Excitation of the sarcolemma is coupled or linked to the contraction of a skeletal muscle fiber. what specific event initiates the contraction?
Excitation of the sarcolemma is coupled to the contraction of a skeletal muscle fiber through the release of calcium ions (Ca2+).
Explanation:The specific event that initiates the contraction of a skeletal muscle fiber is the release of calcium ions (Ca2+). When an action potential reaches the neuromuscular junction, it triggers the release of acetylcholine (ACh) into the synaptic cleft. ACh attaches to receptors on the sarcolemma, generating an action potential that spreads along the surface of the muscle fiber and into the transverse tubules. This action potential causes the release of Ca2+ from the sarcoplasmic reticulum, which then binds to the protein troponin, initiating the contraction process.
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Cigarette smoke can affect cell differentiation during embryo development. which birth defect is most likely the effect of exposure to cigarette smoke?
childhood asthma - apex
The thickest sedimentary deposits are found? near land, around the equator or in the middle of the ocean
promineces may be seen in the sun's ___
Prominences may be seen in the sun's corona
when a virus infects a bacterium what does the virus inject into the cell
In cross-fostering studies, the young of one species are placed in the care of adults from another species. in broad terms, what do researchers learn from such studies?
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Which of the following is not true about the group of birth control strategies collectively known as natural family planning?
It requires women to keep close track of their menstrual cycle.
If carefully practiced, it is almost 100 percent effective in preventing pregnancy.
It demands a disciplined focus on bodily changes.
It requires that women refrain from sex on days when they are ovulating.
What are the two major divisions of the overall nervous system?
What is the typical dental formula of catarrhines?
The answer is 2 / 1 / 2 / 3. This means that all of the catarrhines have 2 premolars and 3 molars, making a dental formula of 2.1.2.3. there are also different kind of species called anthropoid has a catarrhine dental formula like chimpanzee, all old world monkeys, apes and even humans.
The catarrhines, including humans, apes, and Old World monkeys, typically have a dental formula of 2-1-2-3, meaning two incisors, one canine, two premolars, and three molars on each side of their jaws.
Explanation:The typical dental formula of catarrhines, a grouping of primates that includes humans, apes, and Old World monkeys, is 2-1-2-3. This means they usually have two incisors, one canine, two premolars, and three molars on each side of their upper and lower jaws. This formula varies somewhat between species, with the primary variation usually being in the number of premolars. For example, in some species of baboons, one of the more common Old World monkey species, the dental formula can sometimes be 2-1-3-3.
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Read the dermatology clinic note below. a skin bx performed in my office confirmed the diagnosis of ak. after explaining the results to mr. johnson, i recommended cryotherapy for the smaller lesions on his arms and dermabrasion for his scalp lesions. i explained to mr. johnson that ak can lead to squamous cell carcinoma and taught him about the risks of sun exposure, including further aks and melanoma. according to the clinic note, which is not true?
Nearly one billion dollars a year are spent on clearing sediment from streams and lakes in the United States.
Which is the most common source of this sediment?
A. productive farmland that is over-irrigated
B. waste dumped by mining industries into the waterways
C. hilly areas where protective vegetation has been removed
Answer: Option C
Explanation: Hills are the most common source of sediments because they lack vegetation. Plants and trees hold the soil and thus prevent erosion of soil layer with water. The sediments from the hilly areas get carried by rain water or runoff, and add to the water bodies, like lakes and streams.
Waste from mining industries don’t have sediments in their waste, so option B is incorrect.
Option A is incorrect because over-irrigation will not affect the soil layer, as it is firmly held by the roots of the crops.
An _________ wave is created when a medium experiences evenly timed disturbances
What law covers all conservation issues in New Zealand?
CERCLA
soil and water resources conservation act<--- i chose
super fund
resource management act
Answer:
Option D, resource management act
Explanation:
In 1991, resource management act was passed in New Zealand, It is the main government legislative document which is referred for formulation of regulation for conservation of environment and natural resources
There are total thirteen regulations with in this legislative which broadly talks about
- Mandatory approvals from authorities for any activity affecting environment
- Approvals from authority to conserve the resources.
- Set of procedure
- Details of form, fees and laws
- Environmental standards for soil, water, air protection and usage
hence, option D is correct.
In the ocean, small remora fish are often found cleaning bacteria and other parasites from the mouths and gills of swordfish. Which of the following phrases best explains this interaction? A. animal affecting the life of an animal B. climate affecting the life of an animal C. plant affecting the life of an animal D. weather affecting the life of an animal
The __________ of the heart rests on the diaphragm, and from its __________, the great vessels emerge (hint: not chambers)
Mammals produce milk to nurse their young. In humans, which hormone controls milk production?
A) estrogens
B) progestogens
C) prolactin
D) testosterone
Answer: C. Prolactin
Prolactin is a hormone that controls milk production together with oxytocin. The anterior lobe of the pituitary gland secretes prolactin and the posterior lobe secretes oxytocin when a baby suckles at the breast. The level of prolactin in the blood slowly increases during pregnancy, and stimulates the growth and development of the mammary tissue, in preparation for the production of milk after delivery.
Moreover, Prolactin is in the highest level in about 30 minutes after the beginning of the feed, which is most important for producing milk for the next feed.
Which is a homologous structure to the human forearm?
Answer: The leg of a horse.
Explanation:
APEX
Why is a transcription and translation so important?
Which best describes nitrogen fixation? Nitrogen fixation is the process of creating free nitrogen for plants to absorb. Nitrogen fixation is the breakdown of nitrogen in the soil. Nitrogen fixation is the conversion of nitrogen gas into a usable form. Nitrogen fixation is the destruction of the bonds between nitrogen and other elements.
Answer:
C. Nitrogen fixation is the conversion of nitrogen gas into a usable form.
Explanation:
The process of assimilation of atmospheric nitrogen into organic compound by some type of micro-organisms is called nitrogen fixation. It is the conversion of nitrogen gas into a usable form for plants and other microbes.
What are the steps in nitrogen cycle?Nitrogen is the most important complex for the environment and is the most abundant gas. Nitrogen fixation is a step by step procedure that involves various steps.
The steps of nitrogen fixation is as follows:
Nitrogen fixation: nitrogen enters soil and surface waters, here it gets converted into two atoms, which combines to form ammonia.Nitrification: The conversion of ammonia into nitrates and nitrites. It involves different kinds of bacteria.Assimilation:The consumption of nitrites and nitrates by plants.Ammonification: it is the release of nitrogen back to organic form by death of plants and animals.Denitrification: The conversion of ammonia back to nitrogen is called as denitrification.Thus, the correct option is C.
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Which trait would most likely lead a scientist to investigate folk remedies of tribes living in the rain forest for new medicines?
openness
curiosity[wrong]
creativity
skepticism
The answer to the question is openess.
Skepticism will lead the scientist with his research.
Scientific skeptics evaluate claims based on verifiability and falsifiability.They discourage accepting claims which rely on faith or anecdotal evidence.What are the skills a scientist should have?Observation.Curiosity. Logic. Creativity. Skepticism.Objectivity. Peer review.To know more about skills here
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The Phanerozoic eon is made up of all of the following except the _______ era.
How does the adrenal gland respond to stress? the adrenal cortex secretes mineralocorticoids and glucocorticoids in response to short-term stress. the adrenal medulla secretes epinephrine and norepinephrine in response to long-term stress. the adrenal cortex secretes epinephrine and norepinephrine in response to short-term stress. the adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress. the adrenal medulla secretes mineralocorticoids and glucocorticoids in response to long-term stress?
The adrenal medulla secretes epinephrine and norepinephrine in response to short-term stress. The adrenal cortex responds to long-term stress by secreting glucocorticoids and mineralocorticoids, which affect various metabolic processes and are necessary for the body to adapt to chronic stress conditions.
The question concerns how the adrenal gland responds to stress. In response to short-term stress, the adrenal medulla secretes epinephrine and norepinephrine, which are hormones that mediate the fight-or-flight response. This process is mediated by the sympathetic nervous system (SNS). On the other hand, the adrenal cortex is responsible for responding to long-term stress by secreting glucocorticoids like cortisol and mineralocorticoids like aldosterone after being stimulated by adrenocorticotropic hormone (ACTH) from the anterior pituitary gland, which is triggered by the hypothalamus.
The corticosteroids released by the adrenal cortex play essential roles, from affecting glucose metabolism and stimulating glucose synthesis to the breakdown of fat into fatty acids in the adipose tissue which are then used for ATP production. Such hormones are necessary for the body's adaptation to long-term stress conditions but should not be used excessively in a medicinal capacity due to potential immune-suppressing effects, such as increased susceptibility to disease.
Based on the results of the feeding experiment, what conclusions can you draw? select all that apply. (for help interpreting the results, see the hints.) roaches ate about the same amount from the dish with no hydramethylnon as they did from the control dish. roaches ate about the same amount from the dish with no oleic acid as they did from the control dish. roaches ate about the same amount from the dish with no corn syrup as they did from the control dish. roaches are refusing hydramethylnon. roaches are refusing oleic acid. roaches are refusing corn syrup.
Answer:
1. The roaches ate about the same amount from the dish without hydramethlynon as they did from the control dish.
2. Roaches ate about the same amount from the dish with no oleic acid as they did from the control dish.
6. Roaches are refusing corn syrup.
Explanation: The cockroaches ate the most bait when it did not have corn syrup in it, and ate very little of any bait that had corn syrup. Further experiments like this one have shown that it is actually the glucose in the corn syrup that the cockroaches detect and refuse.
Final answer:
Conclusions from the feeding experiment indicate that both hydramethylnon and oleic acid act as repellents to cockroaches if they are refusing to eat from dishes containing these substances, while corn syrup is likely an attractant if they eat less from dishes without it.
Explanation:
Based on the results of the feeding experiment, several conclusions can be drawn about cockroach behavior and preferences. If roaches ate about the same amount from the dish with no hydramethylnon as they did from the control dish, it suggests that hydramethylnon is not acting as a deterrent. Similarly, if they ate about the same from the dish with no oleic acid as from the control dish, this indicates that oleic acid is not repelling the roaches. On the other hand, if roaches are refusing to eat from dishes containing hydramethylnon or oleic acid, it shows these substances are effective repellents. Finally, if roaches ate less from the dish without corn syrup compared to the control, it implies that corn syrup is an attractant to cockroaches.
A gas has?
no definite shape or definite volume.
a definite shape but no definite volume.
a definite volume and definite shape.
a definite volume but no definite sh
Answer: The answer would be a
The number of atp produced during aerobic cellular respiration from one glucose molecule is
The failure of which body systems can cause an immediate problem
Answer:
Nervous system
Explanation:
Nervous system is the set formed by connections of nerves and organs of the body, with the function of capturing information, messages and other external stimuli, as well as answering them, besides being responsible for commanding the execution of all body movements. , whether they are voluntary or involuntary.
Which description of synapses is not correct? which description of synapses is not correct? second messengers can activate gene activities in the postsynaptic neuron. excitatory synapses cause depolarization. direct signaling involves the activation of g proteins. ionotropic receptors are ion channels that open and influence the polarization of the membrane?
Synapses are specialized junctions between neurons that allow for communication and transmission of signals in the nervous system. The description of synapses that is not correct is "Second messengers can activate gene activities in the postsynaptic neuron."
While three of the given descriptions of synapses are accurate, the statement that second messengers can activate gene activities in the postsynaptic neuron is not correct. Second messengers, such as cyclic AMP or calcium ions, play important roles in intracellular signaling and can modulate various cellular processes.
However, they do not directly activate gene activities. Gene activities in the postsynaptic neuron are regulated through complex processes involving transcription factors, DNA binding, and gene expression. Second messengers primarily participate in modulating intracellular signaling cascades and enzyme activities rather than directly influencing gene activities at the synapse.
While second messengers can play a role in intracellular signaling and modulating various cellular processes, including gene expression, they do not directly activate gene activities in the postsynaptic neuron at the synapse. Gene activities are typically regulated by transcription factors and complex cellular mechanisms, not directly by second messengers at the synapse.
Therefore, the description of synapses that is not correct is "Second messengers can activate gene activities in the postsynaptic neuron."
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What were the 4 scenarios of griffiths experiment?
Griffith's experiment was an experiment performed in 1928 by Frederick Griffith. It was one of the initial experiments demonstrating that bacteria can get DNA via a process known as transformation. Griffith used two strains of Streptococcus pneumoniae. These bacteria manifested mice.
Eighty-nine percent of illnesses among children in child care settings are attributed to which of the following
When muscle cells have more glucose than they need for energy, they may store some of the excess as?
Answer:
The answer is glycogen.
Explanation:
Glycogen is a polysaccharide of glucose that serves as a store of energy for muscle cells in animals and fungus.
Muscle glycogen turns into glucose in muscle cells and also in the liver is turned to glucose to assist the whole body including the central nervous system, which is the brain and the spinal cord.
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