Answer:
Mitochondria
Explanation:
The mitochondrion is a relatively small, double membrane organelle that primarily serves as the site of oxidative phosphorylation; a process that generates energy in the form of ATP for the running of cell's activities.
Hence, a cell that requires a lot of energy might need a large number of mitochondria in order to meet the energy demand of the cell.
The answer is mitochondria.
Answer:
A cell that requires a lot of energy might contain large numbers of mitochondria.
Explanation:
Mitochondria are the cellular organelles that are responsible for producing the greatest amount of energy that cells require to activate their biochemical reactions. They produce adenosine triphosphate (ATP), which is an energy-carrying molecule and it's essential for the cell to perform its functions.
is a disease that affects the voluntary muscles (those controlled by one's will) in which nerve impulses are impaired, resulting in fatigue, weakness, and difficulties controlling muscles.
Answer:
Myasthenia gravis
Explanation:
Myasthenia gravis is an uncommon (20 per 100000) chronic autoimmune neuromuscular disorder characterized by weakness in the skeletal muscles that worsens with exertion and improves with rest, this happens due to an error in the transmission of nerve impulses to the muscle. Its causes are unknown but it is treatable.
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When examining the two complementary strands of nucleotides in one DNA molecule, it would be expected that the sum of ________ in one strand would be ________ the sum of the ________ in the other strand.
Answer: Purine; is equal to; pyrimidine
Explanation:
When a segment of DNA is examined then the nucleotide in one DNA molecule, it will be expected that the sum of purine in one strand will be equal to the sum of the pyrimidine in the other strand.
Adenine combines with Thymine and Cytosine combines with Guanine in 1:1 ratio.
More specifically the ratio of purine is to pyramidine is 1:1 in an organism. This pattern is seen in both the strands of the DNA.
Final answer:
When examining the two complementary strands of nucleotides in one DNA molecule, it would be expected that the sum of adenine (A) in one strand would be equal to the sum of the thymine (T) in the other strand, and vice versa.
Explanation:
Similarly, the sum of guanine (G) in one strand would be equal to the sum of the cytosine (C) in the complementary strand. This relationship is due to the rules of base pairing, where adenine always pairs with thymine, and guanine pairs with cytosine.
These rules are fundamental to the structure of DNA and its replication process, ensuring that each new molecule is an accurate copy of the original.
A biochemist isolates, purifies, and combines in a test tube a variety of molecules needed for DNA replication. When she adds some DNA to the mixture, replication occurs, but each DNA molecule consists of a normal strand paired with numerous segments of DNA a few hundred nucleotides long. What has she probably left out of the mixture?a. DNA ligase
b. nucleotides
c. DNA polymerase III
d. Okazaki fragments
Answer:
a. DNA ligase
Explanation:
DNA ligase is the enzyme of DNA replication that joins DNA segments together by catalyzing the formation of new phosphodiester bonds. These reactions use the energy of ATP molecules to form the bonds. The function of the DNA ligase enzyme is to join the Okazaki fragments together which in turn are formed during replication of the lagging strand. In the absence of DNA ligase, the Okazaki fragments cannot be joined together.
According to the given information, the process of DNA replication obtained shorts DNA segments of a few hundred nucleotides. This means that the reaction mixture lacked the DNA ligase enzyme and the DNA segments could not be joined together.
Using the 10 percent rule, explain why there is typically smaller populations of quaternary consumers compared to primary consumers in an ecosystem.
Answer:
As we know 10% law is transfer of energy from higher trophic level to lower trophic level. So as the energy are transfer from one organism to another there is a loss of energy as that energy are utilised by the oragnism and only 10% of the total energy is transferred to the second consumer.
Explanation:
Quetinary consumer are at the higher position in the food chain so they do not get enough energy from prey they have to feed on several organism for the enegy. And also they are at the top of the food chain so they are not eaten by other animal, their life span are also more than primary consumer.
In other hand primary consumer get enough energy but they are prey for other higher tropic level.
Primary and secondary consumer are maintend in such a way by the nature thats make a ecological balance of the habitant.
Connective tissue is different from other major tissue
a) types in that it covers the surface of the body.
b) has cells that are sparsely scattered through a nonliving matrix.
c) is made of cells.
d) conducts electrical impulses throughout the body.
Answer:
The correct answer is b) has cells that are sparsely scattered through a nonliving matrix.
Explanation:
Connective tissue is the most diverse and widespread of the body. It can be found in bone, ligaments, tendons and more. It's one of its main characteristics is the presence of cells in a matrix called ground substance.
Which of the following definitions is INCORRECT? Which of the following definitions is INCORRECT? epidemic: a disease that is constantly present across the world endemic: a disease that is constantly present in a population pandemic: a disease that affects a large number of people in the world in a short time incidence: number of new cases of a disease
Answer:
epidemic: a disease that is constantly present across the world.
Explanation:
An epidemic is a sudden outbreak of a disease that spreads over a large area within a short period.
Endemic disease is a disease that is found regularly within an area at every point in time.
Pandemic disease is a disease that is prevalent over the whole world within a short period.
Incidence is the number of newly reported cases of a disease.
From the definition of each of the term. epidemic is the only one defined incorrectly of all the options.
The incorrect definition is that of an endemic disease, which is correctly defined as a disease that is always present at low incidence, not high incidence, in a population.
Explanation:The definition provided in the question that is INCORRECT is that of an endemic disease. The correct definition is that an endemic disease is one that is constantly present, usually at low incidence, in a population, not at high incidence as suggested in one of the erroneous definitions. In contrast, an epidemic is an outbreak of a disease that occurs in an unusually high number of individuals within a population at the same time. A pandemic is an epidemic that becomes widespread across multiple populations or continents, or even worldwide. Incidence refers to the number of new cases of a disease that appear in a population during a specific period of time. These terms are crucial for understanding the spread of diseases and for public health management.
The process in which related dna sequences from two different sources are exchanged is called
Answer: Homologous Recombination
Explanation:
In DNA recombination, homologous recombination is a type of gene repair in which nucleotide sequences are exchanged between two identical molecules of DNA.
When DNA damages occur such as DNA double-stranded breaks or DNA gaps during DNA synthesis.
To conserve genome, cells uses a homologous recombination (HR), a type of DNA repair.
In genetic engineering a foreign DNA with identical nucleotide sequence similar to that of the missing DNA gaps or breaks are introduced into a target cell. The cell recognizes the identical DNA sequences as homologues, causing target gene to be exchanged with the foreign DNA sequence during DNA repair.
HR also occur naturally.
Crossing over is the exchange of DNA sequences between non-sister chromatids of homologous chromosomes during meiosis I, leading to recombinant chromosomes and increased genetic variation.
Explanation:The process in which related DNA sequences from two different sources are exchanged is known as crossing over. This biological mechanism occurs during meiosis I, when homologous chromosomes pair closely together. During crossing over, non-sister chromatids exchange genetic material, which results in the formation of new combinations of genes, or recombinant chromosomes.
The purpose of crossing over is to increase genetic diversity within a species. It is a critical part of sexual reproduction and ensures that offspring have a unique combination of DNA from both parents, leading to genetic variation within a population. The process is also known as recombination, and the points where the chromatids break and rejoin are called chiasmata.
There is a misconception that girls cannot inherit recessive X-linked disorders. Girls can in fact inherit these disorders, but at a lower rate than boys. The following choices give the genotypes for pairs of mothers and fathers. Which pair of parents could have a daughter with the recessive disorder a?
Choose one:a. XAXA × XAYb. XAXA × XaYc. XAXa × XAYd. XAXa × XaY
Answer:
d. [tex]X^{A}X^{a}[/tex] × [tex]X^{a}Y[/tex]
Explanation:
Since the disorder is a recessive one, the daughter will need to inherit two recessive alleles, each one from the two parents in order for the disorder to manifest.
A cross between [tex]X^{A}X^{a}[/tex] and [tex]X^{a}Y[/tex] will yield the following offspring;
[tex]X^{A}X^{a}[/tex] female, carrier of disorder
[tex]X^{a}X^{a}[/tex] female, affected with disorder
[tex]X^{a}Y[/tex] male, affected with disorder
[tex]X^{A}Y[/tex] male, unaffected
Hence, the only parental pair that can have a daughter with the recessive disorder is [tex]X^{A}X^{a}[/tex] × [tex]X^{a}Y[/tex]
The correct option is d.
Theodor W. Engelmann illuminated a filament of algae with light that passed through a prism, thus exposing different segments of algae to different wavelengths of light. He added aerobic bacteria and then noted in which areas the bacteria congregated. He noted that the largest groups were found in the areas illuminated by the red and blue light.If you ran the same experiment without passing light through a prism, what would you predict?A) There would be no difference in results.B) The bacteria would be relatively evenly distributed along the algal filaments.C) The number of bacteria present would decrease due to an increase in the carbon dioxide concentration.D) The number of bacteria present would increase due to an increase in the carbon dioxide concentration.E) The number of bacteria would decrease due to a decrease in the temperature of the water.
Answer:
The correct answer will be option-B
Explanation:
Theodor Engelmann performed the experiment to study the relationship between the production of oxygen in response to the wavelength of light. This was observed by the congregation of the bacteria in the red and blue wavelength.
In the given condition, if no light is passed through prism then the bacteria will not be accumulated in a particular area instead will be evenly distributed as the algae will produce the oxygen evenly and the concentration is not high in any particular area.
Thus, Option-B is the correct answer.
Final answer:
Without a prism to separate light into its components, aerobic bacteria would likely be relatively evenly distributed along the algal filaments since all areas would receive red and blue light uniformly, resulting in more uniform oxygen production across the algae.
Explanation:
The experiment conducted by Theodor W. Engelmann involved illuminating a filament of algae with light from a prism, which allowed different segments of the algae to be exposed to different wavelengths of light. The addition of aerobic bacteria to this setup led to the observation that the bacteria congregated in areas where the red and blue light illuminated the algae, indicating that these areas had the highest rates of photosynthesis and oxygen production.
If the same experiment were conducted without the prism, so that the algae were exposed to uniform white light containing all wavelengths, based on Engelmann's results, the prediction would be that the bacteria would be relatively evenly distributed along the algal filaments. This is because all areas would receive red and blue wavelengths equally, alongside other wavelengths, so the oxygen production should in theory be more uniform across the entire filament of algae without the prism separating the light into its component colors.
Therefore, the correct prediction for what would happen if the same experiment were run without passing light through a prism is: B) The bacteria would be relatively evenly distributed along the algal filaments.
Pumps move substances ____________ a concentration gradient, a process that requires energy. Channels instead provide the means to move a substance ____________ a concentration gradient. Neurons contain the following major types of channels: • Channels that are always open, allowing continuous diffusion of a specific ion from a region of ____________ concentration to a region of ____________ concentration are leak channels. • Channels that are normally closed that open in response to the binding of a ____________ are chemically gated channels. When open, they allow a specific ion to ____________ across the plasma membrane. • Channels that are normally closed, but open in response to changes in ____________ across the plasma membrane are voltage-gated channels. When open, they allow a specific ion to diffuse across the membrane.
The answers to the blank spaces are: against, with, higher, lower, ligand, flow, membrane potential. All answers stated respectively .
What is concentration gradientThe difference between two areas' concentrations of a material is referred to as a concentration gradient. It is the difference in concentration over a certain distance, usually between two areas of different concentrations. It could be a molecule, an ion, or another type of chemical compound.
Traveling "against" the concentration gradient entails traveling from a region of higher concentration to a region of lower concentration, while moving "with" the concentration gradient entails doing the opposite.
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Which of the pictured cell types influences neuronal function by ""mopping up"" leaked potassium ions and by recapturing and recycling released neurotransmitters? These cells also participate in information processing in the brain.
Answer:
Astrocytes
Explanation:
In the central nervous system, astrocytes, also collectively known as astroglia, are distinctive star-shaped glial cells.
It is not well known the ratio of astrocytes in the brain.
Research has found that the astrocyte proportion varies by area depending on the counting technique used and varies from 20% to 40% among all glia.
These fulfill many roles, namely biochemical reinforcement of tumor cells that build the blood-brain barrier, nutritional supply to the nervous tissue, extracellular ion balance maintenance, as well as a function in the brain and spinal cord repair and scarring cycle after severe injuries.
appointment and learns that her baby weighs about 9 ounces and is covered with lanugo. She has felt some slight movements from the baby recently. About how many weeks along is she in her pregnancy?
A.28 weeks
B.20 weeks
C.10 weeks
D.16 weeks
Answer:
The correct answer is option B.20 weeks.
Explanation:
By week 20 the mother will already find a pregnancy in half way, remember that a pregnancy lasts 40 weeks.
At this stage the baby's facial features begin to take shape, and the baby begins to develop a sleep-wake cycle. Another feature is that it will probably start sucking its finger.
It is possible that the mother already begins to feel slight movements from her baby in week 20, which should be weighing between 9 and 11 ounces of pounds.
For this week, the baby's skin is covered with an amniotic fluid and a waxy covering that is called vernix.
This vernix is associated with the lanugo, which helps it maintain and is a type of fine and soft hair.
The _____________ is primarily responsible for the identification, diagnosis, and design of the treatment plan and curriculum for children with communication, language, and speech disorders.
Answer:
The correct answer is Speech-language pathologists.
Explanation:
There is a type of language disorder which treats people who have trouble understanding other people and expressing themselves.
This should be distinguished from speech disorder, which is when a person has difficulty producing sounds or speaking fluently.
Those who work to help people with these types of disorders are called Speech-language pathologists. They are professionals who are responsible for the identification, diagnosis, and design of the treatment plan and curriculum for children with communication, language, and speech disorders.
They usually form teams with other professionals such as therapists, teachers, audiologists, etc.
Together they try to solve the problems presented by this disorder that are usually semantic or grammatical problems, difficulty in social communication or problems to relate the sound of a word with its meaning, among others.
When two frog species, Rana pipiens and Rana sylvatica, mate, the offspring die early in embryonic development. This is an example of ________.
a) hybrid sterility
b) reduced hybrid fertility
c) reduced hybrid viability
d) mechanical isolation
Answer:
The correct answer is c) reduced hybrid viability.
Explanation:
As the offspring dies early in embryonic development, it's possible to understand that the organism isn't viable, which is very common among hybrid organisms as well as their sterility or reduced fertility.
Cholecalciferol (an inactive form of vitamin D) must undergo 2 conversion steps before it becomes the active form of vitamin D, calcitriol. Those steps take place in the _____ and the _____
Answer:
Those steps take place in the liver and the kidneys.
Explanation:
Cholecalciferol, which is the inactive form of vitamin D, is first transported in the blood via vitamin D binding protein (DBP) to the liver.
Upon reaching the liver, cholecalciferol will undergo chemical changes, forming calcidiol, the deposit form of vitamin D.
After that, calcidiol goes to the kidneys, which will form calcitriol, the metabolically active form of vitamin D.
Cholecalciferol must be converted in both the liver and the kidney to become the active form of vitamin D, known as calcitriol. In the liver, it becomes calcidiol, and then in the kidney, it is finally converted to calcitriol, regulating vital bodily processes.
Explanation:Cholecalciferol, an inactive form of vitamin D, must undergo two conversion steps before it becomes the active form of vitamin D, calcitriol. These steps take place in the liver and the kidney.
In the liver, cholecalciferol is hydroxylated to become 25-hydroxycholecalciferol (calcidiol), also known as 25(OH)D. This is the main circulating form of vitamin D in the blood. From there, it travels to the kidney, where it undergoes another hydroxylation step. The kidneys convert calcidiol into 1,25-dihydroxycholecalciferol (calcitriol), which is the biologically active form of vitamin D. This transformation is crucial for regulating calcium and phosphorus levels in the blood and is important for maintaining healthy bones and teeth among other physiological processes.
AZT is an effective drug for treating HIV-infected individuals because it prevents the replication of new viral particles. The HIV virus has a genome made of RNA. Of the following, which represents the most likely target for the action of AZT?a. DNA polymeraseb. RNA polymerasec. reverse transcriptased. DNA ligase
Answer:
Enzyme reverse transcriptase RT
Explanation:
This enzyme is what is needed by the virus to make several copies of itself. Reverse transcriptase is inhibited by this drug thereby reducing the numbers of the virus. The drug is a nucleoside analog of thymidine
All the following are true of the movement of Earth's atmosphere except :
a.cool air is denser than warm air so it tends to sink toward the Earth's surface.
b.the movement of air within the atmospheric convection cells generates the Earth's major wind belts.
c.a column of cool, dense air produces high pressure at the Earth's surface. a column of warm, less dense air produces low pressure at the Earth's surface.
d.warm air is less dense than cool air so it tends to sink toward the Earth's surface.
Final answer:
The accurate statement about Earth's atmosphere movement is that warm air rises because it is less dense, and cool air sinks due to higher density. This creates convection currents which are essential in generating wind belts and pressure systems.
Explanation:
The correct answer to 'All the following are true of the movement of Earth's atmosphere except:' with the listed statements is option d: warm air is less dense than cool air so it tends to sink toward the Earth's surface. This statement is false because in reality, warm air is less dense and therefore it tends to rise, not sink. This rising of warm air and the sinking of cooler air form convection currents, which are a major factor in the movement of Earth's atmosphere.
The rest of the statements are true: a. cool air is denser than warm air so it tends to sink, b. the movement of air within the atmospheric convection cells generates the Earth's major wind belts, and c. a column of cool, dense air produces high pressure at the surface while a column of warm, less dense air produces low pressure.
Superoxide turns toxic to cell membrane by association with free radical of ________.A) Nitric oxideB) Hydrogen peroxideC) Sulfur dioxideD) Aminoxyls
Answer:
Nitric oxide.
Explanation:
Superoxide may be defined as the compounds that contain the superoxide anions like oxygen anion (O2-). This is also known as the reactive oxygen species.
These anions are generated by the immune system to kill the pathogens. These superoxide include the species like NO, NO2. These super oxide anions are toxic to the cell membrane and also plays an important role in the process of ageing.
Thus, the correct answer is option (A).
During which processes does independent assortment of chromosomes occur?
Independent assortment occurs during anaphase I of meiosis I and to some extent during metaphase II and anaphase II, leading to the formation of gametes with diverse combinations of paternal and maternal chromosomes.
Explanation:Independent assortment of chromosomes occurs during meiosis, a critical process for producing genetically diverse gametes in eukaryotic organisms. Specifically, this event takes place during anaphase I of meiosis I, where bivalent chromosomes separate, and again, although indirectly, during metaphase II and anaphase II as sister chromatids segregate. During the phase of prophase I, chromosomes align randomly at the metaphase plate, setting the stage for the independent assortment. The physical basis for the law of independent assortment lies here, as different homologous pairs line up in random orientations, allowing any combination of paternal and maternal chromosomes to segregate into each gamete, thus increasing genetic variation.
Additionally, recombination or chromosomal cross-over during meiosis further increases genetic diversity by producing new combinations of alleles. At the end of meiosis II, four different gametic combinations are produced, each containing a haploid set of chromosomes. As the number of chromosomes increases, the number of possible assortment combinations increases dramatically, leading to a vast potential for genetic diversity.
Suppose that, while on a forest hike, you notice a blue fungus and a pink plant growing along the hiking trail. As you continue walking, you observe that if a blue fungus and a pink plant are growing side by side, they are both much larger than if the fungus and the plant are farther apart. What can you hypothesize about the relationship between the fungus and the plant?
Answer:
Symbiosis can be described as a biological interaction between organisms of different species.
There are different forms of symbiosis. A type of symbiosis in which both the organisms benefit from each other is called as mutualistic symbiosis.
The blue fungus and the pink plant are able to grow more in size when placed side by side because they undergo symbiosis. They both help each other and develop a symbiotic relationship which allows both of them to have enhanced growth.
Improve the student’s model of gas exchange by drawing the missing component.
The diagram can be improved by:
Lungs
↓
oxygen
↓
Red blood cells (carrying oxygen)
↓
Organs (like stomach and liver etc) from where carbon is taken and oxygen is supplied
↓
RBC's carrying Carbon dioxide to the lungs
Lungs: The lungs are where oxygen is taken in during the process of breathing. Oxygen is a vital element required by the body for cellular respiration.
Red Blood Cells (carrying oxygen): Red blood cells (RBCs) are specialized cells in the bloodstream responsible for carrying oxygen from the lungs to different parts of the body. They contain a protein called hemoglobin, which binds with oxygen in the lungs and carries it to where it is needed.
Organs (like stomach and liver, etc.) from where carbon is taken and oxygen is supplied: This part of the diagram signifies that various organs in the body, including the stomach and liver, require oxygen for their metabolic processes. They receive oxygen from the red blood cells to function properly. At the same time, these organs produce carbon dioxide (a waste product) as a result of their metabolic activities.
RBC's carrying Carbon dioxide to the lungs: After delivering oxygen to the organs, the red blood cells pick up carbon dioxide, which is a waste product of cellular metabolism. The red blood cells then carry this carbon dioxide back to the lungs.
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At the conclusion of an interventional radiographic examination, the examination room is cleaned and major components are wiped down with chemical disinfectants. By performing this important task the radiographer is practicing_________.a. medical asepsis.b. sterilization.c. surgical asepsis.d. fomite asepsis
Answer: A medical asepsis
Explanation:
Medical Asepsis: this is one of the principles of sterile techniques. It is the state of having a sterile equipment and facility free from disease causing micro-organisms such as germs, bacteria, viruses, and other diseases causing microorganisms.
The answer is Medical asepsis and it is concerned mainly with eliminating the spread of disease causing microorganisms through facility practices, to prevent the spread of disease microorganisms from one patient to another.
Look at the cross section of a cell membrane of a eukaryotic cell. H+ ions are being pumped from a low concentration to a high concentration. transport How do you describe this type of transport across the cell membrane?
Answer:
it is an active transport
Explanation:
Active transport involves movement of ions or molecules against a concentration gradient (from region of lower concentration to region of higher concetration) using energy from hydrolysis of ATP as the drive
Answer:
Active Transport is the answer
Explanation:
Ruth is quite attractive (a 4 on a 5-point scale), but Naomi is strikingly attractive (a 5 on a 5-point scale). Research suggests that if Ruth makes $35,000 a year on her job, Naomi will probably make _____ doing the same job. slightly less money the same amount more money significantly less money
A. Slightly less money
B. the same amount
C. More money
D. Significantly less money
Answer:
The correct answer is C. More money.
Explanation:
There' a correlation that has been studied, between physical appearance and the money that people get paid. It's a psychological factor that leads to handsome people being paid more and not so pretty people being paid less. Therefore, as Naomi is more attractive, she will be paid more.
Pea flowers may be purple (P) or white (p). Pea seeds may be round (R) or wrinkled (r). What proportion of the offspring form a cross between purple-flowered round-seeded individuals (heterozygous for both traits) will have both white flowers and round seeds?
Answer:
3/16
Explanation:
The following is the punnet square which represents the probabilities of offsprings being produced for this cross:
PR Pr pR pr
PR PPRR PPRr PpRR PpRr
Pr PPRr PPrr PpRr Pprr
pR PpRR PpRr ppRR ppRr
pr PpRr Pprr ppRr pprr
This cross shows that the probability of the offsprings to have white flowers and rounded seeds would be 3/16.
As children grow, they generally consume more calories, decide if they want to eat, and how much they want to eat. What is the rule-of-thumb guideline to determine an age-appropriate serving size for a 3-year-old?
A) 3 teaspoons
B) 2 tablespoons
C) 3 tablespoons
D) Equal to that of an adult
Answer:
Option C
Explanation:
In general, the amount of nutrient served to an adult is equal to 50% of the nutrient served to adults. The amount of calories consumed by an adult is equal to 2000 to 2800 calories per day. Therefore, the calories required by a young kid is equal to 1000 to 1400 calories per day. Considering this, a nutrient feed of 3 tablespoon is sufficient to cater the calorie requirement of young children of age above 3 years
Hence, option C is correct
Dated to approximately 500,000-400,000 years ago, the site of _______ has yielded a sample of 4,000 fossil fragments representing about 28 premodern Homo sapiens individuals, more than 80% of all Middle Pleistocene hominin remains in the world.
a. Steinheim
b. Ehringsdorf
c. Sima de los Huesos
d. Petralona
e. Swanscombe
Answer:
c. Sima de los Huesos
Explanation:
A crime scene reveals a tiny amount of genetic material that may be linked with the guilty person. This small amount of DNA may be amplified, or copied many times over, through a process called ___________ ___________ ___________.
Answer:
Polymerase Chain Reaction (PCR)
Explanation:
Polymerase chain reaction is a molecular biology procedure/technique used to amplify or multiply specific segments of a DNA. The process makes use of taq polymerase (an enzyme), primers, the DNA of interest and nucleotides.
All the reactants are subjected to repeated heating and cooling cycles during which the DNA of interest is synthesized in multiples. The process can be broken down to 3 basic steps:
Denaturation of the target DNA by heat to separate the DNA strandsBinding of primers to their complementary DNA sequence at lower temperatureSynthesis of new DNA through addition of nucleotides to primers by the taq polymerase. This happens at higher temperature than the second step but lower than the first step.The steps are repeated at the end of each cycle which can last between 2 to 4 hours depending on the length of the target DNA. Newly synthesized DNA at every cycle forms a template for the production of another strand. Hence, multiple copies of the target DNA can be produced within a short period.
In the caterpillar, molting and metamorphosis are under the control of the same hormone. What is the hormone? How are these separate developmental pathways controlled by the same hormone?
Answer:
The correct answer will be- 20-hydroxyecdysone
Explanation:
Ecdysone is a steroid hormone produced in the Arthropods which plays an important role in coordinating and regulating the different developmental transitions like larval moulting and the metamorphosis.
The other effector hormone also plays an important role in molting and metamorphosis called Juvenile hormone.
The presence of juvenile hormone prevents the ecdysone induce changes which regulate molting and gene expression during metamorphosis.
Therefore the presence of the juvenile hormone leads to the different stages of molting while the absence of juvenile hormone promotes the development of metamorphic stages like the development of pupa.
Thus, 20-hydroxyecdysone is the correct answer.
Genetic variation leads to genetic diversity in populations and is the raw material for evolution. Biological systems have multiple processes, such as reproduction, that affect genetic variation. They are evolutionarily conserved and shared by various organisms.
Which statement best represents the connection between reproduction and evolution?
A) Plants that use sexual reproduction are rare since this type of reproduction in plants does not contribute to genetic diversity.
B) In order to increase genetic diversity for evolution in sexually reproducing organisms, mutations must occur in the zygote after fertilization.
C) Since prokaryotic organisms reproduce asexually, there is no mechanism for them to add genetic diversity for evolution.
D) Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.
Answer:
D) Sexual reproduction increases genetic variation because random mutations can be shuffled between organisms.
Explanation:
Sexual reproduction involves the combination of two gametes from two different parents one from the male parent and another from female parents. So as the two different gene combination occurs in sexual reproduction, therefore, it increases the genetic variation.
Also, the random mutation that occurs in the DNA can be shuffled between organisms during the fertilization event of reproduction. This increases the genetic variation because new alleles and genes get added to the gene pool. So good mutation is selected naturally and through reproduction, it passes to a new generation. So the right answer is D.
Mutation and sexual reproduction are the two main mechanisms that contribute to genetic diversity in a population. Mutation introduces new alleles and can have various effects on the phenotype, from reducing fitness to providing a beneficial advantage. Sexual reproduction brings together unique combinations of alleles from two parents, resulting in genetic diversity among offspring.
Explanation:Genetic diversity in a population comes from two main mechanisms: mutation and sexual reproduction. Mutation, a change in DNA, is the ultimate source of new alleles, or new genetic variation in any population. The genetic changes caused by mutation can have one of three outcomes on the phenotype. A mutation can affect the phenotype of the organism in a way that gives it reduced fitness-lower likelihood of survival or fewer offspring. Alternatively, a mutation may produce a phenotype with a beneficial effect on fitness. And, many mutations will also have no effect on the fitness of the phenotype; these are called neutral mutations. Mutations may also have a whole range of effect sizes on the fitness of the organism that expresses them in their phenotype, from a small effect to a great effect. Sexual reproduction also leads to genetic diversity: when two parents reproduce, unique combinations of alleles assemble to produce the unique genotypes and thus phenotypes in each of the offspring.