natural killer cells definition
Natural killer (NK) cells are cytotoxic lymphocytes that play a vital role in innate immunity by identifying and destroying cells that appear abnormal or are infected, primarily through changes in major histocompatibility complex (MHC) I expression. They induce apoptosis in these cells without the need for prior antigen sensitization, making them a swift response against infections and cancers.
Explanation:Natural killer (NK) cells are a critical component of the innate immune response, functioning as cytotoxic lymphocytes. These NK cells patrol the body, seeking out cells that exhibit 'non-self' proteins on their membranes or that have foreign or abnormal markers indicative of infection or cellular transformation, such as that which occurs in cancer. Unlike T cells of the adaptive immune response, NK cells do not require prior sensitization to specific antigens and thus provide a rapid response to invasions or cellular abnormalities.
One way NK cells are able to discern unhealthy cells from healthy ones involves the detection of changes in the expression of major histocompatibility complex (MHC) I molecules on the surface of nucleated cells. Healthy cells present normal 'self' peptides via MHC I to the immune system, signaling their healthy state. Conversely, cells that are infected or becoming cancerous often have altered MHC I expression, which is recognized by NK cells, triggering a targeted response.
Once an NK cell identifies a potential target, they can induce apoptosis, or programmed cell death, within the aberrant cell. Through the release of cytotoxic granules, NK cells deliver potent molecules like perforin and granzymes, which penetrate the target cell's membrane and initiate the apoptosis cascade, leading to cell death and the removal of the threat they posed.
Which structures are common to both prokaryotic and eukaryotic cells? check all that apply. vacuole cell membrane golgi body ribosome cytoplasm endoplasmic reticulum?
The structures that are common to both prokaryotic and eukaryotic cells are:
Cell membraneRibosomeCytoplasmThe cells of multicellular organisms are different in their function, because they are structurally different, but they all agree with a common pattern.
Prokaryotic cells, like eukaryotic cells, have a plasma membrane, but lack internal membranes, which form organelles.
Main common characteristics between eukaryotic and prokaryotic cells:
In both cell types, DNA is the genetic material.Both cell types have plasma membranes as cell boundaryThey have ribosomes for protein synthesis.The cytoplasm is common to both eukaryotic and prokaryotic cells, although they contain different types of organelles.Therefore, we can conclude that the structures that are common to both prokaryotic and eukaryotic cells are: cell membrane, ribosomes, cytoplasm.
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competitive exclusion principle definition biology
Most of the energy in the typical animal cell is produced in the __________.
The main action of the fibularis longus is to __________. invert the foot dorsiflexes the foot evert the foot plantar flexes the foot
the answer is 10 feet in total
Explanation:
Brad seems to be in a continuous state of anxiety though he is unable to identify the source of his feelings. the most likely diagnosis for brad is:
The answer is generalized anxiety. The symptoms of this disorder is that the person tend to always expect that there is a disaster that will going to happen and also they can’t stop worrying about health, money, work, family and everything under the sun. Generalized anxiety disorder is defined by exaggerated anxiety, excessive worrying about everyday life events with no basis and obvious reasons.
The Animal Functional Genomics Laboratory at Mississippi State University conducts genetic research involving farm animals. The results can be used to genetically modify commercially useful animals. Which idea can BEST be used to argue in favor of this research? A) Genetic changes can be designed to make cows yield more milk. B) Genetic changes can be used to create an entirely new species. C) Genetic changes can be used to control the populations of farm animals. D) Genetic changes can be designed to control the animals' group behavior.
Genetic modifications can be used to produce or select potentially useful properties of an organism. This is the major advantage of genetically modified organisms.
For example, genetic changes can be designed to make cows yield more milk or fight diseases better.
Your kidneys have an important effect on blood pressure. The kidneys controls plasma volume by controlling how much _____________________.
Answer:
C. Water a person excretes
Explanation:
The kidneys controls the amount of water a person excretes which effects the blood pressure by controlling the volume of plasma.
__________ are underground areas that have the ability to contain and provide water sources.a.shamalsb.wadisc.seasd.aquifers please select the best answer from the choices provided.
Answer:
Aquifers
Explanation:
Groundwater is an important source of water. It is the water present in the deeper layers of soil below the water table. Some of the important sources of groundwater are rainfall, rivers, ponds, etc. When it pours, water goes down in the soil layers to fill the spaces present below the ground. When the groundwater is accumulated between the hard rock layer, it becomes aquifer. The aquifers serve as a source of fresh water as the water present in them can be pumped out using techniques such as tube wells.
What is the ratio of heterozygous offspring to total offspring in the Punnett square?
In a Punnett square representing a cross between two heterozygous parents for one gene, the ratio of heterozygous offspring to total offspring is 1:2, or alternatively 50%. In other words, for every four offspring produced in such a cross, two are expected to be heterozygous.
When two heterozygous parents are crossed (Bb x Bb), the possible genotypes of the offspring are BB, Bb, bB, and bb. Here, we notice that Bb and bB are actually the same genotype as the letters represent alleles from different parents but do not designate the order of alleles on the chromosome. Therefore, if we consider Bb and bB as identical, and sum the heterozygous genotypes (Bb + bB), we get two out of four possible offspring that are heterozygous. Since a Punnett square has four boxes, and each box represents an equally likely outcome, the ratio is 2 heterozygotes out of 4 total offspring, which simplifies to a 1:2 ratio (50% of the offspring). This is consistent with the Mendelian inheritance predictions for a monohybrid cross.
The growth and secretion of the adrenal cortex is stimulated by the
Mitochondria transfer ________ energy from ________ to atp; chloroplasts transform ________ energy into the chemical energy of atp. food . . . light . . . nuclear chemical . . . food . . . light light . . . food . . . kinetic food . . . light . . . chemical
Mitochondria transfer chemical energy from food to ATP, acting as the cell's energy producers. Chloroplasts transform light energy into chemical energy through the process of photosynthesis.
Explanation:The mitochondria transfer chemical energy from food to ATP (Adenosine Triphosphate). ATP is the main energy source for the majority of cellular functions. However, it is not a long-term energy storage molecule. That's where the food we consume comes into play. When we consume food, our bodies break down the organic molecules within, releasing energy that is then converted into ATP.
Chloroplasts, on the other hand, are responsible for taking in energy from light and converting it into chemical energy via the process of photosynthesis. In photosynthesis, light energy is absorbed by chlorophyll, which drives the synthesis of glucose and other nutrients. These glucose molecules can then be used by the mitochondria to produce ATP.
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Mitochondria convert chemical energy from food into ATP, while chloroplasts convert light energy into ATP's chemical energy.
Mitochondria are responsible for the process of cellular respiration, where they use the chemical energy stored in food molecules to produce ATP, which is the energy currency of the cell.
Chloroplasts, found in plant cells, convert light energy into chemical energy during the process of photosynthesis, particularly in the light-dependent reactions where ATP is produced alongside NADPH
When alzheimer disease appears in middle age rather than old age, it:
a. progresses more slowly.
b. progresses more rapidly.
c. causes death within a year.
d. is benign?
If a doctor prescribes tylenol iii with codeine, he or she has prescribed a __________.
a. stimulant
b. depressant
c. narcotic
d. hallucinogen please select the best answer from the choices provided. a b c d
The right option is c. narcotic
Tylenol iii with codeine belongs to the group of medications called narcotic analgesics (pain relievers). Narcotics are drugs that are administered to provide relief from severe pain. Narcotics are sometimes prescribed when other forms of pain relievers are not working. Examples of narcotics are hydrocodone, codeine, tramadol and opium.
The natural and synthetic drugs derived from morhphine are know as
Which of the below is an example of an indirect food additive?
Which is the correct order of events of sound transmission through the ear? 1. sound waves strike the eardrum 2. the ear ossicles vibrate 3. hair cells of the organ of corti vibrate 4. the perilymph in the cochlea moves 5. sound waves enter the external auditory canal?
The correct order of events of sound transmission through the ear is;
5. Sound waves enter the external auditory canal
1. Sound waves strike the eardrum
2. The ear ossicles vibrate
4. The perilymph in the cochlea moves
3. Hair cells of the organ of corti vibrate
Final answer:
The correct order of events of sound transmission through the ear is as follows: sound waves enter the external auditory canal, sound waves strike the eardrum and make it vibrate, ear ossicles vibrate and amplify the vibrations, the perilymph in the cochlea moves, and hair cells of the organ of Corti vibrate.
Explanation:
The correct order of events of sound transmission through the ear is as follows:
The sound waves enter the external auditory canal.The sound waves strike the eardrum (tympanic membrane) and make it vibrate.The ear ossicles (hammer, anvil, and stirrup) vibrate and amplify the vibrations.The stapes presses into the oval window, causing the perilymph in the cochlea to move.The hair cells of the organ of Corti vibrate in response to the moving perilymph, generating nerve impulses that are transmitted to the brain.Which molecule contributes to the greenhouse effect?
The molecule that contributes to the greenhouse effect are water molecules and methane.
What is the greenhouse effect?The greenhouse impact is the manner wherein warmth is trapped near Earth's floor by “greenhouse gases.” These warmth-trapping gases may be idea of as a blanket wrapped round Earth, retaining the planet toastier than it'd be with out them.
Carbon dioxide: Made of 1 carbon atom and oxygen atoms, carbon dioxide molecules make up a small fraction of the atmosphere, however have a big impact on climate.The molecules that make a contribution to the greenhouse impact are people with a nontrivial vapor stress at Earth’s floor temperature (in any other case they won’t be capable of evaporate into the atmosphere) and that are compounds withinside the experience of together with or extra elements.Read more about the greenhouse :
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The phase of cell division during which the chromatids are pulled apart and move to the opposite
In _____ the heterozygote's phenotype is somewhat intermediate between the two homozygotes. select one:
a. codominance
b. complete dominance
c. incomplete dominance
d. epistasis
Which of these people has the lowest risk of suffering serious consequences from a foodborne illness?
Although the open ocean is among the least productive ecosystems, it contributes greatly to the overall productivity of the biosphere. How can this situation be explained?
The open ocean contributes greatly to the biosphere's productivity due to the massive scale of ocean ecosystems and the vital role of phytoplankton in oxygen production through photosynthesis. The ocean upwelling also redistributes nutrients, enhancing productivity.
Explanation:Although the open ocean is among the least productive ecosystems, it plays a significant role in global productivity, largely due to the extent of ocean ecosystems which encompass over 70% of the Earth's surface. The ocean's vastness houses numerous species, ranging from large marine mammals to the tiniest of organisms, such as phytoplankton.
Phytoplankton are crucial for the biosphere as they release over 50% of the oxygen produced on Earth through photosynthesis. This process not only contributes to the oxygen we breathe but also forms the foundation of the marine food web. The neritic zone, with its high biodiversity and productivity, plays a significant role in supporting marine life and fisheries. However, it's the sheer scale of the open ocean that allows its contribution to overall biosphere productivity.
Moreover, phenomena such as ocean upwelling help redistribute nutrients from the ocean floor back to surface waters, aiding in the productivity of these ecosystems. Therefore, the open ocean's significant contribution to Earth's productivity can be explained by the large area it covers, the oxygen production by phytoplankton, and the mechanisms that redistribute nutrients within these aquatic systems.
Which cells are responsible for his ability to see the objects and people?
How long does a letter take from boston to amsterdam?
The spinal cord is protected by the
Brain Stem
Lower Cord
Back Bone
Tail Bone
Modern h. sapiens differ from the archaic form in that moderns have
Final answer:
Modern Homo sapiens are distinguished from archaic forms by their larger, more complex brains, smaller faces, jaws, and front teeth, and changes in skull morphology such as less pronounced brow ridges and the development of a prominent chin. They also have a more elaborate tool kit, including the blade tool industry.
Explanation:
Differences between Modern Homo sapiens and Archaic Homo sapiens:
The evolutionary journey from archaic Homo species to modern Homo sapiens has been marked by significant changes in physical anatomy and behavior. Modern humans are biologically distinct from their archaic predecessors in a number of ways. One of the most notable physical differences is the size and structure of the brain. Modern H. sapiens have a much larger brain capacity, averaging around 1,200 to 1,400 cubic centimeters, just like some archaic forms, but with a more developed prefrontal cortex and smaller face, jaws, and front teeth. Another distinctive characteristic of modern humans is their skull morphology, which generally includes a rounder skull, less prominent brow ridges, and a prominent chin, unlike their archaic counterparts who had thicker skulls and more pronounced brow ridges.
Furthermore, the behavioral changes that accompany these physical evolutions are substantial. Modern humans demonstrate a significant leap in tool-making abilities, transitioning from the Mousterian prepared-core flake tools to a more sophisticated blade tool industry. This advancement allowed the crafting of tools from a wider variety of materials including bone, antler, and ivory, which facilitated the development of a rich material culture in the Upper Paleolithic period. Additionally, modern H. sapiens displayed advanced cognitive functions and social behaviors, leading some researchers to speculate about their use of language and complex social structures.
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EXTRA POINTS
The overuse of antibiotics is causing a rise in the number of bacteria which are resistant to antibiotics. Which mechanism would most likely account for this?
Select one:
a. Through competition for reduced resources, the antibiotic-resistant bacteria thrive.
b. Through mutation, the bacteria change into other species.
c. Through natural selection, a few surviving antibiotic-resistant bacteria multiply.
d. Through movement to other habitats, bacteria find more places to live.
T cells produce and secrete factors that do not directly interact with invading microorganisms but that augment the body's defense mechanisms. these molecules are
A 3-base deletion in the aauaaa sequence in the 3' untranslated region of an mrna that eliminates the aau, thereby preventing rna polymerase from polyadenylation the mrna would have the effect of:
stanley has entered a rehabilitation facility for treatment of his addiction to barbiturates. he is immediately prevented from using the drugs and experiences agitation, restlessness, increased respiration, and insomnia. this phase of treatment is called ____.
Answer:
Stanley has entered a rehabilitation facility for treatment of his addiction to barbiturates. He is immediately prevented from using the drugs and experiences agitation, restlessness, increased respiration, and insomnia. this phase of treatment is called detoxification.
Explanation:
Detoxification is the physiological or medicinal removal of toxic substances from a living organism. Detox from drugs or opioids can be dangerous for the person engaging in the detox, therefore having medical supervision during this phase of the treatment is highly needed. After a long time of the body being addicted to a specific drug, the more severe the detoxification symptoms are going to be, including agitation, restlessness, anxiety, flu like symptoms, and others.