If a DNA molecule has 23% Cytosine (C), what percent of the molecule

After nervous stimulation stops, calcium ions returning to the sarcoplasmic reticulum prevent ACh in the synaptic cleft from con

zhuklara [117]

Answer:

False.

Explanation:

Neurotransmitter release occurs from the nervous terminal or varicosities in the neuronal axon. When an action potential reaches the nervous terminal, the neurotransmitter is released by exocytose. The molecule binds to its receptor in the postsynaptic neuron, triggering an answer. As long as the signal molecule is in the synaptic space, it keeps linking to its receptor and causing a postsynaptic response. To stop this process the neurotransmitter must be taken out from the synaptic space. There are two mechanisms by which the neurotransmitter can be eliminated:

• Enzymatic degradation/deactivation: There are specific enzymes in the synaptic space, which are in charge of inactivating the neurotransmitter by breaking or degrading it. The enzyme acetylcholinesterase prevents ACh from continuing to stimulate contraction.

• Reuptake: Receptors located in the presynaptic membrane can capture de molecule to store it back in new vesicles for posterior use. These transporters are active transport proteins that easily recognize the neurotransmitter.

7 0

3 years ago

Jon likes hiking. He observes that whenever he hikes up a hill, he breathes heavier than when he is on flat ground. Which two st

Firlakuza [10]

When climbing a hill or mountain, there are different condions which the body reacts to, first: the body begins to exercise, since it must carry all our weight when climbing up a hill, this generates that the heart accelerates and pumps the blood more quickly so that it reaches our whole body out, and the second one, is that at a higher height, less oxygen, if already, our body comes with the heart shaken by the physical exercise, now it has to accelerate your breathing to get the necessary oxygen for the blood and the body, these two things make us breathe heavily.

5 0

3 years ago

Read 2 more answers

The primary reason organisms require large amounts of carbohydrates (sugars and starches):

tekilochka [14]

Answer:

Is to supply energy for their metabolic activities

Explanation:

6 0

2 years ago

18. Refer to Models 1 and 2 to complete the chart below. Write yes or no in the box for cach cell.

Ostrovityanka [42]

The most primitive cells are prokaryotic. They are simple, with no organelles and no nucleus. Animal and plant cells are eukaryotic, but they express some differences such as the cell wall, chloroplasts, or centrioles.

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BACTERIA CELLS

Bacteria are prokaryotic cells.

Prokaryotic cells lack a nucleus, nucleolus, and organelles.

They only present plasmids, ribosomes, and genetic material in their cytoplasm.

DNA not surrounded by membrane

They have a cell wall that protects the cell and a cell membrane that surrounds the cytoplasm. Some of them can also present a capsule.

Some of them have flagellum.

These organisms are capable of inhabiting places with extreme temperature, salinity, acidity, or pH, among others.

ANIMAL AND PLANT CELLS

Both the animal and plant cells are eukaryotic.

They carry their genetic material in the nucleus and mitochondria.

Organelles are located in the cytosol, and both of them are surrounded by a protector cell membrane.

However, they have some differences:

⇒Cell wall : A rigid structure that provides support and protection.

• Animal cells do not have a cell wall. They are only surrounded by the cell membrane, which is flexible so they can adopt different shapes.

• Plant cells have a wall, so their shape is usually prismatic and regular. The cell wall is composed mainly of cellulose.

⇒ Chloroplast: these are organelles that accumulate chlorophyll.

• Animal cells do not have chloroplasts because they do not photosynthesize.

• Plant cells have chloroplasts, and they are in charge of the photosynthesis process that allows plants to release oxygen. These organelles use solar light as the source of energy.

⇒ Vacuoles:

• Animal cells have many and small vacuoles whose function is to store water, ions, and waste intracellular substances.

• Plant cells have a unique big-sized vacuole that might occupy almost 90% of the cell. Their principal function is to store water and keep the turgidity. When the vacuole gets empty, the plant loses rigidity.

⇒ Other differences are: