Answer: There are 4¹⁰⁰ possible strands, approximately 1.61x10⁶⁰
Explanation:
This is a combinatorics problem. Each nucleotide has the possibility of being one of the four common nucleotides, adenine (A), guanine (G), thymine (T) and cytosine (C).
If the strand would be 1 nucleotide long, the possibilities would be 4, one for each possible nucleotide. If the strand would be 2 nucleotides long, for each nucleotide on the first position there would be four possible nucleotides on the second position, giving 4x4=4²=16 possible strands.
For 3 nucleotides long you have 4 possible nucleotides for each of the 2-nucleotide-long strands, 4x4x4=4²=64 possible strands. Following that pattern, for a 100 nucleotide long DNA strand, there would be 4x4x...x4x4=4¹⁰⁰ possible strands.
Using at least two examples, explain how the process of evolution is revealed by the imperfections of living organisms.
Answer:
Evolution is driven by rare mutations that occur in the DNA of organisms. These mutations could be lethal, neutral and some advantageous. The lethal mutations cannot exist in a population because the offspring is unable to survive to term in pregnancy or dies just after birth. The neutral are ones that do not considerably affect the organisms – though they could result in a disadvantage. The beneficial ones are the one that is kept in the population by natural selection because they confer an advantage e.g in the fight for resources or escaping predation and etcetera. Therefore, it's like a game of chances by nature. Paleontologists discover many species of organisms some of which are imperfect because nature produced them but they died off because their mutations gave them a disadvantage against better-adapted individuals.
The Tiktaalik fish from 375 million years ago became extinct because it did not well-developed eardrum for detecting vibrations in water which is significant in survival.
Dinosaurs during development of feathers had many imperfect species before the right wings for flight were conjured up by nature. An imperfect species is the Tianyulong confucius had stiff feathers that lacked vanes hence were not ideal for flight
Evolution is revealed by an organism's imperfections, such as vestigial structures like the human appendix or suboptimal adaptations such as the panda's “thumb,” which demonstrate that evolution does not lead to perfection but rather sufficient adaptation for survival.
Explanation:The process of evolution is often revealed through the imperfections of living organisms. Two examples that illustrate this are vestigial structures and suboptimal adaptations.
Vestigial structures are anatomical features or behaviors that have lost their original function through evolutionary change. The human appendix, for instance, is considered a vestigial structure. It is a remnant of an organ that was likely larger and more functional in human ancestors who had diets rich in cellulose. Over time, changes in diet and other factors have rendered the appendix largely useless, although it can still become inflamed, causing appendicitis.
Another imperfection is seen in suboptimal adaptations. For example, the panda's “thumb,” which is actually an enlarged wrist bone, allows the animal to grasp bamboo stems. This adaptation is not as efficient as a true opposable thumb but demonstrates how natural selection can produce workable, albeit imperfect, solutions.
These imperfections indicate that evolution is not a process leading to perfection but rather to sufficient adaptation that allows organisms to survive and reproduce within their environments. As environments change, so too do the pressures of natural selection, often retaining or modifying structures that are no longer ideal.
We can be sure that a mole of table sugar and a mole of vitamin C are equal in their
a.mass c. number of atoms.
b.volume d. number of molecules
Answer:
The correct answer is option d, that is, the number of molecules.
Explanation:
Mole is illustrated as the given mass of the substance divided by the molecular mass of that substance. A mole of table sugar and a mole of vitamin C are not equivalent in mass. Volume is directly equivalent to mass. Mass can be different, thus, the volume can also be different.
The vitamin C and sugar are the compounds, which are formed of distinct elements combined in the particular molecular ratio. Thus, the number of atoms cannot be similar, also the mass and volume will not be similar for both vitamin C and sugar.
One mole of a substance comprises 6.023 * 10^23 molecules. This is called Avagadro's number. This is similar for all the components, hence, one mole of vitamin C and one mole of table sugar comprise a similar number of molecules.
Why are there villi in the small intestine? How do they improve absorption?
Answer:My answer is in the picture
XD
Explanation:Hope this help
in a pea plant that is heterozygous for seed color what
proportionof gametes will carry the recessive allel?
3/4
1/2
1/4
none above.
Answer:
1/4.
Explanation:
The Mendel is known as father of genetics. He explained the concept of dominance, law of segregation and law of independent assortment while working on the pea plant.
The cross between the heterozygous seed color (Ss × Ss), result in the 3/4 dominant phenotype ( SS, Ss and Ss ) and 1/4 recessive phenotype with alleles ss.
Ss × Ss
progeny obtained are SS, Ss, Ss and ss.
Thus, the correct answer is option (3).
Name one enzymatic step of the TCA cycle wherein a universal electron carrier (in its reduced form) is a product of the reaction: ____________
Answer:
Oxidation of Malate to Oxaloacetate by Malate Dehydogenase
Explanation:
An electron carrier is able to accept and donate electrons in a reaction. The most popular is NADH. NADH in its oxidized form is NAD+. NAD+ received two (2) electrons and an H+ to be reduced to NADH. Other electron carriers are NADPH & FADH₂
There are several steps in the TCA where NAD+ is reduced to NADH by accepting an electron. One of this step is the last step where malate is oxidized and is converted back to oxaloacetate the beginning molecule of the cycle.
Which of the following is NOT a function of Sertoli cells?
A. Synthesis of inhibin.
B. Removal of damaged germ cells.
C. Production of seminiferous tubular fluid.
D. Production of primary spermatocytes.
E. Formation of Blood-testis barrier
Sertoli cells do not produce primary spermatocytes (option D); instead, they support spermatogenesis, create a blood-testis barrier, produce tubular fluid, remove damaged germ cells, and secrete inhibin.
The function that is NOT a function of Sertoli cells is D. Production of primary spermatocytes. Sertoli cells, also known as sustentacular cells or sustentocytes, indeed have several important roles in sperm production within the seminiferous tubules of the testes. They also form the blood-testis barrier, produce substances such as inhibin that regulate spermatogenesis through a negative feedback mechanism, create, seminiferous tubular fluid, and remove damaged germ cells. However, the production of primary spermatocytes is not one of their functions. Primary spermatocytes are derived from germ cells and undergo meiosis to form spermatids, which are then transformed into mature spermatozoa. The Sertoli cells support this process but do not produce the spermatocytes themselves.
A yeast associated with leukemic patients that produces arthrospores is
A) Cyptococcus neoformans
B). Trichosporon species
C) Candida parapsilosis
D) Candida glabrata
Answer: B). Trichosporon species
Explanation:
The Trichosporon is the genus of the anamorphic fungi. In includes the yeast that exhibit no sexual states. These are known for their production of the arthrospore an asexual mode of reproduction in these fungi. These can be found in the soil, or in skin microbiota of the animals and humans. The Trichosporon species is known for severe infections in individuals with weak immune system.
How can mutations change the gene pool of a population?
Answer:
Explanation:
The changes in the gene pool occurs from the one generation to another this process is called as the microevolution. The allele frequencies in the gene pool change due to many processes such as gene flow, natural selection, genetic drift, and mutation. In mutation the genetic variations occurs in the genome of the organisms due to change in the genetic makeup of the organisms new traits are produced which are passed on to the new generation and this brings change in diversity of genes in the gene pool.
George W. Beadle and Edward L. Tatum refined the concept of the gene to state which of the following original ideas?
a. one gene - one enzyme
b. one gene - one metabolic block
c. one gene - one transcript
d. one gene one polypeptide
e. one gene - one allele
Answer:
one gene - one enzyme.
Explanation:
The Garrod's explain the hypothesis one gene enzyme and one enzyme. According to this hypothesis, the single gene codes for the single enzyme that plays an important role in the body metabolism.
The Garrod's hypothesis was experimentally performed by the George W. Beadle and Edward L. Tatum. They performed the biochemical studies and genetic tests on Neurospora to explain the one gene one enzyme hypothesis.
Thus, the correct answer is option (a).
What is the fastest way to administer nicotine to the brain?
a. Intravenous route (IV)
b. Snorting
c. Chewing
d. Smoking
e. IV and smoking are equally fast
Answer:
d. Smoking
Explanation:
Nicotine is a chemical found in many plants such as tobacco. It is one of the 4000 chemicals that tobacco presents and the main component that acts in the brain.
This chemical is absorbed through the skin and lining of the mucosa of the nose and mouth, or in the lungs by prior inhalation. Nicotine can quickly reach the bloodstream and brain and reach maximum levels. The action of smoking cigarettes causes nicotine to reach the brain in just 10 seconds after inhalation. Although the acute effects dissipate in a few minutes, they cause the need to continue the intake of the substance (addiction)
The final electron acceptor in aerobic respiration is:
a. water
b. carbon dioxide
c. oxygen
d. NAD and FAD
Answer:
The correct answer will be option-C.
Explanation:
Cellular respiration is a slow process which oxidizes food to form energy molecules like ATP. The process proceeds in four steps: Glycolysis, pyruvate decarboxylation, citric acid cycle and electron transport chain.
During the electron transport chain, the electrons from the reducing equivalents like NADH and FADH₂. The electrons move downhill by electron acceptors which gets reduced and lose the energy. The electron is finally accepted by an oxygen molecule which forms metabolic water after reacting with free hydrogen atoms.
Thus, Option-C is the correct answer.
In aerobic respiration, the final electron acceptor is oxygen, which allows for the efficient production of ATP and water as byproducts.
Explanation:The final electron acceptor in aerobic respiration is oxygen (O₂). When aerobic respiration occurs, high-energy electrons carried by NADH and FADH₂ are passed to the electron transport chain, and this process leads to the production of ATP. The oxygen molecule accepts these electrons and, together with hydrogen, forms water as a byproduct. Therefore, the correct answer is c. oxygen.
In contrast, if aerobic respiration does not occur, other mechanisms such as fermentation or anaerobic respiration may take place, which involve different final electron acceptors. However, these processes are less efficient at producing ATP compared to when oxygen is present in aerobic respiration.
In his work with pneumonia-causing bacteria and mice, Griffith found that
a. the protein coat from pathogenic cells was able to transform nonpathogenic cells.
b. heat-killed pathogenic cells caused pneumonia.
c. some substance from pathogenic cells was transferred to nonpathogenic cells, making them pathogenic.
d. the polysaccharide coat of bacteria caused pneumonia.
Answer:
Option (c).
Explanation:
Griffith is known as the father of transforming principle. He worked on the virulent and a virulent bacteria that causes pneumonia. He done his experiment on different heat conditions.
When he heat killed the S strains of bacteria and R strains of bacteria into the mice, the mice was killed. He concluded that there was some substance or transforming principle converts the non pathogenic bacteria into the pathogenic strain.
Thus, the correct answer is option (c).
Which of the following diseases is more likely to occur through contact with contaminated water in industrialized countries than in non-industrialized countries?
a. hepatitis A
b. typhoid fever
c. legionellosis
d. hepatitis B
e. tuberculosis
Answer:
The correct answer is option b, that is, typhoid fever.
Explanation:
Typhoid refers to an infection caused by bacteria, which can cause high fever, vomiting, and diarrhea. It can be deadly. It is caused by the bacteria S. typhi. The infection generally passes due to consumption of contaminated water and food. It is more common in places where maintenance of hygiene is less frequent.
The condition generally causes due to the spreading of the bacteria via drinks, food, and drinking water, which gets contaminated with fecal waste. The condition also spreads if contaminated water is used for washing vegetables and fruits.
Midphalangeal hair (hair on top of the middle segment of the fingers) is a common phenotype caused by a dominant allele M. Homozygotes for the recessive allele (mm) lack hair on the middle segment of their fingers. Among 1000 families in which both parents had midphalangeal hair, 1853 children showed the trait while 209 children did not. Explain this result.
Answer:
40% families have heterozygous genotype (Mm).
Remaining 60% of the families will have one parent with homozygous genotype (MM)
Explanation:
If both the parents are heterozygous, then the ration of children without hair to those with hair is 1:3
So, parents with genotype Mm and Mm will produce 209 kids without hair and 209 X 3 i.e 627 kids with hair.
Thus, nearly 40% families have heterozygous genotype (Mm). And the remaining 60% of the families will have one parent with homozygous genotype (MM)
Final answer:
The presence and absence of midphalangeal hair among the children of 1000 families can be explained by Mendelian inheritance, where both parents are likely heterozygous, resulting in a 3:1 ratio of children displaying the trait versus those who do not.
Explanation:
The observation that among 1000 families, both of which have parents displaying midphalangeal hair, resulted in 1853 children with the trait and 209 without can be explained by the Mendelian inheritance pattern. Since midphalangeal hair is caused by a dominant allele (M), and the absence of it by homozygous recessive (mm), we can infer that both parents were heterozygous (Mm) for the trait.
Using a Punnett square, we can predict the possible offspring from two heterozygous parents:
MM (has midphalangeal hair)
Mm (has midphalangeal hair)
mM (has midphalangeal hair)
mm (lacks midphalangeal hair)
This results in a 3:1 ratio of children with the trait to those without, closely reflected in the provided offspring count of 1853 showing the trait and 209 not showing it.
The slight variation from the expected 3:1 ratio can be attributed to the large sample size and possible environmental influences or misclassification. Essentially, this example demonstrates the classic Mendelian inheritance of a trait determined by a single gene with two alleles, where one is dominant over the other.
Primase is an enzyme that synthesizes RNA polymers to provide a 3'OH end for DNA polymerase to use. Which of the following is Primase going to need?
a. a DNA template and deoxyribonucleoside triphosphates (dNTPs)
b. an RNA template and ribonucleoside triphosphates (NTPs)
c. a DNA template and ribonucleoside triphosphates (NTPs)
d. an RNA template and deoxyribonucleoside triphosphates (dNTPs)
Answer:
c. a DNA template and ribonucleoside triphosphates (NTPs)
Explanation:
Primase is an enzyme that makes short RNA fragments using DNA as a template. For the purpose, the primase enzyme uses the ribonucleoside triphosphates (NTPs) and makes an RNA copy of the existing DNA template.
The enzyme is DNA primase as it uses the DNA template strand. The newly formed short RNA fragments are called primers. Primers are required by DNA polymerases which in turn are the enzymes of elongation only and can not start the de novo synthesis of new DNA strand.
The free 3' OH end of the RNA primer is extended by DNA polymerase by adding deoxyribonucleotides.
Muscle cells in oxygen deprivation convert pyruvate to ______ and in this step gain _______
A) lactate ATP
B) alcohol... CO2
C) alcohol..ATP
D) ATP... NAD+
E) lactate ..NAD+
Answer: E) lactate ..NAD+
Explanation:
In conditions of oxygen deprivation, cells can't undergo normal cellular respiration and must rely on other processes to obtain energy.
Muscle cells in particular, under anaerobic exercise, do not obtain enough oxygen to produce the energy needed and end up obtaining energy form a process different than cellular respiration: lactic fermentation.
Lactic fermentation turns a molecule of pyruvate into a molecule of lactate, at the same time it turns NADH into NAD+.
Group of similar cells is called ___________
a. organelles
b. organ
c. tissue
d. organ system
Answer:
C. Tissues
Explanation:
Tissues are the group of similar cells all of that perform specific function. The cells that make a tissue mostly have a common origin and function together to perform some specialized tasks.
For example, the human body consists of four basic types of tissues. Muscular tissues are one of the tissue types of the human body. The cells that make the muscular tissues are specialized for contraction and force generation to support the movement of body parts.
Which of the following is a plant adaptation to living in a cold climate?
a. Requiring burning
b. Vernalization
c. Seed coat
d. Endosperm
Answer:
b. Vernalization
Explanation:
Vernalization is a phenomenon in which plants require low temperature for the flowering. There is either qualitatively or quantitatively dependent on exposure to very low temperature. This process is known as vernalization. Vernalization defines especially to the promotion of flowering by a period of low climate. For example; Vernalisation occurs in biennial plants. Biennials are monocarpic plants which normally flower and may die in the second season. Some common examples of biennials are carrots, Sugarbeet, cabbages, etc.
The achoo syndrome (sneezing in response to bright light) and trembling chin (triggered by anxiety) are both dominant traits in humans. a. What is the probability that the first child of parents who are heterozygous for both the achoo gene and trembling chin will have achoo syndrome but lack the trembling chin? b. What is the probability that the first child will not have achoo syndrome or trembling chin?
Answer:
a. 18.75% (3 of 16)
b. 6.25% (1 of 16)
Explanation:
o answer this kind of question you need to make a Punnet square, this kind of diagrams is used to predict the probability of an outspring having a particular genotype. In this case, you need to predict two different traits, I added an image for you to see how this square is done.
First, you need to assign a letter for your traits, I used A for the achoo syndrome and T for the trembling chin, now you need to determine alleles for the parents since both of them are heterozygous both of them will have AaTt (one dominant allele and one recessive allele). Now you are going to take the first allele of you your first trait and combine it with the first allele of your seconds trait (AT), now with the second allele of your second trait (At), now you take the send allele of your first trait and combine it with the first allele of your second trait (aT) and then with the second (at), this is going to be the same for both parents, finally you cross one pair from the mother with one from the father following the order of your square.
Now you'll have 16 combinations, observing them you can find that for your question a. 3 of 16 combinations have at least one dominant allele for achoo syndrome and receive for trembling chin and b. only 1 of 16 with both recessive traits
Final answer:
The first child of parents who are heterozygous for both the achoo gene and trembling chin has a 50% chance of having achoo syndrome but lacking the trembling chin. The probability that the first child will not have achoo syndrome or trembling chin is 25%.
Explanation:
In this case, the first child of parents who are heterozygous for both the achoo gene and trembling chin will have a 50% chance of having achoo syndrome but lacking the trembling chin. Since these traits are both dominant, if the child inherits the dominant allele for achoo syndrome from one parent and the recessive allele for trembling chin from both parents, they will have achoo syndrome but lack the trembling chin.
The probability that the first child will not have achoo syndrome or trembling chin can be calculated by multiplying the probability of not having achoo syndrome (1 - 0.5) and the probability of not having trembling chin (1 - 0.5), which equals 0.25 or 25%.
Which of the following statements is true about mutations induced by radiation?
a. xrays, cosmic rays, and UV rays are all classified as ionizing radiation
b. ionizing radiation results in raising electrons to an atom's outer orbitals, a state referred to as excitation.
c. in mammals, chronic irradiation is as effective in inducing mutations as acute irradiation
d. UV radiation results in the formation of purine dimers and purine hydrates
e. xrays can result in gross changes of chromosome structure, such as large deletions, duplications and inversions.
Answer:
The correct answer is option e.
Explanation:
X-rays refers to the ionizing radiation exhibiting shortest wavelengths and possessing the tendency to pass through the tissues. This tendency of passing through the tissues on getting exposed to X-rays even for brief duration will lead to displacement of electrons from the orbital of molecules and atoms like witnessed in chromosomes.
X-rays are not stable and possess high energy and when this energy passes on to the electrons, it gets displaced resulting in the modifications of the structure of nucleic acid bases in the DNA resulting in chromosomal modifications like inversion, transversion, duplication, and deletion mutations.
All of the following are correct descriptions of photosynthesis except:
A) The Calvin Cycle is endergonic.
B) Electrons are supplied to the reaction center via the splitting of water, which yields O2 as a byproduct
C) Chlorophyll and accessory pigments capture energy from the sun in the form of electrons, which they use to drive the electron transport chains of photosystems I and II.
D) ATP and NADPH generated in the light-dependent reactions are used to power CO2 fixation via the Calvin cycle in the light-independent reactions.
Answer:
The correct answer is option C.
Explanation:
The chlorophyll and the accessory pigments captivate energy from the Sun in the form of light. This energy is used to dissociate water known as photolysis to generate electrons, protons, and oxygen.
The oxygen is produced as a by-product of the process, while the electrons are provided to the reaction centers, and the protons are further used in the process of building up of proton gradient.
Answer:
The correct answer will be option- C.
Explanation:
Photosynthesis is a complex process which synthesizes the glucose molecules by converting sunlight energy into chemical energy. Photosynthesis proceeds in two phases: light-dependent and light-independent reaction.
The light-dependent reactions take place in the thylakoid membrane where the photo-system chlorophyll absorbs the sunlight photons which excites the electrons of the chlorophyll.
Chlorophyll transfers the electron to antenna molecules and finally to reaction center form where it enters the electron transport chain.
This creates instability which causes the photolysis of water molecules and release of oxygen as a byproduct. The light reaction produces intermediates like ATP and NADPH which are utilized during the Calvin cycle.
Thus, Option-C is the correct answer.
Testosterone and its derivative dihydrotestosterone prompt the Mullerian ducts to develop into male accessory structure, epididymis, vas deference and seminal vesicle.
a. True
b. False
Answer:
The given statement is false.
Explanation:
The paramesonephric ducts or the Mullerian ducts refers to a paired ducts of mesodermal in origin found in the embryo. They run sideways down the urogenital ridge and culminates at the Mullerian eminence in the embryonic urogenital sinus.
The Mullerian ducts are the elemental organ of the female reproductive tract. They further divide to produce the uterus, the fallopian tubes, the superior part of the vagina, and the uterine cervix. A wide array of abnormalities can take place when this system gets hampered.
What are the two types of orientation behavior? Provide an example of each.
Answer:
Two types of orientation behavior are as follows:
Taxis behavior:
This is a type of orientation behavior that mainly occur in response towards the external stimulus. Taxis may be positive (movement towards the stimulus) or negative ( movement away from the stimulus). Different types of taxis behavior are phototaxis, aerotaxis, chemotaxis and magnetotaxis.
Kinesis:
Kinesis may be defined as a type of orientation behavior that can change the complete movement or orientation of the organism. Kinesis is a random movement and organism can move in either direction. Different type of kinesis are klinokinesis and orthokinesis.
Which of the following are phagocytic?
a. neutrophils only
b. lymphocytes only
c. monocytes and macrophages
d. all of these cells are phagocytic
e. macrophages only
f. monocytes, macrophages and neutrophils
g. monocytes only
Answer:
The correct answer is option F. monocytes, macrophages and neutrophils.
Explanation:
Phagocytic cells are the cells that engulf harmful substances or foreign particles, bacteria and other dead cells. These cells destroy them by engulfing the foreign particles and degrade them by chemical releases.
The phagocytic cells include - monocytes, macrophages, neutrophils, and dendritic cells. All these three types of cells are further divided. The neutrophils are the first cell to appear at the site of the infection or injury.
Thus, the correct answer is option F. monocytes, macrophages and neutrophils.
What is the significance of the industrial practice of waiting for cultures to enter the stationary phase of growth before harvest?
a. An optimal combination of primary and secondary metabolites is being produced.
b. Secondary metabolites are often the desired product, and are only produced in stationary phase.
c. The desired primary metabolites are produced in stationary phase.
d. The cells are at peak metabolic activity.
e. Potential toxins from log phase growth have been depleted
Answer: b. Secondary metabolites are often the desired product, and are only produced in stationary phase.
Explanation:
The secondary metabolites are the organic compounds that are produced by the microbes such as bacteria, fungi and even by the plants. These are not involved in the growth, development and reproduction of the organisms. But they can provide a advantage for the survival. It helps in plant defense against the process of herbivory and other interspecies defense. Humans take the secondary metabolites from these organisms in the form of medicines, pigments, and recreational drugs.
The secondary metabolites are produced only in the stationary phase of growth. Thus it is significant for the collection of these secondary metabolites in the stationary phase.
What are the four factors that determine a population's growth rate?
a. Birth rate, death rate, doubling time, and carrying capacity
b. Birth rate, death rate, doubling time, and compounding
c. Birth rate, death rate, carrying capacity and emigration rate
d. Birth rate, death rate, immigration rate, and emigration rate
e. Birth rate, death rate, compounding, and immigration rate
Answer:
I think it's d
Explanation:
Which of the following proteins is vital to the process of recombination?
a. RecA
b. CroA
c. HemA
d. Gyrase
e. Topoisomerase
Answer:
The correct answer will be option-A.
Explanation:
Recombination is a process in which the DNA sequences get exchanged between two homologous chromosomes. It occurs during gamete formation and is the basis of genetic diversity.
The process requires many enzymes, the key enzyme of which is Recobinase A or RecA protein which catalyzes the homologous recombination using ATP as an energy molecule.
RecA binds to the single-stranded DNA at the break site and forms pre-synaptic structure. Thus, it initiates the reaction of strand exchange and is the correct answer.
Estrogen is most likely to exert its effect by regulating
a) protein kinases.
b) phospholipase C.
c) expression of genes and production of
specificproteins.
d) cyclic AMP
e) Ca2+.
Answer:
c) expression of genes and production of specific proteins.
Explanation:
Estrogen is a lipid-soluble steroid hormone that diffuses through the lipid bilayer of the plasma membrane of its target cell. The hormone binds to its nuclear receptor and receptor-hormone complex then alters the expression of particular genes.
It triggers transcription of specific DNA sequences into mRNA which in turn enters the cytoplasm and serves as a template for synthesis of specific proteins.
Estrogen is the female sex hormone and stimulates development of secondary sexual characters in females as well as required for maturation of egg.
Which of these is an example of chemoprevention?
A. Research into a phytochemical from a plant which might inhibit cancer development.
B. Research into cancer prevention in animals other than humans.
C. Research into the use of chemotherapy to cure cancer.
D. Research into chemotherapy which might prevent cancer.
E. Research into the use of diet to cure cancer.
Answer: A. Research into a phytochemical from a plant which might inhibit cancer development.
Explanation:
The chemoprevention is a process of utilization of chemical formulations such as medication, supplements and vitamins to the stop the growth of cancer cells. This is necessary and important for people which are at high risk of developing cancer.
The research for the phytochemical derived from the plants can be an example of chemoprevention as this will help in inhibiting the cancer development.
The correct answer is A. Chemoprevention involves the use of substances to inhibit cancer development, specifically through research into phytochemicals. Other options either address treatment or general prevention unrelated to chemoprevention.
The correct answer is A. Research into a phytochemical from a plant that might inhibit cancer development.
This is an example of chemoprevention as it involves the study of substances that prevent or inhibit the development of cancer.Why other options are incorrect:
B. Research into cancer prevention in animals other than humans: This does not specifically relate to chemoprevention but rather to general cancer prevention studies.C. Research into the use of chemotherapy to cure cancer: Chemotherapy is a treatment for existing cancer, not a preventive measure.D. Research into chemotherapy that might prevent cancer: Chemoprevention typically involves the use of non-chemotherapeutic agents to prevent cancer; chemotherapy is generally used to treat established cancer.E. Research into the use of diet to cure cancer: This focuses on curing cancer through diet, not on preventing it through specific chemicals or medicines.Propose a hypothesis for the evolution of life on earth from single-celled organisms to multicellular organisms. What is the most significant step in the evolution of multicellularity?
Answer:
there are tree hypothesis
Explanation:
There are several mechanisms by which multicellularity could have evolved:
1. A group of cells were added in a slug-shaped mass called grex, which was moved as a multicellular unit, as the Myxomycota do.
2. The primitive cell suffered an incomplete division of the cell nucleus generating a cell with multiple nuclei or syncytium. Next, membranes formed around each nucleus and the space was occupied by organelles. This resulted in a group of cells connected in an organism, an observable mechanism in Drosophila.
3. Daughter cells did not separate after cell division, resulting in a conglomeration of identical cells in an organism, which later developed specialized functions. This is observed in embryos of plants, animals and colonial cyanoflagellates.
Should read more about the topic here, google it:
Multicellular development in a choanoflagellate; Stephen R. Fairclough, Mark J. Dayel and Nicole King
In a Single-Cell Predator, Clues to the Animal Kingdom’s Birth