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.
Individuals who are allergic to penicillin generate _______ antibody against the antibiotic.
a. IgM
b. IgG
c. IgA
d. IgE
e. IgD
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.
Write a short essay (about 100–150 words) evaluating whether changes to an organism’s physical environment are likely to result in evolutionary change. Use an example to support your reasoning.
Answer:
Explanation:
Change in an organism's physical environment will cause the organism to adapt to fit in the surrounding environment. This process is called as adaptation. This process causes the evolution of the organism into a new species. The environment affects the evolution of the species , because change in environment put pressure on the species to adapt in change environmental conditions. Natural selection brings the change in the organism as the organism best suited for the environment survives.The example of evolution is the giraffe neck. Giraffe evolved by the development of tall neck slowly by increasing their neck length, so that they can eat leaf from the tall plants.
Changes to an organism's physical environment can lead to evolutionary change within a population through the process of natural selection. The example of the peppered moth during the Industrial Revolution demonstrates this, where the dark-colored moths became more prevalent due to their increased camouflage against pollution-darkened trees.
Explanation:Changes to an organism's physical environment can indeed catalyze evolutionary change within a population. This process, described by the theory of natural selection, posits that individuals with phenotypes best suited to the new environment will survive and produce more offspring. Over time, these genetic traits become more common within the population, leading to evolutionary change.
For example, the peppered moth (Biston betularia) during the Industrial Revolution provided evidence of this process. Prior to industrialization, the white-colored moths were more common due to their camouflage against lichen-covered trees. Once pollution darkened the trees, the once rare dark-colored moths became more common because they were less visible to predators.
This example clearly illustrates how a population, not individual organisms, evolves over generations through changes led by environmental pressures, which in turn affects the prevalence of certain genetic traits.
Describe the chemical changes a neuron goes through when a nerve impulse is generated
Explanation:
A nerve impulse is a result of a difference in electrical charges across the plasma membrane of a neuron, this difference comes from ions which are electrically charged atoms or molecules.
Before the nerve impulse happens there's a resting potential in the neuron ready to transmit the impulse, this resting potential happens thanks to the sodium-potassium pump that uses ATP to pump Na+ out of the cell and K+ into it, resulting in the inside of a neuron negatively charged.
When a nerve impulse happens (thanks to the receiving of a chemical signal from another cell) a sudden reversal of the electrical charge of a resting neuron occurs, the inside of the neuron becomes positive when the gates in sodium channels open allowing positive sodium ions to flow back into the cell.
I hope you find this information useful! Good luck!
The ATP and NADPH produces in the light reaction are used to drive the synthesis of sugars from CO2.
a. True
b. False
Answer:
The correct answer will be option-true.
Explanation:
Photosynthesis reaction proceeds in two phases: light-dependent and light-independent reaction.
During light-dependent reaction which takes place in thylakoid membrane intermediates like ATP and NADPH are produced through electron transport chain.
These intermediates are directly utilized in the light-independent reaction which performs cyclic reactions known as the Calvin cycle. Calvin cycle produces glucose molecules using ATP and NADPH in the reactions.
Thus, option-true is the correct answer.
This bacterium is sometimes called "flesh eating bacteria."
A) Proteus vulgaris
B) Clostridium tetani
C) Staphylococcus epidermis
D) Streptococcus pyogenes
Answer: Option D
Explanation:
The bacterium which is known as flesh eating bacterium is known as Streptococcus pyrogenes.
The disease caused by this bacterium is an infection in which one or more than one bacterium is used to describe this disease.
This bacterium releases toxin that destroys tissues inside the body such as skin, fat, mucous.
This disease is known necrotizing fasciitis. Hence, the correct answer is Option D.
Chlorophyll a is the primary plant pigment capturing light
forphotosynthesis and is a green color. How is this so when most
lightenergy for photosynthesis derives from red and
bluewavelengths?
Answer:
Chlorophyll a absorbs maximum light in blue and red regions of the spectrum while reflecting the green light.
Explanation:
The light reflected by any object reaches our eyes. “Chlorophyll-a” molecules are the pigments that do not absorb the green light and reflect it. The reflected green light imparts the chlorophyll-rich leaves a green color.
Since the absorption peak for Chlorophyll-a lies in red and blue regions of the spectrum, the maximum rate of photosynthesis is experienced in the presence of red and blue wavelengths.
The light absorbed by Chlorophyll-a drives light reactions to produce ATP and NADPH which in turn are consumed during the Calvin cycle to fix CO2 into glucose.
Why are there nucleotides (A, T, G, and C) in the master mix? What are the other components of the master mix, and what are their functions?
Answer: Nucleotides are the monomers used for DNA synthesis. The mix also contains a template, DNA taq polymerase, buffer, reverse and foward primer and magnesium ions.
Explanation:
A PCR master mix is a premixed solution that has all of the components for a Polymerase chain reaction (PCR). This reaction is a laboratory technique that amplifies small fragments of DNA into millions of copies.
The master mix used for that contains dNTPs (nucleotides). In the DNA there are four types of nucleotides that are differentiated by the nitrogen base they have: adenine (A), guanine (G), cytosine (C) and thymine (T).
Since nucleotides are the monomers that make DNA, they are found in the mix because they are the material for DNA synthesis.
The reaction mixture also requires;
DNA template, the sequence of DNA to be amplifiedDNA taq polymerase, a heat resistant enzyme that assembles nucleotides into a new DNASalt buffer, for an optimum ionic environment and pHOligonucleotide primers (reverse and foward), pieces of DNA complementary to the template. Each hybridizes with one of the DNA chains. Magnesium ions, a catalyst required by DNA polymerase to workThe nucleotides (A, T, G, and C) in the master mix provide the building blocks for DNA synthesis during PCR, while other components such as DNA polymerase, buffer, magnesium ions, stabilizers, surfactants, and preservatives maintain optimal conditions for efficient and specific DNA amplification.
The polymerase chain reaction (PCR) master mix contains nucleotides (A, T, G, and C) to supply the building blocks required for DNA synthesis throughout the amplification process.
The PCR master mix usually consists of the following additional ingredients:
1. DNA polymerase: This enzyme, which is typically thermostable and works with given nucleotides and template DNA strands to catalyse the synthesis of new DNA strands, is known as Taq polymerase.
2. Buffer: During the PCR process, this pH-stabilizing solution keeps the pH at the ideal level for the DNA polymerase activity.
3. Magnesium ions (Mg2+): Vital cofactors for DNA polymerase activity, enabling the enzyme's binding to template DNA and nucleotide incorporation into the expanding DNA strand.
4. Stabilisers and Enhancers: A number of substances, including betaine, DMSO (dimethyl sulfoxide), and bovine serum albumin (BSA), are frequently added to the master mix to increase the PCR reaction's robustness, specificity, and efficiency—especially in difficult or GC-rich templates.
5. Surfactants: To promote reagent mixing and lower surface tension, agents like Tween-20 can be added, improving the reaction mixture's homogeneity.
6. Preservatives: To stop reagent deterioration and contamination during storage, certain master mixes may include preservatives.
Because the master mix contains all the necessary components to provide ideal circumstances for DNA amplification, such as the right buffer conditions, enzyme activity, nucleotide availability, and reaction specificity, each component is essential to the success of the PCR reaction.
Which one of the following is true concerning retinoblastoma protein and the transcription factor E2F?
a. E2F phosphorylates Rb
b. E2F binds phosphorylated Rb
c. E2F is phosphorylated by Rb
d. E2F binds unphosphorylated Rb
Answer:
d. E2F binds unphosphorylated Rb
Explanation:
Rb (Retinoblastoma) is a protein which suppresses tumor. During G1 phase of cell cycle it regulates cell cycle progression.
When Rb is unphosphorylated, E2F is bound to it. But the growth factors in G1 phase cause synthesis of cyclin D. Cyclin D then interacts with a serine - threonine kinase named as CDK-4 which phosphorylates Rb. As soon as Rb gets phosphorylated it gets degraded and E2F becomes free to induce expression of cyclin A and cyclin E which leads to progression of cell cycle from G1 phase to S phase.
Describe several functions of the circulatory system.
Answer:
Explanation:
The circulatory system, also called the vascular system or cardiovascular system. It consists of three important components such as heart or cardiovascular system, lungs or pulmonary system, vascular system such as arteries, veins and capillaries.
This system is responsible for the transport of gases, blood and nutrients to all the parts of the body. It helps in maintaining the homeostasis of the body by stabilizing the pH, body temperature and fighting the diseases. Also maintains the balance of hormones.
Conclude from ratios of progeny in a dihybrid cross whether two genes are linked.
Answer:
Linked genes may be defined as the genes that are present on the same chromosomes and transfer to the next generation as well. The linked gene are responsible for the formation of recombination in the progeny. The genes that follow the independent assortment are present on different chromosome.
If the ratio of progeny is 9:3:3:1, then the genes are not linked. The deviation from this ration explains that the genes are linked. The parents number are more in than recombinant in case of linkage. The recombination frequency can never exceeds 50%.
Conversion of spermatids to spermatozoa involves cell division.
a. True
b. False
Answer:
The correct answer will be option-False.
Explanation:
Spermatogenesis or formation of sperm cells in humans takes place in two stages: cellular division called "spermatocytogenesis" and metamorphic changes in spermatids to spermatozoa called "Spermiogenesis".
The mitotic and meiotic cellular division produces round spermatids which undergo much physical change during the process called Spermiogenesis. During Spermiogenesis spermatids modify themselves for fertilization like acrosome cap formation, tail development and nuclear condensation.
Thus, option-false is the correct answer.
Conversion of spermatids to spermatozoa is a transformation process called spermiogenesis and does not involve cell division, therefore, the statement is false.
Explanation:The conversion of spermatids to spermatozoa does not involve cell division but a process called spermiogenesis. Spermiogenesis is the final stage of spermatogenesis, during which spermatids undergo physical changes to become mature spermatozoa. This transformation includes reducing the cytoplasm, beginning the formation of the parts of a true sperm such as developing a tail (flagellum) and compacting the head to streamline the cell for mobility. Despite these changes, there is no division of the spermatid cells, hence the statement is false.
What enzyme complex is responsible for DNA replication?
a. DNA polymerase
b. RNA polymerase
c. hexokinase
d. amylase
Answer:
DNA polymerase.
Explanation:
DNA replication may be defined as the process of formation of daughter DNA from the template DNA strand. The process of DNA synthesis occurs in the 5' to 3' direction.
The enzyme responsible for DNA replication is DNA dependent DNA polymerase or DNA polymerase. This enzyme moves in 5' to 3' direction. DNA pol III is main replicating enzyme in prokaryotes and DNA pol alpha initiates DNA replication in eukaryotes.
Thus, the correct answer is option (a).
Which is considered to be a process by which electrons aregenerally
removed from biomolecules catabolism
or anabolism? You must spell out the answer correctly to
receivecredit.
Answer: Catabolism
Explanation:
The addition of electrons to the compound is called as the reduction reaction. On the other hand, the removal of electrons is called as the oxidation.
The catabolism is a process by which electrons are removed from the compound. This is a oxidation reaction.The anabolism is a process by which electrons are added to the compound. This is the reduction reaction.
The anabolism is a process of formation of new complex substance from simple ones. This is a constructive process. The catabolism is a process of formation of simple substance from break down of complex ones. This is a destructive process.
How are old blood cells removed from the circulation? How are the various components of the red blood cell disposed of?
Answer:
Explanation:
When the red blood cells get matured, old or even rupture these are destroyed by the cells of the lymph nodes and spleen.
The haptoglobin protein binds to the hemoglobin and carries the blood components to the spleen or the lymph nodes where these components are recycled.
Distinguish between a monohybrid cross and a testcross.
Answer:
Monohybrid cross:
Monohybrid cross may be defined as the cross done by taking single trait at a time. The ratio of the monohybrid cross by the pure parent breed result in the formation of 3:1 phenotype in the second generation.The genotype ratio is 1:2:1.
Test cross:
Test cross may be defined as the cross between the unknown genotype and the recessive parents. This cross is done to determine whether the genotype is heterozygous or the homozygous dominant trait. The ration of the cross may vary depending on the genotype of the organism.
Barred feather pattern is a Z-linked dominant trait in chickens. What offspring would you expect from (a) the cross of a barred hen to a non-barred rooster? (b) the cross of an Fl rooster from part (a) to one of his sisters?
Answer:
Let the "barred" allele be caller B and the "non-white" allele b. Since chickens use chromosomes [tex]Z[/tex] and [tex]W[/tex] to determine sex, hens would have chromosomes [tex]ZW[/tex], and roosters would have chromosomes [tex]ZZ[/tex]. A Z-linked gene is represented as a superscript on the [tex]Z[/tex] chromosome, [tex]Z^{B}[/tex] for the dominant allele and [tex]Z^{b}[/tex] for the ressesive allele.
A barred hen would have a copy of B on its Z chromosome, a non-barred rooster would have both copies of b on both Z chromosomes. Using Punnet squares to represent the crosses we get the following cases:
[tex]\begin{center}\begin{tabular}{ |c|c|c|c| }\ & Z^{B} & W \\ \ Z^{b} & Z^{B}Z^{b} & Z^{b}W \\ \ Z^{b} & Z^{B}Z^{b} & Z^{b}W \\ \end{tabular}\end{center}[/tex]
That is a ratio of two barred heterozygote roosters to two non-barred hens. Crossing them we get:
[tex]\begin{center}\begin{tabular}{ |c|c|c|c| }\ & Z^{b} & W \\ \ Z^{B} & Z^{B}Z^{b} & Z^{B}W \\ \ Z^{b} & Z^{b}Z^{b} & Z^{b}W \\ \end{tabular}\end{center}[/tex]
That is a ratio of one barred heterozygote rooster to one barred hen to one non-barred rooster to one non barred hen.
For part a) crossing barred hen with non-barred rooster produces 50% barred and 50% non-barred offspring of both genders. In part b) cross between their barred F1 offspring will again result in a mix of barred and non-barred offspring.
The barred feather pattern in chickens is a Z-linked dominant trait. In chickens, males have ZZ sex chromosomes, and females have ZW sex chromosomes.
(a) Cross of a barred hen (ZW) to a non-barred rooster (ZZ)
The barred hen has genotype [tex]Z^BW[/tex], and the non-barred rooster has genotype ZZ. The offspring will be:
50% barred males ([tex]Z^BW[/tex])50% non-barred males (ZZ)50% barred females ([tex]Z^BW[/tex])50% non-barred females (ZW)(b) Cross of an F1 barred rooster ([tex]Z^BW[/tex]) to one of his barred sisters ([tex]Z^BW[/tex]) Since they both possess the barred trait, their genotypes are [tex]Z^BZ[/tex] and ([tex]Z^BW[/tex]), respectively. The offspring from this cross will be:
25% barred males [tex](Z^BZ^B)[/tex]25% non-barred males (ZZ)25% barred females [tex](Z^BW)[/tex]25% non-barred females (ZW)Describe the helical and coiled-coil structures of either collagen or α-keratin. What type of covalent bond holds the coiled-coils in staggered arrangements to form larger fibrous structures of this protein?
Answer:
Collagen is an extracellular matrix protein and one of the most abundant protein in the body. Its triple-helical structure is a result of the 3 coiled chains. Each chain mainly comprises of Glycine, Proline and Hydroxyproline. The Glycine hydrogen bonds with residues of the adjacent chain while the proline and hydroxyproline C-N bonds provide stability in the structure.
Explanation:
Animals, including humans, produce antibiotics in response to an infection.
a. True
b. False
Answer:
It depends on what your considering antibiotics to be. If you are referring to anything that kills bacteria then technically yes that’s the point of your immune system which releases many types of white blood cells to fight bacteria/bacterial infections. Just so I don't confuse you the immune system fights all forms of pathogens not just bacteria.
Which of the following is a fomite?
a. a prairie dog infested with fleas infected with the plaue bacterium
b. a river contaminated with the Giardia protozoan
c. a doorknob contaminated with the cold virus
d. an asymptomatic person infected with HIV
e. a mosquito infected with the malaria protozoan
Answer:
The correct option is: c. a doorknob contaminated with the cold virus
Explanation:
Fomites are the inanimate objects or substances that can get contaminated with the pathogens and are capable of transferring the pathogens to the new hosts.
Sterilization of the possible fomites should be done in order to prevent cross-infection.
Examples of fomites are hair, towels, clothes, door knobs, cups, switches, handrails, remote controls, pens, syringes, bedding, etc.
Differential medium can separate Gram negative bacteria from
Grampositive bacteria.
True or False?
Answer: True. Selective media can be used to separate gram negative from gram positive bacteria.
Explanation: Selective media allow certain types of organisms to grow, and inhibit the growth of other organisms.
For example: Media containing potassium tellurite will inhibit the growth of gram negative bacteria while media supplemented with penicillin will inhibit the growth of gram positive bacteria.
Which of the following are important features for transcription?
a. promoter
b. RNA polymerase
c. 5' and 3' UTRs
d. ORF
e. all of the above
Answer:
The correct answer will be option-A and B.
Explanation:
Transcription is a process which synthesizes a complementary molecule of DNA which acts a messenger called RNA.
The gene contains a sequence of the nucleotide at the beginning of gene called promoter sequence. The promoter sequence has the ability to attach an RNA synthesizing enzyme called RNA polymerase.
The RNA polymerase is the enzyme which synthesizes the RNA molecules using a single strand of DNA called template strand. RNA polymerase binds nucleotide at 3' end of the strand thus proceeding the strand in 5' to 3' direction.
The promoter and RNA polymerase begins the process of transcription and thus option-A and B is the correct answer.
Why do scientists think that all forms of life on earth have a common origin?
Answer:
There are several facts that linked life to a common origin such as:
Comparative anatomy, where different species have common traits. This includes homology and analogy, vestigial structures. Fossil record.Species distribution in different continents, some others.I believe the most valuable evidence is that DNA is the molecule that carries information in all living things ( eukaryotes and prokaryotes) even viruses contain either DNA o RNA. Is difficult to think that life started in different ways but then converged in the same kind of molecule to carry the information.
Distinguish between the effects of mutation in somatic and germ-line cells.
Answer:
Somatic cells:
When normal body cells mutate usually the effects are harmful in different ways which end up killing the cell.
Another type of scenario is where the cells survives but cells from the immune system recognized it and end up killing it.
sometimes somatics cells can accumulate mutations and survive which leads to a tumor or cancer.
Germ-line:
When germ-line cells produce gametes with mutations this mutations can end up killing the embryo. If the embryo survives the mutation can generate all sorts of genetic disorders, the spectrum here is massive and depends on the site of the DNA mutation.
The atomic number of sulfur is 16. Sulfur combines with hydrogen by covalent bonding to form a compound, hydrogen sulfide. Based on the number of valance electrons in a sulfur atom, predict the molecular formula of the compound.
a. HS c.H2S
b. HS2 d. H4S
Answer:
H2S.
Explanation:
Ions may be defined as the element that contains either positive or negative charge over them. Two types of ions are cations and anions. The outermost electrons are involved in the formation of ions.
The atomic number of sulfur is 16. Its outermost electronic configuration is K=2, L= 8, M= 6. The sulfur requres two more electrons to complete its orbit and accquire -2 charge.
H S
+1 -2
Then, the formula will be H2S.
Thus, the correct answer is option (c).
What information about the structure of DNA was obtained from X-ray crystallographic data?
Answer:
With the crystallographic data you can obtain the space between the base paris on the DNA, yo can also predict that the DNA have a double helix structure, and with this information and some chemical simulations you can obtain the exact amount of nucleotides in each turn.
A typical prokaryotic cell has about 3,000 genes in its DNA, while a human cell has about 20,500 genes. About 1,000 of these genes are present in both types of cells. Explain how such different organisms could have this same subset of genes ?
Answer:
same DNA bases and HGT
Explanation:
Even though we are different species, so much as different kingdoms, the DNA is always going to be the molecule that contains our genetic information and constitute our genes. This molecule is made up by the same structure: a sugar, a phosphate and a base like adenine, guanine, cytosine, thymine. Regardless if its a human, bacteria, fungi or a plant cell we all share this in common.
It is well known that we acquire our whole set of genes from our ancestors but some studies have shown that we also acquire genes from other organisms and its called horizontal gene transfer (HGT). HGT involves the movement of genetic material between different species. Since we've been sharing the world with a lot of prokaryotic organisms we might have experienced the HGT at some point of the evolution, and since our genetic material is made up of the same molecules, we can have the same subsets of genes working in both organisms.
Answer:
The subset of genes shared by humans and prokaryotes originates from a common ancestor and has been retained over billions of years of evolution.
Explanation:
This is was the right answer on my teachers test.
Light reactions of photosynthesis occur
a. Within the thylakoid lumen
b. In the stroma
c. Across the thylakoid membrane
d. Across the inner membrane
Answer:
both stages of photosynthesis. The light reaction takes place in the thylakoid discs. ... The dark reaction occurs outside of the thylakoids. In this reaction, the energy from ATP and NADPH are used to fix carbon dioxide
Which description accurately compares cellular respiration and photosynthesis?
A) Photosynthesis uses energy captured from sunlight to power the reduction of carbon dioxide to sugars; cellular respiration oxidizes sugars to yield energy for the cell.
B) The ATP produced via cellular respiration is needed to power the reactions of photosynthesis
C) The pathways of photosynthesis are those of cellular respiration run in reverse.
D) Photosynthesis captures energy from sunlight to oxidize carbon dioxide to sugars; cellular respiration reduces these sugars to yield energy for the cell.
Answer:
The correct answer will be option-A.
Explanation:
Photosynthesis is a process which uses sunlight energy to synthesize food in the form of glucose. The process takes place in the chloroplast in two stages: light-dependent reactions and light-independent reactions.
The light-independent reaction produces to convert the carbon dioxide from the atmosphere to glucose through the Calvin cycle. The carbon gets fixed and reduced form+4 state to +1 state.
Respiration is the process which oxidizes the glucose molecule to produce energy in the form of ATP molecules. This ATP is utilized by the cell to perform various functions.
Thus, option-A is the correct answer.
Describe the structural differences between DNA and RNA.
Answer:
Explanation:
DNA is a double helical structure. It is a long polymer molecule which has deoxyribose sugar and phosphate backbone. It have four nitrogenous bases which are supported by the phosphate backbone. These are the adenine, guanine, thymine and cytosine.
RNA is a single stranded molecule. It is a polymer with a ribose sugar and phosphate backbone. It also exhibit four nitrogenous bases that are supported by phosphate backbone these are adenine, guanine, cytosine and uracil.
Deoxyribose sugar and thymine make up the double-stranded DNA, whereas ribose sugar and uracil make up the single-stranded RNA.
These distinctions are critical to their unmistakable jobs in organic frameworks. Here are the key distinctions: Strand Design:
DNA is ordinarily twofold abandoned, framing a twofold helix, though RNA is generally single-abandoned. However, self-complementary base pairing allows RNA to fold into complex three-dimensional shapes. Sugar Component: Ribose, the sugar in RNA, has a hydroxyl group (-OH) attached to the 2' carbon. Deoxyribose, on the other hand, lacks this hydroxyl group at the 2' carbon and only has a hydrogen atom (-H) instead. Nitrogenous bases include adenine (A), cytosine (C), and guanine (G). Notwithstanding, RNA utilizes uracil (U) instead of thymine (T), which is tracked down in DNA.An intrinsic value biodiversity stems form religious, moral, or either obligations to preserce the worl's species.
a. True
b. False
Answer:
a. True
Explanation:
As the word biodiversity itself is the diversity of plant and animal life keeping in mind that ecological biodiversity. This being an inherited value and must be protected as every citizen of the country has a moral obligation and duty toward the laws of land and protection of the biotic wealth of the nation. Apart from this biodiversity also has a genetic, social and economic value along with the cultural and spiritual aspects this biodiversity has scientific and educational significance. Various obligations on the part of the state government to word the protection of the species from any kind of changes in the ecological cycles, like protection of biosphere and give value to this genetic makeup that provides fuel and energy to the planet.