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>.
How DNA supports the idea that life change over time is the DNA follow life history and can adopt to thinks very quick
Answer:
A,B and E
Explanation:
- I+: I refers to the lac repressor, the + indicates that the repressor is functional
- P+: P refers to the promoter region and the + indicates that the promoter is functional
- Oc: O refers to the operator region, but the Oc indicates that the operator is constitutive ie. that it is always on/ can't be turned off.
- Z-: Z refers to the LacZ gene which produces β-galactosidase. Z- indicates that this gene is non-functional
- Y+: Y refers to the LacY gene which produces the permease protein. Y+ indicates that this gene is functional
So based on the breakdown above:
- C is not true because the lac operon is an inducible system. The operator needs to be able to be repressed. In this case the operator is constitutive (always on) which is not the correct form.
- D is not true because Z-, no β-galactosidase is produced.
Only A, B and E apply.
Answer:
through years of evolution as natural selection shaped animal adaptations to Earth's environments.
Explanation:
Over the years, biologists have been able to successfully name more than one (1) million animal species across the world. These species arose through years of evolution as natural selection shaped animal adaptations to Earth's environments.
Natural selection can be defined as a biological process in which species of living organisms having certain traits that enable them to adapt to environmental factors such as predators, competition for food, climate change, sex mates, etc., tend to survive and reproduce, as well as passing on their genes to subsequent generations.
Simply stated, natural selection entails the survival of the fittest. Therefore, the species that are able to adapt to the environment will increase in number while the ones who can't adapt will die and go into extinction.
Iodine, like all other minerals, is required in considerable quantity in the body. The function of iodine is that it is necessary for proper metabolic function in an animal.
The lack of iodine in a mammal will cripple the physical and metabolic functions and causes developmental delays in the mammal.
