Answer the following question given this paragraph: membrane is a positive 15 mV, meaning that the membrane depolarizes from -70 mV to -55 mV, then the graded potentials will result in the membrane reaching threshold. For receptor potentials, threshold is not a factor because the change in membrane potential for receptor cells directly causes neurotransmitter release. However, generator potentials can initiate action potentials in the sensory neuron axon, and postsynaptic potentials can initiate an action potential in the axon of other neurons. Graded potentials summate at a specific location at the beginning of the axon to initiate the action potential, namely the initial segment. For sensory neurons, which do not have a cell body between the dendrites and the axon, the initial segment is directly adjacent to the dendritic endings. For all other neurons, the axon hillock is essentially the initial segment of the axon, and it is where summation takes place. These locations have a high density of voltage-gated Na+ channels that initiate the depolarizing phase of the action potential. Summation can be spatial or temporal, meaning it can be the result of multiple graded potentials at different locations on the neuron, or all at the same place but separated in time. Spatial summation is related to associating the activity of multiple inputs to a neuron with each other. Temporal summation is the relationship of multiple action potentials from a single cell resulting in a significant change in the membrane potential. Spatial and temporal summation can act together, as well. Q: What is the relationship of multiple action potentials from a single cell resulting in a significant change in the membrane potential? Choices: - nature summation - bipolar summation - distinct summation - temporal summation A:
temporal summation
(Question)
Answer the following question given this paragraph: Clubmosses are so named because they can look similar to mosses ( Figure below ). Clubmosses are not true mosses, though, because they have vascular tissue. The "club" part of the name comes from club-like clusters of sporangia found on the plants. One type of clubmoss is called the "resurrection plant" because it shrivels and turns brown when it dries out but then quickly turns green when watered again. Q: Clubmosses are not true mosses, though, because they have what? Choices: - smooth tissue - cambrium - hydrothermal tissue - vascular tissue A:
(Answer)
vascular tissue
Ques: Answer the following question given this paragraph: Q: Fruit begins to ripen because what gas is released? Choices: - sulfur - chloride - hydrogen - ethylene A:
Ans: ethylene
(Q).
Answer the following question given this paragraph: Exponential Growth Charles Darwin, in his theory of natural selection, was greatly influenced by the English clergyman Thomas Malthus. Malthus published a book in 1798 stating that populations with unlimited natural resources grow very rapidly, and then population growth decreases as resources become depleted. This accelerating pattern of increasing population size is called exponential growth. The best example of exponential growth is seen in bacteria. Bacteria are prokaryotes that reproduce by prokaryotic fission. This division takes about an hour for many bacterial species. If 1000 bacteria are placed in a large flask with an unlimited supply of nutrients (so the nutrients will not become depleted), after an hour, there is one round of division and each organism divides, resulting in 2000 organismsan increase of 1000. In another hour, each of the 2000 organisms will double, producing 4000, an increase of 2000 organisms. After the third hour, there should be 8000 bacteria in the flask, an increase of 4000 organisms. The important concept of exponential growth is that the population growth ratethe number of organisms added in each reproductive generationis accelerating; that is, it is increasing at a greater and greater rate. After 1 day and 24 of these cycles, the population would have increased from 1000 to more than 16 billion. When the population size, N, is plotted over time, a J-shaped growth curve is produced (Figure 45.9). The bacteria example is not representative of the real world where resources are limited. Furthermore, some bacteria will die during the experiment and thus not reproduce, lowering the growth rate. Therefore, when calculating the growth rate of a population, the death rate (D) (number organisms that die during a particular time interval) is subtracted from the birth rate (B) (number organisms that are born during that interval). This is shown in the following formula:. Q: What is the accelerating pattern of increasing population size called? Choices: - induced growth - reproducing growth - limited growth - exponential growth A:
(A).
exponential growth
Ques:Answer the following question given this paragraph: When hot water gently rises to the surface, it creates a hot spring . A hot spring forms where a crack in the Earth allows water to reach the surface after being heated underground. Many hot springs are used by people as natural hot tubs. Some people believe that hot springs can cure illnesses. Hot springs are found all over the world, even in Antarctica!. Q: When hot water gently rises to the surface, it creates a what? Choices: - steam cloud - volcano - fissure - hot spring A:

Ans:hot spring
Answer the following question given this paragraph: Complement System The complement system is a series of proteins constitutively found in the blood plasma. As such, these proteins are not considered part of the early induced immune response, even though they share features with some of the antibacterial proteins of this class. Made in the liver, they have a variety of functions in the innate immune response, using what is known as the "alternate pathway" of complement activation. Additionally, complement functions in the adaptive immune response as well, in what is called the classical pathway. The complement system consists of several proteins that enzymatically alter and fragment later proteins in a series, which is why it is termed cascade. Once activated, the series of reactions is irreversible, and releases fragments that have the following actions: Bind to the cell membrane of the pathogen that activates it, labeling it for phagocytosis (opsonization) Diffuse away from the pathogen and act as chemotactic agents to attract phagocytic cells to the site of inflammation Form damaging pores in the plasma membrane of the pathogen Figure 21.13 shows the classical pathway, which requires antibodies of the adaptive immune response. The alternate pathway does not require an antibody to become activated. Q: The complement system is a series of proteins constitutively found in the what? Choices: - nucleus - organs - platelets - blood plasma A:
blood plasma