats for the young. This would influence the life quality and development of the young.
Due to the increase in life expectancy, there would be an elevation in the demand for basic needs, and increased consumption of food increased utilization of land, and larger population. The use of global resources would increase by humans, therefore, declining the resources at a greater rate. Hence, overall, the ratio of the old to the young would get influenced, and therefore, the quality of life would get affected.
Ecological: With longer life expectancy, there will be an enhanced burden of human species on the planet Earth. Due to this, the balance between the humans and the other species would get disturbed. Human activities have been substantially related to the issues of global warming, issues of deforestation, endangering of other species resulting in ecological imbalance.
Enhancement in the life expectancy of humans would cause further destruction of endangered species and huge imbalance in the ecosystems that would eventually influence life of human beings. Therefore, ecological in combination with socioeconomic influence of greater life expectancy incline towards reduced quality of life, and it is not desirable.
Increased life expectancy due to enhanced understanding of aging at a cellular level could potentially yield social and ecological issues, due to increased demand for resources and societal changes. The role of telomeres, absence of telomerase in somatic cells, and the effects of oxidative stress are crucial in understanding the aging process.
Explanation:The question posed involves the biological process of aging at a cellular level, tied to factors like the shortening of telomeres regions with repeated cell divisions. Primary and secondary aging, which concern molecular/cellular changes and controllable factors like exercise and diet respectively, play key roles in the aging process. The implication of an extended human life span involves exploring potential social and ecological impacts.
Social implications could cover areas like increased demand for healthcare, living spaces, and resources, and a shift in societal structures due to the increased proportion of aging populations. Ecological considerations may revolve around the fact that a larger aging population might drive greater consumption of resources, potentially exacerbating environmental issues.
Moreover, telomerase and aging are closely linked, as most somatic cells do not produce telomerase, leading to progressive telomere shortening and aging. With advancements in modern medicine and lifestyle changes, humans have extended their lifespan, prompting desires to maintain youth and a higher quality of life into old age.
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Which cell would be best for studying lysosomes?
(A) muscle cell
(B) nerve cell
(C) bacterial cell
(D) phagocytic white blood cell
Answer:
(D) phagocytic white blood cell
Explanation:
Lysosomes are cell organelles which contain hydrolytic or digestive enzymes. They engulf waste materials, dead cells, and microorganisms. They break them down them using digestive enzymes. Muscle cell, nerve cell s do not perform phagocytic or lysosomal activities and the bacterial cell is a prokaryotic cell which does not contain lysosomes. Therefore, white blood cells are phagocytic contains lysosomes. Due to the presence of lysosomes, white blood cells or leucocytes protect our body from infectious diseases.
Answer:
(D) phagocytic white blood cell is the correct answer.
Explanation:
phagocytic white blood cell is best for studying lysosomes.
lysosomes are the cell organelles, its function is to digest the dead cells, bacteria and waste substance with help enzymes such as lipases, amylases, and proteases.
Phagocytic white blood cells are best for studying lysosomes because many white blood cells are found in lysosomes.
White blood cells function is to ingest or engulf the foreign materials and protect the body from the infection.
emochromatosis is an inherited disease caused by a recessive allele. If a woman and her husband, who are both carriers, have three children, what is the probability of each of the following?
(a) All three children are of normal phenotype.
(b) One or more of the three children have the disease.
(c) All three children have the disease.
(d) At least one child is phenotypically normal.
Answer:
(d) At least one child is phenotypically normal.
Explanation:
To be a carrier means that you have the gen but you are not affected by it.
If both parents have that recessive gene, this means, both are heterozygous for that trait.
Let's say this gen is A, for the dominant trait, and "a" if it's recessive.
The mother and the father are Aa.
If you cross them you have Aa x Aa = AA Aa aA aa
This means you have 50% of Aa, carrier children
25% AA, not a carrier or affected by this gen.
25% aa, affected by the gen.
Which statements describe molecules? Check all that apply. Molecules are made of two or more atoms. Molecules are all the same size Molecules range in size. Molecules are only made of atoms of the same element. Molecules are only made of atoms of different elements. Molecules are made of atoms of the same element or different elements
Molecules are composed of two or more atoms, which can be the same or different elements, and they vary significantly in size from simple to complex structures like DNA.
To describe molecules, several statements are necessary. Firstly, molecules are made of two or more atoms; this is a fundamental component of their definition. Whether they are composed of the same element or different elements, the atoms are bound together chemically.
As an important distinction, molecules of elements contain only one type of atom, such as O2, which has two oxygen atoms, whereas molecules of compounds contain two or more types of atoms, like H2O, which includes hydrogen and oxygen.
Next, molecules range in size. They can be relatively simple with just a few atoms, or they can be incredibly complex, such as DNA molecules, which are composed of millions of atoms. Lastly, it is incorrect to say that molecules are all the same size or that they are made only of atoms of the same element or only of different elements.
What evolutionary mechanisms might account for the origin and persistence of cell-to-cell signaling systems in prokaryotes?
Answer:
Quorum sensing.
Explanation:
Quorum sensing may be defined as the phenomena by which the bacteria can detect the specific stimuli and respond towards the cell population density. This process helps in coordinating gene expression.
Quorum sensing is used in prokaryotes for the cell to cell signalling and cell communication as well. The main evolution of quorum sensing in bacteria was to relay the information and helps in cell signalling by releasing the specific toxins. From the evolutionary point, the organism that are capable of quorum sensing would survive more in their environment, adapt well in their environment.
Thus, the answer is quorum sensing.