Darwin meets Mendel—not literally
When Darwin came up with his theories of evolution and natural selection, he knew that the processes he was describing depended on heritable variation in populations. That is, they relied on differences in the features of the organisms in a population and on the ability of these different features to be passed on to offspring.
Darwin described evolution as "descent with modification," the idea that species change and give rise to new species over extended periods of time and that all species can trace their descent to a common ancestor. Today, evolution is typically defined as a change in the genetic makeup of a population over generations—a definition that encompasses both the large-scale evolution Darwin envisioned and the smaller-scale processes we'll discuss in this article.
Natural selection is the mechanism that Darwin proposed to explain how evolution takes place and why organisms are typically adapted, well-suited, to their environments and roles.
The basic idea of natural selection is that organisms with heritable traits that help them survive and reproduce—in a certain environment—will leave more offspring than organisms without those traits. Because the traits are heritable, they will be passed on to the offspring, who will also have a survival and reproduction advantage. Over generations, differential survival and reproduction will lead to a progressive increase in the frequency of the helpful traits in the population, making the population as a group better-suited to its environment.
Natural selection is not the only mechanism of evolution. Populations can also change in their genetic composition due to random events, migration, and other factors. However, natural selection is the one mechanism of evolution that consistently produces adaptation, a close fit between a group of organisms and its environment.
Darwin did not, however, know how traits were inherited. Like other scientists of his time, he thought that traits were passed on via blending inheritance. In this model, parents' traits are supposed to permanently blend in their offspring. The blending model was disproven by Austrian monk Gregor Mendel, who found that traits are specified by non-blending heritable units called genes.
Although Mendel published his work on genetics just a few years after Darwin published his ideas on evolution, Darwin probably never read Mendel’s work. Today, we can combine Darwin’s and Mendel’s ideas to arrive at a clearer understanding of what evolution is and how it takes place.
Microevolution is sometimes contrasted with macroevolution, evolution that involves large changes, such as formation of new groups or species, and happens over long time periods. However, most biologists view microevolution and macroevolution as the same process happening on different timescales. Microevolution adds up gradually, over long periods of time to produce macroevolutionary changes.
Let's look at three concepts that are core to the definition of microevolution: populations, alleles, and allele frequency.
Populations
A population is a group of organisms of the same species that are found in the same area and can interbreed. A population is the smallest unit that can evolve—in other words, an individual can’t evolve.
Alleles
An allele is a version of a gene, a heritable unit that controls a particular feature of an organism.
For instance, Mendel studied a gene that controls flower color in pea plants. This gene comes in a white allele, w, and a purple allele, W. Each pea plant has two gene copies, which may be the same or different alleles. When the alleles are different, one—the dominant allele, W—may hide the other—the recessive allele, w. A plant's set of alleles, called its genotype, determines its phenotype, or observable features, in this case flower color.
Phenotype—flower color
Genotype—pair of alleles
Allele frequency refers to how frequently a particular allele appears in a population. For instance, if all the alleles in a population of pea plants were purple alleles, W, the allele frequency of W would be 100%, or 1.0. However, if half the alleles were W and half were w, each allele would have an allele frequency of 50%, or 0.5.
In general, we can define allele frequency as
Total number of A/a gene copies in population
Number of copies of allele Ain population
start subscript, i, end subscript_ alleles of a gene). In that case, you would want to add up all of the different alleles to get your denominator.
Let’s look at an example. Consider the very small population of nine pea plants shown below. Each pea plant has two copies of the flower color gene.
The frequencies of all the alleles of a gene must add up to one, or 100%.
Phenotype frequency: How often we see white vs. purple
Allele frequency: how often we see each allele
What are the advantages and disadvantages of using RNA or protein as genetic material?
Disadvantage
RNA and proteins are less stable than DNA. In addition RNA and proteins have shorter life spans that DNA
Advantage
This same property can be an advantage because a mutation on DNA can be permanent but one on RNA or proteins will cease after the short life spans of these biomolecules.
How is hemoglobin's affinity for oxygen affected by the presence or absence of oxygen? rank hemoglobin molecules with the described conditions from most likely to bind oxygen molecules to most likely to release oxygen molecules. (for help approaching this problem, open hint 1.)?
In order from the most likely to bind an oxygen to least likely;
3 bound o2, po2=100mmhg1 bound o2, po2=100mmhg3 bound o2, po2=40mmhg1 bound o2, po2=40mmhg
Explanation;Haemoglobin is more likely to bind oxygen if its other oxygen binding sites have already bound to an oxygen molecule. The higher the partial pressure of oxygen in the blood also makes it more likely that the hemoglobin will bind oxygen.Hemoglobin is a protein-rich in iron that has an affinity (combining ability) to oxygen and with oxygen, it forms oxyhemoglobin in red blood cells. The amount of hemoglobin in normal blood is 15 grams per 100 ml of blood, and the hour is usually called "100 percent".
Further ExplanationHemoglobin is a substance found in red blood cells. Hemoglobin is actually a globular protein in the form of 4 subunits, and each subunit contains hame.
Hemoglobin plays an important role in oxygen transport as long as it can re-bind oxygen. Hemoglobin tends to bind oxygen when the environment is full of oxygen and releases oxygen in a relatively low oxygen environment. This means hemoglobin takes oxygen in the lungs and releases it to tissues such as active muscle. In people who have normal hemoglobin, the capacity of the blood carries about 20 mL of oxygen per 100 mL of oxygen. In almost all situations, blood contains a lot of oxygen as it moves through the lungs.
Hemoglobin is carried by circulating red blood cells (erythrocytes). This circulation rotates for about 10 days containing approximately 3 x 10 red blood cells. A rough estimate of blood hemoglobin levels can be obtained from the amount of hematocrit or from the amount of blood by consuming each red blood cell that has normal hemoglobin
The heat produced by the metabolism reaction of muscle contractions releases a lot of acid & heat causes the body temperature to rise and the active cells need a lot of O2 to spur the release of O2 from OxyHb (Hb affinity towards O2 decreases) the curve shifts to the right.
Hypothermia causes slow cell metabolism so that the O2 needed by the tissue to release a small amount of O2 from Hb is also slow (Hb affinity for O2 decreases) and the hemoglobin oxygen dissociation curve shifts to the left.
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Class: High School
Subject: Biology
Keywords: hemoglobin, affinity, oxygen
What does the right hemisphere of the brain control?
Answer:
The right hemisphere controls the left side of the body and our creativity.
Explanation:
The right hemisphere coordinates the left side of the body, and performs tasks that have do with creativity and the arts.
The left side of the brain is responsible for controlling the right side of the body and controls the way we think logically.
The right hemisphere of the brain primarily controls the left side of the body and is often associated with spatial and nonverbal reasoning. It's important to note, however, that the brain functions as a whole unit and most functions are distributed globally around the cerebrum.
Explanation:The right hemisphere of the brain primarily controls the left side of the body. It plays a significant role in spatial and nonverbal reasoning, arousal, negative emotions, and pitch perception. Language processing, a task typically associated with the left hemisphere, can cross over to the right hemisphere via the corpus callosum, which bridges the two hemispheres together.
While the left hemisphere tends to be dominant in language functions in about 95% of the population, it must be noted that the brain functions as a whole and most of its functions are globally distributed. Misconceptions of people being 'right-brained' or 'left-brained' oversimplify the complex nature of the cerebral hemispheres.
In certain cases of intractable epilepsy, the corpus callosum is surgically severed as a treatment option, resulting in 'split-brain' patients. These patients highlight the roles of the individual hemispheres as we observe their behaviors and abilities post-surgery.
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Which of the following is not true about viruses
The answer is:
A. They do NOT reproduce on their own without hosts.
Hope this helps!
The answer is A - They reproduce on their own w/out hosts
they can only replicate
Simon is a 35-year-old lawyer who works in a large law firm in New York City. He’s noticed that since he turned 30, his body seems to need more time on average to recuperate from illnesses. To top it off, since he started working at the firm about two years ago, he has seemed vulnerable to catching every infectious illness that his co-workers come down with – from a little cold to a full-blown flu. Simon always seems to be coughing, sniffling, and fighting fatigue. He’s also recently developed a skin condition on his face that looks greasy and flaky, and feels irritable most of the time. Although he considers his diet pretty healthy and his lifestyle relatively active, Simon is now thinking of taking vitamin supplements. Do you think Simon might need supplements? If so, which one(s)? 1. Simon learns that supplementing with water-soluble vitamins is potentially safer (compared to fat-soluble varieties) because they aren't stored in the body for as long, which reduces their ability to cause a toxicity. Which vitamin is water soluble? a. vitamin A b. vitamin K c. vitamin E d. vitamin D e. vitamin C
The answer is c because they are easily destroyed and washed away during food storage preparation
Answer: Vitamin C is Water Soluble Vitamin
Explanation: Water soluble vitamins include vitamin B complex group and Vitamin C.
Vitamin B complex group includes the following:
o Thiamine (B1)
o Riboflavin (B2)
o Niacin (B3)
o Pantothenic acid (B5)
o Pyridoxine (B6)
o Folic acid (B9)
o Biotin
o Cobalamin (B12)
Vitamin B complex members are grouped together because, often, they are found together in the same food with the exception of vitamin B12
Some common properties of water soluble vitamins are:
o They are readily absorbed from intestine and excreted in urine.
They are not stored like fat soluble vitamins and so do not cause toxicity. However vitamin B₁₂ is stored in body.
o Their dietary intake is needed on a regular basis.
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What gas made up the largest portion of earth's atmosphere for most of earth's history
Gases in Earth's Atmosphere. Nitrogen and Oxygen are by far the most common. Dry air is composed of about 78% Nitrogen (N2) and about 21% Oxygen (O2). Argon, Carbon Dioxide (CO2), and many other gases are also present in much lower amounts; each makes up less than 1% of the atmosphere's mixture of gases.
So therefore Oxygen is the gas that makes up the largest portion of the Earths Atmosphere.
The gas that made up the largest portion of Earth's atmosphere for most of Earth's history was hydrogen. Hydrogen was the most abundant gas in the solar nebula from which the Earth formed, and it made up about 90% of the Earth's atmosphere for the first few hundred million years of its history.
However, over time, hydrogen escaped from the Earth's atmosphere and was replaced by other gases, such as nitrogen and oxygen.
Today, nitrogen is the most abundant gas in Earth's atmosphere, making up about 78% of the atmosphere. Oxygen is the second most abundant gas, making up about 21% of the atmosphere. Hydrogen is only a very small fraction of the atmosphere today, making up about 0.00005% of the atmosphere.
The change in the composition of Earth's atmosphere over time is due to a number of factors, including the escape of gases from the atmosphere, the formation of new gases, and the interaction of gases with the Earth's surface.
The escape of hydrogen from the atmosphere is thought to have been caused by the high temperature of the Earth's early atmosphere. The formation of new gases, such as nitrogen and oxygen, is thought to have been caused by the interaction of solar radiation with the Earth's atmosphere.
The interaction of gases with the Earth's surface is thought to have been caused by the weathering of rocks and the formation of oceans.
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Which transformation of energy takes place when a slingshot launches a stone
The region known as the macula densa is part of
The region known as the macula densa is part of excretory system.
More precisely, macula densa is a structure located in the kidney, in the wall of the distal tubule. The macula densa is composed of tightly packed specialized cells on the place where the distal tubule touches the glomerulus.
The role of this structure is to detect changes in concentration of sodium chloride and to send a signal to the afferent arterioles (to change blood pressure) or to the juxtaglomerular cells (renin release).
The macula densa is a group of cells located in the Distal Convoluted Tubule of the kidney that play a pivotal role in maintaining the body's sodium balance.
Explanation:The region known as the macula densa is a group of cells that is a part of the kidney's structure. Specifically, it's located in the part of the Distal Convoluted Tubule (DCT) that forms the Juxtaglomerular Apparatus (JGA). These cells play a vital role in regulating the body's balance of sodium ions. When triggered by certain hormones due to changes in sodium concentration, blood volume, or blood pressure, macula densa cells can communicate rapidly with afferent and efferent arterioles. Depending on the signal, these arterioles can constrict or relax to alter the glomerular filtration rate which in turn affects the balance of sodium ions and overall kidney function.
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A change in the order of DNA bases code for a respritory protein will most likely cause?
A change in the sequence of amino acids determined by the gene
Answer:
B) A change in the sequence of amino acids determined by the gene.
Explanation:
Suppose a mutation greatly increases the affinity of a rod's sodium channels for cgmp, such that once cgmp binds to a channel, it remains bound for much longer than normal. what would be the effect of this mutation on the rod's sodium channels?
The effect of this mutation is a gain in function that will stimulate the sodium channel and allow more sodium to pass inside the cell.
There are two types of consequence of mutations on proteins, loss of function, gain of function or neutral.
Mutation gain of function (which is rare) is that the protein is gaining activity, this is the example shown with the sodium channel. This has negative consequences (toxic effect) if the protein works more than it should. This will affect the function of the cell and may destroy it. the rod cells are cells found at the level of the photoreceptor of the eye, this mutation can have serious consequences on the sight.
A mutation that increases the affinity of the rod's sodium channels for cGMP would result in the sodium channels remaining open for longer periods, impairing the rod cells' ability to hyperpolarize and, thus, potentially affecting vision.
If a mutation greatly increases the affinity of the rod's sodium channels for cGMP, the channels would stay open longer once cGMP binds to them. Under normal circumstances, light exposure causes rhodopsin to activate the G-protein transducin, which in turn activates phosphodiesterase. This enzyme converts cGMP to GMP, leading to the closure of sodium channels and resulting in the hyperpolarization of the rod cell membrane.
However, with increased affinity for cGMP due to the mutation, sodium channels would remain open for extended periods, making it more difficult to hyperpolarize the membrane, and thereby slowing down or preventing the reduction in the release of glutamate to interneurons like bipolar cells. As a consequence of maintaining a more depolarized state, the rod cell might continuously release glutamate, potentially leading to a reduction in the discriminating ability of the retina to differentiate between light and dark, possibly affecting vision.
During a laboratory investigation, biology students were asked to classify organisms on prepared slides as either eukaryotes or prokaryotes. Which of the following features should the students be able to observe in BOTH types of cells?
Question 1 options:
ribosomes
mitochondria
nucleus
Golgi apparatus
Answer:
Ribosome
Explanation:
A prokaryotic cell is a primitive cell and it lacks membrane bound organelles. One major cell structure that distinguish both cell types is the nucleus.
Eukaryotic cells have nucleus whereas prokaryotes lacks them.
Ribosome, the site of synthesis of protein can be found in both cell types.
In what way do lightning strikes play an important role in a nutrient cycle?
converting phosphorus into a form that can enter the atmosphere
converting phosphorus into phosphates that can dissolve in water
splitting atmospheric nitrogen allowing it to combine with oxygen
converting ammonia into atmospheric nitrogen that can be returned to the atmosphere
The right option is; splitting atmospheric nitrogen allowing it to combine with oxygen
Lightning is the flash of light caused by the discharge of atmospheric electrical charge. In nitrogen cycle, lightning play an important role by indirectly adding nitrogen to the soil. It transforms atmospheric nitrogen into a form that can be used by plants (a process known as nitrogen fixation). The strong bonds of atmospheric nitrogen molecule are broken (split) by the bolts of lightning that transmits electrical energy. After the molecules are separated, the nitrogen atoms quickly combine with oxygen in the atmosphere to form nitrogen dioxide which also dissolves in water (within the atmosphere) to form nitric acid. The nitric acid also form nitrates which is being released to the ground in rain drops. The nitrates then spread into the soil in a form that can be used by plants.
Part d - how do you sequence the coi gene from your salmon sample?
Once you have obtained your salmon sample from a local store, you need to isolate the DNA from it and make many copies of the COI gene using the polymerase chain reaction (PCR).
To sequence the COI gene from a salmon sample, mitochondrial DNA is extracted, the COI gene fragment is isolated, amplified via PCR using specific primers, and the sequence is determined and compared with a database.
The cytochrome c oxidase I (COI) gene sequencing process begins with the extraction of mitochondrial DNA from the salmon sample. After extraction, a specific fragment from the 5' end of the COI gene is isolated, which is approximately 648 base pairs in length, although the entire gene consists of roughly 1500 base pairs.
This fragment is then amplified by polymerase chain reaction (PCR) using primers that are designed to bind specifically to the conserved regions flanking the COI gene of interest. The forward and reverse primers typically used for the amplification of the COI gene in animals are mentioned: lepF1, lepR1, vflf, and vf1r. PCR amplification is crucial as it generates multiple copies of the gene fragment, making it easier to determine its sequence.
Once amplified, the DNA sequence of the COI gene fragment is then determined using sequencing technologies. The obtained sequence is compared with reference sequences in a database to confirm the identity of the species or to explore genetic diversity among similar species. This comparison enables researchers to make determinations on species identification or evolutionary relationships based on the similarities or differences in the COI sequences.
Advances in DNA barcoding and the development of hand-held sequencers show promise for more practical and immediate applications, such as species identification in the field. Efforts are also underway to identify comparable barcoding genes for other organisms like plants and fungi, which may not have as much variability in the COI sequence or face complexities such as introns in the gene.
Based on information in the lesson, which of the following foods is most likely to be imported?
A.) lettuce
B.) almonds
C.) shrimp
D.) strawberries
Answer:
The answer would definitely be C.) Shrimp
Explanation:
In the United States, the FDA estimates that one-third of our fruit and nuts and one-eighth of our vegetables come from other countries. Only about 10 percent of our meat is imported. Imports of meat come mostly from Canada, Australia, and New Zealand. About 80 percent of our fish and shellfish is imported. These imports come mostly from China, Thailand, and Canada.
On the basis of the lesson, the food that is most likely to be imported is known as shrimp. Thus, the correct option for this question is C.
What is Food import?Food import may be defined as the process that involves the movement of food and its derivative products into the Europian union from countries outside the EU. It also explains the migration of food from other countries to their own country.
When we talk about the United States, it is estimated that approximately 35% of fruits and nuts and 15% of vegetables approaches from other countries of the world.
Apart from this, about 80-85% of the fish and shellfish are also imported from different countries like China, Canada, Russia, Thailand, etc.
Therefore, the food that is most likely to be imported is known as shrimp. Thus, the correct option for this question is C.
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What is the function of the palisade mesophyll cells
Palisade cells are found in the mesophyll of a leaf and their main function is the absorption of light so that photosynthesis can take place. The palisade mesophyll consists of chloroplasts with chlorophyll that absorb the light energy. The mesophyll layer is made up of the palisade cell and spongy parts.
Final answer:
Palisade mesophyll cells are specialized for photosynthesis, packed with chloroplasts to maximize light capture, and work in tandem with the spongy mesophyll to facilitate gas exchange.
Explanation:
The function of palisade mesophyll cells in plant leaves is primarily to carry out photosynthesis. These cells, as their name suggests, form the palisade mesophyll layer located just below the upper epidermis of dicot leaves. The cells are elongated and densely packed with chloroplasts, which are essential for capturing light energy and converting it into chemical energy through the process of photosynthesis. The palisade mesophyll's structure, with its tightly packed columnar cells, maximizes light absorption. Additionally, below this layer is the spongy mesophyll, which has more loosely packed cells to facilitate gas exchange. Together, the palisade and spongy mesophyll layers make up the mesophyll and play a crucial role in the plant's ability to synthesize food and intake carbon dioxide while releasing oxygen.
during what phase do chromosomes move to the middle of the cell
Estuaries are characterized by _[blank]_.
the presence of fresh water and salt water
fast-moving water
coral reefs
chemosynthetic bacteria
Final answer:
Estuaries are characterized by the mixing of fresh water and salt water, resulting in brackish water with variable salinity that influences the lives and adaptations of many aquatic organisms.
Explanation:
Estuaries are characterized by the presence of fresh water and salt water. These biomes are unique areas where a freshwater source like a river meets the ocean, resulting in a mix of fresh and salt water that creates a diluted (brackish) saltwater environment. Estuaries are crucial for the lifecycle of many aquatic species, providing a protected area for the young offspring of crustaceans, mollusks, and fish. The salinity in these areas can vary greatly and plays a significant role in the adaptations of the organisms living there. These environments experience twice-daily changes due to tides, which can bring challenges for the flora and fauna, such as the need for halophytes, plants that tolerate salty conditions, and behavioral adaptations in animals like mussels and clams.
Question 1 unsaved in the experiment, resistance will be measured using what instrument? question 1 options:
a.ph meter
b.voltmeter
c.multimeter
d.pipet
e.balance
the answer is multimeter
Sylvia's name means "forest." how does this aid in her characterization?
it aids her because it is part of her name and it is helping her by letting her know that she is one of a kind
Which of the following elements would NOT be typically found in an mRNA molecule?5′ untranslated regionPromoter3′ untranslated regionStart and stop codonsProtein-coding region
The correct answer is: Promoter
Promoter is a sequence on DNA molecule that initiates transcription of a particular gene (RNA polymerase binds to a promoter).
mRNA is a product of transcription from DNA and it has
5′ untranslated region-
Protein-coding region- composed of codons that caries the information for protein synthesis (translation).
Start (the first codon, usually AUG triplet) and stop codons (the last codon for the termination of translation)
3′ untranslated region-after the start codon, usually responsible for mRNA stability and localization.
Brenda made the heliocentric model shown below to represent the sun, universe, Mercury, and solar system.
The picture shows a rectangle. Within the rectangle there is an oval. At the center of the oval there is a rhombus. On the right of the rhombus, within the oval, there is a symbol showing a small circle within a slightly larger circle, the two circles being concentric. On the right of the picture the key shows A equals rectangle, B equals oval, C equals rhombus, and D equals concentric circles.
What does the symbol for D in Brenda's diagram most likely represent? (2 points)
sun
universe
Mercury
solar system
D most likely equals Mercury
Answer:
The correct answer is option C, mercury
Explanation:
As per the Brenda’s venn diagram of Universe, the symbols used in this figure represents the following -
The rectangle shape – This represents the universe as it is the outermost shell that consist of solar system
The oval shape – This represents the solar system as the it is a galaxy of star. There are several galaxies of star that lies with in the universe.
The rhombus – The rhombus represents the center of the solar system and considering the heliocentric model of solar system, the sun lies at its center
The concentric circle – this represents mercury as it is a celestial body that revolve around the sun.
Which of the following chordates is most likely to look least like other chordates?
a. adult tunicate b. lancelet c. embryonic human d. larval tunicate e. adult human
Adult tunicates is most likely to look least like other chordates.
What is Adult tunicates?Sea squirts are another name for tunicates. Simple creatures are adult tunicates. They resemble a barrel-shaped bag with two siphons or apertures through which water flows. They use one siphon to suck water into their bodies, filter out food like plankton, and then use the second siphon to discharge the leftover water.
Tunicates remain affixed to a stationary object, such as a rock, throughout adulthood. Tunicates resemble little tadpoles while they are in the larval stage. They are capable of swimming and possess the notochord, dorsal nerve cord, and pharyngeal slits of chordates.
Tunicates develop a sticky material as they get older, which helps them stick to rocks or other fixed surfaces. Its body absorbs all of the structures in the area once they are linked to a surface.
Therefore, Adult tunicates is most likely to look least like other chordates.
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The major function of the _[blank]_ is to filter waste out of the blood.
kidney
small intestine
bladder
lung
Answer:
Kidney
Explanation:
Which of the following is the correct sequence of events for muscle contractions?a) motor neuron action potential, meurotransmitter release, muscle cell action potential, release of calcium ions from SR, AtP-driven power stroke, sliding of myofilamentsb) neurotransmitter release, muscle cell action potential, motor reuron action potential, release of calcium ions from SR, sliding of myofilaments, ATP-driven power strokec) muslce cell action potential, neurotransmitter release, atp-driven power stroke, calcium ion release from SR, sliding of myofilamentsd) neurotransmitter rlease, motor neuron cation potential, muscle cell action potential, release of calcium ions from SR, ATP-driven power stroke
The answer is; A
When an impulse from the motor neuron reached the neuromuscular junction, the voltage-dependent calcium channels are activated and the neurotransmitter released from the presynaptic cleft. When the neurotransmitter binds to their receptors on the sarcolemma, the muscle fibers become depolarised; the calcium is released from their vesicles. The Ca2+ ions are important in the power stroke because they bind to troponin. Upon binding calcium, troponin moves tropomyosin away from the myosin-binding sites on actin. Powered by the energy from ATP molecule, the myosin is able to bind on the actin and slides over the actin filament.
The binding of the neurotransmitter to receptors on the motor end plate causes which of the following to occur?
Binding causes voltageÂgated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell.
Binding causes chemically gated potassium channels to open in the motor end plate (junctional folds of the sarcolemma) and potassium enters the cell.
Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell.
Binding causes potassium voltageÂgated channels to open in the motor end plate (junctional folds of the sarcolemma) and potassium enters the cell.
The correct answer is: Binding of the neurotransmitter causes chemically gated sodium channels to open in the motor end plate (junctional folds of the sarcolemma) and sodium enters the cell.
Action potential travels through the membrane of the presynaptic cell causing the voltage-gated channels permeable to calcium ions to open. Ca2+ flow through the presynaptic membrane and increase the Ca concentration in the cell which will activate proteins attached to vesicles that contain a neurotransmitter (e.g. acetylcholine). Vesicles fuse with the membrane of the presynaptic cell, thereby release their contents into the synaptic cleft-space between the membranes of the pre- and postsynaptic cells. Neurotransmitter ACh binds to its receptors on the postsynaptic membrane and its binding causes depolarization of the target cell (muscle cell). Depolarization occurs because sodium enters the cell as a result of neurotransmitter receptor binding.
Populations of _________ live in the human large intestine. These benficial organisms help make certain vitamins and digest polysaccharides.
Food live in the human large intestine
Populations of bacteria live in the human large intestine. These beneficial organisms help make certain vitamins and digest polyacrylamide.
So the answer is bacteria .
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Which process can be used to power your home. Solar thermal energy solar electric energy both neither
Which describes the light-dependent stage of photosynthesis?
(Select all that apply.)
A. Photosynthetic pigments absorb energy from light.
B. Carbon dioxide is incorporated into a preexisting sugar molecule.
C. Water is split, which produces oxygen.
D. Hydrogen ions (H+) are moved against their concentration gradient.
Answer: Option A and Option C
Explanation:
The whole procedure of photosynthesis takes place in two stages of photosynthesis.
It includes light dependent reaction and light independent reactions or dark reaction.
The light dependent reaction includes absorption of light energy. The green pigment known as chlorophyll is required to absorb sunlight and convert it into chemical energy.
During this process the water is broken down into H+ ions and Oxygen is released into the environment.
So, the correct answer is option A and Option C
A worker uses a jackhammer to break up a sidewalk. What kind of waves does the jackhammer produce
Answer:
Longitudinal waves
Explanation:
These are also similar to the P-waves of an earthquake. They are transmitted by the compression and rarefaction of the molecules of the medium as it propagates along. The wave radiates outwards from the point where the jackhammer hits the sidewalk.
Bottled water is regulated by the ______, whereas tap water is regulated by the ______.
Bottled water is regulated by the FDA (Food and Drug Administration), whereas tap water is regulated by the EPA (Environmental Protection Agency).