What mechanism prevents or slows some chemicals from entering the brain, while allowing others to enter?

Answers

Answer 1

Answer:

The blood brain barrier blocks chemicals from entering brain tissue.

Explanation:


Related Questions

When curare, a neuromuscular poison, is dropped onto an isolated muscle-nerve preparation in a laboratory, the muscle does not contract when the nerve is stimulated, even though neurotransmitter is released from the nerve cell. Why does this happen

Answers

Answer:

Explanation:

Whenever the nerve terminal's action potential depolarizes, calcium enters the cell through the channels. Calcium allows acetylcholine (ACh) to be released more easily.  These ACh molecules subsequently circulate into the synaptic cleft and attach to the motor end-plate of the nicotinic cholinergic receptors. Acetylcholine molecules connect to nicotine ion-channel receptors present on cell membrane the of muscle cells, enabling the ion channels to open. Calcium ions then enter the muscle cell, kicking off a series of events that eventually result in muscular contraction.

Curare is a kind of neuromuscular relaxant blocker that is non-depolarized in nature. Nondepolarizing muscle relaxants work as competitive agonists, binding to ACh receptors but failing to activate ion channels. As a result, they inhibit ACh from bonding, preventing the development of endplate potentials and inducing muscle paralysis.

Which food has the greatest amount of polyunsaturated fat?

Answers

there are multiple foods that do, some examples are:
walnuts
sunflower seeds
fish
There are multiple foods

The bacterium Methylophilus methylotrophus can use methanol and ammonia for protein synthesis. The glutamate dehydrogenase gene from E. coli was introduced into M. methylotrophus using recombinant DNA techniques. Under high ammonia conditions, the introduction of the glutamate dehydrogenase gene into M. methylotrophus resulted in an increase in protein yield. Select the statements that are reasonable explanations for the increased protein yield in the modified M. methylotrophus. Glutamate dehydrogenase catalyzes the formation of glutamate and glutamine in a two-step process. Both glutamate and glutamine play a key role in amino acid synthesis, thus an increase in levels of glutamate and glutamine increase protein synthesis. Glutamate dehydrogenase has a low affinity for NH^+_4, and can only catalyze the formation of glutamate from alpha-ketoglutarate and NH^+_4, when the concentration of NH^+_4 is high. Glutamate dehydrogenase has a high affinity for NH^+_4, thus the rate of glutamate synthesis increases exponentially under high ammonia conditions. Glutamate is the amino group donor for most transamination reactions involving amino acids, thus an increase in glutamate concentration increases protein synthesis.

Answers

Answer:

- Glutamate dehydrogenase has a low affinity for NH+4, and can only catalyze the formation of glutamate from alpha-ketoglutarate and NH+4, when the concentration of NH+4 is high.  

- Glutamate is the amino group donor for most transamination reactions involving amino acids, thus an increase in glutamate concentration increases protein synthesis.

Explanation:

Glutamate dehydrogenase (GLDH) is an enzyme found in prokaryotic and eukaryotic cells, which is known to catalyze the reversible oxidative deamination of glutamate (Glu) to alpha-ketoglutarate and ammonia at the same time the oxidation of NADH to NAD. In bacteria, this enzyme (GLDH) is efficient only at high concentrations of the ammonium cation (NH4+), because it has a low affinity for NH4+. Moreover, transamination is a pathway that involves the transfer of an amino group from one amino acid to a ketoacid in order to form new amino acids (this reaction is responsible for the deamination of most amino acids). Glu is the donor of amino groups in most of the reactions catalyzed by enzymes involved in the transamination between an amino acid and an alpha-keto acid. In consequence, in presence of GLDH, a high concentration of Glu will increase the production of new amino acids and therefore also protein synthesis.

Which gas is exhaled along with used air?




SCIENCE QUESTION... ☺️​

Answers

Explanation:

When we take a breath, we pull air into our lungs that contains mostly nitrogen and oxygen. When we exhale, we breathe out mostly carbon dioxide.

a phlebotomy technician has collected a neonatal screening card. which of the following actions should the technician take to properly dry the blood stop collection card?

Answers

Answer:

place the card on a flat dry surface

Select the correct answer.
How does the high specific heat of water help maintain the temperature of earth?
A By heating and cooling more slowly than land or air
B. By heating and cooling faster than land or air
с.
By heating faster but cooling more slowly than land or air

Answers

i’m pretty sure it is B

The high specific heat of water help maintain the temperature of the Earth by heating and cooling more slowly than land or air. Thus, the correct option is A.

What is the specific heat of water?

The specific heat of an object is the amount of heat which is required to increase or raise the temperature of unit mass of that particular substance through one degree celsius. Specific heat is represented by the symbol 'c'. Its unit in SI system is Joule /(kg °C) and in CGS is cal / (gm °C).

The high specific heat of water helps in regulating the rate at which air changes its temperature, which is why the temperature of the planet change between different seasons is gradual rather than sudden, especially the geographical locations near the ocean.

Therefore, the correct option is A.

Learn more about Specific heat here:

https://brainly.com/question/11297584

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Explain why you would recommend the nguni cattle meat to consumers in your locality.​

Answers

Answer:

Below

Explanation:

All different combinations were catalogued in the beginning of the century by a South African herdmaster. This work inspired the Nguni Cattle Register, a compilation of terms to describe in full a Nguni cow or bull. The cattle are medium-sized, with bulls weighing between 500 and 600 kg,[3] while cows weigh between 300 and 400 kg.

Which of the following techniques employs a probe consisting of a labeled, single-stranded DNA of known sequence that can find and bind to a complementary sequence present in a large sample of different DNA sequences?

a. DNA hybridization
b. RFLP
c. PCR
d. DNA sequencing

Answers

Answer:

Explanation:

PCR

Gina is lactose intolerant but she loves to eat cheesy fries from her local restaurant. What do you suggest Gina does differently so she gets the same nutrients but does not suffer with the bloating and pain she feels after eating cheesy fries?

a. Eat a smaller portion of fries and order a cup of vegetable soup.
b. Add jalapeño peppers to the fries since the spice will counteract the effects of the dish.
c. Order macaroni and cheese instead.
d. Ask for a low-fat cheese option

Answers

Answer:

A

Explanation:

Its the most logical one

Which of the following is true
about true-breeding plants if they are allowed to self-pollinate?

A. They never have offspring with the same traits as the parent plant.

B. They have offspring with traits that are identical to the parent plant with one or two differences.

C. They always have offspring with traits identical to the parent plant.

Answers

Answer:

b

Explanation:

some are the same while others are different (traits)

The Earth and the moon are kept in orbit by gravity and mass. Please select the best answer from the choices provided T F

Answers

Answer:

True

Explanation:

the Earth and the Moon are kept in orbit by gravity and mass.

Answer:

True (T)

Explanation:

Yeah, the Earth and the moon are kept in orbit by gravity and mass. Hence, this statement is True (correct).

Which nutrient cycle has NO atmospheric (gas) form

A) Carbon

B) Nitrogen

C) Phosphorus

D) Water

Answers

Answer:

c.) phosphorus

Explanation:

it can be found in the atmosphere as very little dust particles

A cell has twice as many mitochondria as a typical cell. It also has a large amount of rough ER. What functions
might that cell have?

Answers

Answer:

below

Explanation:

While alive, an organism absorbs (radioactive) carbon 14 at such a rate that the proportion of carbon 14 in the organism remains at a known constant level. When it dies, it no longer absorbs carbon 14, so its proportion of carbon 14 begins to decrease. The half-life of carbon 14 is 5,600 years. A human skeleton is discovered whose level of carbon 14 is 15% that of a living human. To the nearest 100 years, how long ago did the person die

Answers

Answer:

The person has been dead for approximately 15,300 years

Explanation:

Available data:

The half-life of carbon 14 is 5,600 yearsThe human skeleton level of carbon 14 is 15% that of a living human

To answer this question we can make use of the following equation

Ln (C14T₁/C14 T₀) = - λ T₁

Where,

C14 T₀ ⇒ Amount of carbon in a living body at time 0 = 100%C14T₁ ⇒ Amount of carbon in the dead body at time 1 = 15% λ ⇒ radioactive decay constant = (Ln2)/T₀,₅T₀,₅ ⇒ The half-life of carbon 14 = 5600 yearsT₀ = 0T₁ = ???

Let us first calculate the radioactive decay constant.

λ = (Ln2)/T₀,₅

λ = 0.693/5600

λ = 0.000123

Now, let us calculate the first term in the equation

Ln (C14T₁/C14 T₀) = Ln (15%/100%) = Ln 0.15 = - 1.89

Finally, let us replace the terms, clear the equation, and calculate the value of T₁.

Ln (C14T₁/C14 T₀) = - λ T₁

- 1.89 = - 0.000123 x T₁

T₁ = - 1.89 / - 0.000123

T₁ = 15,365 years

The person has been dead for approximately 15,300 years

Without replication, organisms could not successfully


move.

grow and reproduce.

feed.

make proteins.

Answers

Answer: grow and reproduce

Explanation:

information of vertebrates mammal​

Answers

Answer:

A vertebrate is an animal with a spinal cord surrounded by cartilage or bone. The word comes from vertebrae, the bones that make up the spine. Animals that are not vertebrates are called invertebrates. Vertebrates are adapted to life underground, on the surface, and in the air. They feed upon plants, invertebrate animals, and one another. Vertebrate faunas are important to humans for food and recreation.Vertebrate Classes

Agnatha (Jawless Fish) Aves (Birds) Amphibia (Amphibians) Chondrichthyes (Rays, Sharks, Skates) Mammalia (Mammals) Osteichthyes (Bony Fish) Reptilia (Reptiles)

Explanation:

The graph below shows the changes in the number of species in an ecosystem
Species Diversity
300
200
Number of Species
|..
100
و 12 19 0
1989
1994
1980
Year
Which event was most likely the cause of the changes in species diversity in this ecosystem?
A large volcanic eruption
B A flash flood
Amatorado
D Amigration of cuts

Answers

A flash flood because it could wipe out people

how many homologous pairs of chromosomes are present in a haploid cell that has 8 chromosomes and is in anaphase II of meiosis ll? explain your answer

Answers

Answer:

In many ways, meiosis is a lot like mitosis. The cell goes through similar stages and uses similar strategies to organize and separate chromosomes. In meiosis, however, the cell has a more complex task. It still needs to separate sister chromatids (the two halves of a duplicated chromosome), as in mitosis. But it must also separate homologous chromosomes, the similar but nonidentical chromosome pairs an organism receives from its two parents.

These goals are accomplished in meiosis using a two-step division process. Homologue pairs separate during a first round of cell division, called meiosis I. Sister chromatids separate during a second round, called meiosis II.

Since cell division occurs twice during meiosis, one starting cell can produce four gametes (eggs or sperm). In each round of division, cells go through four stages: prophase, metaphase, anaphase, and telophase.

Some microorganisms cause human disease. Other microorganisms are used in making cheese, yogurt, and bread. Based on this information, the relationship between humans and microorganisms can be

A) beneficial, only
B) harmful, only
C) beneficial or harmful

Answers

the correct answer is c

WRITE THE DEFINITIONS OF EACH ANIMAL ORGANELLE LISTED. (1) nucleolus (2) nucleus (3) ribosome (4) vesicle (5) rough endoplasmic reticulum (6) Golgi apparatus (7) cytoskeleton (8) smooth endoplasmic reticulum (9) mitochondria (10) vacuole (11) cytosol (12) lysosome (13) centriole

Answers

Answer: nucleolus: a small dense spherical structure in the nucleus of a cell during interphase. nucleus: the positively charged central core of an atom, consisting of protons and neutrons and containing nearly all its mass. ribosome: a minute particle consisting of RNA and associated proteins found in large numbers in the cytoplasm of living cells. They bind messenger RNA and transfer RNA to synthesize polypeptides and proteins. vesicle: a small fluid-filled bladder, sac, cyst, or vacuole within the body. rough endoplasmic: reticulum (RER), series of connected flattened sacs, part of a continuous membrane organelle within the cytoplasm of eukaryotic cells, that plays a central role in the synthesis of proteins. Golgi apparatus: a complex of vesicles and folded membranes within the cytoplasm of most eukaryotic cells, involved in secretion and intracellular transport.

Explanation:

How many kinds of mosquito are common in Nepal l​

Answers

there are 130 kinds of mosquito are common in Nepal l

definition of human rights

Answers

Answer: a right that is believed to belong justifiably to every person.

Explanation:

Answer:

Human rights are standards that allow all people to live with dignity, freedom, equality, justice, and peace. Every person has these rights simply because they are human beings.

Explanation:

Human rights are rights inherent to all human beings, regardless of race, sex, nationality, ethnicity, language, religion, or any other status. Human rights include the right to life and liberty, freedom from slavery and torture, freedom of opinion and expression, the right to work and education, and many more.

•. otal genomic structure of an organism inherited from parents is known as -
a) Gene
b) Allele
c) Phenotype
d) Genotype​

Answers

I think the answer is a sorry if I get it wrong

Scientists have been studying the size of three populations in a river in Ireland. In this ecosystem, pike (a type of big fish), and perch eat snails. The data showed that all three populations were stable. Then the snail population increased suddenly. What will likely happen to the size of the perch population as a result? The size of the perch population will...

Options:

A. Stay the same. The size of it's consumer population did not change, so the number of deaths in the perch population did not change. There will be the same number of births and deaths in the perch population.

B. Decrease. The larger snail population will take more energy storage molecules from the ecosystem, leaving fewer available for the perch population. This will lead to more deaths than births in the perch population.

C. Increase. The larger snail population will provide more energy storage molecules for the perch population, so they will reproduce more. This will lead to more births than deaths in the perch population.

D. Increase. An increase in any population within an ecosystem will lead to an increase in the sizes of all other populations in the ecosystem.

Answers

Answer:

C. Increase. The larger snail population will provide more energy storage molecules for the perch population, so they will reproduce more. This will lead to more births than deaths in the perch population.

Explanation:

14. What do the embryos of different vertebrate species have in common?​

Answers

Answer:

Similarities in embryos are evidence of common ancestry. All vertebrate embryos, for example, have gill slits and tails. Most vertebrates, except for fish, lose their gill slits by adulthood.

Explanation:

itz from gologolo lol I hope it helps uh

keep smiling #smilies

What is a plant nucleus

Answers

Answer:

All plant cells contain a nucleus, a structure that stores DNA and acts as a cell's command center. It is surrounded by the nuclear envelope and is filled with nucleoplasm. ... DNA is copied during DNA replication for new cells, as well as copied to RNA to make proteins in the nucleus.

What is the role of RNA?

Answers

Answer:

It is the 1st one ○ to provide the original blueprint for protein production

Explanation:

RNA polymerase (green) synthesizes RNA by following a strand of DNA. RNA polymerase is an enzyme that is responsible for copying a DNA sequence into an RNA sequence, duyring the process of transcription.

what is cyclin dependent kinase?​

Answers

Answer:

please mark as brainliest answer as it will also give you 3 points

Explanation:

Cyclin-dependent kinases (CDKs) are the families of protein kinases first discovered for their role in regulating the cell cycle. They are also involved in regulating transcription, mRNA processing, and the differentiation of nerve cells.[1] They are present in all known eukaryotes, and their regulatory function in the cell cycle has been evolutionarily conserved. In fact, yeast cells can proliferate normally when their CDK gene has been replaced with the homologous human gene.[1][2] CDKs are relatively small proteins, with molecular weights ranging from 34 to 40 kDa, and contain little more than the kinase domain.[1] By definition, a CDK binds a regulatory protein called a cyclin. Without cyclin, CDK has little kinase activity; only the cyclin-CDK complex is an active kinase but its activity can be typically further modulated by phosphorylation and other binding proteins, like p27. CDKs phosphorylate their substrates on serines and threonines, so they are serine-threonine kinases.[1] The consensus sequence for the phosphorylation site in the amino acid sequence of a CDK substrate is [S/T*]PX[K/R], where S/T* is the phosphorylated serine or threonine, P is proline, X is any amino acid, K is lysine, and R is arginine.[1]

Which of the following findings would lead you to determine that an infant's airway is open

Answers

Answer:

blowing air into his/her mouth and checking for an increase in the thoracic region........I GUESS

Phân tích các yếu tố cho thấy ĐẤT là môi trường đa dạng nhất về các loại sinh vật?

Answers

.... what you wrote isn’t a question.... you wrote a statement.....

Here is what you wrote translated to English

Analysis of factors shows that SOIL is the most diverse environment in terms of organisms?

Answer:

I don't no answer sorry

Explanation:

follow

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