Answer:
d. IgE
Explanation:
Immunoglobulin E (IgE) are antibodies that respond to allergic reactions. The response leads to the release of the anti-inflammatory histamine and vasoactive chemicals.
The strong force is one of the four fundamental forces of the universe and it holds protons and neutrons in the nuclei of atoms.
a. True
b. False
Answer:
The given statement is true.
Explanation:
In the nuclei atoms we know that there are 2 type of particles named protons and neutrons.As we know that the neutrons are uncharged and protons are positively charged thus in such a close proximity when the proton's are just touching each other the electrostatic forces of repulsion between the particles becomes exceedingly large thus rendering the nucleus theoretically unstable. But as we know that the nucleus is inherently stable indicating that there is another type of force that must act between the nucleons (proton's and neutrons) this fundamental force is known as strong nuclear force and is the strongest force among the 4 fundamental forces in nature.
Answer:
true
Explanation:
hope it helped
Explain the differences between prokaryotes, eukaryotes and mitochondria(eukaryotic organelle). Which 2 of those 3 are most similar?
Eukaryotic
Cells with a differentiated nucleus that contains all the DNA, limited by nucleus membrane, and has a cytoplasm limited with the plasma membrane that contains organelles.
The ribosomes are bigger, 80 S (svedbeg is the measuring unit)
Procaryotic
All its genetic material spread on the cytoplasm.
This kind of cell does not have organelles. All biologic processes made in specific places in the plasma membrane.
The ribosomes are smaller, 70 S.
Mitochondria
It's an organelle you can find inside a eukaryotic cell.
It has two membranes, one outsider, and one insider.
The insider one has folded.
Scientific believe that millions of years ago, the mitochondria was a bacteria and the eukaryotic cell phagocyte it and became part of it.
The ribosomes are the same size that procaryotic cells.
How does the hypothalamus monitor water in the body?
A. If blood is too concentrated, the hypothalamus nerve cells will contain too much salt.
B. If blood is too concentrated, the hypothalamus it registers dehydration in its own cells.
C. If blood is too concentrated, the hypothalamus registers ADH in the blood.
D. If blood is too concentrated, nerve cells in the hypothalamus it has nerve cells that lose water by osmosis and fire more slowly.
E. If blood is too concentrated, in the hypothalamus it registers that its cells are losing water by osmosis.
Answer:
The correct answer will be option-C.
Explanation:
Hypothalamus is a part of the brain which controls many important functions of the body by producing hormones.
When the amount of water gets reduced in the blood, it leads to a change in the osmolarity which can be easily detected by the osmorecpetors present in the neurons of the hypothalamus.
In response, neurons secrete Anti-diuretic hormone in the blood which acts in the tubules of the kidney where they help in re-absorption of the water from the body.
Thus, Option-C is the correct answer.
Explain the biological basis for assigning all human populations to a single species. Can you think of a scenario by which a second human species could originate in the future?
Answer:
Molecular biology (DNA sampling) is the best proof.
Explanation:
An study published in the journal of science found that 99.9% of humans are quite similar. The scientific team analysed DNA from 1,056 people from 52 populations in Africa, Eurasia (Europe, the Middle East, Central and South Asia), East Asia, Oceania and the Americas.
The phenotype ( visible appearance) results from a very small proportion of differences in genetic traits, hence the concept "race" is more a cultural concept than a biological concept.
Which of the following represents the number of premolars in deciduous dentition of teeth in humans?
a. 2
b. 4
c. 8
d. 12
e. 0
The correct answer is E. 0
Explanation:
The deciduous dentition or baby teeth refer to the first set of teeth human have before the permanent teeth, these teeth are prevalent during infancy and include 20 teeth: 4 central incisors, 4 lateral incisors, 4 canines and 8 molars divided into 4 primary molars and 4 secondary ones. In the case of premolars, these are part of permanent teeth but not of deciduous teeth as they only appear after deciduous teeth begin being replaced and these replace the molars in deciduous dentition. Thus, the number of premolars in deciduous dentition in humans is 0.
Relate the structure of DNA to its function.
Answer:
Explanation:
DNA is deoxyribose nucleic acid. It is a double helical structure. It remains in the coiled form so as to make the information stored in the small region within the cell. The sequence of bases allows the information to be stored in the coded form so as to promote the synthesis of proteins. Complementary base pairing allows the DNA molecule to replicate itself.
A controlled experiment is one that
a. proceeds slowly enough that a scientist can make careful records of the result.
b. tests experimental and control groups in parallel.
c. is repeated many times to make sure the results are accurate.
d. keeps all variables constant.
A controlled experiment is one that tests experimental and control groups in parallel, with all other variables kept constant. This enables the scientist to observe the impact of a single variable.
Explanation:A controlled experiment is one that can be defined as an experimental set up in which the scientist keeps all variables constant, except for the one being studied. The correct option here would be option 'b'. Such an experiment tests experimental and control groups in parallel.
This methodology allows the researcher to observe the effect of one variable on the study subject while ensuring that all other conditions remain the same. For example, if you were to experiment with plant growth, you might keep factors like sunlight, water, and type of soil constant while changing the type of fertilizer used.
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Which of the following is a type of tissue in plants that is dead at maturity?
a. Parenchyma
b. Sclerenchyma
c. Collenchyma
d. All of these are alive at maturity.
Answer:
The correct answer will be option-B.
Explanation:
The plant tissues are composed of three types of cells: parenchyma, collenchyma and sclerenchyma.
The parenchyma and collenchyma remain alive at their maturity but sclerenchyma loses their protoplasm and become dead. These cells deposit lignin in their secondary walls and form hard tissues of the plant-like hard shell of a coconut. Sclerenchyma provides mechanical strength to the plant.
Thus, Option-B is the correct answer.
During purification of many cytosolic proteins, it is important to
include either dithiothreitol or b-mercaptoethanol in the
buffers. Why?
Answer:
To reduce thiol-groups of the protein
Explanation:
Dithiothreitol of b-mercaptoethanol act as reducing agents. Including them in a buffer would prevent oxidation of thiol-groups in amino acids of the protein and preventing its denaturation.
Simply, translation is a copy of _______________
a. DNA from mRNA
b. DNA from DNA
c. protein from RNA
d. RNA from DNA
Answer:
c. protein from RNA
Explanation:
Translation is a process that occurs in the ribosomes where tRNA is used to read the mRNA strand and translate the codons into complementary amino acids.
Which of the following is NOT a hormonal type of contraception?
A. Depo-Provera
B. Contraceptive diaphragm
C. Injectable progestin.
D. Birth control patch.
E Oral contraceptives.
Answer:
The correct option is: B. Contraceptive diaphragm
Explanation:
Contraception, also known as birth control, are the various methods like barrier methods, hormonal contraception, sterilization, intrauterine devices, and behavioral methods, that are used to prevent pregnancy.
The hormonal method of contraception includes vaginal rings, injections, patches and oral contraceptive pills. This contraceptive method involves the use of steroid hormones- estrogen, progestin, and progesterone.
Whereas, the barrier method of contraception includes condoms, contraceptive sponges, diaphragms and the fertility awareness methods.
Therefore, contraceptive diaphragm is not a hormonal method of contraception.
Mutations that occur without a known cause are known as:
a. spontaneous mutations
b. induced mutations
c. harmful mutations
d. adaptive mutations
e. reversion mutations
Answer:
a. spontaneous mutations
Explanation:
Spontaneous mutations occur randomly in all cells and without any agents. Induced mutations are the result of some exposure to a physical or chemical agent called a mutagen. Mutations can be classified as harmful and adaptive regardless of whether they were spontaneous or induced mutations. The reversal mutation is when a given mutation is reversed by another mutation so that the nucleotide is changed back to its original state.
A cancerous tumor eventually grows faster than surrounding tissues because a greater proportion of its cells are dividing. True or false?
A) true
B) false
C) none of the above
What might be a use for fluorescence in situ hybridization (FISH)?
a. For identification of a specific gene in a DNA extraction by hybridization to a DNA probe
b. For identification of a specific gene by hybridization to a DNA probe within live cells that have had their DNA denatured by heat.
c. For identification of an mRNA within an RNA extraction by hybridization to a DNA probe.
d. For identification of both mRNA and DNA in cellular extracts using an RNA probe
e. None of the above
Answer:
B.
Explanation:
Flourescent insitu hybridization-This technique permits the direct analysis of sequences of DNA or RNA in tissues
-Through this technique various chromosomal abnormalities can be determined as it focuses on that part of the DNA for which a complementary probe has been used.
-The method involves the denaturation of DNA in a tissue section followed by the application of a labeled probe which is complementary to the sequence of interest.
Plant species A has a diploid chromosome number of 12. Plant species B has a diploid number of 16. A new species, C, arises as an allopolyploid from A and B. The diploid number for species C would probably be
a. 14. b. 16. c. 28. d. 56.
Answer:
c. 28
Explanation:
Plant A has a dipoid chromosome number of 12, so its gametes will have an haploid number of 6 chromosomes.
Plant B has a dipoid chromosome number of 16, so its gametes will have an haploid number of 8 chromosomes.
Plant A Plant B2n = 12 2n = 16 n = 6 n = 8The new species C arises as an allopolyploid from A and B. An allopolyploid usually originates from the breeding of two different species.
In this case, a gamete from plant A combines with a gamete from plant B to form a hybrid with 14 chromosomes (6 from A and 8 from B). These chromosomes are unpaired, so the hybrid is sterile.
In order to become a fertile diploid individual of species C, the most common mechanism is polyploidization, where the genome duplicates. That way, the resulting plant C has a diploid number of 14 x 2 = 28 chromosomes, of which 12 are A and 16 are B.
Species C, being an allopolyploid of species A and B, would likely have a diploid number that is the sum of the diploid numbers of species A and B. In this case, that is 28.
Explanation:The new species C, being an allopolyploid of species A and B, is formed by a combination of the whole sets of chromosomes from both species A and B. Thus, we would add together the diploid numbers of both species to determine the diploid number of species C. Plant species A has a diploid chromosome number of 12 and plant species B has a diploid number of 16. Adding these together gives us a total diploid number of 28. Therefore, the correct answer would be option c. 28.
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Fossilized stromatolites
(A) formed around deep-sea vents.
(B) resemble structures formed by bacterial communities that are found today in some shallow marine bays.
(C) provide evidence that plants moved onto land in the company of fungi around 500 million years ago.
(D) contain the first undisputed fossils of eukaryotes.
Answer:
(B) resemble structures formed by bacterial communities that are found today in some shallow marine bays.
Explanation:
Extant stromatolites represent real "living fossils" for they are decendents of ancient forms that are associated with one of the first living forms on earth. Particularly, stromatolites are real bacteria communities where the autotrophic organism of the community are represented by cyanobacteria, which live along with heterotrophic bacteria. This clearly indicates that fossilized stromatolites points to bacteria (prokaryotes) as the first living things on earth (dated with not less than 3.5 billion year old)
Nowadays, stromatolites with cyanobacteria allows to reconstruct and understand fossilized forms. These current structures live in shallow marines ambients (e.g. Australia) but also in continental salt flats (e.g. Argentina) where few others bacteria can survive to these extreme conditions (high light exposure and salt concentration).
Stromatolites are sedimentary formations created by cyanobacteria that resemble structures found today in some shallow marine bays. They provide key insight into early photosynthetic life on Earth.
Explanation:Stromatolites are layered mounds, columns, and sheet-like sedimentary rocks that were originally formed by the growth of layer upon layer of certain cyanobacteria, a primitive form of photosynthetic life. Option (B) is correct - Stromatolites resemble structures formed by bacterial communities that are found today in some shallow marine bays. The cyanobacteria secrete a sticky substance to which sediment adheres, and if conditions are right and undisturbed by other organisms or strong currents, a new layer of cyanobacteria grows over it and the process repeats, leading to the formation of a fossilized layered structure.
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From which part of the embryvo are embryonic stem cell lines derived?
Answer:
Undifferentiated inner cell mass
Explanation:
Human embryo has two types of cells in its initial stage, trophoblast and inner cell mass. Trophoblast forms the placenta and inner cell mass form the entire human body. Inner cell mass are pluripotent in nature i.e. they can give rise to any body part under right conditions.
Embryonic stem cells are derived from the inner cell mass. They are derived from pre implantation embryo since after implantation the inner cell mass begins to differentiate. Embryonic stem cells can replicate indefinitely without differentiating. They can give rise to all the three germ layers: ectoderm, mesoderm and endoderm. They can treat a number of disorders like genetic disorders, Parkinson's, spinal cord injury, cancers etc.
what happens to the molecules of water when the temperature of water increases?
Answer:
Water carries several physical properties such as chemical formula, appearance, boiling point, freezing point, density, viscosity and solvency.
An increase in temperature changes the density of water. When a water is heated or its temperature is allowed to increase it causes the water molecules to gain energy and move faster, which results in increase in water volume due to movement of water molecule far from each other. on the other side if temperature of water is decrease, it's molecules come closer to each other and decrease in the volume of water takes place.
Most amino acids are specified by two to four different codons. This means that the genetic code is:
a. nonoverlapping
b. degenerate
c. ordered
d. non-degenerate
e. universal
Answer:
Degenerate.
Explanation:
Genetic code may be defined as the codons of three nucleotides that can be inherited to the next generation. The codons codes for the particular amino acids.
The degeneracy of the genetic code means the a single amino acids is coded by more then one codons. For example: Leucine is coded by UUG as well as UUA.
Thus, the correct answer is option (b).
(5th grade science)
In each set, circle the item in the group that doesn’t belong. Justify your reasoning
1.) consumer
Producer
Predator
Prey
2.) mouse
Snake
Mushroom
Lion
3.) Decomposers
Animals
Plants
Sunlight
Answer:
2. Mushroom 3. Sunlight
Explanation:
2. A mushroom is a fungus not an animal
3. Sunlight is not alive animals, plants, and decomposes are.
What is the correct scientific name for the cane toad?
a. Bufo
b. Bufo Marinus
c. Marinus
d. Cane toad
Answer:
The correct answer is option B. Bufo Marinus.
Explanation:
The cane toad a american species of toads that is known as its scientific name Rhinella marina which is formerly known as Bufo Marinus. Commonly called neotropical toad which is large, land toad found in central and south America.
These toads are the world's largest toads that are known for their invasive properties as they grow and reproduce incredibly fast.
Thus, the correct answer is option B. Bufo Marinus.
Define reading frame and discuss its significance to the genetic code.
Basically, a reading frame is the result of DNA or RNA nucleotide sequencing in non-overlapping triplets. It's like taking the strand of DNA and / or RNA and stretching it into a straight line. Thus, all nitrogenous bases would be in sequence and aligned as in a row. Each three nitrogenous bases (codon) encodes a protein.
The reading structure has revolutionized the field of genetics and evolution, since we can see the sequencing of the genes of individuals, we can make comparisons between their DNAs to discover possible evolutionary relationships between them. In addition, it is also very important in medicine to locate sequences where there are genetic mutations (base exchanges or subtractions).
What happens to the bronchioles in an asthma attack? How do regular rescue inhalers treat asthma? (i.e. bronchodilators). How do steroids treat asthma symptoms in the long term (HINT: they are NOT rescue inhalers)
Answer:
Asthma refers to a disease in which swelling of the airways results in the restriction of airflow into and out of the lungs. During the occurrence of an asthma attack, the production of the mucus gets increased, the bronchial tree muscles become constricted, and the inflammation of the air passages lining occurs. This further minimizes the flow of air and generates a kind of wheezing sound.
The bronchodilators quickly help in relieving the symptoms of acute asthma by opening the airways. The activity of inhaled bronchodilator begins some minutes post inhalation and endures for two to four hours.
All the kinds of steroids minimize swelling in the airways, which transports air towards the lungs and minimize the generation of mucus produced by the bronchial tubes. This makes one breathe easily.
The inhaled steroids cure swelling of the airways, and only a very minute concentration of it gets captivated by the body. Thus, these medicines do not seem to result in any kind of serious side effects in a long run.
Explain what is meant by the antiparallel polarity of the two strands of DNA within the double helix.
Answer:
The two DNA strands have anti parallel polarity which means that they are directional and anti parallel to each other. The polarity to these strands is conferred by the deoxyribose sugar molecule in nucleotide. The sugar molecule has 5 Carbon atoms. The third carbon is attached to an OH group and the fifth carbon is attached to a phosphate molecule. This asymmetry is responsible for giving DNA molecule a direction.
The double helix structure has both these strands in opposite direction so that the 5 prime carbon of one strand faces the 3 prime carbon of another. The anti parallel structure of DNA strands lets the base pairs complement each other. Anti parallel structure is also more stable than parallel structure.
A large percentage of bacteria are harmful to humans and cause disease.
a. True
b. False
Answer:
The correct answer is b. False
Explanation:
More than 90% of bacteria present in the world is not harmful to human beings. Human body contains trillions of bacteria in their intestine which play important role digestion of food absorption of nutrients inside the small intestine.
Human gut contains 10 times more bacteria than the cells present in human body. This proves that bacteria lives in symbiotic association with humans and human body cannot survive without them.
Thus a large percentage of bacteria are not harmful to humans rather they are important part of human body and these bacteria are called human microbiota.
Which of these are found in both eukaryotes and prokaryotes (choose all that apply)
a. Centromere
b. replication bubbles
c. telomeres
d. replication forks
Answer:
The correct answers are option b. "replication bubbles" and d. "replication forks".
Explanation:
The nucleic acids replication systems share some similarities between eukaryotes and prokaryotes. For instance, both organism have replication bubbles. However, prokaryotes have a single replication bubble because its replication process starts from a single origin, while eukaryotes have several replication bubbles. Also, the replication forks are well conserved from prokaryotes to eukaryotes with only some differences among the enzymes present within the fork.
Q:- Short hair rabbit is goverened by a dominant gene (L)
andlong hair by its recessive alleles (l). Black hair results from
theaction of the dominant genotype (B) and brown from therecessive
genotype (b).
A. In cross between dihybrid short ,black and homozygousshort,
brown rabbits, what genotypic and phenotypic ratios areexpected
among their progeny?
B. Determine the expected genotypic and phenotypic ratios
inprogeny from cross LlBb*Llbb.
Answer:
A) he phenotypic ratio is
short & black : short & brown
8:8
1:1
Genotypic Ratio is
LLBb : LLbb: LlBb : Llbb
4:4:4:4
1:1:1:1
B)
Genotypic Ration
LLBb : LLbb: LlBb: Llbb: llBb: llbb
2: 2: 4: 4: 2:2
1:1:2:2:1:1
Phenotypic ratio
Short & Black : Short & brown: Long & black : Long & brown
6: 6: 2: 2
3:3:1:1
Explanation:
Given -
Allele for short hair (L) is dominant over long hair allele (l)
And Black hair allele (B) is dominant over brown hair allele (b)
A) Genotype for dihybrid short and black rabbit is LlBb
Genotype for homozygous short and brown rabbits is LLbb
Cross between LlBb and LLbb will result into following offspring
LB Lb lB lb
Lb LLBb LLbb LlBb Llbb
Lb LLBb LLbb LlBb Llbb
Lb LLBb LLbb LlBb Llbb
Lb LLBb LLbb LlBb Llbb
Hence, the phenotypic ratio is
short & black : short & brown
8:8
1:1
Genotypic Ratio is
LLBb : LLbb: LlBb : Llbb
4:4:4:4
1:1:1:1
B) LlBb*Llbb.
LB Lb lB lb
Lb LLBb LLbb LlBb Llbb
Lb LLBb LLbb LlBb Llbb
lb LlBb Llbb llBb llbb
lb LlBb Llbb llBb llbb
Genotypic Ration
LLBb : LLbb: LlBb: Llbb: llBb: llbb
2: 2: 4: 4: 2:2
1:1:2:2:1:1
Phenotypic ratio
Short & Black : Short & brown: Long & black : Long & brown
6: 6: 2: 2
3:3:1:1
Which of the following statements about eukaryotic mRNA processing is not correct?
a. the mRNA transcript must be exported from the nucleus.
b. a 5' cap and a 3' poly(A) tail must be added
c. the introns are removed
d. a 3' cap and a 5' poly(A) tail must be added
e. exons are spliced together to form the mRNA transcript
Answer:
The correct answer will be option-D.
Explanation:
In eukaryotes, the process of transcription takes place inside the nucleus whereas translation takes place in the cytosol. So, mRNA has to export to the cytosol from the nucleus.
Before export, the post-transcriptional modification takes place like 5' capping, 3' tailing and splicing mechanism.
The capping is done at 5' end by adding modified guanine (G) nucleotide which protects the mRNA from exonuclease activity and tailing is done at 3' end by adding adenine nucleotides which provides stability to the mRNA.Splicing removes the junk DNA called introns and joins the exons before export.
Thus, option-D is the correct answer.
The incorrect statement about eukaryotic mRNA processing is 'a 3' cap and a 5' poly(A) tail must be added.' In actuality, a 5' cap is added and a 3' poly(A) tail is added.
Explanation:The statement that is not correct about eukaryotic mRNA processing is: 'd. a 3' cap and a 5' poly(A) tail must be added.'
In eukaryotic mRNA processing, there are several modifications made. Firstly, a 5' cap is added to the beginning of the mRNA molecule, not a 3' cap. Additionally, a poly(A) tail is added at the 3' end, not the 5' end. Therefore, option 'd' is incorrect. The rest of the modifications, which include the removal of introns, the export of the mRNA transcript from the nucleus, and the splicing together of exons to form the final mRNA transcript, are correct.
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You are trying to figure out what molecule, DNA, RNA, or protein, is responsible for making your bacterial cell lysate turn blue when you add a certain chemical. You divide your lysate into 4 tubes and add (a) Nothing, (b) protease, (c) RNase, and (d) DNase. Then you add your chemical of interest to each tube. Tubes (a), (b), and (d) turned blue but (c) remained colorless. You conclude:
a. The molecule responsible for making the blue color is DNA.
b. Your RNase didn't work.
c. The molecule responsible for making the blue color is RNA.
d. The molecule responsible for making the blue color is a protein.
Answer:
c. The molecule responsible for making the blue color is RNA.
Explanation:
Tube (a): DNA, RNA and proteins present ⇒ BLUE
Tube (b): DNA and RNA present ⇒ BLUE
Tube (c): DNA and proteins present ⇒ COLORLESS
Tube (d): RNA and proteins present ⇒ BLUE
RNA is the only molecule that is present every time the chamical is added and the tubes turn blue, and not present when the color doesn't change, meaning in tube (c) there's no reaction with the added chemical.
In conclusion, RNA is the only molecule reacting with the chemical and responsible for blue appearance.
Which of the following traits evolved multiple times over the course of the evolution of vertebrates?
a. Hair
b. Flight
c. Oviparity
d. Homodonty
Answer:
The correct answer is option b, that is, flight.
Explanation:
Our atmosphere is comparatively thick, and it possesses the tendency of supporting the creatures, which are light. The factual flight, however, relies upon the fact that whether an individual is sufficiently light, and is equipped with appropriate characteristics, and has a desire to make a since the attempt to make aloft.
The birds are the most apparent fliers in the world we live in. The first bird appeared in the fossil about sixty-five million years ago. Like birds, bats also have developed an elegant approach to flight. Similarly to birds, they exhibit lightweight and slender bones, and a compact skeleton, and have developed strong muscles for flapping flight.
Final answer:
b) Flight is the trait that evolved multiple times in vertebrates, with different species developing unique wing structures through convergent evolution.
Explanation:
The trait that evolved multiple times over the course of the evolution of vertebrates is flight. Flight has evolved independently in different vertebrate lineages through a process known as convergent evolution. This is evident in the wings of pterodactyls, birds, and bats, which are structures adapted for the purpose of flight, but each has a unique anatomical development despite the forelimbs being homologous structures. On the other hand, hair has evolved only in the lineage leading to mammals, and oviparity, though widespread, is not an example of multiple independent evolutionary events. Homodonty, the condition of having teeth uniform in shape, may have appeared in different lineages but is not as clear an example of repeated evolution as flight. The development of traits like a high metabolism, a four-chambered heart, and other modifications have supported the evolution of flight in vertebrates.