Ultimately, the oxygen necessary for cellular respiration come from
a. Waste products of photosynthesis.
b. Water vapor
c. Carbon dioxide
d. glucose

Answer:

A poly-A tail.

Explanation:

Transcription may be defined as the process of formation of the RNA molecules from the DNA template. Eukaryotic RNA undergoes the process of mRNA processing.

The mRNA processing involves the post translation modification of RNA. The poly A (adenine) tail is added to the 3' end of the RNA transcript after the elongation. This poly A tail protects the RNA from the degradation and helps to export the RNA into the cytoplasm.

Thus, the correct answer is option (a).

Answer:

a. population

Explanation:

Gene flow cannot occur in hybrids because 99.9% of the time hybrids offspring are not fertile.

At genus level is not possible either because a hybrid is a cross breed at the genus level (horse-donkey).

A population is a group of species of 1 kind. A population of donkeys.

Answer:

False

Explanation:

As one moves from species to kingdom in a taxonomic hierarchy, the categories become more general. This is due to the grouping of distantly related organisms in a higher category as compared to the evolutionary relationships between the organisms of a lower category.

In binomial nomenclature, the name of the genus is written first followed by the name of the species.

Since the genus is a "more general category" than a species, the more general category is mentioned first in binomial nomenclature.

Answer:

The correct answer is option a. "recoil of the lungs".

Explanation:

Normal respiration is passive, which means that no energy is needed to release the air from the lungs. Passive respiration is preceded by the recoil of the lungs that happens without any effort because of the elasticity of the lungs tissue. After inspiration, the diaphragm and intercostal muscles relax and the thoracic cavity and lungs decrease in volume. This causes that the interpulmonary pressure rises above atmospheric pressure, creating an air pressure gradient that put the air out of the lungs without the need of energy.

Answer:

Leukemia may be defined as the cancer of the blood cells especially white blood cells. The leukemia may occur due to mutation or may also occur due to the biological agents.

Leukemia causes the abnormal and uncontrolled growth of the blood cells. These white blood cells are unable to fight with infections and causes the bone marrow to produce impair formation of blood cells. The patient shows abnormal growth and large count of leukocytes.

Answer: A. A blockage in the aorta

Explanation:

A heart attack happens when one or more aorta or coronary arteries get blocked. With the passage of time, the coronary artery becomes narrow that is because of the deposition of various substances such as fat, cholesterol and other reserves. This restricts the smooth circulation of blood hence results in heart attack or heart stroke.

A heart attack is usually caused by a blockage in a coronary artery due to atherosclerosis, with genetics and lifestyle factors influencing the risk.

The cause of a heart attack, also known as myocardial infarction, is usually a blockage in a coronary artery, which supplies blood to the heart muscle. This blockage is often a result of atherosclerosis, a condition where cholesterol plaque builds up in the arteries and can rupture, forming a clot. This clot obstructs the flow of blood, depriving the heart muscle of oxygen and nutrients, leading to damage or death of the heart muscle cells. Genetics and lifestyle choices such as diet, exercise, and smoking can contribute to the risk of heart attack. A blockage in an artery in the brain or carotid artery can lead to a stroke, not a heart attack.

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Answer:

Two types of orientation behavior are as follows:

Taxis behavior:

This is a type of orientation behavior that mainly occur in response towards the external stimulus. Taxis may be positive (movement towards the stimulus) or negative ( movement away from the stimulus). Different types of taxis behavior are phototaxis, aerotaxis, chemotaxis and magnetotaxis.

Kinesis:

Kinesis may be defined as a type of orientation behavior that can change the complete movement or orientation of the organism. Kinesis is a random movement and organism can move in either direction. Different type of kinesis are klinokinesis and orthokinesis.

Answer:

d. Calvin cycle

Explanation:

During the light reactions or photochemical reactions of photosynthesis, chlorophyll molecules absorb sunlight and convert light energy into assimilatory power in the form of the electron carrier molecule nicotinamide adenine dinucleotide phosphate (NADPH) and the ATP.

The ATP and NADPH used as a source of energy to fix or reduce carbon dioxide into glucose.

The reduction of carbon dioxide to glucose occurs in the stroma of the chloroplast. The reactions of the conversions are called the Calvin cycle.  

Sertoli cells do not produce primary spermatocytes (option D); instead, they support spermatogenesis, create a blood-testis barrier, produce tubular fluid, remove damaged germ cells, and secrete inhibin.

The function that is NOT a function of Sertoli cells is D. Production of primary spermatocytes. Sertoli cells, also known as sustentacular cells or sustentocytes, indeed have several important roles in sperm production within the seminiferous tubules of the testes. They also form the blood-testis barrier, produce substances such as inhibin that regulate spermatogenesis through a negative feedback mechanism, create, seminiferous tubular fluid, and remove damaged germ cells. However, the production of primary spermatocytes is not one of their functions. Primary spermatocytes are derived from germ cells and undergo meiosis to form spermatids, which are then transformed into mature spermatozoa. The Sertoli cells support this process but do not produce the spermatocytes themselves.

Answer:

Option (C).

Explanation:

Cancer may be defined as the phenomena of the uncontrolled growth of the cell division and the cells require less nutrient medium to grow. Two main types of tumor are benign tumor and malignant tumor.

Proto- oncogenes generally regulates the growth and metabolism. The mutation may leads to the formation of proto-oncogenes to the oncogenes. These oncogenes are responsible for the formation of cancer. The main function of tumor suppressor gene is the suppressor inactivates the tumor genes. There suppression may result in the formation of tumor.

Thus, the correct answer is option (C).

Final answer:

Cancer development involves the mutation of proto-oncogenes into oncogenes, resulting in uncontrolled cell growth, and the inactivation of tumor-suppressor genes, which fail to put the necessary checks on this growth. The correct answer to the question is C) proto-oncogenes, oncogenes, tumor-suppressor genes.

Explanation:

Cancer is often the result of activation of proto-oncogenes to oncogenes and the inactivation of tumor-suppressor genes. Therefore, the correct answer is C) proto-oncogenes, oncogenes, tumor-suppressor genes.

Proto-oncogenes are genes that normally help cells grow. When these genes are mutated, they can become oncogenes, which may cause cells to grow out of control. Oncogenes can be thought of as a car's accelerator stuck in the 'on' position. On the other hand, tumor-suppressor genes are like the brakes of a car; when these genes are turned off or inactivated, cells can multiply uncontrollably because there's nothing to stop them.

In summary, cancer development can be compared to a failing car's cruise control, where there is an overactive accelerator (due to oncogenes) and malfunctioning brakes (due to inactivated tumor-suppressor genes).

Answer:

Explanation:

The changes in the gene pool occurs from the one generation to another this process is called as the microevolution. The allele frequencies in the gene pool change due to many processes such as gene flow, natural selection, genetic drift, and mutation. In mutation the genetic variations occurs in the genome of the organisms due to change in the genetic makeup of the organisms new traits are produced which are passed on to the new generation and this brings change in diversity of genes in the gene pool.

Answer: b. Secondary metabolites are often the desired product, and are only produced in stationary phase.

Explanation:

The secondary metabolites are the organic compounds that are produced by the microbes such as bacteria, fungi and even by the plants. These are not involved in the growth, development and reproduction of the organisms. But they can provide a advantage for the survival. It helps in plant defense against the process of herbivory and other interspecies defense. Humans take the secondary metabolites from these organisms in the form of medicines, pigments, and recreational drugs.  

The secondary metabolites are produced only in the stationary phase of growth. Thus it is significant for the collection of these secondary metabolites in the stationary phase.

Answer:

Catabolism

Explanation:

Catabolism refers to the metabolic pathways to break down the complex biomolecules into simpler substances and release the energy stored in their chemical bonds.

The catabolic reactions are oxidizing reactions and remove the electrons from the substances.

For example, cellular respiration is a catabolic pathway for glucose as it oxidizes glucose into CO2 and H2O. During aerobic cellular respiration, molecular oxygen serves as the terminal electron acceptor and is reduced into water.

Answer:

d. meiosis

Explanation:

Bacterial cells don't go through meiosis, it is unique to the eukaryotic cells.

Genetic variation in bacterial populations cannot result from meiosis, but it can occur through other mechanisms such as a. transduction, c. mutation, and b. conjugation.

Genetic variation in bacterial populations cannot result from meiosis because meiosis is a process that only occurs in eukaryotic cells, not in prokaryotic bacteria. However, genetic variation in bacterial populations can occur through other mechanisms such as transduction, mutation, and also conjugation.

In addition to this, the process of transduction involves the transfer of genetic material between bacterial cells by viruses. Mutation is the spontaneous change in the DNA sequence, which can result in new genetic variations. Conjugation is a process where bacteria directly exchange genetic material, usually plasmids, with other bacteria.

Answer:

SSB protein.

Explanation:

DNA replication may be defined as the process of formation of daughter RNA molecule from the template DNA. The process of DNA replication occur in 5' to 3' direction.

The DNA strand must be unwound to initiate the DNA replication. The DNA strands must not reanneal for the replication process. Single stranded binding protein (SSB) bounds to the DNA strands and prevent them from re anneal.

Thus, the correct answer is option (d).

The protein that keeps unwound DNA strands from reannealing is the single-strand DNA binding protein (SSB protein), not DNA primase, sliding clamp, or helicase. In eukaryotes, DNA is organized around histones.

After the DNA is unwound during replication, the protein that keeps the DNA strands from reannealing is the single-strand DNA binding protein (SSB protein). These proteins bind to the separated strands of DNA, thereby ensuring that these strands remain single-stranded and accessible for the next steps in DNA replication. This prevents the DNA strands from spontaneously forming double-stranded DNA again.

In eukaryotes, DNA is wrapped around proteins called histones, not single-stranded binding proteins or sliding clamps. The attachment of DNA to histones helps in compacting the large eukaryotic genomes so that they fit within the cell nucleus, and also plays a role in the regulation of gene expression.

Answer:

c) expression of genes and production of  specific proteins.

Explanation:

Estrogen is a lipid-soluble steroid hormone that diffuses through the lipid bilayer of the plasma membrane of its target cell. The hormone binds to its nuclear receptor and receptor-hormone complex then alters the expression of particular genes.

It triggers transcription of specific DNA sequences into mRNA which in turn enters the cytoplasm and serves as a template for synthesis of specific proteins.

Estrogen is the female sex hormone and stimulates development of secondary sexual characters in females as well as required for maturation of egg.

Answer:

The correct answer is a.  Helicase unwinds DNA

Explanation:

DNA replication is a process in which DNA make it's own copy. There are several enzymes and factors which access the DNA replication process like helicase, primase, SSB protein, DNA polymerase etc.

The first step in DNA replication is the unwinding of double stranded DNA which is accomplished by an enzyme called Helicase. Helicase opens up the double stranded DNA at replication fork by breaking the hydrogen bond between the nucleotides of complementary strands.

This provides a single stranded template for DNA polymerase to form a new complementary strand. In E. coli Dna B is the primary helicase and in humans the primary helicase is MCM( minichromosome maintenance protein complex).

Answer:

The active site residues include Serine, Histidine and Aspartatic acid

Explanation:

The catalytic triad at the active site of Chymotrypsin includes Ser-105 (Serine), His-57 (Histidine) and Asp-102 (Aspartic acid).

His-57: Deprotonates and polarizes Ser-105 so that it is able to react with substrate.

Asp-102: The carboxyl group of Asp-102 hydrogen bonds with the R-group of the His-57 which facilitates the deprotonation of Ser-105.

Ser-105: The strong nucleophile of serine attacks the substrate leading to hydrolysis.

Answer:

a. True

Explanation:

Viruses are nor living nor non-living things. They do not metabolize, and only consist of nucleic acid in the inside of a protein cover which protects it. This proteinous layer is known with the term capsid, and is usually formed by units of certain proteins called capsomeres. Besides protection, these proteins serve as the structures that actually allows viruses contact and adhere to host cells during infection, that's why they are key components for the viruses success.

Answer:

Nucleotides.

Explanation:

Two types of nucleic acids are DNA and RNA. DNA is present as the genetic material in all the living organisms except some viruses. RNA is present as genetic material in some viruses only.

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 RNA consists of oxyribose sugar and uracil instead of thymine.

Thus, the correct answer is option (d).

Answer:

The post transcription modification include three ways i.e., capping, polyadenylation and splicing.

1. 5' Capping- mRNA capping is catalyzed by capping enzyme which is associated with RNA polymerase II. This enzyme adds the guanosin residue to 5' end of mRNA then methyl transferase adds methyl group to N⁷ position this guanine. Capping protects mRNA from degradation by enzymes presents in the cell.

2. Polyadenylation: In polyadenylation many adenosine residue is added at 3'end of mRNA by poly(A) polymerase. This poly A tail helps in exporting mRNA out of nucleus and binding of translational factors.

3. Splicing: In splicing process the non coding introns are removed from RNA so that only coding region i.e., exons are left in mRNA. It is important to remove unwanted sequence like introns which hinders in protein formation.

Answer:

Oxidation of Malate to Oxaloacetate by Malate Dehydogenase

Explanation:

An electron carrier is able to accept and donate electrons in a reaction. The most popular is NADH. NADH in its oxidized form is NAD+. NAD+ received two (2) electrons and an H+ to be reduced to NADH. Other electron carriers are NADPH & FADH₂

There are several steps in the TCA where NAD+ is reduced to NADH by accepting an electron. One of this step is the last step where malate is oxidized and is converted back to oxaloacetate the beginning  molecule of the cycle.

Answer: Gluconeogenesis

Explanation:

Gluconeogenesis is a pathway that is used by the body to create glucose from the other molecules. It is an important pathway that allows the body to store energy for brain in the form of glucose.

This process is regulated by insulin, which helps in this process of storing energy. Insulin inhibits the secretion of glycogen which is a activator of gluconeogenesis.

This hormone helps in maintaining a significant amount of glucose in the blood and rest of the glucose is stored for the vital organs of the body.

Answer:

The correct answer is option F. monocytes, macrophages and neutrophils.

Explanation:

Phagocytic cells are the cells that engulf harmful substances or foreign particles,  bacteria and other dead cells. These cells destroy them by engulfing the foreign particles and degrade them by chemical releases.

The phagocytic cells include - monocytes, macrophages, neutrophils, and dendritic cells. All these three types of cells are further divided. The neutrophils are the first cell to appear at the site of the infection or injury.

Thus, the correct answer is option F. monocytes, macrophages and neutrophils.

Answer:

Body of an organisms have a range of the normal temperature that is maintained by the body by homeostasis. When the range of the body temperature rise above that range it it known as fever. The normal temperature of human body is normally 36-37 degree centigrade. Mild fever is not need any assistance to bring it back to normal range it is doe by the body to fight against infection or change takes place. Fever can be measured in mouth, rectum, and underarms.

It is considered as nonspecific response mechanism as it is take place due to different type of reasons and its affect or mechanisms is same for all, not specific as the cell mediated or antibody mediated responses of specific defense mechanism.

Answer:

c. False

This statement is incorrect because the DNA of bacteria is circular without histones.

Explanation:

a. True

Some archaea have very specific lipids in their membrane. Differently of the bacterias that have usual lipids in their membranes.

b. True

Archaebacteria do not have peptidoglycans in their cell wall

d. True

Methanogenic archaeobacteria are those that use carbon dioxide and hydrogen to produce methane. They are found in the digestive system of ruminants, sewers and swamps.

Final answer:

The incorrect statement is that only bacteria have histones associated with DNA because both archaea and eukaryotes have histones, highlighting a common misconception about cellular biology. Option c

Explanation:

The statement that is not true among the given options is c. Only bacteria have histones associated with DNA. This is because both archaea and eukaryotes have histones associated with their DNA, which is contrary to what the statement implies. Let's clarify the true statements:

Archaea and bacteria have different membrane lipids: Indeed, archaea have membrane lipids that are ether-linked with branches (phytanyl), whereas bacteria have ester-linked fatty acids.

The cell walls of archaea lack peptidoglycan: Correct, archaea typically do not have peptidoglycan in their cell walls, which is a major component in the cell walls of bacteria.

Only some archaea use CO₂ to oxidize H₂, releasing methane: True, this is a process known as methanogenesis and is specific to certain archaea known as methanogens.

Therefore, the myth about histones being exclusive to bacteria is debunked, showcasing that archaea share this characteristic with eukaryotes, not bacteria. Option c

Answer:

Suillus lakei mushroom refers to a mycorrhizal fungus, which grows in company with Douglas fir, and can be witnessed in the locations where this tree is found.  

This association illustrates a symbiotic relationship, known as mycorrhizae, which is produced between the plant and the fungi. The fungi colonize the root system of the host plant, in this case, Douglas fir, and provide enhanced nutrient and water absorption tendencies, while the plant offers the fungus with carbohydrates produced from the process of photosynthesis.  

The Suillus lakei mushroom's preference for growing around conifers, particularly the Douglas fir, can be a result of a mycorrhizal association. This symbiotic relationship allows the fungus to draw nutrients from the tree, while also offering benefits to the plant such as increased nutrient and water uptake.

The Suillus lakei mushroom, commonly associated with conifers like the Douglas fir, is a perfect example of a symbiotic relationship known as mycorrhizal association. In this mutually beneficial relationship, the mushroom obtains nutrients from the tree's root system, particularly the sugars produced through photosynthesis.

In return, the fungus helps the tree by increasing its water and nutrient absorption capacity from the soil, as fungal mycelium forms a vast network that can reach sources of nutrients and water far beyond the tree roots' range. Thus, the mushroom's habitat preference can be driven by a combination of nutritional need and a unique ability to form productive symbiotic relationships with some specific trees like the Douglas fir.

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Answer:

DNA is made up of sugar-phosphate backbone and the phosphate in the DNA contains the negative charge, therefore, DNA is a negatively charged molecule present in the nucleus.

This negative charge is very important in separating the DNA according to their charge and size during gel electrophoresis. During gel electrophoresis DNA of different size is run on an agarose gel in the presence of current and DNA fragments move toward positive charge due to negative in nature.  

Small size DNA moves fast through the gel large size DNA moves slow towards negative pole, therefore, separating the DNA according to their size. In gel electrophoresis, red pole is positive pole and the black pole is negative so runs to the red phrase is signifying that the DNA is always run towards the red pole.

Answer:

a. True

Explanation:

pH can be regulated by the collecting duct of the kidney. Collecting duct play an important role in the maintenance of pH and ionic balance of the blood by the selective secretion of hydrogen ions (protons) and potassium ions. Collecting duct is long duct which extends from the cortex of the kidney to the inner part of the medulla. In the collecting duct, a large amount of water reabsorption occurs.