Answer:
B. Primary spermatocytes
Explanation:
The germ cell line is a group of cells found inside the seminiferous tubules. This germ cells undergo mitosis (creating spermatogonia) to have a steady supply of cells that will divide by meiosis to produce gametes. When spermatogonia divide by meiosis at the end of meiosis I the newly created cells are known as primary spermatocytes.
The hypothalamus is our brain's appetite control center.
a. True
b. False
Answer:
A
Explanation:
Hunger, fullness, and energy balanced are regulated by the hypothalamus. Hunger and fullness signals, in the form of hormones, travel through the bloodstream from tissues that consume energy to the brain. The hypothalamus is the region where these neuronal and hormonal signals integrate. After the reception of this signals the hypothalamus orchestrates a signaling cascade containing other hormones to create the hunger sensation.
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.
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.
A change in DNA resulting in an incorrect protein is the problem in sickle cell disease. Is this normally the problem in genetic diseases?
A. Yes, the DNA may be "correct" but can produce abnormal proteins which cause disease.
B. No. In other genetic diseases, the proteins are all correctly made, but then they damage the DNA.
C. No. Most genetic diseases result from errors in cell division.
D. Yes, abnormal proteins created by abnormal DNA is the problem in all genetic diseases.
E. It's not clear what the problem is in most genetic diseases.
Answer:
D. Yes, abnormal proteins created by abnormal DNA is the problem in all genetic diseases.
Explanation:
DNA carries the information for the correct development and function of the human body. A gene is defined as a DNA fragment that codifies for a protein, this means that genes carry the information to shape a protein in the ribosomes. If the information is "corrupted" proteins can still be formed but can't work correctly.
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!
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.
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.
Although none are represented in the web diagram, mollusks are eaten by raccoons. Freshwater mussels are filter feeders. If the mussel population were decreased by a lengthy period of dry conditions, which organisms population would decrease?
"The correct answer is the raccoons' population would decrease.
To understand the impact of a decreased mussel population on the ecosystem, one must consider the food web dynamics. Mussels are a food source for raccoons; therefore, if the mussel population were to decrease due to prolonged dry conditions, the raccoons would have less food available to them. This scarcity of food would likely lead to a decrease in the raccoon population due to starvation, reduced reproductive success, or the need to find alternative food sources which might not be as nutritious or abundant.
Freshwater mussels are filter feeders, which means they play a crucial role in their aquatic habitats by filtering water and removing pollutants, thereby maintaining water quality. A significant decrease in the mussel population could lead to deteriorating water quality, which might affect other aquatic organisms as well. However, the direct impact of the mussel population decline, as per the information provided, would be most immediately felt by their predators, in this case, the raccoons.
It is important to note that in a complex ecosystem, the effects of a population decline can be far-reaching and can affect multiple trophic levels. However, based on the information given and the direct predator-prey relationship mentioned, the population that would decrease as a result of the mussels' decline would be the raccoons."
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.
Where is ATP synthase located in the mitochondrion?
A) ribosomes
B) cytochrome system
C) outer membrane
D) inner membrane
E) matrix
Answer:
D) inner membrane is the correct answer.
Explanation:
ATP synthase located in the inner membrane of the mitochondrion.
ATP synthase has two subunits knowns as rotating subunit
FO F1that support in the ATP generation by oxidative phosphorylation.
ATP synthase is an enzyme that produces adenosine triphosphate Which is called an Energy molecule.
ATP function is to provide energy to the cells.
ATP synthase is located in the inner membrane of the mitochondrion, which has folds called cristae to increase surface area for ATP synthesis.
Explanation:The location of ATP synthase in the mitochondrion is within the inner membrane. This enzyme is crucial for the production of ATP (adenosine triphosphate), the cell's primary energy currency. The inner membrane of the mitochondrion contains folds called cristae, which increase its surface area and are integral to the function of the electron transport chain where ATP synthesis takes place. Therefore, the correct answer is D) inner membrane.
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.
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.
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.
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)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.
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).
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.
What might be one reason for not finding any cells when you examine a slider under the microscope?
Answer:
Well, there can be various causes of not finding any cells while examining a slider under the microscope. Some of them are as follows:
a. The light of the microscope might be switched off and the slide does not comprise any cells.
b. The microscope is not focused appropriately so that one can witness the cells.
c. The region of the slide comprising the cells is not coming in the field of vision.
d. The magnification of the microscope is not appropriate, that is, either it is very low or is very high.
e. Destruction of the sample would have taken place.
A microbiologist obtained two pure biological samples: one of a virus, and the other of a viroid. Unfortunately, the labels had been lost. The microbiologist felt she could distinguish the two by analyzing for the presence or absence of a single molecule. What molecule would she search for and why?
The researcher could look for the presence of proteins, because viruses have a envelope (capsid) composed of proteins that involve their genetic material. The capsid may have a helical or icosahedral structure and is extremely regular. Viroids cannot synthesize any type of protein, so differentiation is possible.
The microbiologist should look for the presence of protein to distinguish between the virus and the viroid, as only the virus will contain a protein coat.
Explanation:The molecule the microbiologist should search for to distinguish between a virus and a viroid is protein. Viruses have a protein coat known as a capsid that encloses their nucleic acid core, which can be either DNA or RNA. Viroids, on the other hand, consist solely of a short strand of circular, single-stranded RNA without a protein coat. By analyzing the samples for the presence of protein, she can determine which is the virus (which has protein) and which is the viroid (which lacks protein).
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%.
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 type(s) of cell division (mitosis, meiosis l, meiosis Il) reduce(s) the chromosome number by half? Which type(s) of cell division can be classified as reductional? Which type(s) of cell division can be classified as equational?
Answer:
Which type(s) of cell division reduce(s) the chromosome number by half?
Meiosis l
Which type(s) of cell division can be classified as reductional?
Meiosis I
Which type(s) of cell division can be classified as equational?
Mitosis and Meiosis II
Explanation:
Meiosis is a type of cell division which occurs in the germ or reproductive cells to produce gametes. It is completed in the two stages, meiosis I and meiosis II. The cells which are going to divide by meiosis are diploid having two sets of chromosomes. Meiosis I is the first stage of the meiosis. At the end of meiosis I two daughter cells are formed having only 1 set of chromosomes and chromosome numbers are reduced to half. Thus, meiosis I is a reductional division.
Mitosis and meiosis II is the equational division as after division chromosome number remains the same as in the parent.
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.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.
Discuss the concept of the null hypothesis and its use in data analysis.
Answer:
Null hypothesis may be defined as the any type of assumption in which the observed difference between two sample in the statistical population is accidental. Null hypothesis is used in the field of genetics as well.
If one accepts the null hypothesis this means that there is no significant differences between the observed values and the expected values of the experiment. The rejection of null hypothesis explains that there may be significant difference between the expected value and observed value.
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.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.
Which process in eukaryotic cells will normally proceed whether O2 is present or absent?
A) electron transport
B) glycolysis
C) the Krebs cycle
D) oxidative phosphorylation
E) fermentation
Answer:
b) glycolisis
Explanation:
Glycolisis precedes the Krebs cycle and can take place under aerobic or anaerobic conditions. Under aerobic condition, energy is directed towards the Krebs cycle in the form of piruvate and NADH to create more ATP. Under anaerobic conditions piruvate does not enter the Krebs cycle and it is oxidized to produce lactate.
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.
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.