Mutations can occur before, during, and after mitosis and meiosis. If a mutation occurs in cells that will make gametes by meiosis or during meiosis itself, it can be passed on to offspring and contribute to genetic variability of the population
Answer:
Neurons, as with other excitable cells in the body, have two major physiological properties: irritability and conductivity. A neuron has a positive charge on the outer surface of the cell membrane due in part to the action of an active transport system called the sodium potassium pump. This system moves sodium (Na+) out of the cell and potassium (K+) into the cell. The inside of the cell membrane is negative, not only due to the active transport system but also because of intracellular proteins, which remain negative due to the intracellular pH and keep the inside of the cell membrane negative.
Explanation:
Neurons are cells with the capacity to transmit information between one another and also with other tissues in the body. This information is transmitted thanks to the release of substances called <em>neurotransmitters</em>, and this transmission is possible due to the <em>electrical properties </em>of the neurons.
For the neurons (and other excitable cells, such as cardiac muscle cells) to be capable of conducting the changes in their membranes' voltages, they need to have a<em> resting membrane potential</em>, which consists of a specific voltage that is given because of the electrical nature of both the inside and the outside of the cell. <u>The inside of the cell is negatively charged, while the outside is positively charged</u> - this is what generates the resting membrane potential. When the membrane voltage changes because the inside of the cell is becoming less negative, the neuron is being excited and - if this excitation reaches a threshold - an action potential will be fired. But how does the voltage changes? This happens because the distribution of ions in the intracellular and extracellular fluids is very dissimilar and when the sodium channels in the cell membrane are opened (because of an external stimulus), sodium enters the cell rapidly to balance out the difference in this ion concentration. The sudden influx of this positively-charged ion is what makes the inside of the neuron become less negative. This event is called <em>depolarization of the membrane</em>.
Answer:
The minimum number of nucleotides per codon necessary to specify all 20 amino acids that are found in proteins is <u>3</u>
Explanation:
There are four nucleic acids in the RNA, adenine uracil, guanine, cytosine. Each of them combines in groups of three to give the different amino acids. In total, there are 64 different combinations of nucleic acids that codify the 20 amino acids that we need for our vital functions.
Answer:
conditioned stimulus
Explanation:
Conditioned stimulus -
It refers to as the neutral stimulus , which triggers or initiates the conditioned response , is referred to as the conditioned stimulus .
Ivan Pavlov was the very first one to give meaning to the term conditioned stimulus , by experimenting on the dogs .
Hence , from the given scenario of the question ,
The correct answer is conditioned stimulus .
A species that is involved in a facultative mutualism with another: can utilize different resources outside of the mutualism.
Explanation:
- Mutualism is a type of ecological relationship in which two organisms are related to each other in such a way that both of them could benefit from the relationship.
- A type of mutualism in which the two organism cannot depend on any other resource outside their mutualistic relationship is called obligate mutualism.
- A type of mutualism, in which the participating organisms can opt for other resources outside their mutualistic relatonship i.e. they are not completely dependent on each other, is called facultative mutualism.
