When curare, a neuromuscular poison, is dropped onto an isolated muscle-nerve preparation in a laboratory, the muscle does not contract when the nerve is stimulated, even though neurotransmitter is released from the nerve cell. Why does this happen

Answers

Answer 1

Answer:

Explanation:

Whenever the nerve terminal's action potential depolarizes, calcium enters the cell through the channels. Calcium allows acetylcholine (ACh) to be released more easily.  These ACh molecules subsequently circulate into the synaptic cleft and attach to the motor end-plate of the nicotinic cholinergic receptors. Acetylcholine molecules connect to nicotine ion-channel receptors present on cell membrane the of muscle cells, enabling the ion channels to open. Calcium ions then enter the muscle cell, kicking off a series of events that eventually result in muscular contraction.

Curare is a kind of neuromuscular relaxant blocker that is non-depolarized in nature. Nondepolarizing muscle relaxants work as competitive agonists, binding to ACh receptors but failing to activate ion channels. As a result, they inhibit ACh from bonding, preventing the development of endplate potentials and inducing muscle paralysis.


Related Questions

a phlebotomy technician has collected a neonatal screening card. which of the following actions should the technician take to properly dry the blood stop collection card?

Answers

Answer:

place the card on a flat dry surface

How do organisms have a negative impact on the water cycle? And how can they affect other organisms with your answer? Please help.

Answers

Too much of one organism can cause an imbalance in the habitat because of its niche occupation

This mountain slope towers over a town several hundred feet below. Which two weather events present the highest risk to the town

Answers

avalanche or rock slide

Complete each sentence with the correct word or phrase

a. An action potential reaches the axon terminal causing __________to open.
b. Acetylcholine diffuses across the synaptic cleft before binding to its receptor, which is located on the _____
c. When the membrane potential reaches ________an action potential spreads across the sarcolemma due to the opening of ___________
d. In response to acetylcholine binding, ________ move into the muscle fiber causing the membrane potential to rise.

Answers

Answer:

a). Voltage-gated Ca2+ channels

b). the motor end plate

c). Threshold, voltage-gated Na channels

d). sodium ions

Explanation:

a). The voltage-gated [tex]Ca^{2+}[/tex] channels are the key transducers of the membrane potential that changes into a intracellular [tex]Ca^{2+}[/tex] transients which initiates the  physiological events. When the action potential makes a contact with axon terminal, the voltage-gated [tex]Ca^{2+}[/tex] channels opens.

b). The acetylcholine is the main neurotransmitter of the parasympathetic nervous system. It helps in blood vessels dilation, muscle contraction, and perform many more functions.

It diffuses with the synaptic cleft that is located on the motor end plate of the nervous system.

c). The membrane potential is also known as the membrane voltage or the  transmembrane potential. When it recaches the threshold, the  voltage-gated Na channels opens to spread the action potential across sarcolemma.

d). The sodium ions in case of acetylcholine binding moves to the muscle fiber due to which the membrane potential rises.

Critical thinking is the ability to reason and solve problems using facts and concepts. These questions can be approached from a number of angles, and in most cases, they do not have a single correct answer.
Give the common name of a eukaryotic microbe that is unicellular, walled, nonphotosynthetic, nonmotile, and bud-forming.

Answers

Answer:

Yeast

Explanation:

The correct answer would be yeast.

Yeast belongs to the fungi kingdom. Organisms in the fungi kingdom are generally eukaryotic in that their cells contain a nucleus and membrane-bound organelles such as mitochondrion. Fungal cells lack chlorophyll and are therefore nonphotosynthetic. They are also nonmotile

While fungi exhibit different body forms in terms of body complexity, the only unicellular form is yeast. The organism possesses all the attributes of fungi highlighted above, has a cell wall made largely of chitin, and reproduces through budding.

Answer: Yeast.

Explanation:

Yeasts are eukaryotic organisms, more precisely microscopic fungi that do not form filamentous networks (hyphae), classified as ascomycetes or basidiomycetes and are predominantly unicellular in their life cycle. The cell wall of yeasts is composed of complex "B"-glucan polysaccharides, mannoproteins and chitin. Also, yeast are non-motile organisms when they grownon a solid media.

They usually reproduce asexually by budding or bipartition and by having sexual stages that are not attached to a sporocarp (fruiting body). During asexual reproduction, a new bud emerges from the mother yeast when suitable conditions are met, after which the bud separates from the mother upon reaching adult size. In the case that they reproduce sexually, this occurs by means of ascospores or basidiospores. In conditions of nutrient scarcity, yeasts that are able to reproduce sexually will form ascospores.

Yeasts are important because of their ability to carry out the decomposition by fermentation (predominantly alcoholic) of various organic compounds, mainly sugars or carbohydrates, producing different substances. Therefore, they do not photosynthesize to obtain energy, since they do not possess chlorophyll (pigment responsible for capturing solar energy for photosynthesis).

3. DNA and Protein similarities are often used for molecular evidence of evolution. What is being compared to show relatedness among species? Explain how this works.​

Answers

Answer:

The sharing of common ancestors

•. What is the phenotypic ratio of complementary gene?
a) 1:2:1
b) 9:7
c) 13:3
d) 9:3:3:1​

Answers

I think the answer is b

Consider the factors that affect muscular strength. Read each scenario and then identify each label into the appropriate category based on whether each would result in a stronger or weaker muscle contraction.

a. Potassium accumulate in the sarcoplasm
b. Increase in muscle belly circumference
c. Lesser proportion of motor neurons to muscle fibres
d. Begin contractions with muscle already 50% contraction
e. Lower sarcoplasm pH
f. Increased stimulus frequency.
g. Circular arrangement of muscle fascicles
h. increased requirement.

Answers

Answer:

1. Weaker contraction:

a. Potassium accumulate in the sarcoplasm

d. Begin contractions with muscle already 50% contraction

e. Lower sarcoplasm pH

g. Circular arrangement of muscle fascicles

2. Stronger Contraction

b. Increase in muscle belly circumference

c. Lesser proportion of motor neurons to muscle fibres

f. Increased stimulus frequency.

h. increased requirement.

Explanation:

Sarcoplasm refers to the cytoplasm of muscle cells which contains ATP, enzymes, and a variety of ions, including potassium (K+). The negative potential required during muscle activity is produced from the disequilibrium of ionic concentrations (mostly Na+ and K+) across the membrane, which is generated through Na+/K+ ATPase pumps. During contraction, a muscle shortens, and thus its circumference increases. The generation of lactic acid is known to lower pH in the sarcoplasm and thus hinder the force and power development of the muscle fibers. Muscle fascicles can be arranged in concentric rings, it is a common pattern in sphincter muscles that modulate the opening and closing of orifices (which have weak contractions). A motor unit refers to a single efferent neuron and all of the muscle fibers it modulates. Each individual muscle fiber is innervated by one motor neuron, whereas a single motor neuron can innervate many muscle fibers. Finally, higher intensity/frequency are known to induce stronger muscular contractions, but also produce a stronger decline in force and cause more rapid muscle fatigue.

At her initial evaluation, Ms. Jones reports that she has lost 25 pounds over the past eight months despite an increase in her appetite. She complains of extreme fatigue, heart palpitations and irritability. Clinical observations reveal a protrusion of the eyeballs and hand tremors. You suspect that she might have:

a. hypothyroidism
b. diabetes mellitus
c. hypopituitarism
d. hyperthyroidism

Answers

Answer:

d. hyperthyroidism

Explanation:

Hyperthyroidism is a condition that occurs when the thyroid gland in our body secretes too much of the thyroxin hormone. Thyroid gland is a butterfly shaped gland that is located in our neck and it produces the hormone called thyroxin. Excess production of thyroxin leads to a condition named hyperthyroidism.

A person's metabolism increases when he or she is suffering from hyperthyroidism. One's weight is lost but the appetite increases. Other symptoms are extreme fatigue, irritability, heart palpitations, sweating and puffy eyes.

Thus in the context, Ms. Jones is suspect to have hyperthyroidism as she she is showing all the above symptoms.

Birds differ from their closest relatives, the reptiles, in what ways?
(choose all that apply)
the bones of reptiles are too lightweight to permit flight
birds are capable of powered flight, while some reptiles can glide
birds have feathers, reptiles have scales
only the birds lay eggs on land; the reptiles can only lay their eggs in water
the reptiles have a series of internal air sacs that allow a very efficient extraction of oxygen
birds are endothermic, while reptiles are generally ectothermic
1 pts

Answers

Answer:

birds have feathers, reptiles have scales

birds are endothermic, while reptiles are generally ectothermic

Explanation:

The main difference between birds and reptiles  is that birds have feathers on their body while on the other hand, reptiles ahve dry skin and have scales. Reptiles are ectotherms, while birds are endotherms. An ectotherm relies on its external environment to regulate the temperature of its body whereas Endotherms are able to regulate their body temperatures by producing heat within the body.

Without replication, organisms could not successfully


move.

grow and reproduce.

feed.

make proteins.

Answers

Answer: grow and reproduce

Explanation:

The number of organisms that an area of land can sustain over a long period time is known as

Answers

Answer:

Carrying Capacity

Explanation:

……………,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

Answers

Answer:

these r so many which one?

Explanation:

Dehydration synthesis leads to WICH formation

Answers

Answer:

Polymers...........

Explanation:

Two different enzymes catalyze the same reaction and both exhibit the same Vmax. When Enzyme A was run with a 40 uM substrate, the initial rate (Vo) was 10 uM/min, and when g it was run with a 4 mM substrate, the Vo was 20 uM/min. Estimate the approximate Vmax and Km of Enzyme A. When Enzyme B was run with 80 uM substrate, the initial rate (Vo) was 10 uM per minute. Estimate the Km of Enzyme B.

Answers

Answer:

a) k_m = 4.08 uM

  V_{max} = 20.07 uM/min

b) k_m = 8.16 uM

Explanation:

Given that:

For Enzyme A:

the substrate concentration [S] = 40 uM

the initial velocity rate v = 10 uM/min

when it was 4mM, v = 20 uM/min

i.e.

at 4mM = 4000 uM;

Using Michealis -menten equation;

when v = 10

[tex]V = \dfrac{V_{max}[S]}{k_m+[S]}[/tex]

[tex]10 = \dfrac{V_{max}\times 40}{k_m + 40}[/tex]

[tex]10 (k_m + 40) = V_{max}40[/tex]

[tex]40V_{max} -10k_m = 400 --- (1)[/tex]

when v= 20

[tex]20= \dfrac{V_{max}\times 4000}{k_m + 4000}[/tex]

[tex]20 (k_m + 4000) = V_{max}4000[/tex]

[tex]4000V_{max} -20k_m = 8000 --- (2)[/tex]

equating equation (1) and (2):

[tex]40V_{max} -10k_m = 400 --- (1)[/tex]

[tex]4000V_{max} -20k_m = 8000 --- (2)[/tex]

let multiply equation (1) by 100 and equation (2) by 1

4000V_{max} - 1000K_m = 4000

4000V_{max} - 20 k_m = 8000    

  0        -980k_m = 4000

k_m = 4000/-980

k_m = 4.08 uM

replacing the value of k_m into equation (1)

40{V_max } - 10(4.08) = 400

40{V_max } - 40.8 = 400

40{V_max } = 400 +  40.8

40{V_max } = 440.8

V_{max} = 440.8/40

V_{max} = 11.02 uM/min

b)

Since V_{max} of A ie equivalent to that of B; then:

V_{max} of B = 11.02 uM/min

Here;

[S] = 80  uM

V = 10 uM/min

[tex]10 = \dfrac{11.02 \times 80}{k_m + 80 }[/tex]

10(k_m +80) = 881.6

10k_m = 881.6  - 800

10k_m = 81.6

k_m = 81.6/10

k_m = 8.16 uM

14. What do the embryos of different vertebrate species have in common?​

Answers

Answer:

Similarities in embryos are evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails. Most vertebrates, except for fish, lose their gill slits by adulthood.

Explanation:

itz from gologolo lol I hope it helps uh

keep smiling #smilies

What is a plant nucleus

Answers

Answer:

All plant cells contain a nucleus, a structure that stores DNA and acts as a cell's command center. It is surrounded by the nuclear envelope and is filled with nucleoplasm. ... DNA is copied during DNA replication for new cells, as well as copied to RNA to make proteins in the nucleus.

Describe the biome in which you currently live, or one in which you want to live, or have lived. What are the atmospheric conditions (wind pattern, humidity level, etc), solar intensity, and geographic/oceanographic features that have produced this unique ecosystem

Answers

Answer:

Southern Texas

Explanation:

The Wind pattern often is represented by the westerlies, which are the winds that flow in the northern latitude of the world. The humidity level in this zone varies from 10-20%, since we are in the desert we do not have much humidity, the solar intensity is high, often found in the 9-10 uv range, it is not advised to spend more than 10 minutes on direct sun without solar protection.  We have the Rio Grande to the south and some spare mountains.

Answer:

Southern Texas

Explanation:

Explain the role of enzymes to living organisms

Answers

Explanation:

enzymes create chemical reaction in the body.But they actually speed up the rate of chemical reaction to help support life.. Enzymes is important to our body as it supports in building muscles and destroying toxins..

Enzymes create chemical reactions in the body. They actually speed up the rate of a chemical reaction to help support life. The enzymes in your body help to perform very important tasks. These include building muscle, destroying toxins, and breaking down food particles during digestion.

which organism in the food web might be found in the first tropic level of a food chain
cougar
mouse
acorns
coyote

Answers

Answer:

Acorns would be found at the first trophic level of a food chain.

Explanation:

Comb jellies are:____.
A. Bilaterally symmetrical.
B. Similar to a cnidarian polyp.
C. Distinguished by eight bands of cilia.
D. Colonial animals.
E. Carnivores that use nematocysts to capture prey.

Answers

Answer:

C. Distinguished by eight bands of cilia.

Explanation:

Ctenophora, also known as comb jellies, represents a phylum of transparent, mostly pelagic, invertebrate marine animals that live around the world. This group characterized by eight rows of cilia (singular cilium) that are used for locomotion. Cilia are organelles and/or structures that extend from the surface of eukaryotic cells, which can be used to move the surrounding fluid, resulting in cell movement. This phylum is divided into two classes: Tentaculata (with tentacles) and Nuda (without tentacles).

The Earth and the moon are kept in orbit by gravity and mass. Please select the best answer from the choices provided T F

Answers

Answer:

True

Explanation:

the Earth and the Moon are kept in orbit by gravity and mass.

Answer:

True (T)

Explanation:

Yeah, the Earth and the moon are kept in orbit by gravity and mass. Hence, this statement is True (correct).

What is the complimentary dna strand for TCTTAAATGATCGAT

Answers

Answer:

AGAATTTACTAGCTA

Explanation:

The DNA strand pairs are:

Adenine (A) -- Thymine (T)

Cytosine (C) -- Guanine (G)

and vice versa.

The given strand:

TCTTAAATGATCGAT

Based on the given pairs above, your answer will be:

AGAATTTACTAGCTA

~

Over the past few hundred years, the human population on Earth has

Answers

Answer:

7.9 billion

in June 2021 to the United nations Estimated elaborted by worldmeter.

High altitude adaptation is a complex physiological process that involves an increase in both the number of Hb molecules per erythrocyte and the total number of erythrocytes. It normally requires several weeks to complete. However, even after one day at high altitude, there is a significant degree of adaptation. This effect results from a rapid increase in the erythrocyte BPG concentration.


a. Try to do this without looking at the graphs. If oxygen-binding curves for both high altitude adapted hemoglobin and normal, unadapted Hb were plotted together, would the curve for high altitude adapted Hb be to the left of, to the right of or the same as the curve for unadapted Hb? Explain.
b. Is the oxygen binding affinity of high-altitude adapted Hb higher, lower, or the same as that of unadapted Hb? Explain.

Answers

Answer:

a. To the right

b. higher

Explanation:

From the information given:

a.

The oxygen-adsorption curve of the elevated high altitude modified the hemoglobin and this will move to the right because there is a reduced amount of oxygen available at high altitude, as well as an increase in carbon dioxide and H+ ion concentration, temperature, and all of which raise pH and shifts the curve towards the right.

b.

As there is a low relative partial pressure of oxygen at high altitude, the oxygen-binding attraction of high altitude adaptable hemoglobin is greater and higher than that of unadapted hemoglobin under pulmonary oxygen loading. This is important to optimize the oxygen concentration levels in blood circulation and blood tissues.

What is the role of RNA?

Answers

Answer:

It is the 1st one ○ to provide the original blueprint for protein production

Explanation:

RNA polymerase (green) synthesizes RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription.

ba kiểu truyền tín hiệu của tế baò

Answers

Repost it in English please

what will most likely happen if a population is large and no migration, mutation, or environmental change occurs?
1. natural selection will increase
2. nonrandom mating will start to occur
3. the rate of evolution will increase
4. gene frequencies will remain constant

Answers

4. Gene frequencies will remain constant

In a Nitrogen metabolism study, the following data were obtained over the test period:

Nitrogen consumed 175 grams
Total Fecal N 35 grams
Metabolic Fecal N 10 grams
Total Urinary N 80 grams
Endogenous Urinary N 10 grams

Calculate:
a. Apparent Nitrogen digestibility (%)
b. True Nitrogen digestibility (%)
c. Nitrogen Balance (g)
d. Apparent Nitrogen Retention (%)

Answers

Answer:

a. 80%

b. 86%

c. 60 g

d. 34.29%

Explanation:

From the given information:

The apparent nitrogen digestibility (AD) is the ratio of the difference between the consumed nitrogen and fecal nitrogen to the consumed nitrogen.

Mathematically:

[tex]AD = \dfrac{consumed \ nitrogen - fecal \ nitrogen }{consumed \ nitrogen }[/tex]

[tex]AD = \dfrac{175 -35 }{175}[/tex]

AD = 0.8

To percentage, the apparent Nitrogen digestibility = 80%

b. True Nitrogen digestibility is calculated by the formula:

[tex]=\dfrac{consumed \ nitrogen - (fecal \ nitrogen -metabolic \ fecal)}{consumed \ nitrogen}[/tex]

[tex]= \dfrac{175 -(35-10)}{175}[/tex]

[tex]= \dfrac{175 -25}{175}[/tex]

= 0.86

= 86%

c. Nitrogen Balance = consumed Nitrogen - Fecal nitrogen - total uninary

Nitrogen Balance = (175 - 35 - 80) grams

Nitrogen Balance = 60 g

d. Apparent Nitrogen Retention (ANR) is computed as follows:

[tex]ANR = \dfrac{(consumed \ nitrogen-fecal\ nitrogen - total \ uninary )}{nitrogen \consumed }\times 100\%[/tex]

[tex]ANR = \dfrac{(175-35- 80 )}{175 }\times 100\%[/tex]

[tex]ANR = \dfrac{(60 )}{175 }\times 100\%[/tex]

ANR = 34.29%

Which of the following techniques employs a probe consisting of a labeled, single-stranded DNA of known sequence that can find and bind to a complementary sequence present in a large sample of different DNA sequences?

a. DNA hybridization
b. RFLP
c. PCR
d. DNA sequencing

Answers

Answer:

Explanation:

PCR

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