1. The proportion of mottled fish will increase over time.
Explanation:
The mottled appearance of the bottom of the lake provided a survival benefit to the mottled skinned fishes. This is because a mottled background allows the mottled fishes to camouflage against it and escape predation . On the other hand light brown fishes will become more distinct and visible to the birds and will be hunted. So, soon the proportion of mottled fish in the lake will rise.
The semilunar valves prevent backflow of blood into the _____.
Answer:
The semilunar valves prevent backflow of blood into the ventricles.
Explanation:
The semilunar valves are valves found at the junction between the left ventricle and the aorta and also between the right ventricle and the pulmonary artery. They are cup-like in shape and prevent blood from flowing back into the ventricles which are the pumping chambers.
There are two types of semilunar valves. The aortic semilunar valves and the pulmonary semilunar valves. They are made up of the endocardial and connective tissue.
The closure of the semilunar valves causes the second heart sound detected on the stethoscope.
Diseases that arise from the semilunar valves are caused by its stenosis which is the narrowing of the valves and regurgitation where the heart valves can no longer hold firm enough to prevent the backflow of blood.
Semilunar valves prevent backflow of blood into the aorta and the pulmonary artery.
Explanation:The semilunar valves prevent backflow of blood into the aorta and the pulmonary artery. These valves are located between the ventricles and the major arteries leaving the heart. When the ventricles contract, the semilunar valves open to allow blood to be ejected into the arteries. However, when the ventricles relax, the semilunar valves close to prevent blood from flowing back into the heart.
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In industry, microorganisms are often cultured in an environment where ideal conditions are maintained through continual nutrient provision and waste renewal. Such a system is called a _______.
Answer: Continuous Culture
Explanation:
In industry, a continuous culture is maintained by providing the nutrient on time and removing the waste materials on time so that the optimum conditions inside the medium is maintained.
It is done to minimize the efforts which is required when the preparation is done to prepare the nutrient and inoculate the bacterial species.
Then by the time the bacterial species starts growing and then the useful product is extracted. In order to save the time and efforts the nutrient is supplied and waste materials is removed along with the useful products.
The organelle in which photosynthesis takes place is the
Photosynthesis takes place within the chloroplasts, which contain thylakoids with chlorophyll, where light is captured for the light reactions. The surrounding stroma is the site of the Calvin cycle.
Explanation:Chloroplasts: The Site of Photosynthesis
The organelle in which photosynthesis takes place is the chloroplast. These are specific to plant cells and certain algae and are found in chloroplast-containing cells in the mesophyll of leaves. Inside the chloroplast, there is a double membrane envelope, consisting of an outer and an inner membrane. Within these membranes, are disc-shaped structures called thylakoids, where the light reactions of photosynthesis occur. The thylakoids contain chlorophyll, the green pigment responsible for capturing light energy, which is essential for starting the photosynthesis process. The thylakoid membranes are arranged in stacks known as grana. The surrounding fluid is called the stroma, where the Calvin cycle occurs. Photosynthesis is a two-part process involving the light reactions in the thylakoid membranes and the Calvin cycle in the stroma.
What type of rock is made of particles .05 cm?
Answer:
sedimentary rocks
Explanation:
How are sedimentary rocks formed? Forms from when sediments are deposited, buried, compacted & cemented together.
The sedimentary rocks are made up of particles whose size is about 0.05cm.
What are sedimentary rocks?Sedimentary rocks are the type of rocks which are formed by the accumulation or deposition of mineral or organic particles at the surface of Earth, followed by cementation of the deposit. Sedimentation is the collective term used for the processes which cause these particles to settle in place.
The sedimentary rock pebbles size ranges from 0.2 centimeters in diameter to up to 6.4 centimeters in diameter. Cobbles are the second-largest sediment size and it ranges from 6.4 centimeters in diameter to up to 25.6 centimeters.
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describe why Darwin's finches were different on each of the galapagos island
Answer: discovered several species of finches that varied from island to island, which helped him to develop his theory of natural selection. ... They also helped investigate evolutionary changes in Darwin's finches.
Explanation: native birds––14 of which make up the group known as Darwin’s finches. These finches are considered to be the world’s fastest-evolving vertebrates because their appearance and behavior quickly adapted to this closed and rapidly changing environment.
Molecular data can be used to assess relationships among the major groups of living organisms whose common ancestors lived millions or billions of years ago. Similar techniques can be used to assess relationships among populations within a species. How can molecular techniques be useful for such varied comparisons?
Answer: Faster-evolving gene sequences provide better data for comparisons among close relatives, whereas very slowly evolving sequences work best for distantly related tax.
The genes for miniature wings (m) and garnet eyes (g) are approximately 8 map units apart on chromosome 1 in Drosophila. Phenotypically wild-type females (m + g / mg +) were mated to miniature-winged males with garnet eyes.
Which of the following phenotypic classes reflect offspring that were generated as a result of a crossover event?
1. garnet eyes
2. wild type
3 .miniature wings
4 .miniature wings, garnet eyes
Explanation:
Two types of posterity can be created subsequent to mating: parental and recombinant. Recombinants are created because of the traverse of non-sister chromatids at the hour of gamete arrangement. Here, mating happens between m+g/mg+ female and mg/mg male so the posterity would be separated as follows: m+g/mg : Parental mg+/mg : Parental m+g+/mg : Recombinant mg/mg : Recombinant m+g+/mg (wild sort) and mg/mg (smaller than usual wings, garnet eyes) are the recombinants thus they were created because of the hybrid occasion.Hence,the right answer is option 2 & 4 "wild type and miniature wings,garnet eyes"Question 6
Darwin realized that Malthus’ ideas about human population growth applied even more to other organisms, such as ____.
a. tigers are overpopulating the earth.
b. mammals carefully raise one or two young per year.
c. insect populations grow unchecked each year.
d. cockroaches produce millions of eggs but only a few survive.
Answer:
D.
Explanation:
Charles Darwin applied Thomas Malthus' theories to organisms, with the best example being 'cockroaches produce millions of eggs but only a few survive'. This concept forms the basis of Darwin's belief in natural selection.
Explanation:Charles Darwin recognized that Thomas Malthus' theories related to human population growth were even more applicable to other types of organisms. The option that best aligns with this concept is 'd. cockroaches produce millions of eggs but only a few survive'. This is essentially the crux of Malthus' idea that resources such as food and habitat are limited, while populations have the potential to grow exponentially if unchecked. In nature, this leads to struggle for survival, and only a few organisms manage to survive and reproduce, illustrating Darwin's natural selection belief.
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the process which causes potholes in roads is called ______ when it occurs under glacial ice
Answer:
Expansion and Contraction of underneath or base water
Explanation:
When ice lands on a road, it weakens the soil beneath the pavement, cement by expansion. The slight varying temperatures that leads to the combination of contraction and expansion affects road this leading to potholes on road.
Answer:EXPLANATYION
Explanation:
ITS EASY
Viral DNA makes mRNA by the process of _____. Viral DNA makes mRNA by the process of _____. replication infection translation lysis transcription
Explanation:
Viruses do not possess any machinery necessary for the purpose of their reproduction.They only possess their genetic material enclosed within a capsid structure.The capsid is constituted of glycoproteins.They completely depend upon the components and organelles of the host cells whom they infect to help them carry out their reproduction process.After infecting a host cell, the viruses hijack all the machinery and components of the host cell and use them for the purpose of transcribing their genetic material (DNA or deoxyribonucleic acid) to produce the virus-specific mRNAs (messenger Ribonucleic Acid).These mRNAs are further translated into virus-specific proteins using the host-specific Ribosomes. These virus-specific proteins are required for replicating the viral genetic material and producing the capsid structure. The virus-specific proteins and glycoproteins are synthesized by utilizing the raw materials from the host cells.Transcription is the process by which an enzyme called RNA polymerase or DNA dependent RNA polymerase copies the protein coding region of the DNA (gene) in the form of an RNA sequence (mRNA). The synthesis of the mRNA happens in the 5' to 3' direction. This mRNA is further recognized and converted into the amino acid sequence with the help of the Ribosome. The amino acid sequence folds to give rise to the protein.Viral DNA creates mRNA through the process of transcription, often involving reverse transcriptase if dealing with retroviruses.
Explanation:Viral DNA makes mRNA by the process of transcription. This process involves the viral DNA being used as a template to produce messenger RNA or mRNA. The main steps in this process typically involve reverse transcriptase making DNA from the RNA genome, and then the DNA being incorporated into the host genome. Once integrated into the host genome, mRNA is transcribed from the incorporated DNA. These mRNAs are critical as they instruct the host cell to produce viral proteins and enzymes, allowing for new virions, or virus particles, to be assembled. Specific types of viruses such as retroviruses use the additional step of reverse transcription where RNA is converted back into DNA before transcription can occur.
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Which of the following vaccines should NOT be stored frozen? Group of answer choices Pneumococcal polysaccharide vaccine Varicella vaccine Zoster vaccine live Measles, mumps, rubella vaccine
Answer:
Pneumococcal polysaccharide vaccine
Explanation:
This is a liquid vaccine, and these types of vaccines should not be frozen, because if they do they lose their potency and no longer protect the individual from infections. In fact when these types off vaccines are frozen they can cause local reactions such as sterile abscesses.
In many organisms, one set of chromosomes comes from the maternal parent, while the other set comes from the paternal parent. Similar chromosomes in these sets are said to be ________.
Answer: Homologous
Explanation:
Homologous pair of chromosomes are the pair of chromosome pair which are of same height, same length, same staining pattern, same centromere position for the genes with same corresponding loci.
In this pair of chromosome, one is inherited from the mother's body and the other is inherited from the father's body.
These pair of chromosomes are transferred from the parents to the children.
Final answer:
In sexually reproducing organisms, the similar chromosomes in a set that come from each parent are known as homologous chromosomes. They contain the same genes, although they may have different alleles. In humans, one set of chromosomes is inherited from each parent, including the sex chromosomes which determine the offspring's sex.
Explanation:
In sexually reproducing organisms, homologous chromosomes are similar chromosomes in a pair where one is inherited from the maternal parent and the other from the paternal parent. These chromosomes contain the same genes in the same order but may have different alleles. In humans, DNA is organized into 46 chromosomes, with one set of 23 coming from the mother (maternal chromosomes) and the other set from the father (paternal chromosomes). The 22 pairs of autosomal chromosomes have genes present at the same locations. The last pair, the sex chromosomes, determine the phenotypic sex of an individual with XX individuals typically developing into females and XY into males.
The enzyme acetylcholinesterase, located in the synaptic cleft and on the postsynaptic membrane, breaks ACh down into acetate and choline, thereby stopping the stimulation of a postsynaptic cell.True / False.
Answer:
True
Explanation:
The action of aceetylcholine in the synaptic cleft is normally terminated by metabolism to acetate and choline by the enzyme acetylcholinesterase and the stimulation of the post-synaptic cell is stopped.
This esterase is anchored to the postsynaptic cell but acts extracellularly.
The products of acetylcholinesterase are not released , infact they are reabsorbed to make more ACh.
Hence, the statement the enzyme acetylcholinesterase, located in the synaptic cleft and on the postsynaptic membrane, breaks ACh down into acetate and choline, thereby stopping the stimulation of a postsynaptic cell is true.
The statement about the role of the enzyme acetylcholinesterase breaking down Acetylcholine (ACh) in the synaptic cleft to halt stimulation of postsynaptic cells is accurate. (True)
Explanation:The enzyme acetylcholinesterase, located in the synaptic cleft and on the postsynaptic membrane, does indeed break Acetylcholine (ACh) down into acetyl and choline.
This action stops the stimulation of a postsynaptic cell which prevents unwanted extended muscle contraction. This is due to the ACh no longer being bound to the ACh receptors as seen in neurotransmission.
Acetylcholinesterase plays a crucial role in ensuring that ACh does not rebind to a receptor and reopen its channel, which might result in unwanted extended muscle excitations and contractions.
Once neurotransmission has occurred, neurotransmitters need to be removed from the synaptic cleft to ensure that the postsynaptic membrane can be 'reset' and ready to receive another signal. This can be achieved through the neurotransmitter degrading by enzymes in the synaptic cleft.
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why is the modification or change in an organ or tissue during the lifetime of an individual is not inherited?
Answer: It is because the organ change is acquired and not inherited
Explanation:
Genetics explains that only traits inherited from parents can also be passed down to offspring since they are carried in the genes. Hence, other traits acquired as a result of organisms trying to survive in an environment are acquired traits, and cannot be passed down to offspring.
Changes within an individual's lifetime such as those associated with lifestyle or environment are not usually inherited because they do not alter the DNA code that's passed onto offspring. The concept of inheriting such changes known as Lamarckian inheritance, has largely been invalidated. Mutations that occur naturally during DNA replication can add to genetic variance but they are unrelated to an individual's experiences.
Explanation:The reason that a modification or change in an organ or tissue during an individual's lifetime is not inherited is largely due to the nature of genetic inheritance and evolution. Traits and genetic characteristics are passed down from generation to generation through DNA which exists in every cell in an organism's body and is locked in at conception. Change during an individual's lifetime can occur in the form of epigenetic modifications which are changes in how genes are expressed or activated, not changes in the genetic code itself. Although these epigenetic changes can be influenced by the environment and can even have long-lasting effects on an individual, they are not transferred to offspring via sexual reproduction.
Lamarckian inheritance, which proposed the inheritance of acquired traits, such as strength gained from physical labor or knowledge from learning, has been largely disproven. DNA replication and mutation, which are responsible for transferring genetic traits from parents to offspring, can't be influenced by the experiences or lifestyle of an organism, aside from certain cases like DNA damage through exposure to toxins or radiation. Mutations can arise naturally during DNA replication and can add variations to a population's gene pool, but these changes don't reflect the experiences or changes an organism goes through in its lifetime. Instead, they are the result of random genetic changes.
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You are preparing to conduct a contrast study of the GI tract of budgerigar. You are aware that food left in the ___ decreases the volume of contrast media that can be safely administered. Group of answer choices
Explanation:
crops are plants developed by the ranchers. Agribusiness assumes a significant job in the Indian economy. 70% of the Indian populace relies upon horticulture for nourishment and cash. It is the significant occupation in the country zones. The development of yields relies basically upon the climate and soil conditions The yields that are developed to take care of the human populace are known as nourishment crops. There are various nourishment crops developed in the nation. Crop production is a branch of agriculture that deals with growing crops for use as food and fiber. Hence, the right answer for the fill in blank is "crop"
What are the products of the light reactions of photosynthesis that are utilized in the calvin cycle?
Answer:
The correct answer is ATP and NADPH
Explanation:
During the light reaction, the light energy is absorbed by the chlorophyll pigment present in the thylakoid membrane which moves through different electron acceptors and allows the formation of NADPH and ATP.
This ATP and NADPH get utilized into the Calvin cycle during carbon fixation, reduction and regeneration steps. This utilization converts ATP and NADPH into ADP and NADP+. The energy released by them is used to fix carbon to produce organic compounds. Therefore the correct answer is ATP and NADPH.
An experiment was conducted by Diane Dodd in which a single population of fruit flies was divided into two, with one of the populations fed with starch-based food and the other with maltose-based food. After the populations has diverged over many generations, the groups were again mixed; it was observed that the flies continued to prefer mating with others from the same original population. This process could eventually result in:___________.
Final answer:
An experiment was conducted by Diane Dodd in which a single population of fruit flies was divided into two, with one of the populations fed with starch-based food and the other with maltose-based food. After the populations has diverged over many generations, the groups were again mixed; it was observed that the flies continued to prefer mating with others from the same original population. This process could eventually result in:.speciation.
Explanation:
The experiment conducted by Diane Dodd involving fruit flies fed with starch-based food and maltose-based food showed that after many generations, the flies continued to prefer mating with others from the same original population. This process is known as assortative mating. Assortative mating can result in the formation of distinct populations within a species over time. These populations can eventually lead to speciation, where two different species emerge from a common ancestor.
The process described in Diane Dodd's experiment could eventually result in sympatric speciation.
Sympatric speciation is a mode of speciation that occurs when two populations of the same species share the same geographic range but become reproductively isolated from each other as a result of adapting to different ecological niches or behaviours within that range. In the case of Dodd's fruit fly experiment, the populations diverged due to differences in their diet, with one group adapted to starch-based food and the other to maltose-based food. Over many generations, these dietary preferences led to assortative mating, where flies preferentially chose mates that consumed the same type of food as they did.
Assortative mating can lead to reproductive isolation because it reduces gene flow between the two groups. If this process continues, the genetic differences between the two populations may accumulate to the point where they are considered separate species. This is because reproductive isolation is a key component of the biological species concept, which defines a species as a group of organisms that can reproduce with one another but not with members of other species.
In summary, the continued preference for mating with individuals from the same original population, as observed in Dodd's experiment, can lead to reproductive isolation and, ultimately, sympatric speciation, where two new species arise from a single ancestral species without any geographic barriers to gene flow.
Which is an example of chronic physiological toxicity? a. amotivational syndrome b. high blood pressure from smoking c. respiratory arrest from an alcohol overdose d. paranoia from methamphetamine use
Answer: Option B
Explanation:
Chronic physiological toxicity can be defined as the condition in which the toxicity is developed inside the body due to being in exposure to the toxicant or stressor.
One of the example is increased in the level of blood pressure due to smoking. Smoking from a longer period of time increases the toxic materials inside the body and results in adverse effects.
Hence, the correct answer is option B.
An acute non-contagious respiratory tract infection that produces severe pneumonia-like symptoms caused by bacteria that thrive in warm aquatic environments and are inhaled through contaminated aerosolized water droplets is known as:_______.
Streptococcus infection carries all the symptoms mentioned.
Explanation:Streptococcus pneumoniae and Diplococcus pneumoniae are the organisms that gram positive bacteria. These bacteria enters the respiratory system from droplet method propagation which is through aerosol or water droplet inhalation which are infected with these bacteria. These bacteria leads to the severe antigen antibody reaction inside lungs which leads to high rate of mucous secretion. This leads to formation of pneumonia.
These bacteria are mainly seen in tropical countries with warm climate and humid environment. These bacteria doesn't spread through contagious methods like touching. But the protection must be taken as these patients cough can contain lakhs of these bacteria which are enough to infect a healthy individual.
Legionella infection
Explanation:
Legionella genus of bacteria are pathogenic gram-negative bacteria. The species Legionella pneumphila causes legionella infection which leads to legionellosis.
Legionellosis includes both the flu-like Pontiac disease as well as the acute highly severe pneumonia called the Legionnaires.
Legionellosis occurs when water droplets or aerosolized water contaminated with Legionella species is inhaled. These bacteria mostly are present in aquatic environment and can thrive and survive in water with warm temperatures.
Legionella infections are non-contagious and does not spread from person to person but only spreads through inhalation of contaminated water droplets.
Legionnaires causes lung inflammation and severe pneumonia and if untreated can also be fatal
.
Why is your respiratory system necessary for your body to live
Answer:
The respiratory system is necessary for an organism's body to live because it introduces oxygen-rich air, which is needed to perform vital functions, while at the same time promoting the elimination of carbon dioxide.
Explanation:
Oxygen (O₂) is necessary for life because it participates in the process of cellular respiration, a mechanism that allows the oxidation of glucose to form energy in the form of ATP.
The respiratory system is made up of a set of organs that carry air into the body and facilitate gas exchange, i.e. the entry of O₂ into the blood and the elimination of potentially harmful carbon dioxide (CO₂).
This exchange of gases occurs in structures called pulmonary alveoli, whose surface is located in relation to the pulmonary capillary vessels.
The entry of air into the lungs brings O₂ to the alveoli, which will diffuse into the pulmonary capillary for the process of hematosis or oxygenation of the blood. CO₂, a product of metabolism, leaves the capillary to the alveoli, to join the air that will be expelled during expiration.Both O₂ and CO₂ require a transport molecule in the blood, red blood cell hemoglobin, which binds the gases and allows them to be transported to and from the tissues.
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Because the Respiratory System is VERY necessary for you to live because your Respiratory System is what makes your Able to BREATH... Without The Respiratory System you Will DIE! ...
During the conversion of glucose into a free form of energy only a small percentage is converted into useable ATP. What is the rest of the energy converted into?
Explanation:
ATP, or adenosine triphosphate, is synthetic vitality the cell can utilize. The particle gives vitality to your cells to perform work, for example, moving your muscles as you stroll down the street.When ATP is separated into ADP (adenosine diphosphate) and inorganic phosphate, vitality is discharged. ATP is converted into ADP which can be recycled back into ATP Is Converted into A waste product that The cell excretes ATP Is broken down into its individual parts and would need to be re-made Through metabolism to be used again. At the point when one phosphate bunch is expelled by breaking a phosphoanhydride bond in a procedure called hydrolysis, vitality is discharged, and ATP is changed over to adenosine diphosphate (ADP). ATP works as the vitality cash for cells. It permits the cell to store vitality quickly and transport it inside the cell to help endergonic concoction reactions.As ATP is utilized for vitality, a phosphate gathering or two are withdrawn, and either ADP or AMP is created.During the conversion of glucose into useable energy through cellular respiration, only a portion of the energy is converted into ATP, while the majority (approximately 60%) is converted into heat, which maintains our body temperature.
Explanation:During the conversion of glucose into a form of usable energy, which is the process of cellular respiration in our bodies, only a portion of this energy (about 40%) is converted into ATP (adenosine triphosphate). The rest of this energy (approximately 60%) is converted into heat.
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A new microorganism has been isolated from hot springs in Yellowstone National Park. It consists of single cells, which appear to lack a nucleus. Chemical analysis shows the presence of both DNA and RNA in the cytoplasm and peptidoglycan in the cell wall. In which of the following groups will this organism be classified?a. Fungi
b. Bacteria
c. Archaea
d. Protists
e. Plants
Answer: B- Bacteria
Explanation: Bacteria are infinitesimal organisms that have single cells that grow in different atmospheres. They have an easily understood inside arrangement. Their cells are normally surrounded by two shielding coverings which are an external cell continuous vertical structure and a cell pliable sheet-like structure acting as a boundary inside. However, some bacteria do have a third shielding sheet furthest from the center named the capsule.
Answer:
b. Bacteria
Explanation:
Bacterias have following characteristics :
Simplest organisms with a very small size.Lack membrane bound organellesUnicellularLack nucleus and contain genetic information in a circular loop called plasmid.Cell wall contains peptidoglycanContains both DNA and RNA.Hence option b) Bacteria is the right option,
It cannot be fungi because their cell wals contain chitin. It cannot be arcahe, protists or plants because all of them have a nucleus.
_____ grow and turn into very large fatty foam cells, which stimulate smooth muscle cells from the middle layer of the arterial wall to migrate to and congregate at the site, causing atherosclerotic plaque to form inside the vascular wall.
Explanation:
Cholesterol is a fat like waxy substance which is present in all the cells in our body.
Cholesterol is required by our body to make vitamin D, hormones and the substances which help us to digest our food. Our body makes all the cholesterol that we require.
For adults, the cholesterol level less than 200mg/dl are considered desirable.
Imagine a poison was ingested that destroyed the hypothalamic cells that produce TRH (thyroid-releasing hormone). The effects on the anterior pituitary and thyroid glands would result in
The release of thyroid stimulating hormone i.e. TSH from the anterior pituitary will be decreased and in turn thyroid glands will not release thyroxine in adequate amounts.
Explanation:
Hypothalamus secretes certain hormones that triggers the release of certain hormones from the pituitary glands. Among these hypothalamic hormones , Thyrotropin releasing hormone (TRH) is responsible for stimulating the release of TSH and prolactin from anterior pituitary. If hypothalamic cells are damaged ,TRH will not be released and thus TSH and thyroid hormone secretion will also decrease.
A sarcomere is best described as ______. Multiple Choice a group of fascicles a group of myofibrils a contractile unit within a myofibril a part of the sarcoplasmic reticulum
Answer:
Arrangement of the actin and Myosin filament
Explanation:
SACROMERE :An elastic membrane which serves for the *arrangement of the actin and myosin filament *
The fasciculi consist of still smaller bundles of elongated, cylindrical muscle cells, the fibre. Each fibre is a syncytium, i. e, has many nuclei. With the aid of an electron microscope, it can be seen that the muscle fibre is made up of smaller units, the myofibrils. Each myofibrils consists of small protein filaments known as *ACTIN and MYOSIN* filaments. The myosin filaments are slightly thicker and make up the darkband(or A-band). The actin filaments make up the light bands(I-band) which are situated on either side of the dark band. The actin filaments are attached to the Z-line.
During the contractions of skeletal muscle, the actin filaments slide inwards between the myosin filaments. Mitochondria provides the energy for this to take place. This action causes the shortening of the sacromeres(Z-lines move closer together, which in turn causes the whole muscle fibre to contract.This can bring shortening of the entire muscle such as biceps, depending on the number of muscle fibres that were stipulated. The contraction of the skeletal muscle is very quick and forceful.
A sarcomere is a contractile unit within a myofibril, making it the smallest contractile part of a muscle. It's responsible for the striated appearance of skeletal muscle. Its contraction leads to the overall contraction of the muscle cell.
Explanation:A sarcomere can be best described as a contractile unit within a myofibril. The sarcomere, composed of thick and thin filaments, is the smallest contractile portion of a muscle. It's positioned between two Z-lines in a myofibril, giving the muscle its characteristic striated appearance. Thin filaments are primarily composed of the protein actin, coupled with regulatory proteins troponin and tropomyosin. Thick filaments, on the other hand, contain the protein myosin.
Moreover, multiple sarcomeres make up the entirety of a myofibril which runs along the muscle fiber. The contraction of the myofibrils leads to the contraction of the entire muscle cell. Thus, the sarcomere plays a critical role in the functioning of muscle fibers.
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The "diving response" of the human body refers to the typical reaction of a person who submerges his/her face in cold water and is most characterized by...
Explanation:
The plunging reaction in human beings is described by breath-holding, easing back of the pulse (jumping bradycardia), decrease of appendage blood stream and a continuous ascent in the mean blood vessel circulatory strain. The bradycardia results from expanded parasympathetic upgrade to the cardiovascular pacemaker. Hydrostatic weight on the outside of the body because of head out drenching in water causes negative weight breathing which movements blood into the intrathoracic circulation.In an important experiment, radioactively labeled bacteriophages were allowed to infect bacteria. In the first trial, the phages contained radioactive DNA, and radioactivity was detected in the bacteria. Next, other phages containing radioactive protein were allowed to infect bacteria, and radioactivity was not detected in the bacteria. These experiments led to the conclusion that __________.
Answer:
In an important experiment, radioactively labeled bacteriophages were allowed to infect bacteria. In the first trial, the phages contained radioactive DNA, and radioactivity was detected in the bacteria. Next, other phages containing radioactive protein were allowed to infect bacteria, and radioactivity was not detected in the bacteria. These experiments led to the conclusion that genes of phage are made of DNA.
Explanation:
Bacteriophages are the viruses which infect the bacteria. They bind to the surface of bacteria and inject the inner core and genetic material in the bacteria.
As in the first trial, the phages contained radioactive DNA, and radioactivity was detected in bacteria, it clearly shows that genes of phage are made of DNA. While, on the other hand,other phages containing radioactive protein were allowed to infect bacteria, and radioactivity was not detected in the bacteria clearly indicating that protiens are not entering the bacteria.
Answer:
The correct answer is: the genetic material of the phage is DNA.
Explanation:
In the experiments performed, the phages from the first trial contained radioactive DNA, while the phages from the second trial contained radioactive protein. If radioactivity was only detected in the bacteria that was infected by the phages from the first trial, but not in the bacteria from the second trial, the only possible explanation is that the genes in the bacteriophages were made of DNA much like the genes in bacteria.
Please help me help with some of my Botany questions!
7. If the leptoids of mosses were found to contain a protein whose gene had the same nucleotide sequence as the gene that codes for P-protein, would that be significant evidence for either the homology or analogy of leptoids and phloem?
8. You will see sporophytes only if you examine mosses closely. They look like green or brown “__________” standing up on the green gametophyte, but sporophytes are (circle one: present almost all the time, only present at certain times of the year).
9. Do mosses have an alternation of isomorphic or heteromorphic generations? That is, can you easily tell a moss gametophyte from a moss sporophyte? When we look at leafy green moss plants, what are we seeing---the gametophyte or the sporophyte? In a flowering plant species, would the equivalent stage be the plant or the pollen grains and megagametophytes?
10. The leafy, green moss plants that are so familiar are gametophytes, haploid plants. This is very different from flowering plants and other seed plants. Does leafy green moss plant grow from a spore or from a fertilized egg? Does the moss plant have both a paternal parent and a maternal parent?
11. Draw a single moss plant, similar to the one in Figure 20-10. Be certain to show the gametophyte and the sporophyte. Now draw one without the sporophyte, showing only the gametophyte. The sporophytes usually have only a very brief life, and after they shed their spores, the gametophytes let them die.
12. Draw and label the life cycle of a moss, be certain to show gametangia and sporangia. Which parents are haploid and which are diploid? Where and when does meiosis occur? Plasmogamy? Karyogamy?
13. In the majority of mosses, which lack hydroids and leptoids, water is conducted along the __________ of the plant by __________ action.
14. The leafy, green moss plants being gametophytes have gametangia, structures that produce gametes. What is the name of the gametangium that produces sperm cells? The gametangium that produces egg cells? Can one single moss gametophyte bear both of these? Do some species have plants that produce only egg cells?
15. The sporophyte of a moss usually has a stalk called a __________ and a simple apical sporangium called a __________.
16. Many people often think of mosses as plants adapted to rainy areas, areas that are usually wet. Are any mosses adapted to deserts? Can some mosses lose much of their water---the way a seed does before being planted---and still survive?
If the nucleotide sequence of the gene in moss leptoids matches that of the P-protein gene, it provides significant evidence for the homology of leptoids and phloem. Mosses have an alternation of generations, with the leafy green moss plant being the gametophyte and the sporophyte being a brief stage in their lifecycle. The moss plant grows from a spore and only has a maternal parent.
Explanation:If the leptoids of mosses were found to contain a protein whose gene had the same nucleotide sequence as the gene that codes for P-protein, it would be significant evidence for the homology of leptoids and phloem. Homology refers to the similarity between structures or genes in different organisms due to their common ancestry. The presence of the same gene sequence suggests that leptoids and phloem have a shared evolutionary history.
Mosses have an alternation of generations where both the gametophyte and the sporophyte stages are present. The gametophyte is the leafy, green moss plant that we see, while the sporophyte is the tiny stalk-like structure that grows on the gametophyte. In a flowering plant, the equivalent stage would be the plant itself, not the pollen grains and megagametophytes.
The leafy, green moss plant grows from a spore, not from a fertilized egg. It only has a maternal parent and does not have a paternal parent.
When individuals of the same species are reproductively isolated, genetic differences may accumulate in sufficient number so that new species could emerge. What would such an event be an example of:__________
Answer:
macroevolution
Explanation:
Macroevolution is said to be the evolutionary changes that occur on a larger scale beyond a single species as a result of evolutionary forces such as mutation, gene flow, genetic drift. Macroevolution, unlike microevolution, usually results into the emergence of two new species with pronounced changes. The event as illustrated in the question is an example of macroevolution.
Which of the following is the correct description of a myocardial infarction and what it is caused by? View Available Hint(s) Which of the following is the correct description of a myocardial infarction and what it is caused by? A region of heart muscle dies due to a lack of glucose supply. A region of heart muscle becomes overly active. A region of heart muscle dies due to a lack of blood supply. A region of muscle becomes inactive due to a lack of neuronal stimulation.
Explanation:
Heart is one of the most essential organ in the human body as it is responsible for supplying nutrients and oxygen to all the parts of the body and collecting waste materials and carbon dioxide from all the parts of the body through the blood.The cells (fibroblasts, cardiomyocytes, etc.) of the heart itself are provided with the nutrients and oxygen by a specialized blood vessel called the Coronary Artery.Waste materials and carbon dioxide are removed from the cells of the heart by another specialized blood vessel called the Coronary Vein.Due to aging or consumption of excess fat and cholesterol rich food, the concentration of lipid molecules in blood get increased beyond normal. These lipid molecules get deposited in the walls of the arteries, including the coronary artery, forming plaques, resulting in the development of atherosclerosis.This reduces the diameter of the arteries, including the coronary artery, thereby reducing the blood flow through them.Due to plaque deposition, the coronary artery is incapable for carrying sufficient oxygen and nutrients to the heart cells, causing their death.This results in the development of a sharp pain in the chest that is diagnosed as Heart Attack or Myocardial Infarction.