Answer:
C
Explanation:
The damage to DNA usually occurs where there are two consecutive thymine nucleotides on a DNA strand. The energy from the UV light causes the two dimers to form a cyclobutane pyrimidine structure. Proofreading and repair mechanism of DNA find it difficult to repair this kind of damage on DNA. During replication, therefore, DNA polymerase is unable to replicate this region hence leading to a mutation on the replicated strand at this local point.
Expression of the A and B antigens on red blood cells is influenced by the FUT1 gene. This gene encodes fucosyl transferase, an enzyme that helps produce the H substance. Which of the following statements about the H substance is incorrect?
(A) Individuals that cannot produce the H substance appear to be type O even if they have functional A and/or iB alleles.
(B) Individuals that fail to produce the H substance are said to have the Bombay phenotype.
(C) Individuals that are heterozygous for the FUT1 gene cannot produce the H substance
(D) The H substance is a substrate for the enzymes produced by the n and β genes. These enzymes add the appropriate terminal sugar to the H substance producing the A and B antigens, respectively.
Answer: The correct answer is option C
Explanation:
Bombay phenotype refers to a rare genetic trait in which a person appears as blood group O even in presence of functional A, B, or AB alleles.
It is because of recessive mutation that occurs in other locus, that is, FUT1 gene. Normal gene produces H antigen or protein in the cell. This antigen is essential for the final expression of the ABO alleles.
If a person is homozygous recessive then he or she is not able to produce H antigen due to which the blood group appears as O.
However, if a person carries even a single functional copy of FUT1 gene, that is, heterozygous or homozygous then he or she can efficiently produce H antigen and then ABO alleles are expressed accordingly.
Thus, option C contains incorrect statement.
Which of the following is present in a prokaryotic cell?
a. mitochondrion
b. ribosome
c. nuclear envelope
d. chloroplast
The correct answer is B. Ribosome
Explanation:
In biology, cells are mainly classified as eukaryotic or prokaryotic. Each of these types of cells has different features, to begin with, eukaryotic cells are those that contain a defined nucleus and are part of both unicellular and multicellular organisms. On the opposite, prokaryotic cells do not have a defined nucleus or a nuclear envelope and are mainly present in unicellular organisms, besides this, they lack mitochondrion, Golgi apparatus or chloroplasts that are present in eukaryotic cells. However, prokaryotic cells still contain DNA, ribosomes, vesicles, and vacuoles. According to this, the one that is present in a prokaryotic cell is ribosome.
The only option from the list present in a prokaryotic cell is a ribosome. Prokaryotic cells do not contain mitochondria, nuclear envelopes or chloroplasts which are associated only with eukaryotic cells.
Explanation:The correct answer to the question 'Which of the following is present in a prokaryotic cell?' is (b) ribosome. Prokaryotic cells, such as bacteria, do not contain mitochondria, nuclear envelopes, or chloroplasts as these are structures associated only with eukaryotic cells. However, they do contain ribosomes which play a crucial role in protein synthesis.
It's important to note that eukaryotic cells also contain ribosomes, the primary difference being that the ribosomes in eukaryotic cells are larger and more complex than those found in prokaryotic cells.
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Compare the means of sex determination in different organisms.
Answer:
Sex determination may be defined as the phenomena of determining the sex whether the organism is male, female or hermaphrodite. Different methods of sex determination are present in different organism.
In case of humans, the sex chromosome of an individual with XY is male whereas XX is female. Humans male are heterogametic. In case of birds the chromosome with ZZ are males (homogametic) whereas ZW is female. In case of Drosophila XY and XO flies are males , while XX, XXY, and XXYY flies are females.
Discuss the relationship between the recombination frequency and the map distance separating two loci on a chromosome.
Answer:
Linkage chromosomes may be defined as the chromosome present at the same chromosomes and has the ability to undergo the process of recombination. The linkage results in the production of recombinant gametes that differ from their parents.
Map distance may be defined as the distance between the two gene on a chromosome. The recombination frequency is equal to the map distance. For example: Gene A and B has the recombination frequency of 10%, this means there map distance is 10 mu.
Bioinformatics includes all of the following except
a. using computer programs to align DNA sequences.
b. using DNA technology to combine DNA from two different sources in a test tube.
c. developing computer-based tools for genome analysis.
d. using mathematical tools to make sense of biological systems.
Bioinformatics involves using computer programs to align DNA sequences, developing computer-based tools for genome analysis, and using math tools to interpret biological systems. It does not directly involve using DNA technology to combine DNA from different sources.
Explanation:The question at hand is asking which of the given options is not included in the field of bioinformatics. Bioinformatics is a multidisciplinary field involving biology, computer science, and statistics. It utilizes computer programming for aligning DNA sequences, developing computer-based tools for genome analysis, and mathematical tools to interpret biological systems. So, options a, c, and d are within its scope. However, option b describes a process known as recombinant DNA technology, not directly related to bioinformatics. Thus, the answer must be option b: Using DNA technology to combine DNA from two different sources in a test tube.
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Option b, which refers to the use of DNA technology to combine DNA from different sources, is not a part of bioinformatics. This task is more closely associated with the field of molecular biology.
Explanation:Bioinformatics is a rapidly developing branch of biology that is mainly involved in the development and application of computational tools to analyze, integrate, and interpret large sets of biological data. Among the four options presented, the only task that doesn't fall under bioinformatics is b. using DNA technology to combine DNA from two different sources in a test tube. This is more closely related to the field of molecular biology, specifically recombinant DNA technology or genetic engineering. The tasks described in a, c, and d are all common in bioinformatics. They involve the use of computer programs, development of computational tools for genome analysis, and the application of mathematical tools to interpret complex biological systems.
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If you were using cladistics to build a phylogenetic tree of cats, which of the following would be the best outgroup?
a.wolf c.lion
b.domestic cat d.leopard
Answer: a. Wolf
Explanation:
A phylogenetic tree is a diagrammatic representation in which the premitive living species are compared with the modern organisms on the basis of morphological as well as genetic similarities and differences. Hence, they are separated into distinct groups.
All the given organisms in the options (wolf, domestic cat, lion, and leopard) belong to the vertebrata phyllum. Among the options given all the organisms, except wolf, the other organisms are morphologically close to one other. Thus for constructing a phylogenetic tree for these organisms, wolfs will be an out-group. The other organisms will be the descendent belonging to the same group.
When using cladistics to build a phylogenetic tree of cats, then a WOLF would be the BEST outgroup (Option a).
Cladistic is an evolutionary approach to classify taxonomic groups (i.e., clades) based on the most recent common ancestor of these clades.In cladistics, phylogenetic trees are graphical representations that show lines of evolutionary descent of different clades from a common ancestor.An outgroup is a more distantly related clade that helps to determine the level of evolutionary relationships among organisms or taxonomic groups (e.g., species) within a phylogenetic cladistic tree.In conclusion, when using cladistics to build a phylogenetic tree of cats, then a WOLF would be the BEST outgroup (Option a).
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RNA viruses require their own supply of certain enzymes because
a. host cells rapidly destroy the viruses.
b. host cells lack enzymes that can replicate the viral genome.
c. these enzymes translate viral mRNA into proteins.
d. these enzymes penetrate host cell membranes.
Answer: The correct answer is option b.
Explanation:
RNA viruses have RNA as genetic material whereas the host cells usually have DNA as genetic material.
So, in order to integrate its genome with host DNA, the virus must form DNA from RNA, that is, reverse transcription.
It is the process by which DNA is formed using RNA as a template strand.
However, reverse transcriptase (enzyme which catalyzes reverse transcription) is usually not present in host cells.
Thus, RNA viruses carry their own set of enzymes which help in the replication of viral genome and its recombination with host DNA as host cells lack these enzymes.
RNA viruses require their own supply of certain enzymes because
b. host cells lack enzymes that can replicate the viral genome.Why does RNA viruses require their own supply of certain enzymesRNA viruses require their own supply of certain enzymes because host cells do not possess the specific enzymes necessary for replicating the viral genome. Unlike DNA viruses, RNA viruses typically rely on viral enzymes, such as RNA-dependent RNA polymerase, to replicate their RNA genome within the host cell.
These viral enzymes are not present in the host cell and must be brought in by the virus itself. Without these enzymes, the host cell's replication machinery would not be able to synthesize new copies of the viral RNA genome, hindering viral replication and propagation.
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What sugar makes up a part of a DNA nucleotide?
a. glucose
b. ribose
c. deoxyribose
d. sucrose
Answer: Deoxyribose
Explanation:
The Deoxyribonucleic acid is the genetic material found in all the living organism.
The genetic information is transferred in the form of codes from one generation to another in the from of DNA.
The DNA consists of sugar, nitrogenous bases and phosphate group. The sugar part is ribose sugar which is a type of pentose sugar.
Hence, the correct answer is option C
Refer to the chart of amino acid structures to help answer this question. Which four statements about amino acids are true? Ser and Gln are polar amino acids. The Leu side chain does not form hydrogen bonds with other amino acids. The form of glycine used by the human body is D‑glycine. Methionine is a thiol. Phe can undergo oxidation to form Tyr. Proline has an overall charge at physiological pH (7.4). Lysine has one stereocenter (chiral center).
Answer:
1. Ser and Gln are polar amino acids.
2. The Leu side chain does not form hydrogen bonds with other amino acids.
3. Phe can undergo oxidation to form Tyr.
4. Lysine has one stereocenter (chiral center).
Explanation:
Serine and glutamine are the polar amino acids with uncharged side group. Serine has a "CH2OH" group as its side chain and the presence of hydroxyl group makes it a polar amino acid. Glutamine is one of the amides derived from other amino acids present in proteins.
Leucine is a nonpolar amino acid with an aliphatic side chain and tends to cluster within the proteins to stay away from the surrounding watery medium. Its aliphatic R group does not form any hydrogen bonds to other amino acids.
Phenylalanine is a nonpolar amino acid with an aromatic R group. Oxidation of aromatic R group of phenylalanine converts it into tyrosine which has an additional hydroxyl group in its side chain.
The chiral center is the carbon to which four different functional groups are bonded. The central alpha carbon atom of lysine is bonded to an amino group, carboxyl group, a hydrogen atom, and one positively charged R group which in turn makes it a chiral center.
Four true statements about amino acids are: Ser and Gln are polar amino acids, Methionine is a thiol, Lysine has one stereocenter, and The Leu side chain does not form hydrogen bonds with other amino acids.
Explanation:Four true statements about amino acids are:
Ser and Gln are polar amino acids. Serine (Ser) and Glutamine (Gln) have polar side chains, which means they have a partial positive and partial negative charge and can interact with water molecules.Methionine is a thiol. Methionine (Met) contains a sulfur atom in its side chain, making it a thiol amino acid.Lysine has one stereocenter (chiral center). Lysine (Lys) has one carbon atom with four different groups attached, making it a stereocenter or chiral center.The Leu side chain does not form hydrogen bonds with other amino acids. The Leucine (Leu) side chain is nonpolar and hydrophobic, meaning it does not interact with polar molecules like water or form hydrogen bonds.Learn more about Amino acids here:https://brainly.com/question/31442968
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Which of the following statements about the DNA in one of your brain cells is true?
a. Most of the DNA codes for protein.
b. The majority of genes are likely to be transcribed.
c. It is the same as the DNA in one of your liver cells.
d. Each gene lies immediately adjacent to an enhancer.
Answer:
C
Explanation:
The DNA in all the cells of an organism are the same. The reason there are different types of cells in the organism even through their DNA is the same is because genes are deferentially expressed in the cell types. The genes that are expressed in the brain cells are different from those expressed in the liver. The rest of the genes that are not being expressed are silenced through folding by histones – so they are not exposed to DNA polymerase.
Final answer:
The correct statement is c. It is the same as the DNA in one of your liver cells, since all cells contain the same DNA but only express a subset of genes necessary for their specific function.
Explanation:
The statement about the DNA in one of your brain cells that is true is: c. It is the same as the DNA in one of your liver cells. All the cells in your body pretty much have the same DNA, but not all of it is used or 'expressed' in every cell. Instead, each type of cell expresses only a subset of genes, which are necessary for the specific functions that cell performs. Gene expression is the process by which information from a gene is used to construct a functional product, commonly a protein.
The majority of DNA does not code for proteins, and the genes required for a cell's function are selectively transcribed into mRNA and then translated into proteins as needed. Therefore, options a, b, and d are incorrect. Each gene does not lie immediately adjacent to an enhancer, and not all genes are transcribed in a given cell at any specific time.
What are the two categories of behavior? Provide an example of each.
Answer:
Explanation:
The two categories of the behavior includes the operant behavior and respondent behavior.
Operant behavior: The operant behavior can be define as the behavior that is under the control of the consequences. These consequences are likely to control the future frequency of behavior. For example, A child who is allowed to hit other children and take their toy, is likely to be aggressive to other people in the future.
Respondent Behavior: The behavior which is under the influence of a specific stimuli is a respondent behavior. For example, Snapping of hand away from a hot pan, and Salivation of the mouth due to food.
Each DNA strand contains bases but also a structure that can be described as "sugar- lipid-sugar-lipid-sugar-lipid...", repeating this simple sequence from one end to the other
a. True
b. False
Answer:
False.
Explanation:
DNA is present as genetic material in all the organism except some viruses. RNA is present as genetic material in some viruses only. The DNA strands are complimentary with each other.
DNA is made of the polymers of nucleotides. The nucleotides consists of the nitrogenous bases (adenine, guanine, thymine and cytosine), deoxyribose pentose sugar and phosphate group. The DNA molecule doesnot contain sugar..lipid in its structure.
Thus, the answer is false.
When is high density liproteins (HDL) most prevalent in the body?
Answer:
HDL are most prevalent in the body when the person has high physical activity and a healthy diet.
Explanation:
Physical activity and a diet rich on fruits, fiber, omega 6 and esential fat acids increases the level of HDL, which responsible on drecreasing the levels of cholesterol in blood.
Genetic factors might also impact on the levels of HDL.
Show how two phenotypically normal parents can produce a male child with color-blindness.
Answer:
The female (XcX) is carrier for color blindness while the male (XY) is normal. The carrier female transmits its one X chromosome with gene for color blindness to one of her sons making him color blind.
Explanation:
Color blindness is X linked recessive disorder and followed the criss-cross inheritance wherein the color blind sons get the gene from their carrier/affected mother while the color blind father would transmit the gene to his daughters along with X chromosome.
Since both the parents are normal, the mother (XcX) should be carrier for the disease to get the color blind son. A cross between carrier mother (XcX) and normal father (XY) would make 50% of their sons color blind.
A paleontologist has recovered a bit of tissue from the 400-year-old preserved skin of an extinct dodo (a bird). To compare a specific region of the DNA from a sample with DNA from living birds, which of the following would be most useful for increasing the amount of dodo DNA available for testing?
a. SNP analysis
b. polymerase chain reaction (PCR)
c. electroporation
d. gel electrophoresis
Answer:
b. polymerase chain reaction (PCR)
Explanation:
PCR is the technique that generates millions of copies of DNA starting from a small amount of template.In this reaction, a molecule of double stranded DNA is denatured and the chains separated. Then, the single strands of DNA are hybridized with a small complementary fragment of DNA called a primer, which is then extended by an enzyme called DNA polymerase by adding complementary nucleotides to the template strand. The result will be two double stranded DNA molecules. If you repeat the process many times, you can amplify the original DNA material exponentially, and the final PCR product will be millions of DNA molecules that can be used for testing.
A SNP analysis is a method that allows scientists to detect variations of a single nucleotide in the DNA sequence of different individuals.Electroporation is a technique that creates temporary pores in a cell membrane, allowing the delivery of drugs or DNA to a cell.Gel electrophoresis is a method to analyze the PCR product in which the DNA molecules are separated by size.The polymerase chain reaction (PCR) would be the most useful technique for increasing the amount of dodo DNA available for testing, as it allows rapid amplification of specific DNA sequences.
Explanation:To increase the amount of dodo DNA available for testing when comparing a specific region of the DNA from a sample with DNA from living birds, the most useful technique would be polymerase chain reaction (PCR). This method allows for the rapid amplification of specific DNA sequences, thereby increasing the number of copies of the dodo DNA for further analysis. PCR is a highly effective tool in molecular biology for the amplification of DNA from limited samples, such as those obtained from extinct species like the dodo or other ancient remains.
Cite the most common molecular explanations for dominant and recessive alleles.
Answer: Dominant allele codes for a functional protein. Recessive allele codes for a less functional or nonfunctional protein, or it does not code for any protein.
Explanation:
Alleles are different forms of a gene. There are two types, dominant and recessive allele. Heterozygous organisms have one of each, and the dominant allele is expressed. Homozygous organisms have either two dominant alleles or two recessive alleles.
A dominant allele produces a functional protein, even in the presence of a recessive allele, because only one copy of the allele is enough and it masks the effects of the recessive allele. This dominant trait is shown in individuals who are homozygous dominant or heterozygous,
A recessive allele produces a less functional or nonfunctional protein, or it does not code for any protein at all. A recessive allele does not become a trait unless both copies of the gene are present.
8) Each time a molecule of glucose is completely oxidized via aerobic respiration, how many oxygen (O2) molecules are required?
A) 1
B) 2
C) 6
D) 12
E) 38
Answer:
C) 6
Explanation:
The balanced equation for aerobic cellular respiration is:
C₆H₁₂O₆ + 6 O₂ ----> 6 CO₂ + 6 H₂O + Energy (ATP)
For each glucose molecule that's oxidized, 6 oxygen molecules are used in order to produce ATP. Carbon dioxide and water are byproducts of aerobic respiration..
Each complete oxidation of a glucose molecule through aerobic respiration requires 6 molecules of oxygen (O2). The process, represented by the equation C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP, shows this clearly.
Explanation:In the process of aerobic respiration, glucose (C6H12O6) is oxidized, while oxygen is reduced. The overall equation for this process can be represented as C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP. From this equation, we can see that each molecule of glucose requires 6 molecules of oxygen (O2) to be completely oxidized. Therefore, the correct answer to the question 'Each time a molecule of glucose is completely oxidized via aerobic respiration, how many oxygen (O2) molecules are required?' is C) 6.
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Proposed mode of DNA replication where one daughter cells gets both strands of parent DNA and the other daughter cell gets both strands of new DNA.
a. Bi-directional replication
b. Dispersive replication
c. Conservative replication
d. Semiconservative replication
Answer:
c. Conservative replication
Explanation:
In conservative mode of replication, the parent DNA molecule will direct the synthesis of entirely new DNA molecule. Hence, one daughter cell will get the old DNA with both parental strands and the other daughter cell will get the new DNA with both new strands.But the widely accepted replication model is semi conservative model. Where both the strands separate and act as template for new strands. Hence, the new DNA molecules will have one parental DNA strand and one new DNA strand. According to dispersive replication model, the newly synthesized DNA randomly gets fragments of parental DNA.Hence, the answer is conservative replication.
FMO3 is an enzyme that helps break down a chemical in humans, trimethylaamine, that produces the smell of rotting fish. The gene for FMO3 is located on chromosome 1. The functioning form of the enzyme is coded for by a dominant allele, and the nonfunctioning form of the enzyme is coded for by a recessive allele. Individuals with the nonfunctioning from of the enzyme have trimethylaminuria, also known as fish odor syndrome. Neither Maggie nor Mark has the fish odor syndrome, but their daughter Melissa does. If Maggie and Mark have another baby, what is the chance that child will also have fish odor syndrome?
Answer:
The fish odor syndrome is a recessive disorder, and thus, requires two alleles in order to manifest the condition. In the given case, both the parents do not exhibit the syndrome, however, their daughter does. It signifies that both the parents are carriers, and thus, are heterozygous.
In such situations, the heterozygous parents exhibit a 25 percent chance of having a child with the condition, while 75 percent chance of having a non-affected child. Thus, they have zero percent chance of exhibiting a child with fish odor syndrome.
Humans have 46 chromosomes in each somatic cell. a. How many chromosomes does a child receive from its father? b. How many autosomes and how many sex chromosomes are present in each somatic cell? c. How many chromosomes are present in a human ovum? d. How many sex chromosomes are present in a human ovum?
Answer:
Explanation:
a. How many chromosomes does a child receive from its father?
Every person receives half of their chromosomes from their father and half from their mother. For that reason, if humans have 46 chromosomes in each somatic cell, 23 of them come from the father.
b. How many autosomes and how many sex chromosomes are present in each somatic cell?
Each somatic cell has 46 chromosomes in total; of which 22 pairs are autosomes and 1 pair are sex chromosomes. Therefore, 44 chromosomes are autosomes and 2 chromosomes are sex chromosomes (the X and/or Y chromosomes).
c. How many chromosomes are present in a human ovum?
The human gametes (ovum in women and sperm cell in men) have half of a somatic cell's genetic material, so that when they combine in a zygote to create their child, they form an initial cell with 46 chromosomes in total. The ovum therefore has 23 chromosomes: 22 autosomes and 1 sex chromosome.
d. How many sex chromosomes are present in a human ovum?
As I mentioned in the previous question, a human ovum has 1 sex chromosome. That way, when it combines with a sperm cell, which also has 1 sex chromosome, they form a zygote with a pair of sex chromosomes (one that comes from the mother and one from the father).
a. A child receives 23 chromosomes from its father. b. Each somatic cell has 44 autosomes and 2 sex chromosomes. c. A human ovum contains 23 chromosomes. d. A human ovum has 1 sex chromosome.
Explanation:a. A child receives 23 chromosomes from its father.
b. Each somatic cell has 44 autosomes and 2 sex chromosomes, for a total of 46 chromosomes.
c. A human ovum contains 23 chromosomes.
d. A human ovum has 1 sex chromosome.
Some scientists have proposed that the earliest forms of life may have existed in an "RNA World" where RNA was both the genetic material and responsible for enzymatic activity. Imagine that you have recreated such a life form. What would demonstrate that RNA, but not protein or DNA, is necessary and sufficient for these functions?
(A) The organism lives and replicates despite RNase and DNase treatment, but the organism dies when treated with protease.
(B) The organism lives and replicates despite protease and DNase treatment, but the organism dies when treated with RNase.
(C) The organism lives and replicates despite protease treatment, but the organism dies when treated with DNase and RNase.
(D) The organism lives and replicates despite DNase treatment, but the organism dies when treated with RNase and protease.
Answer:
(B) The organism lives and replicates despite protease and DNase treatment, but the organism dies when treated with RNase.
Explanation:
DNA is the genetic material in present day organisms while some of the proteins serve as enzymes and catalyze the metabolic reactions.
An organism having RNA with the ability to serve as genetic material would not require DNA to survive. Likewise, if RNA molecules in these organisms also serve as the enzyme, proteins would not be required for survival.
Therefore, when treated with DNase and protease that digest the DNA and proteins respectively, these organisms would be able to survive. However, treatment with RNase enzymes that digest the RNA would kill them as RNA was their biocatalyst and genetic material.
Which of the following is an unsual nucleoside that is found in tRNA but not mRNA?
a. Adenine
b. Inosine
c. Proline
d. Phenylalanine
e. Guanine
Answer:
Inosine
Explanation:
Inosine the unusual nucleoside which is found in tRNA but not in mRNA. Inosine is derived from the nucleoside adenosine, adenosine is present in mRNA, however in case of tRNA, there is deamination of adenosine and thus, inosine is formed. The enzyme that is responsible for carrying out this reaction is called as tRNA A:34 deaminases, here the position 34 indicates that the deamination takes place at position 34 of the tRNA. The formation of inosine is essential for the wobble base pairing to take place. The formation of inosine takes place when the hypoxanthine attaches to a ribose ring with the help of the beta glycosidic bond.What leukocytes (white blood cells) are primarily responsible for the specific immune responses such as cellular and humoral immunity?
a) neutrophils
b) lymphocytes
c) eosinophils
d) macrophages
Answer:
The correct answer will be option-B.
Explanation:
Lymphocytes are a type of white blood cells or leukocytes which can be easily distinguished as they have a single round nucleus.
Lymphocytes act as immune cells in the body as they help in providing immunity. These lymphocytes upon maturation get differentiated into two types: B cell and T cell.
The B cell produces specific antibodies in response to the foreign bodies called antigen. They attach with the antigen and mark the antigen for destruction. This takes place in the blood thus provides the humoral immunity.
T cell recognize and respond to the antigen directly by killing the cell with antigen or indirectly by producing lymphokines to kill the cell. This provides immunity tat with the cellular level.
Thus, Option-B is the correct answer.
Lymphocytes are the primary leukocytes responsible for specific immune responses such as cellular and humoral immunity.
Explanation:The leukocytes (white blood cells) primarily responsible for specific immune responses such as cellular and humoral immunity are lymphocytes. Lymphocytes are a type of leukocyte that play a crucial role in the adaptive immune response. They are responsible for recognizing and targeting specific antigens or pathogens. There are two main types of lymphocytes: B cells and T cells.
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Plants are more readily manipulated by genetic engineering than are animals because
a. plant genes do not contain introns.
b. more vectors are available for transferring recombinant DNA into plant cells.
c. a somatic plant cell can often give rise to a complete plant.
d. plant cells have larger nuclei
Answer:
The correct answer is option c. "a somatic plant cell can often give rise to a complete plant".
Explanation:
One characteristic that makes plants readily manipulated organisms for genetic engineering studies is that a somatic plant cell can often give rise to a complete plant. This process is known as somatic embryogenesis, and is widely used with relative ease in biotechnology laboratories. Somatic embryogenesis helps to quickly test genetic manipulation tests in complete plants allowing to check for the final phenotype easily.
Plants are more readily manipulated by genetic engineering than animals due to their ability to regenerate, the availability of vectors for gene transfer, and the direct insertion of synthetic genes into plant genomes.
Explanation:Plants are more readily manipulated by genetic engineering than animals because:
Plant cells have the ability to regenerate and grow into complete plants, making it easier to select and cultivate cells with desired qualities.There are more available vectors for transferring new genes into plant cells, such as plasmids and microscopic pellets.Plant transformation allows for the direct insertion of synthetic genes into plant genomes without the need for generations of breeding.In contrast, animal cells do not have the same regeneration capacity, and the process of introducing new genes and traits is more complex.
Which method would me most efficient to identify where a specific gene is being expressed within the cell?
a. immunofluorescence
b. immunoprecipitation
c. microarray
d. photolithography
e. FRAP
Answer:
b. Immnofluorescence
Explanation:
Immunofluorescence involves the reaction of a fluorescently labelled antibody to an expressed gene or protein making it specific. A microscope is used to locate the expressed gene via the fluorescent dye activated by light of a certain wavelength. It is usually done to analyze intact cells or tissue therefore it is easier to localize the gene expression.
The tissue(s) that is/are considered excitable because of the ability to generate electrical signals is/are called ________ tissue. The tissue(s) that is/are considered excitable because of the ability to generate electrical signals is/are called ________ tissue. muscle neural epithelial muscle tissue and neural muscle tissue, neural tissue, and epithelial
Answer:
Muscle tissue and neural tissue
Explanation:
Excitability refers to the ability of muscle and nerve cells of the respective tissues to respond to a stimulus and generate an action potential. Both muscle cells and neurons respond to a stimulus and convert it into the action potential.
Action potential refers to the electrical signal. Propagation of action potential along the membranes of these cells results in muscle contraction and functioning of neurons.
The membrane potential of these cells changes in response to the stimulus and the changed potential is propagated to the other cells.
The drug cytochalasin B blocks the function of actin. Which of the following aspects of the animal cell cycle would be most disrupted by cytochalasin B?
a. spindle formation
b. spindle attachment to kinetochores
c. cell elongation during anaphase
d. cleavage furrow formation and cytokinesis
Answer:
d. cleavage furrow formation and cytokinesis
Explanation:
Cytochalasin B is a cell permeable toxin produced by fungi. It inhibits actin polymerization and interaction of actin filaments. Cytokinesis is the process in which the cell undergoes cytoplasmic division to form two new cells. It begins in late anaphase and is completed by the end of telophase. It begins by the production of cleavage furrow on the cell surface. This furrow is formed by the contractile ring which in turn is composed of actin and myosin filaments along with other regulatory proteins.
When actin polymerization is inhibited by cytochalasin B, the contractile ring is not able to form so the cleavage furrow does not appear which ultimately inhibits cytokinesis.
Briefly describe the following methods of regulation of enzyme activity in a cell
i) allosteric control
ii) covalent modification
Answer:
Explanation:
i) Allosteric control
-Allosteric modulation is a mechanism whereby the activity of an enzyme is either stimulated or inhibited by a compound that binds to a site, called the allosteric site, that is dimensionaly different from the enzyme’s active site
ii) Covalent modification
-Covalent modification of enzymes, as illustrated by the addition (or removal) of phosphates, is a general mechanism for changing the activity of enzymes.
-Enzymes that transfer phosphate groups to other proteins are called protein kinases and regulate such diverse activities as hormone action, cell division, and gene expression.
Cellular enzyme activity is regulated through allosteric control and covalent modification. Allosteric control involves effector molecules binding to a site other than the enzyme's active site to modulate its activity, while covalent modification changes an enzyme's activity through the reversible addition or removal of chemical groups.
Explanation:Cells regulate enzymes through various mechanisms, significant among which are allosteric control and covalent modification. Understanding these methods is crucial for comprehending how cells control biochemical pathways and respond to changes in the environment.
Allosteric control involves the regulation of an enzyme's activity through the binding of an effector molecule at a site other than the enzyme's active site, known as the allosteric site. This interaction can either enhance (activator) or reduce (inhibitor) the enzyme's activity. Allosteric enzymes exhibit a change in their conformation upon effector binding, which alters the enzyme's affinity for its substrate. Feedback inhibition, a form of negative regulation where the end product of a biochemical pathway inhibits an enzyme involved earlier in the pathway, often works through allosteric control.
Covalent modification involves the reversible addition or removal of chemical groups (such as phosphate, methyl, or acetyl groups) to an enzyme, altering its activity. This modification can either activate or deactivate the enzyme and is often mediated by other enzymes. For example, the addition of a phosphate group (phosphorylation) by a kinase can activate an enzyme, while removal of this group by a phosphatase can inactivate it. Covalent modification allows for rapid changes in enzyme activity in response to cellular signals.
What is the myelin sheath, and why does it speed up nerve transmissions?
Answer:
Myelin sheaths refer to the covering of fatty tissue, which safeguards the nerve cells. These cells are the components of CNS that conduct messages back and forth between the brain and the remaining parts of the body.
The majority of the nerve fibers are enveloped by an insulating, fatty sheath known as myelin that functions to accelerate the impulses. The myelin sheath comprises periodic breaks known as nodes of Ranvier. Hopping from nodes to nodes, the impulse can pass much more briskly than if it had to move along the whole length of the nerve fiber.
Energy pyramids, which display graphically the relative amounts of energy in each trophic level of an ecosystem, are very similar across a wide range of different ecosystems, but biomass and organism abundance at different trophic levels are more variable between different ecosystems.
a. True
b. False
Answer:
a. True
Explanation:
Energy pyramids are a simple representation of the flow of energy at each trophic level in an ecosystem, based on the well known fact that a lot of energy gets lost between consumers (approximately only around 10% is made into tissues, while 90% is used up and is lost as heat).
While the biomass and abundance of the organisms at a trophic level, even the identity of that organisms (species), is highly dependent on the characteristic of the environment. So very different environments (for example, a dessert and a rain forest) will have also very different species with different biomass and abundance fulfilling the same trophic role.