Answer:
B. retain its urine in it’s blood stream
Explanation:
Sharks are cartilaginous fishes that lives in the ocean. Oceans are always salty, hence organisms need to maintain a salt-water balance between their internal and external environment because of osmosis. Sharks are able to maintain this by ensuring that the amount of solutes in their internal environment is as much as that in their external environment.
Sharks retain a chemical contained in urine called UREA in their bloodstream to counter the osmotic effect of the salt concentration in the waters they live. This helps them maintain a concentration balance with their environment.
Umm...
biology is the study of life
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Answer:
D. Many amino acids are encoded by multiple codons. A gene mutation that encodes the same amino acid would have no observable effect on the cell or the organism
Explanation:
If gene mutation does not change code (gene still encodes for the same amino acid), the same protein with its function will be produced. This is called synonymous mutation.
Silent mutations might also occur when codon is altered to produce an amino acid with similar function as previous (e.g. leucine to isoleucine) so that the function of protein is not significantly changed.
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.
B. I did a project on scorpions a few years back.
