Which of the following statements correctly describes why a series of closely spaced action potentials causes a sustained contraction rather than a series of closely spaced twitches?a. Ca2+ ions are released quickly from troponin, keeping the Ca2+ concentration in the cytosol high between closely spaced action potentials.
b. Release of Ca2+ from the sarcoplasmic reticulum through channels is slow compared to the uptake of Ca2+ into the SR via ATP-dependent pumps, resulting in Ca2+ slowly trickling into the sarcomeres between closely spaced action potentials.
c. When a series of action potentials is closely spaced, there is not sufficient time for Ca2+ uptake into the sarcoplasmic reticulum between action potentials, and Ca2+ remains bound to troponin throughout the series.
d. Fewer Ca2+ ions are released from the sarcoplasmic reticulum as a result of several closely spaced action potentials than as a result of a single action potential.

Answers

Answer 1

Answer:

Answer:

The correct answer is - option C.

Explanation:

A series of closely spaced action potentials cause the sustained muscle to contract which is only possible if in the sarcomere of muscles the has high Ca2+ during the complete contraction cycle.

If the Ca2+ level is lower due to the sufficient Ca2+ were taken up into the sarcoplasmic reticulum in the sarcomere below the range between each action potential, the muscle would relax because the myosin-binding sites will be covered by tropomyosin.

The Ca2+ channels in the SR are able to move the ions more rapidly than the Ca2+ pumps can move in SR so this will cause the concentration of calcium to always high which leads to the binding of tropomyosin and therefore, the myosin-binding sites would be exposed until the contraction is achieved.

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A. integumentary, respiratory, digestiveB. Circulatory, respiratory, nervousC. Integumentary, nervous, muscularD. Circulatory, digestive, nervous
9. The blood pressure of a soldier is measured while he is resting. The soldier is then exposed to a stressful environment and his blood pressure is measured again.
Classify each phrase as describing a competitive inhibitor, uncompetitive inhibitor, or mixed (mixed noncompetitive) inhibitor. Note that K m refers to apparent K m .

Where does the RNA cap go? The tail?

Answers

Answer:

The post-transcriptional modifications in the mRNA produced as a result of the transcription in eukaryotes provide many advantages to the mRNA.

The two post-transcriptional modifications are the addition of 7-methylguanosine cap at 5' end of mRNA called capping whereas the addition of the poly(Adenyl) tail at 3' end called tailing.

The advantages of capping are:

1. Protection of nascent mRNA from the degradation.

2. Recognition by transcription factors helps in translation.

The advantages of tailing are:

1. Protection of the mRNA from enzymatic degradation in the cytosol.

2. Transcription termination

3. Export of the mRNA from the nucleus

You are given two solutions containing different purified DNAs. One is from the bacterium P. aeruginosa and has a G + C composition of 68%, whereas the other is from a mammal and has G + C composition of 42%. You measure the UV absorbance of each solution as a function of increasing the temperature. Which solution will yield the higher Tm value and why?

Answers

Answer:

The solution of P. aeruginosa will yield higher Tm value.

Explanation:

The solution of P.aeruginosa contain 68% G+C composition as a result the DNA of P.aeruginosa is more stable than the DNA of mammal contain only 42% G+C composition.G+C composition is most stable because guanine is linked to cytosine by 3 hydrogen bonds whereas adenine linked to thymine by 2 hydrogen bonds.

As P.aeruginosa DNA is more stable than mammalian DNA,as a result the DNA solution of P.aeruginosa will yield high Tm(melting temperature) value than that of mammalian DNA.

Which of Earth's spheres are involved in the water cycle?A. Hydrosphere, atmosphere, lithosphere, and biosphere
OB. Hydrosphere, atmosphere, and lithosphere only
O C. Hydrosphere, atmosphere, and biosphere only
D. Hydrosphere and atmosphere only

Answers

Answer:

Hydrosphere, atmosphere, and biosphere only

Answer:

the atmosphere and hydrosphere

Explanation:

i did my work

5 a.
Describe the disease malaria and its precautions

Answers

Answer:

Malaria is a parasite transmitted by mosquitoes that invades the red blood cells, creating fevers, chills & sweating after a couple weeks of being bit.

Explanation:

Precautions you can take to avoid this would be to apply insect repellent on clothing/skin, using a mosquito net & spraying pyrethrin or other insecticides in your room before heading to bed.

The theory of Copernicus contained six hypotheses:The sun is at the _______ of the planets.

The Earth is ______ of the planets.

All the planets _______around the sun.

Each planet revolves around the sun in its own______ and at different _______
.

The moon______ around the Earth.

The stars are ______part of the solar system.

Answers

Sun is at the Centre

All the planets revolve around sun
Each planet revolves around the sun in its own orbit and at different speed
The moon revolves around the sun

Dont know 2

Answer:

The theory of Copernicus contained six hypotheses:

The sun is at the center of the planets.

The Earth is one of the planets.

All the planets orbit around the sun.

Each planet revolves around the sun in its own orbit and at different distances.

The moon orbits around the Earth.

The stars are not part of the solar system.

Explanation:

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Pattern of evolution in which long stable periods (stasis) are interrupted by brief periods of rapid change