Answer:
Common ancestor is the main factor that determines that all terrestrial animals are quadrupedal.
Explanation:
Phylogeny means the evolution of the organisms or genetically related organism and how they are related. The study of phylogeny is called as phylogenetics. Terrestrial means those who live on land. Mammals are one who gives birth to their offspring directly. They are generally warm-blooded, breath air. Studying each state of the ancestor and also tracing the organism characteristics during evolution.The lagging strand is characterized by a series of short segments of DNA (Okazaki fragments) that will be joined together to form a finished lagging strand. The experiments that led to the discovery of Okazaki fragments gave evidence for which of the following ideas?
A) DNA polymerase is a directional enzyme that synthesizes leading and lagging strands during replication.
B) DNA is a polymer consisting of four monomers: adenine, thymine, guanine, and cytosine.
C) DNA is the genetic material.
D) Bacterial replication is fundamentally different from eukaryotic replication. The key shouldn’t be way longer than the distractors.
Answer: A
Explanation:
During the test that lead to the discovery of okazaki fragments on the lagging strand, a strand which is discontinuously synthesized with small DNA molecules to its own Primer RNA and was called okazaki fragments. The synthesis along the lagging strand is in 5' to 3' direction. As it moves, the primase synthesizes short RNA primer, to which the DNA nucleotides are added by DNA polymerase.
It was discovered that DNA synthesis is always in the 5' to 3'direction in both strands.
DNA polymerase is a directional enzyme that synthesizes leading and lagging strands during replication
The discovery of Okazaki fragments supports the idea that in DNA replication DNA polymerase is a directional enzyme that synthesizes both the leading and lagging strands.
Explanation:The experiments that led to the discovery of Okazaki fragments provided evidence for the idea that DNA polymerase is a directional enzyme that synthesizes both the leading and lagging strands during DNA replication. Okazaki fragments are short, newly synthesized DNA pieces that are formed during the replication of the lagging strand. DNA polymerase adds nucleotides to the fragments in a 5' to 3' direction. The existence of these fragments is due to the directionality of DNA polymerase, highlighting that replication is not simultaneous. Eventually, these fragments are joined together by the enzyme DNA ligase to form the continuous lagging strand.
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Which of the following is not true about the anatomy of the urinary system?a.The right kidney is located more inferiorly than the left kidney.b.The kidneys are retroperitoneal.c.The urethra of males is longer than the urethra of females.d.The kidneys are at equal heights within the pelvic cavity.e.The ureters connect the kidneys to the urinary bladder.
Answer:
The kidneys are at equal heights within the pelvic cavity
Explanation:
The kidneys are the paired organs located between the peritoneum and the posterior abdominal wall. Kidneys are said to be retroperitoneal because of their position posterior to the peritoneum.
Kidneys are located on either side of the vertebral column in the lumbar region where the low rib cage protects them. The right kidney is slightly lower than the left kidney. This is due to the fact that the liver is the largest gland and occupies considerable space on the right side superior to the kidney.
The statement 'The kidneys are at equal heights within the pelvic cavity.' is incorrect. In the anatomy of the urinary system, the right kidney is typically positioned slightly lower due to displacement by the liver. Characteristics of urinary system include the ureters connecting kidneys to the urinary bladder and the length of the urethra being longer in males.
Explanation:The statement 'The kidneys are at equal heights within the pelvic cavity.' is not true about the anatomy of the urinary system. The kidneys are positioned on either side of the spine in the retroperitoneal space between the parietal peritoneum and the posterior abdominal wall. But they are not at equal heights - the right kidney is usually positioned slightly lower due to displacement by the liver. Both kidneys are protected by muscle, fat and ribs.
The ureters, on the other hand, are tubes that connect the kidneys to the urinary bladder. They allow the passage of urine, formed by the kidneys, into the bladder where it is temporarily stored before being excreted through the urethra.
Interestingly, the length of the urethra varies between males and females - it is longer in males. Another key feature of the urinary system anatomy is its retroperitoneal positioning - meaning, structures like the kidneys and ureters are located behind the peritoneum, which is a membrane lining the cavity of the abdomen.
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Name 3 processes that increase genetic variation during the process of meiosis or fertilization. Explain why sexual reproduction increases variation among offspring much more than asexual reproduction does.
Answer:
The three processes that increase the genetic variation during the process of meiosis are independent assortment, crossing over, and random fusion of gamete.
During independent assortment, each gene pair assort independently from the other gene pairs in the gametes which brings the different combinations of gene pairs in gamete that cause genetic variation.
Crossing over between homologous chromosomes makes the exchange of genes possible between chromosomes and random fertilization between gametes of two different parents helps in the production of a genetically different offspring. Therefore independent assortment, crossing over and random gamete fusion increase genetic variation during fertilization.
In sexual reproduction there is combination of two different gametes from two different parents which helps in producing an offspring which is genetically different from parents and in asexual reproduction there is no fusion of gamete of different parents and the offsprings are genetically similar to parent therefore in sexual reproduction chances of variation is plenty.
Athlete's foot is caused by a variety of different fungal infections. The presentation of a severe case would look much like the photograph here. The interdigital spaces and any moist areas of the foot are likely to be affected first. As the disease progresses, the nail and nail bed become affected. Once the nails are infected, the course of treatment must involve three different areas. First, the feet must be kept clean and dry. This includes allowing shoes to air dry for 24 hours between wearings, wearing shoes made of leather or other "breathable" materials, using antifungal powders inside the shoes, changing socks at least twice daily, wearing sandals whenever practical, washing the feet with soap twice daily, and applying an astringent. Additional precautions include always wearing shower shoes in public showers/locker rooms and not sharing towels or wearing another person's shoes to prevent contact with the fungus and reinfection. Second, an appropriate antifungal cream, such as clotrimazole, should be applied to clean, dry feet daily. This helps to kill the infection from the outside toward the inside of the body. Third, in advanced cases that involve the nail bed, oral medications are necessary for at least 12 weeks and often up to 6 months (until the new nail is visible and free of fungal discoloration and texture). This kills the fungus from the inside of the skin toward the surface.
What would be the most effective oral agent to use for treating the condition depicted in this case?
Answer:the most effective oral agent to use for the treatment of athlete's foot is terbinafine.
Explanation: Athlete's foot is a form of fungal infection of the skin that is caused by dermatophytes, fungi (most of which are mold) which inhabit dead layers of skin and digest keratin. Topical antifungal medication or oral antifungals could be given for treatment but this depends on the severity of the infection.
Oral antifungals ( terbinafine) are of recent,the best oral agent for the treatment of athlete's foot.
Terbinafine is considered most effective as an oral agent to treat advanced athlete's foot especially when the nail bed is infected. It acts by disrupting the chemical balance required for fungi to thrive, thereby eliminating the infection. It's used for 12 weeks to 6 months until a clear nail grows.
Explanation:The most effective oral agent to treat the athlete's foot, especially in advanced cases involving the nail bed, is generally terbinafine. Terbinafine is commonly used as it is an antifungal medicine specifically designed to treat fungal infections caused by fungi, including those that lead to athlete's foot. It hinders the ability of fungi to make chemicals they need, causing them to die thereby eliminating the infection. Terbinafine is usually prescribed for a duration of 12 weeks to 6 months until the new nail without fungal signs is visible. However, it's essential to consult with a healthcare professional to choose an appropriate treatment plan, as individual needs might vary.
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As a result of stress the anterior pituitary releases ________, which stimulates release of hormones from the adrenal cortex that retain sodium and water, increase blood sugar, and begin breaking down fats.
A) thyroid stimulating hormone (TSH)
B) ADH
C) growth hormone
D) ACTH
Answer:
D. ACTH
Explanation:
Under stress conditions, corticotrophs of anterior pituitary gland secrete adrenocorticotropic hormone (ACTH). This hormone is also known as corticotropin and serves to stimulate the adrenal cortex to secrete its hormones. The glucocorticoids (mainly cortisol) from adrenal cortex serve to increase protein breakdown (except in liver). Cortisol also stimulates gluconeogenesis (formation of glucose from substances other than carbohydrates and lipolysis.
Cortisol also raises blood pressure and enhances inflammation, depresses immune responses. Mineralocorticoids (aldosterone) from the adrenal cortex target kidneys to stimulate the resorption of sodium and thereby retention of water in the blood.
Under stress, the anterior pituitary gland releases Adrenocorticotropic Hormone (ACTH), which stimulates the adrenal cortex to release hormones. These hormones help to retain sodium and water, increase blood sugar, and start breaking down fats.
Explanation:The anterior pituitary releases several hormones as a response to stress, but the correct option in the given question is D) ACTH or Adrenocorticotropic Hormone. ACTH stimulates the adrenal cortex to release hormones like cortisol that critically regulate the body's stress response. These hormones prompt a range of systemic effects such as retaining water and sodium, increasing blood glucose levels, and initiating the breakdown of fats.
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Flower color in snapdragons is an example of incomplete dominance. When a red-flowered plant is crossed with a white-flowered plant, the offspring have pink flowers. If a pink-flowered plant is crossed with another pink-flowered plant, their offspring will be______
Answer:
25% red flowered
25% white flowered
50% pink flowered
Explanation:
Let the red flower color be represented by RR, the white color by rr.
When RR was crossed with rr, the offspring had pink flowers;
RR x rr = Rr, Rr, Rr, Rr (Pink color)
Crossing Rr with another Rr
Rr x Rr = RR, Rr, Rr, rr
RR = red
Rr = pink
rr = white
Hence, if a pink flowered plant is crossed with another pink flowered plant, 25% of their offspring will be red, 25% will be white and 50% will be pink.
When two pink-flowered snapdragons are crossed, the possible outcomes could be red, pink, or white flowers in a 1:2:1 ratio.
Explanation:In biological terms, this question is about the concept of incomplete dominance, which is evidenced in the flower color of snapdragons. When we cross a pink snapdragon (CRCW) with another pink snapdragon (CRCW), the expected result can be calculated using a Punnett square. There will be three possible outcomes, represented as a 1:2:1 ratio. The plants may either be red-flowered (CRCR), pink-flowered (CRCW), or white-flowered (CWCW). Thus, if you cross two pink-flowered snapdragons, you might see three different colors as offspring: 25% red flowers, 50% pink flowers, and 25% white flowers.
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Aminoglycosides: Select one: a. attach to the 30S ribosomal subunit and disrupt protein synthesis. b. are metabolic analogs of PABA and block folic acid synthesis. c. damage cell membranes. d. block peptidases that cross-link glycan molecules.
Answer:
The correct answer is a. attach to the 30S ribosomal subunit and disrupt protein synthesis.
Explanation:
Aminoglycosides are the antibacterial drugs that are usually used against the gram-negative bacterial infection, for example, gentamycin, streptomycin, etc.
These drugs bind on the 30s ribosomal subunits of the ribosome and allow the misreading of the codon sequence present on mRNA by ribosome which results in the incorporation of a wrong amino acid in the growing polypeptide chain that disrupts the protein synthesis.
The other function that aminoglycosides perform are breakdown of RNA, translation inhibition, interference with electron transport chain, etc. Therefore the correct answer is a.
Stella, a kindergarten teacher, is teaching her students about mammals. She uses human beings as an example to explain this concept because human beings match the key features of mammals. In this scenario, human beings serve as a(n) _____.
Answer:
The human beings serve as replica/model of the mammals.
Explanation:
A mammal is a vertebrate and it has fur, mammary glands (female) and feeds the young ones with milk, a neocortex (region of the brain) and three middle ear bones. This differentiates them from reptiles and birds. All mammals are 'warm blooded' because the body temperature heats the blood. A few mammals like the platypus lay eggs. The mammals are at the top of the food chain.Answer:
(B) Prototype
Explanation:
thats the correct answer
The retinoblastoma protein, pRB, is a tumor-suppressor protein that controls the G1/S cell-cycle checkpoint. While pRB is present in all phases of the cell cycle, regulation of its activity is important in the progression from G1 phase to S phase. Sort each statement depending on whether it is is true of cells that remain at the G1 checkpoint or of cells that progress from G1 to S phase.1. pRB phosphorylated 2. pRB not phosphorylated 3. pRB bound to E2F 4. pRB not bound to E2F 5. E2F bound to DNA 6. CDK4 bound to Cyclin D1
Answer:
1. pRB phosphorylated: The cell will not remain in G1 phase i.e. it will enter S phase because pRB will be degraded.
2. pRB not phosphorylated: The cell will remain in G1 phase i.e. will not enter S phase because pRB will remain bound to E2F.
3. pRB bound to E2F: The cell will remain in G1 phase i.e. will not enter S phase.
4. pRB not bound to E2F: The cell will not remain in G1 phase i.e. it will enter S phase.
5. E2F bound to DNA: The cell will not remain in G1 phase i.e. it will enter S phase.
6. CDK4 bound to Cyclin D1: The cell will not remain in G1 phase i.e. it will enter S phase.
Explanation:
Retinoblastoma protein, pRB supresses tumor by regulating cell cycle progression in G1 phase. When a transcription factor known as E2F is bound to pRB the cell remains in G1 phase and did not proceed further to enter S phase. But as soon as pRB becomes phosphorylated, E2F becomes free and causes gene expression of cyclin E and and cyclin A which are required in progression of cell cycle from G1 phase to S phase.
Signaling involved in cell cycle progression from G1 phase to S phase.
When a cell is unstimulated, pRB is bound to E2F but G1 phase specific growth factors induce the expression of cyclin D through Ras-MAP kinase pathway.
Synthesis of cyclin D leads to the activation of CDK-4 which is a serine-threonine kinase. This kinase causes phosphorylation of pRB which results in the degradation of pRB.
Because of degradation of pRB, E2F becomes free and leads to the expression of cyclin E and and cyclin A which are S phase specific cyclins. This is how cell progresses from G1 phase to S phase.
E2F is a transcription factor which causes expression of S phase specific cyclins i.e. cyclin E and and cyclin A. So, E2F bound to DNA will result in cell cycle progression from G1 phase to S phase.
Like all cells, the neurons' internal organization dictates its function. Neurons have relatively many mitochondria, an extensive network of rough endoplasmic reticulum and many clusters of ribosomes. These cellular features indicate all of the following EXCEPT ________.A) Neurons must meet a high demand for ATP.B) neurons have stable, relatively unchanging internal environments.C) neurons produce many proteins.D) neurons have a relatively high consumption of oxygen.
Answer:
B) neurons have stable, relatively unchanging internal environments.
Explanation:
Rough endoplasmic reticulum (RER) is studded with ribosomes which in turn serve as the site for protein synthesis. A cell with an extensive network of rough endoplasmic reticulum has higher rates of protein synthesis. Mitochondria are the powerhouse of cells and serve as the site for aerobic cellular respiration. A large number of ATP molecules are produced in mitochondria. Therefore, a cell with relatively many mitochondria appears to have a higher demand for ATP and higher consumption of oxygen.
A cell with higher rates of consumption of ATP and protein synthesis should be functionally active. The charge across the membrane and the internal concentration of ions such as Na+, K+ of a neuron keep on changing during the conduction of nerve impulse. Therefore, the presence of many mitochondria and RER does not indicate that the neurons maintain relatively constant internal conditions.
Biochemical, evolutionary, and genetic evidence of functionality can help identify single nucleotide polymorphisms (SNPs) that are important in controlling gene expression or contributing to disease progression. True or False?
Answer:
True
Explanation:
Polymorphism is a phenomenon that arises when proteins, DNA and RNA can appear with different molecular forms. Polymorphism is characterized as single nucleotide polymorphism when molecular variation occurred in only one nitrogenous DNA base, thus causing genetic variation in a population. This type of polymorphism is very important to regulate the gene expression of individuals and to measure the progression of a disease. This requires that the unique nucleotide polymorphism be identified. This identification occurs through biochemical, evolutionary and genetic evidence.
Part B Who demonstrated that DNA is the genetic material of the T2 phage? Who demonstrated that DNA is the genetic material of the T2 phage? Franklin Meselson and Stahl Darwin and Wallace Watson and Crick Hershey and Chase
Answer:
The correct option is D. Hershey and Chase
Explanation:
Experiments carried on by Hershey and Chase proved that DNA is the genetic material. It discarded the former belief that proteins were the genetic material.
Hershey and Chase carried out their experiments by using radioisotope of phosphorus (32P) and sulphur (35S) to prove their point. Phosphorus is present only in DNA whereas sulphur is present in proteins but absent in DNA. Hence, the usage of these isotopes acted as radioactive markers to prove the results of their experiments.
An increasingly intricate relationship exists between the gametophyte and sporophyte generations in vascular plants. As vascular plants live longer, they increase in size and complexity and the ____________ generation becomes dominant, while the ____________ generation becomes smaller and of shorter duration.
Answer:
1. Sporophyte
2. Gametophyte
Explanation:
Sporophyte and gametophyte generations of vascular plants are quite distinct from each other with respect to their shape and size. The gametophyte generation produces gametes while the saprophyte produces spores. In conifers and angiosperms, the sporophyte is diploid and more conspicuous. It is the dominant generation in these vascular plants and includes the roots, stem, and leaves of the plant body. The gametophyte generation is small and inconspicuous in higher plants. For example, the microscopic pollen grains of angiosperms carry the haploid male gametophyte.
On the other hand, the sporophyte of ferns consists of rhizome, fronds and true roots. Although sporophyte is a dominant generation in ferns, the haploid gametophyte also persists for a longer period and immature sporophyte is attached to and dependent on the gametophyte until the embryo matures.
Not only are the kidneys considered organs of excretion, but they have an endocrine function as well as an important role in the maintenance of homeostasis through the regulation of ion concentration.
True or False?
Answer:
True
Explanation:
One of the edocrine processes the kidney is involved in is called the RAAS (Renin-Angiotensin-Aldosterone System) which is a signaling pathway involved in blood pressure control. It involves a number of hormones:
Angiotensinogen is produced by the liver in response tovarious inflammatory proteins
Renin is a protease produced by the kidneys in response tohypotension,
Angiotensin II increases blood pressure via a number of mechanisms:
Aldosterone acts to increase reabsorption of Na+ and water and increase elimination of K+ and H+ in the distal tubules of the kidneys for ion concentration maintenance
If there is complete linkage with genes Ss (for smooth or wrinkled seeds) and Gg (for green or yellow seeds), what phenotypes would you expect in the offspring of a cross with one heterozygous parent (Ss, Gg), which would all produce all smooth and green seeds, and a homozygous recessive parent (ss, gg), which would produce all wrinkled yellow seeds?
Answer:
Smooth and green seeds
Smooth and yellow seeds
Wrinkled and green seeds
Wrinkled and yellow seeds
Explanation:
This is a typical dihybrid cross involving two linked genes; one gene coding for seed texture and the other for seed colour. The allele for Smooth seed (S) is dominant over the allele for Wrinkled seed (s) in the first gene while the allele for green seed (G) is dominant over the allele for yellow seed (g) in the second gene.
The cross is between a heterozygous smooth, green plant and a homozygous recessive wrinkled, yellow plant
According to the law of independent assortment, each parent will undergo meiosis to produce the following gamtes with genotypes:
SsGg: SG, Sg, sG, sg
ssgg: sg, sg, sg, sg
Using a punnet square to perform a cross between these gametes ( check attached image), a total of 16 offsprings with four different phenotypes will be expected. The phenotypes are as follows:
SsGg: Smooth and green offsprings (4)
Ssgg: Smooth and yellow offsprings (4)
ssGg: Wrinkled and green offsprings (4)
ssgg: wrinkled and yellow offsprings (4)
Final answer:
In a genetic cross involving complete linkage between genes for seed texture and color in pea plants, crossing a heterozygous (SsGg) with a homozygous recessive (ssgg) parent will result in a 1:1 phenotypic ratio of smooth green to wrinkled yellow seeds among the offspring due to the inheritance of genes as a linked unit.
Explanation:
The question concerns a genetic cross involving complete linkage between two genes: one responsible for seed texture (Ss) and the other for seed color (Gg), in pea plants. In this scenario, we have one parent that is heterozygous for both traits (SsGg), capable of producing smooth green seeds, and another parent that is homozygous recessive for both traits (ssgg), capable of producing wrinkled yellow seeds. Because of the assumption of complete linkage, these genes are inherited together as a unit without any recombination between them. Therefore, the gametes produced by the heterozygous parent will be SG and sg, and the gametes from the homozygous recessive parent will always be sg.
The offspring, resulting from these gametes, will exhibit two phenotypes associated with the two types of gametes they receive: smooth green and wrinkled yellow seeds. This is because the heterozygous parent can only pass on either the linked dominant alleles (SG for smooth green seeds) or the linked recessive alleles (sg for wrinkled yellow seeds), and the homozygous recessive parent can only pass on recessive alleles (sg). Therefore, the cross will result in a 1:1 phenotypic ratio of smooth green to wrinkled yellow seeds among the offspring.
The four stages of translation, initiation, elongation, and termination __________. The four stages of translation, initiation, elongation, and termination __________. all require at least one protein cofactor all require base pairing between two RNAs all require ATP all have peptidyl synthetase catalyzed reactions
Final answer:
The four stages of translation are initiation, elongation, and termination, each involving specific molecules, reactions, and energy consumption, culminating in the synthesis of proteins.
Explanation:
The four stages of translation, which are initiation, elongation, and termination, each involve several key components and actions that are critical for the synthesis of proteins. Initiation involves the assembly of the ribosome, mRNA, initiation factors, and tRNAMet to form the initiation complex. During elongation, tRNA molecules recognize and base pair with codons on the mRNA template, delivering amino acids which are then linked together by peptidyl synthetase in a process driven by ATP. Finally, termination occurs when the ribosome encounters a stop codon on the mRNA, causing the release of the synthesized polypeptide chain with the help of protein termination factors.
Tall pea plants are dominant over short pea plants. If a heterozygous tall pea plant(Tt) is crossed with a short pea plant(tt), what percentage of the offspring will be homozygous dominant?
Answer: The percentage of the offspring that will be homozygous dominant is zero.
Explanation: Since tall pea plants are dominant to short pea plants, a cross between a heterozygous tall pea plant (Tt) and a homozygous short pea plant (tt) will produce four offsprings: two heterozygous tall pea plants (Tt) and two homozygous short pea plants (tt). Tt x tt = Tt, Tt, tt, and tt.
Tt is heterozygous dominant for tall height while tt is homozygous recessive for short height.
See the attached punnet square for more information.
When a heterozygous tall pea plant (Tt) is crossed with a short pea plant (tt), the offspring will either be heterozygous tall (Tt) or homozygous recessive short (tt), at a ratio of 1:1, or 50% for each. There cannot be any homozygous dominant (TT) offspring from this cross, so the chance is 0%.
Explanation:The short pea plant (tt) can only pass on a recessive allele (t). On the other hand, the heterozygous tall pea plant (Tt) can pass on either a dominant (T) or a recessive (t) allele. When these alleles combine during reproduction, there are two possible combinations: Tt (a tall plant) or tt (a short plant). Because there is only one way to get Tt and one way to get tt, we can say that there is a 1:1 ratio, or 50% chance, for each type of offspring. Interesting to note, however, is that homozygous dominant (TT) is not a possible outcome from this cross, meaning that there is a 0% chance for homozygous dominant offspring in this particular cross.
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disease is spread more quickly between individuals who live in close proximity, such as in a nesting colony of penguins. Disease can be considered a(n):
A. density-dependent factor
B. factor that increases carrying capacity
C. density-independent factor
D. factor that causes greater birth rate than death rate
E. exponential growth factor
Answer:
a
Explanation:
disease is dependent on population density to spread
Diseases spread more quickly among individuals in close proximity, like a penguin colony, due to density-dependent factors, which are more impactful at higher population densities.
The spread of disease in closely packed populations, such as a nesting colony of penguins, is primarily influenced by density-dependent factors. These are factors whose effects on a population are proportional to the population's density. As the density of a population, such as the penguins, increases, so does the potential for disease to spread more rapidly. In this scenario, disease serves as a density-dependent limiting factor that can increase death rates or decrease birth rates due to higher competition for resources and increased contact rates among individuals.
Density-dependent factors such as predation, competition for food and mates, accumulation of waste, and diseases caused by parasites, tend to have greater impacts on populations with higher densities. In contrast, density-independent factors affect population sizes regardless of their density and include events like hurricanes or droughts. Understanding these factors is crucial for conservation biologists managing population sizes and preventing extinction.
Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because ________.
A) hormones alter cellular operations through direct stimulation of a gene
B) peptide hormones are converted by cell membranes enzymes into second messengers
C) G protein acts as the link between first and second messengers
D) the hormone receptor complex moves into the cytoplasm as a unit
Answer:
Cells that respond to peptide hormones usually do so through a sequence of biochemical reactions involving receptor and kinase activation. In order for cells to respond, it is necessary for first and second messengers to communicate. This is possible because C) G protein acts as the link between first and second messengers .
Explanation:
When the first messengers join the receptor, in the external membrane of the cell, it produces a change in the shape of the receptor that causes the join of the G protein to this structure. The G protein joined to the receptor and the first messenger modulates the activity of the second messengers inside the cell.
The Acme Chemical Company has some employees who work in a production plant and some who work in a sales office. The plant workers get paid every Friday; however, the office workers get paid for every fifth sale that they make. The plant workers are paid on a ___ schedule, whereas the office workers are paid on a ___ schedule.
A) variable ratio; fixed interval
B) variable interval; variable ratio
C) fixed interval; fixed ratio
D) fixed ratio; variable interval
Answer:
fixed interval; fixed ratio
Explanation:
The fixed interval rewards employees at specified time intervals. If an employee displays the correct behavior each day, reinforcement may occur every week.
In the fixed ratio, reinforcement occurs after a specified number of desired responses.
Answer: The correct answer is : C) fixed interval; fixed ratio
Explanation: Fixed interval: The period of time in which the worker receives his remuneration is fixed, which has several advantages since the employee can plan his expenses and somehow this provides security to the person.
fixed ratio: This salary does not depend on the time but on the amount or magnitude of results necessary to earn it.
As a ribosome translocates along an mrna molecule by one codon, what happens after it?
Answer:
The tRNA is released from the E site of the ribosome and the elongation process finishes while the termination process starts.
Explanation:
When the translocation process is finished the tRNA that is in the E site of the ribosome is released and the A site of the ribosome reads a stop codon in the mRNA in order to finish the elongation process and start with the termination process. In the termination process a termination factor joins the stop codon, the ribosomal subunits split apart, the protein and the tRNA dissociate from one another and the tARN is not in the P site of the ribosome anymore.
Which of the following is not an effect of complement activation? Select one: Interference with viral replication Increased phagocytic activity Opsonization Increased blood vessel permeability Bacterial cell lysis
Answer:
The correct answer is "Interference with viral replication".
Explanation:
The complement system is an essential part of the immune system that involves the activation of a series of proteins that act as a cascade and result in the development of inflammatory responses that help to fight infections. There are multiple effects of complement activation, however interference with viral replication is not one of them. The molecules that are able to interfere with viral replication are called interferons, and they synthesis and activation are not related with complement activation.
The processes involved in compliment activation include opsonization, increased phagocytic activity, increased blood vessel permeability, and bacterial cell lysis. However, interference with viral replication is not a result of this process.
Explanation:The effect of complement activation includes several outcomes such as opsonization, inflammation, chemotaxis, and cytolysis. All these protective mechanisms are designed to support the immune system in combating pathogens. For the alternatives provided, interference with viral replication is not an effect of complement activation.
'Opsonization', refers to the coating of a pathogen to enhance its recognition and consumption by phagocytic cells. 'Increased phagocytic activity' and 'Increased blood vessel permeability' result from the complement fragments activities.
'Bacterial cell lysis' is another effect, where proteins bind to bacteria and create holes in gram-negative bacterial cell membranes, causing lysis. So, interference with viral replication, is not an immediate direct effect of complement activation.
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Why does an autopsy include an examination of all the body systems and not just the suspected cause of death? For example, if a victim has massive head trauma from an automobile accident, why is a complete autopsy performed, including a toxicology report?
Answer:
Autopsy is an internal/external examination of the body to determine the cause of death.
Explanation:
"Autopsy" is carried out to find the exact "reason" of death by examining the body. It is possible that there is some hidden cause of death even in case of an accident, so autopsy is done. Also, a person dying of a "car accident" could have died because of the heart attack or some other organ failure.
So, it is possible that the suspected cause of death is incorrect and exact reason is something else. Every aspect of death needs to be analysed.
Imagine there are 25 different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. Over the course of a year, the average water temperature of the tide pool increases significantly. Which species are more likely thrive in the changing environment?
A) the sexually reproducing species
B) the asexually reproducing species
Answer:
A) the sexually reproducing species
Explanation:
Although we do not know how the change in temperature directly affects the bacteria species, we can say that the species that reproduces sexually are more likely to thrive because these species are also able to reproduce asexually. In other words, this species handle two mechanisms of reproduction
Unlike the species able to reproduce sexually (and asexually), the other species only reproduces asexually. Therefore, if the change in temperature affects asexual reproduction, the species that have both mechanisms will thrive using sexual reproduction, but the other species (not able to reproduce sexually) will not survive.
What year did theodor schwann contribute to the cell theory
Describe at least three distinguishing features of synovial joints.
Answer:
Synovial fluid
ligaments
Explanation:
1) the ends of the bones of the synovial joints are covered with a connective tissue filled with synovial fluid
2) the outer surface of the joints contains ligaments that strengthen the joint and holds it in position thereby increasing flexibility
3) the synovial fluid present in the synovial cavity , lubricates the ends of the bones and reduces friction
Synovial joints are characterized by three primary features: the presence of articular cartilage, a synovial cavity filled with synovial fluid, and a synovial membrane that secretes the fluid.
Explanation:Synovial joints, also known as diarthroses, are the most common and movable types of joints in the body. They have three main distinguishing features:
Articular cartilage: This is a smooth, slippery, white tissue that covers the ends of the bones, providing a cushion and allowing for smooth motion.Synovial cavity: This is a space between the joint's articulating bones, which contains synovial fluid produced by the synovial membrane.Synovial membrane: This is a thin layer of tissue that lines the joint capsule and secretes synovial fluid, providing lubrication and nutrients to the joint.These components work together to facilitate movement and maintain joint health.
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Arthropod exoskeletons and mollusc shells both ________.a.are secreted by the mantleb.help retain moisture in terrestrial habitatsc.are comprised of the polysaccharide chitind.completely replace the hydrostatic skeleton
Answer:
b. help retain moisture in terrestrial habitats
Explanation:
Arthropods such as cockroach, centipedes, spiders, crab are the members of the largest phylum Arthropoda. These are animals with paired jointed legs and their body is covered with an exoskeleton made of chitin. They live in diversified habitat and exoskeleton helps to retain moisture in theterrestrial habitats.
Similarly mollusks such as sepia, snail are soft bodied animal whose body is covered with calcareous shell as a protection and to retain moisture while living on land.
A researcher has a petri dish containing several species of bacteria, but no viruses. She notices that the population of E. coli in her petri dish has no antibiotic resistance. Two weeks later, she reassesses the bacteria and finds that the E. coli have acquired antibiotic resistance. How could this have happened?
Answer:
Bacteria can get antibiotic-resistant gene through the process of transformation, conjugation, and transduction. In transduction, the virus is required to provide the extra gene to the bacteria.
In transformation bacteria takes the genetic material from its surroundings and in conjugation bacteria can take or transfer antibiotic-resistant gene by sex pills. Therefore in this case virus is not present then transduction can not contribute to the antibiotic resistance gene to E.coli.
So conjugation and transformation are the methods by which E.coli can acquire antibiotic-resistant genes from other bacterial species.
Final answer:
E. coli can acquire antibiotic resistance through horizontal gene transfer or mutations. These mechanisms allow the bacteria to survive in the presence of antibiotics, leading to the development of antibiotic-resistant strains.
Explanation:
E. coli bacteria acquiring antibiotic resistance can occur through various mechanisms. One common way is through the transfer of resistance genes from other bacteria via plasmids. In the case of the researcher's petri dish, it is possible that E. coli acquired antibiotic resistance through horizontal gene transfer. Another possibility is that mutations occurred in the E. coli bacteria, leading to the development of antibiotic-resistant strains over time. These mutations can provide the bacteria with the ability to survive in the presence of the antibiotic, allowing them to outcompete non-resistant bacteria and increase in population.
You are examining a primitive vertebrate and want to determine whether the same part of its brain coordinates muscular movement as in the human brain, so you would do a surgical experiment to disconnect the rest of the brain from the _____.
Answer:
cerebellum
Explanation:
The basal ganglia and cerebellum of the first floor provide basic movement control and store many of our primitive reactions, as well as many of the learned programs that have become automatic. Right next to them is the limbic system, hence the close relationship between emotions and movements, and the feelings linked to the emotional consequences of our actions. This explains why they can accompany emotional changes to certain ailments that are related to the movement; For example, it is not uncommon for depression to accompany Parkinson's disease.
The cerebellum, on the first floor, is primarily responsible for balance, posture and coordination. As thanks to him we can move the attention rhythmically, he has a great participation in most systems, if not all. Cerebellum means in Latin "cerebrito", and sometimes it seems as if he has his own mind. Information regarding the movement and position of the body enters the cerebellum, where it is processed. Instructions are then sent to modify posture and coordinate muscle movements. This has a more fundamental importance than it may seem. In order for the movements to take place, the brain must know the position and speed of the body and each limb, and where you are in space and time. Spatial orientation and posture are essential to know "where you are." The only reason that you remain upright and gravity does not make you fall is the constant monitoring of the cerebellum. It adjusts the reactive changes of the posture in the brainstem, which sends spinal cord messages down, which control the muscles that straighten and extend the trunk and limbs and fight against the force that pulls down.
On the second floor are the motor and premotor cortices, which control things such as specialized movements of the face and extremities, in particular the manipulation movements in which the arm, hand and fingers participate. Good evidence of the extensive interconnection and feedback between the different plants can be seen by studying the effects of the motor cortex.
Salivary amylase is a digestive enzyme not featured in the Concept Map. Which of the following describes its function? breaks down complex starches into smaller units, and where in the body does this occur? View Available Hint(s) Salivary amylase is a digestive enzyme not featured in the Concept Map. Which of the following describes its function? breaks down complex starches into smaller units, and where in the body does this occur? Salivary amylase breaks down steroid hormones into cholesterols in the stomach. Salivary amylase breaks down lipids into fatty acids in the mouth. Salivary amylase breaks down proteins into amino acids in the stomach. Salivary amylase breaks down complex starches into smaller units in the mouth.
Answer:
The correct answer is salivary amylase breaks complex starches into smaller units in the mouth.
Explanation:
Salivary amylase is so named because it is present in our saliva.Salivary amylase plays an important role in the digestion of starch molecules.
Salivary amylase degrade the α-1,4-glycosidic linkages present within the biochemical structure of starch polysaccharide.The cleavage of α-1,4-glcosidic linkage result in the maltose,maltitriose and α limit dextrins.
The so formed disaccharide, trisaccharide and tetrasaccharide are further digested in the small intestine to generate simple carbohydrates.
Salivary amylase, a digestive enzyme, initiates the breakdown of complex starches into smaller units starting in the mouth.
Explanation:The function of the salivary amylase enzyme is to break down complex carbohydrates or starches into smaller, simpler units, specifically, maltose, which is a disaccharide. This process begins in the mouth where the salivary amylase is secreted by the salivary glands. It's important to note that the process is only initiated in the mouth, and the breakdown of starches continues in the stomach and small intestine where other digestive enzymes further contribute to the process.
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