Answer:
You have to finish putting the question
Explanation:
Which of the following kingdoms does not
include eukaryotes?
a. Protista
b. Bacteria
c. Fungi
d. Plantae
Answer:
Bacteria
Explanation:
Bacteria and Archaea are prokaryotes, while animals, plants, fungi, and protists are eukaryotes
Happy Holidays!
Which of the following would most likely promote random distribution?
A) territorial species
B) species that secrete chemicals to attract or inhibit other individuals
C) flocking and schooling behaviors
D) spacing during the breeding season
E) homogeneous chemical and physical factors in the environment
Flocking and schooling behaviours would almost certainly promote random distribution.
Flocking is indeed the phenomenon in which individuals move at roughly the same speed and remain as a group. Flocking animals vary in size from buffalo to bacteria.
'Flocking,' in which 'animals' move in formation. Sheep are an excellent example of flocking throughout nature, with one leader as well as the rest following. Zebras also stick together, which makes each other safe and secure; it's difficult for such a predator to tell one zebra apart from the rest.
In in addition to determining simple density, the distribution of individuals can provide additional information about a population. At a given point in time, species distribution patterns summarise the spatial relationship between a population's members within a habitat.
To know more about the Behaviours, here
https://brainly.com/question/28616660
#SPJ4
Who was the first to identify DNA and what was the name given to it by him Class 12?
Answer:
The molecule now known as DNA was first identified in the 1860s by a Swiss chemist called Johann Friedrich Miescher. Johann set out to research the key components of white blood cells. part of our body's immune system. The main source of these cells was pus-coated bandages collected from a nearby medical clinic.
Explanation:
What is another word for atherosclerosis?
Atherosclerosis, also called "hardening of the arteries," occurs when fat, cholesterol, and other substances build up in the walls of your arteries.
Arteriosclerosis is a type of arteriosclerosis in which abnormalities called lesions occur in the walls of arteries. Due to the accumulation of atherosclerotic plaques, these lesions can lead to strictures. There are usually no symptoms in the early stages, but when symptoms do occur, they usually appear in middle age. Depending on which artery is affected, it can lead to coronary artery disease, stroke, peripheral artery disease, or kidney problems.
Atherosclerosis usually begins in childhood and worsens with age. Nearly everyone is affected to some extent when they turn 65. It is the leading cause of death and disability in developed countries. Because arteries dilate at all plaque sites, blood flow remains unaffected and atherosclerosis remains asymptomatic for decades.
Peripheral arteries that supply blood to the legs, arms, and pelvis are also severely narrowed by plaque tears or blood clots. Numbness and pain in the arms and legs are symptoms of contractions.
To learn more about Atherosclerosis, here
https://brainly.com/question/29626891
#SPJ4
List the significant events of glycolysis. Include which reactants and products (if any) are involved. Highlight what will be released as a product and what will move on to the next stage. Be sure to include where the process occurs in the cell.
Answer:
Glycolysis is a series of chemical reactions that occurs in the cytosol of cells. These reactions are an important part of the process of cellular respiration, which produces energy for the cell.
The key events of glycolysis include the following:
The conversion of glucose to glucose-6-phosphate by the enzyme hexokinase. This reaction requires the input of ATP.
The conversion of glucose-6-phosphate to fructose-6-phosphate by the enzyme phosphoglucose isomerase.
The conversion of fructose-6-phosphate to fructose-1,6-bisphosphate by the enzyme phosphofructokinase. This reaction requires the input of ATP.
The cleavage of fructose-1,6-bisphosphate into two three-carbon molecules, dihydroxyacetone phosphate and glyceraldehyde 3-phosphate, by the enzyme aldolase.
The conversion of glyceraldehyde 3-phosphate to 1,3-bisphosphoglycerate by the enzyme glyceraldehyde 3-phosphate dehydrogenase. This reaction results in the production of NADH.
The conversion of 1,3-bisphosphoglycerate to 3-phosphoglycerate by the enzyme phosphoglycerate kinase. This reaction results in the production of ATP.
The conversion of 3-phosphoglycerate to 2-phosphoglycerate by the enzyme phosphoglycerate mutase.
The conversion of 2-phosphoglycerate to phosphoenolpyruvate by the enzyme enolase.
The conversion of phosphoenolpyruvate to pyruvate by the enzyme pyruvate kinase. This reaction results in the production of ATP.
The end products of glycolysis are two molecules of pyruvate, two molecules of NADH, and a net gain of two molecules of ATP. In the presence of oxygen, pyruvate can be further oxidized in the mitochondria to produce more ATP. In the absence of oxygen, pyruvate is converted to lactate in a process called fermentation
Explanation:
What 6 things do most bacteria need to grow?
Most bacteria need the following six things to grow, Nutrients, Water, Temperature, pH, Oxygen, and Time.
Nutrients: Bacteria require a source of energy and building blocks, such as carbohydrates, lipids, proteins, and minerals, in order to grow and reproduce.
Water: Bacteria need water to survive and grow, as it is essential for many of the chemical reactions that occur within cells.
Optimal temperature: Different types of bacteria have different temperature requirements for growth, but most bacteria grow best within a relatively narrow range of temperatures.
pH: Bacteria have optimal pH ranges for growth, and some are more tolerant of pH changes than others.
Oxygen: Some bacteria require oxygen to grow, while others are able to grow in the absence of oxygen.
Time: Bacteria need time to grow and reproduce, with different species having different generation times.
Overall, these six factors are essential for the growth of most bacteria, and the presence or absence of these conditions can significantly impact the ability of bacteria to grow and reproduce.
Learn more about Bacteria here:
https://brainly.com/question/8695285
#SPJ4
What does cyanide do to the body?
Answer:
Cyanide prevents the cells of the body from using oxygen. When this happens, the cells die. Cyanide is more harmful to the heart and brain than to other organs because the heart and brain use a lot of oxygen
What is the importance of coral reefs to the global environment and economy?
Coastlines can be saved from storms and erosion by coral reefs. Coral reefs create job opportunities for the local communities and offer scopes for recreation.
A variety of food and new medicines can be derived from coral reefs. Commercial fisheries as well as businesses through tourism can be conducted through healthy coral reefs. Approximately half of all federally controlled fisheries are dependent on coral reefs and related habitats for a portion of their life cycles.
By conducting diving tours, recreational fishing trips, and installing hotels, restaurants, and other businesses local economies also earn billions of dollars from visitors.
Though coral reefs have great economic and recreational value, they are severely threatened by pollution, disease, and habitat destruction. Once coral reefs are damaged, many creatures that inhabit them would not get any support for their survival. At the same time, it may also lose value as a tourist destination
Read more about Coral reefs:
https://brainly.com/question/29406837
#SPJ4
What are the effects of cystic fibrosis genetic mutations?
Mutations in the CFTR gene cause the CFTR protein to malfunction or not be made at all, leading to a buildup of thick mucus, which in turn leads to persistent lung infections.
What do you mean by mutations?Mutations is any change in the DNA sequence of a cell. Mutations may be caused by mistakes during cell division, or they may be caused by exposure to DNA-damaging agents in the environment.
Mutations can result from errors in DNA replication during cell division, exposure to mutagens or a viral infection. Germline mutations can be passed on to offspring, while somatic mutations are not passed on.
Harmful mutations may cause genetic disorders or cancer. A genetic disorder is a disease caused by a mutation in one or a few genes. A human example is cystic fibrosis.
Learn more about mutations:
https://brainly.com/question/17130462
#SPJ4
How GM foods are and/or can negatively impact the environment?
The main concerns about GMOs revolve around allergies, cancer, and environmental issues, all of which may have an impact on the consumer.
Crops do not harm the environment simply because they are genetically modified. Some farming practises, such as the excessive use of herbicides, which results in the eradication of wild plants from farmland, have been shown to be harmful to the environment. These issues apply to both types of crops, non-GM and GM.
The most serious GMO risks to humans are the development of allergens to GM-related crops and toxicity from GM crops. However, studies show that GM crops have advantages, such as increased nutritional value in foods.
Genetically Modified foods are intended to be healthier and less expensive to produce. GMO foods have several advantages, including more nutrients, fewer pesticides, and lower prices. GMO foods can cause allergic reactions or increased antibiotic resistance.
To learn more about negative impact of GM foods, here
https://brainly.com/question/15731270
#SPJ4
Explain why restriction enzymes are used in the process of genetic engineering.
Answer:
Restriction enzymes are used in the process of genetic engineering because they can cut DNA at specific locations, allowing scientists to precisely modify the genetic material of an organism.
Restriction enzymes are enzymes that are found in bacteria and other microorganisms. They are used by these organisms to protect themselves from foreign DNA, such as that found in viruses. Restriction enzymes recognize specific sequences of nucleotides (the building blocks of DNA) and cut the DNA at those locations.
In genetic engineering, restriction enzymes are used to cut the DNA of an organism at specific locations. This allows scientists to insert new genetic material into the DNA, modifying the genetic makeup of the organism. For example, restriction enzymes can be used to insert a gene that confers resistance to a particular disease into the DNA of a plant or animal.
Overall, restriction enzymes are used in genetic engineering because they allow scientists to precisely modify the genetic material of an organism, allowing them to create genetically modified organisms with desired traits.
pls award brainliest!
Explanation:
What does the plant start with?
The assembly of a glucose molecule is the ultimate objective of the light-independent processes (or Calvin cycle). The CO2 that the plant absorbs from the air is needed for this stage of photosynthesis.
In essence, the plant requires carbon from CO2 to produce the precursors for glucose. A five-carbon molecule of ribulose biphosphate (RbP) and a carbon dioxide molecule are combined by an enzyme termed ruBisCo in the stroma. This results in the formation of two molecules with three carbons each, each of which has six carbons (3-phosphoglycerate). Carbon fixation is the name given to this phase of the light-independent processes.
The Calvin cycle normally consumes six molecules of carbon dioxide at a time, which is a crucial point to remember. This indicates that twelve G3P molecules are produced.
For more information on light-independent reaction kindly visit to
https://brainly.com/question/14287874
#SPJ4
Complete question: What does the plant start with in light independent reactions?
Explain the following statement... The stomach is an organ in which both physical and chemical digestion occurs.
The digestive system starts in the mouth. In fact, as soon as you eat your first mouthful of a meal, digestion begins here.
Your body mechanically breaks down food during physical digestion
chopping, smashing, or grinding it into smaller bits.
However, during chemical digestion, small proteins or enzymes change the food's structure, which is composed of several atoms connected together.
Chewing is merely a portion of the digestive process.
Digestional enzymes break down food as it moves from your mouth into your digestive system, transforming it into more easily absorbed nutrients.
Chemical digestion is the term for this disintegration.
To Know more about Digestion
Visit:
https://brainly.com/question/29028752
#SPJ1
blood is a fluid made up of several different parts. what level of structural organization best describes blood?
Blood is a fluid composed of numerous components. The tissue level of structural organization best describes blood.
In any multicellular organism, cells rarely work alone. Cells that are similar in structure and function are usually joined together to form tissues. Tissues are the second level of organization. Bone cells in your body from bone tissue, a strong solid tissue that gives you shape and support.
Blood cells in your body are part of blood tissue, a liquid tissue responsible for transporting food and oxygen throughout the body. Tissues are further organized in organs, the third level of organization in living things.
Know more about blood here: https://brainly.com/question/17030548
#SPJ4
What is the evidence from Studies 1 and 2 that capacitors and inductors worked in opposite ways?Passage III
A capacitor is the name for a device that stores electrical charge. Capacitance is the amount of charge that a capacitor can hold at a given voltage. In a science class, a teacher instructed her students to determine the charge on a parallel plate capacitor with a fixed capacitance. Students conducted a few different studies with this capacitor.
Study 1
Students constructed an electrical circuit with the capacitor, as shown in Figure 1. The capacitor was initially uncharged.
Students then charged the capacitor and recorded the voltage at specific time intervals. They then used a computer program to help them graph this information, which is recorded in Figure 2.
With this data, students then calculated the current at each time interval and recorded this information in Table 1. The students noted any trends and determined that voltage and current initially change rapidly before leveling out.
Study 2
The teacher then introduced students to an inductor and explained that, contrary to capacitors, which store energy in an electric field, inductors store energy in a magnetic field produced by the current running through the wire. As a result,
inductors oppose changes in current and act opposite of capacitors, which oppose changes in voltage. She then drew a diagram on the board for students, Figure 3.
The teacher then recorded the decay in voltage over time and represented this in a graph for students, as shown in Figure 4.
Finally, she plotted the drop in voltage and increase in current in a chart similar to the one that the students had produced in Study 1 (see Table 2).
Question 1 of 2
What is the evidence from Studies 1 and 2 that capacitors and inductors worked in opposite ways?
As time progressed, capacitor voltage increased while inductor voltage decreased.
As time progressed, capacitor voltage decreased while inductor voltage increased.
As time progressed, capacitor current increased while inductor current decreased.
The opposition of a capacitor to a change in voltage versus an inductor's opposition to a change in current is one of the key distinctions between the two devices.
What is a capacitor?Once more, a capacitor can be set up in many different ways. With an electric charge on each plate, the most basic design consists of two parallel conducting plates (but a net charge of zero).A magnetic field is produced inside the capacitor by the electric charge on these plates. An alteration in the electric potential across the plates is necessary because there is an electric field. Depending on how much is being charged, this potential difference's worth can vary. One way to express the capacitor's potential difference is as follows:Δvc = Q/C
Here, C, the capacitance measured in Farads, is only affected by the device's physical design.The value of the charge on the plates will change if a current is flowing into the capacitor. If there is a steady (or low frequency) current, this current will keep adding charge to the plates to raise the electric potential until finally, this potential will operate like an open circuit with the capacitor voltage being equal to the battery voltage (or power supply). The capacitor will behave as though it were not there if there is a high frequency current because the charge will be added to and subtracted from the plates in the capacitor without any charge buildup.To Learn more About capacitor refer To:
https://brainly.com/question/27393410
#SPJ1
Lactiferous sinuses merge at the ________ of the breast
The breast's Nipple is where the lactiferous sinuses merge.
In the slice, the primary lactiferous ducts meet at the nipple. Before any blue lobules are created, two large lactiferous channels are visible lengthwise to descend a few millimeters. In fact, this is nature's nursing bottle.
There are around nine milk ducts and nerves in each nipple. Areolae: The region of dark skin that surrounds the nipple and is round in shape is known as an areola.
The nipple is connected to about 15–20 ducts. When nursing, the nipple serves as an outlet for milk flow. Additionally, the nipple has smooth muscles that have the ability to erect the nipple.
Learn more about " Nipple " to visit here;
https://brainly.com/question/14368440
#SPJ4
Click on all of the true statements about blood pressure. Vasodilation increases blood pressure. Decreasing heart rate decreases blood pressure. Low blood pressure can cause health problems. Blood pressure decreases with distance from the heart. Pressure receptors in artery walls detect blood pressure. Increasing blood volume decreases blood pressure.
The true statements about blood pressure are b) Decreasing heart rate decreases blood pressure, c) Low blood pressure can cause health problems, d) Blood pressure decreases with distance from the heart.
A decrease in heart rate means that the time for the heart to pump blood will decrease. This will lead to a decrease in blood pressure.
Low blood pressure or high blood pressure both can cause health complications.
Blood pressure decreases with distance from the heart because the force with which the blood is pumped by the heart grows slower when away from the heart. Hence, those statements that are true to these objectives are true.
Other options, like option f is not true because increasing blood volume will increase blood pressure.
The question will correctly be written as:
Choose all the true statements about blood pressure.
a) Vasodilation increases blood pressure.
b) Decreasing heart rate decreases blood pressure.
c) Low blood pressure can cause health problems.
d) Blood pressure decreases with distance from the heart.
e) Pressure receptors in artery walls detect blood pressure.
f) Increasing blood volume decreases blood pressure.
To learn more about blood pressure, click here:
https://brainly.com/question/25149738
#SPJ4
Which of the following is not how botulism is contracted?
A) adults eating canned vegetables such as beets, carrots, or spinach
B) IV drug users who use needles contaminated with C. botulinum endospores
C) Elderly farmers encounter C. botulinum endospores through wind and dust.
D) Infants encounter C. botulinum endospores through wind and dust.
E) Infants encounter C. botulinum endospores by eating honey.
The process of acquiring botulism is not as follows. The wind and dust carry C. botulinum endospores to elderly farmers.
The bacteria Clostridium botulinum, as well as Clostridium butyricum and Difficile baratii, occasionally produce this toxin. These bacteria have the ability to create the poison in foodstuff, wounds, and newborns' intestines. The most frequent causes of botulism related to housing canning are low-acid foods. The pH of these meals is higher than 4.6. The majority of vegetables, some fruits, all proteins, fish, and other seafood, but also asparagus, bean sprouts, beets, wheat, and potatoes, are low in acid. Botulinum toxins are among the deadliest compounds yet known. Botulinum toxins can cause pulmonary and muscular paralysis by blocking neuronal functions.
Learn more about botulinum here:
https://brainly.com/question/28168466
#SPJ4
Which specific molecule is each food mostly made of?
Each food is mostly made of with carbohydrates, proteins and fat.
Sugar molecules make up carbohydrates, or carbs. One of the three primary nutrients included in meals and beverages, together with proteins and lipids, is carbohydrate.When your body breaks down carbohydrates, glucose is produced.Glucose, also referred to as blood sugar, is your body's main energy source for its cells, tissues, and organs.
Protein makes up the majority of the body's organs, tissues, and body parts, including muscle, bone, skin, and hair.It contributes to the production of haemoglobin, which transports oxygen in the blood, and enzymes, which drive numerous chemical reactions.
There are several different types of fats in food, including saturated, polyunsaturated, and monounsaturated fats. Consuming too much or the wrong kind of fat may not be healthy. Foods that include fats include butter, oil, nuts, meat, fish, and various dairy products, to name a few.
Learn more about fat from:
https://brainly.com/question/18934340
#SPJ4
a car owner decides to leave his car outside on a cold winter day. the next morning, the driver noticed ice on the windshield, a product of deposition. choose the best reason explaining this phenomenon. what happened?
Deposition occurs when water vapor in the air turns into a solid and is deposited onto a surface. When the air temperature is below the freezing point of water, any water vapor that comes into contact with a surface will freeze. In this case, the water vapor in the air likely condensed onto the cold surface of the windshield and froze, forming ice. So your anwser is deposition!
I tried my best and have a happy holidays!
The basic structure of a virus consists of?
The simplest virus is made up of two fundamental parts: a nucleic acid and a protein shell called a capsid. The capsid serves as a shell to protect the viral genome from nucleases and binds the virion to specific receptors on the potential host cell during infection.
What is the structure of a virus made up of?A virus is composed of a core of genetic material, either DNA or RNA, that is encased in a protein-based capsid that serves as its protective covering. The envelope, a second spikey coat, is occasionally present around the capsid. Viruses have the ability to attach to host cells and enter them.
The genetic material that makes up a virus particle is contained inside a capsid, which is a protein shell. A virus's genetic material, or genome, can be either circular or linear and can be made up of single- or double-stranded DNA or RNA.
They lack cytoplasm and other cellular organelles because they are acellular. They require the metabolic apparatus of the host cell to proliferate because they have no independent metabolism.
Thus, The simplest virus is made up of two fundamental parts: a nucleic acid and a protein shell called a capsid.
To learn more about the structure of the virus, follow the link;
https://brainly.com/question/1427968
#SPJ12
A Phage DNA +DNA forms a double- stranded circle. Slow release BHost cell slows reproduction while the phage progeny replicate particle c Cell replicates from circular single- stranded DNA. Phages assemble and exit without lysis EPhage inserts single-stranded DNA. List the steps of the slow-release bacteriophage replication cycle
The tiny icosahedral virus known as Bacteriophage X174 has a single-stranded, closed circular DNA molecule with 5,386 nucleotide bases (for a recent review, see ref. 1). Four of the eleven gene products (J, F, G, and H) contribute to the virion's structure.
The structure of the bacteriophage X174 has an impact on the process of DNA ejection, viral assembly, and evolution. The eight-stranded antiparallel barrel folding pattern that may be observed in many other icosahedral viruses is the main folding motif of the T = 1 capsid that the F protein generates. 12 dominant spikes made up of groups of five G proteins surround a hydrophilic channel with some diffuse electron density. Each G protein has a structure like that of a tight barrel, with its strands extending outward in a radial fashion F protein.
Learn more about DNA here
https://brainly.com/question/264225
#SPJ4
Why blood type B Cannot donate to blood type A?
How do you transcribe DNA to mRNA?
To transcribe DNA to mRNA, pre-mRNA is reused to form a mature mRNA patch that can be paraphrased to make the protein patch decrypted by the original gene.
Protein is set up throughout the body — in muscle, bone, skin, hair, and nearly every other body part or kerchief. It makes up the enzymes that power multitudinous chemical responses and the hemoglobin that carries oxygen in your blood.
DNA is the information patch. It stores instructions for making other large motes, called proteins. These instructions are stored within the cells, and than distributed among chromosomes. These chromosomes are made up of thousands of shorter corridor of DNA, called genes.
To learn more about DNA here
brainly.com/question/264225
#SPJ4
Can water snails asexually reproduce?
Yes, water snails can asexually reproduce. They have both female and male reproductive cells (hermaphrodite) and don't actually need to mate with another snail to reproduce, self fertilization is possible.
Why do snails reproduce asexually?They are hermaphrodite and hence reproduce asexually. Pond snails can also reproduce sexually. They lay jellylike masses of eggs under water on plants and on the sides of the container/aquarium and the eggs hatch in around 10–20 days depending on temperature.
In other words, we can say that, they carry both sperm and eggs and can reproduce without the help of another snail. But, some breeds, like apple snails, needs both a male and female for fertilization.
To know more about reproduction of water snails, refer
https://brainly.com/question/2737411
#SPJ4
A city has an outbreak of a disease that affects an unusually large portion of its population at the same time. which term best describes the outbreak?
Answer:
Epidemic best describes the outbreak.
How many total hydrogen bonds would there be between base pairs of A piece of DNA if the sequence of one side was ATCG ATCG?
Answer:2, 2, 3, 3 and 2
Explanation:If base order in one chain of DNA is "ATCGA" then the number of H bonds will be 2, 2, 3, 3 and 2 respectively for the given nucleotides to base pair. Thus, the total number of hydrogen bonds will be 12.
3- Knowing that the human diploid cell has 2n = 46 chromosomes, Indicate the number of:
a- Chromosomes in each cell obtained at the end of mitotic cell division and the number of chromatids per each chromosome.
b- Chromosomes and chromatids per each chromosome in the cell during metaphase of mitosis.
c- Chromosomes and chromatids per each chromosome in the cell during G1 of interphase.
d- DNA molecules in the cell during G1 of interphase and prophase of mitotic cell division.
e- DNA molecules in the gamete.
f- DNA molecules in the cell during Metaphase 1 of meiosis 1 and Prophase 2 of meiosis 2.
g-Chromosomes and chromatids per each chromosome in the cell during Metaphase 2 of meiosis 2.
h- Chromosomes and chromatids per each chromosome in each cell obtained at the end of meiosis 1.
i-Chromosomes and chromatids per each chromosome in each cell obtained at the end of meiosis 2.
Explanation:
Knowing that the human diploid cell has 2n = 46 chromosomes, Indicate the number of:
a- Chromosomes in each cell obtained at the end of mitotic cell division and the number of chromatids per each chromosome.
b- Chromosomes and chromatids per each chromosome in the cell during metaphase of mitosis.
c- Chromosomes and chromatids per each chromosome in the cell during G1 of interphase.
d- DNA molecules in the cell during G1 of interphase and prophase of mitotic cell division.
e- DNA molecules in the gamete.
f- DNA molecules in the cell during Metaphase 1 of meiosis 1 and Prophase 2 of meiosis 2.
g-Chromosomes and chromatids per each chromosome in the cell during Metaphase 2 of meiosis 2.
h- Chromosomes and chromatids per each chromosome in each cell obtained at the end of meiosis 1.
i-Chromosomes and chromatids per each chromosome in each cell obtained at the end of meiosis 2.
What are the 3 types of selection for a polygenic trait?
3 types Natural selection on polygenic traits can have three effects on phenotypic distributions are Directional selection, Stabilizing selection, Disruptive selection.
What is Directional selection?Directional selection occurs when individuals in a population with traits on one side of the mean outlive or reproduce more than those on the other.Stabilizing selection:When natural selection favors an average phenotype and selects against extreme variations, stabilizing selection reduces a population's genetic variance.When a population is exposed to environmental changes, its genetic variance shifts toward a new phenotype.Hence, 3 types of selection for a polygenic trait are Directional selection, Stabilizing selection, Disruptive selection.
To know more about Polygenic Trait visit:-
brainly.com/question/29918270
#SPJ4
to excite or inhibit an action potential in a receiving neuron, a neurotransmitter must cross the_____-
To excite or inhibit an action potential in a receiving neuron, a neurotransmitter must cross the synapse