Which of the following is true of the blood-brain barrier? a. The barrier is formed by cells that line the capillaries of the brain. b. The barrier is uniform, protecting all brain structures. c. The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells. d. The barrier pumps glucose out of the brain into the bloodstream.

Answers

Answer 1

Answer:

The barrier functions to regulate the chemical composition of the extracellular fluid surrounding the brain cells.

Explanation:

Blood-brain barrier

It is a very selective semipermeable membrane , hence allow some specific substance to pass via it . This barrier separates the  extracellular fluid in the central nervous system  and the circulating blood from the brain .

The barrier is composed of the endothelial cells .

Passive diffusion is shown in this system , and allows molecules like the water , glucose , amino acid to pass .

It regulates the chemical composition of the fluid of brain cell .

Answer 2
Final answer:

The blood-brain barrier, formed by cells lining the brain's capillaries, functions to regulate the chemical composition of the extracellular fluid surrounding brain cells, and isn't uniformly protecting all brain structures. Its primary role is not to pump glucose out of the brain into the bloodstream.

Explanation:

The blood-brain barrier (BBB) is crucial to the health and function of the Central Nervous System (CNS), notably the brain and spinal cord. Rooted in its unique arrangement of blood vessels, the BBB holds strict control over what can move out of the circulatory system and into the CNS, shielding it from toxins or pathogens that may be present.The barrier is indeed formed by cells lining the capillaries of the brain, primarily endothelial cells form tight junctions, limiting the transfer of blood components to the brain. This excludes most microbes, hence there is no normal microbiota in the CNS. Furthermore, the blood-brain barrier also functions to regulate the chemical composition of the extracellular fluid enveloping the brain cells, not to pump glucose out from the brain into the bloodstream.

However, it's not accurate that the BBB is uniformly protecting all brain structures. Certain areas of the brain, like the choroid plexus and parts of the hypothalamus, have a more permeable barrier to allow specific molecules to pass through.

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Related Questions

Wind is considered to be an abiotic becomes it

Answers

Wind is considered to be a biotic factor.

Chitin is a long-chain polymer derived from glucose. It strengthens cell walls of fungi and the outer covering (exoskeleton) of arthropods (including crabs, shrimps, and insects). The presence of chitin in these groups is likely due to ________.

Answers

Answer:

The correct answer is: convergent evolution              

Explanation:

Convergent evolution is a type of evolution, in which analogous traits or analogous structures are formed in organisms that are not closely related, due to their exposure to similar environmental conditions.

It is a type of independent evolution in which the species of different ancestry evolve analogous traits or structures in order to adapt to similar environmental conditions.

Therefore, the presence of chitin in the cell walls of fungi and the exoskeletons of arthropods is most likely due to convergent evolution.

[HELP ASAP]
Which line shows the reaction using an enzyme?


a. reaction 2


b. reaction 3


c. reaction 1


d. none of the reactions

Answers

Answer: b. reaction 3

Explanation: When an enzyme is present in a reaction acts as a catalyst, increasing velocity of reaction and decreasing the activation energy, when not present an enzyme the reaction velocity is very low and implies high activation energy, being unfavorable to the system

which of the following are not used to classify prokarynotes

a. cell shape

b. cell wall structure

c. type of nucleus

d. motility ​

Answers

Answer:

c. type of nucleus

Explanation:

Prokaryotes are called so because they do have genetic material but its not membrane bound and so an organelle defined as nucleus is not present.

Which of the choices below does NOT involve tissue perfusion?
A. absorption of nutrients from the digestive tract
B. blood clotting
C. gas exchange in the lungs
D. delivery of oxygen and nutrients to, and removal of wastes from, tissue cells 4 points

Answers

Answer:

The correct answer is option B. Blood clotting.

Explanation:

Tissue profusion is the path of blood flow or the lymphatic fluid with the help of the lymphatic system or the circulatory system to a tissue area or organ. It is helpful to transport nutrients or eliminating waste from the blood so the adequate tissue profusion is required to maintain.

All three options except blood clotting are related to the transport of nutrients, oxygen of removal of waste with the help of a circulatory system of the lymphatic system. Blood clotting is a region specific event and does not involve profusion.

Thus, the correct answer is option - b. Blood clotting.

Final answer:

Blood clotting (B) does not involve tissue perfusion, as it is a biochemical process rather than one involving the flow of blood to tissues for nourishment or waste removal.

Explanation:

Non-Involved Tissue Perfusion Process

The process that does NOT involve tissue perfusion is B. blood clotting. Tissue perfusion refers to the passage of blood through the circulatory system to an organ or a tissue. It involves the delivery of oxygen and nutrients to the tissue cells and the removal of waste products. Processes such as absorption of nutrients from the digestive tract (A), gas exchange in the lungs (C), and the delivery of oxygen and nutrients to tissue cells (D) all involve tissue perfusion. However, blood clotting is a biochemical process that leads to the formation of a clot to stop bleeding and does not directly involve the flow of blood to tissues for nourishment or waste removal.

A nursing instructor is explaining the stages of fetal development to a group of nursing students. The instructor determines the session is successful after the students correctly choose which time period as representing the pre-embyonic stage?
a. From fertilization and to the end of the second week .
b. Approximately 2 weeks after fertilization and to the end of the eighth week.
c. Approximately 9 weeks after fertilization and to birth.
d. Approximately 6 weeks after fertilization and to the end of 8 weeks.

Answers

The correct answer is A. From fertilization and to the end of the second week

Explanation:

Fetal or embryonic development includes different stages from fertilization to birth. The first stage is the pre-embryonic stage, this occurs after fertilization and lasts the two first weeks of pregnancy, it is called pre-embryonic stage because during this there is no an embryo but the zygote implants and later different processes of cell division occur. Additionally, the pre-embryonic stage is followed by the embryonic stage (week 3 to 8) and finally the fetus stage (week 9 to birth). According to this, if students have correctly learned about fetal development they should choose "from fertilization and to the end of the second week" as the period for the pre-embryonic stage.

Eddie has been feeling very lethargic lately and the doctors think he may have a thyroid problem. They told him the problem could be originating in his brain or at the gland. If it is beginning in his brain, it is coming from his _____ nervous system, and if it is beginning in his gland, it is coming from his _____ nervous system.

Answers

The answers are central and peripheral

Final answer:

Eddie's lethargy may be related to a problem with the central nervous system (brain-based) or the endocrine system (thyroid gland issue). Thyroid-stimulating hormone (TSH) deficiency can cause weight gain and fatigue because it leads to insufficient thyroid hormone production, which slows metabolism.

Explanation:

If the issue with Eddie's energy levels is originating in his brain, it would be related to the central nervous system (CNS), which includes the brain and spinal cord and is responsible for integrating sensory information and responding accordingly. The CNS regulates the activity of all parts of the body and is where the production of thyroid-stimulating hormone (TSH) is controlled, specifically by the pituitary gland in response to signals from the hypothalamus. If the problem originates in his gland, it is related to the endocrine system, which is composed of glands that produce and secrete hormones. The thyroid gland is a part of this system and would be where the hormonal issue would be present if it's not a problem with CNS signaling.

Terry's recent weight gain and fatigue might be due to a deficiency of TSH because this hormone stimulates the thyroid gland to produce thyroxine (T4) and triiodothyronine (T3), which regulate the body's metabolism. If his body does not produce enough TSH, the thyroid may not release sufficient levels of thyroid hormones, leading to a slower metabolism, which can result in weight gain and feelings of lethargy.

Some bacterial pathogens only cause disease when injected into tissue and are not able to grow or cause disease on skin or other surface-exposed regions. One example is Clostridium tetani (tetanus). Which type of metabolism would you expect these pathogens to use?

Answers

Answer:

Anaerobic chemoorganotrophy.

Explanation:

Anaerobic chemoorganotrophs may be defined as the organisms that has the ability to prepare their food with the help of organic chemicals in the basence of oxygen. The microorganism uses this metabolism to cause disease in other organism.

The pathogens like Clostridium tetani use the anaerobic chemoorganotrophs bacteria as they injected into the tissue and do metabolism without the presence of oxygen. They can not cause disease on skin surface as abundant oxygen is present on the body surface.

Thus, the answer is anaerobic chemoorganotrophy.

Proteins
- consist solely of polymerized amino acids.
- can, by definition, consist of no more than 2000 amino acid residues.
- all have similar amino acid compositions.
- can consist of more than one polypeptide chain.

Answers

Answer: Option D.

Explanation:

Protein are large biomolecules which contains one or more long chains of amino acid residues and plays important functions in living organism.

Proteins consist of one or more than one polypeptide chains.

If proteins consist of only one polypeptide chain they form primary structure, secondary, and tertiary structures while if a protein consist of more than one polypeptide chain it forms Quaternary structure.

Proteins with multiple polypeptide chains called subunits and these subunits attach together to give Quaternary structure. Multiple polypeptides chains are arranged in folded protein subunits and allows formation of simple dimers and large complexes with different numbers of subunits. Examples of Quaternary structure d proteins are DNA polymerase, hemoglobin, and ion channels.

Hence, the correct option is D.

Final answer:

Proteins are mainly composed of amino acids linked together. They can be any size, and their amino acid compositions can vary significantly. Moreover, proteins can consist of more than one polypeptide chain.

Explanation:

Proteins are biologically significant molecules composed mainly of amino acids linked in a polypeptide chain. The statement that proteins consist solely of polymerized amino acids, however, is partially incorrect. While amino acids are the building blocks of proteins, proteins also undergo various levels of structural organization and may also contain other non-amino acid entities attached to them.

The notion that a protein can consist of no more than 2000 amino acid residues is not universally true. Proteins can be any size, depending on their function in the organism. The statement that proteins have similar amino acid compositions is also not completely accurate as proteins differ significantly in their amino acid compositions based upon their function and the organisms where they are found. It is correct, however, that proteins can consist of more than one polypeptide chain. These are referred to as quaternary structures.

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Inability to absorb digested nutrients and secrete mucus might indicate a disorder in which epithelial tissue?

Answers

Answer:

The answer is Simple Columnar epithelium.

Explanation:

The simple columnar epithelium may be found at the digestive tract and respiratory tract.

In the digestive system, absorption of nutrients mostly occur in the duodenum (part of the small intestines). This is covered by simple columnar epithelia with microcilia at the apical portion, also called the brush border. The brush border provides the digestive tract a broad surface area to allow optimal nutrient absorption.

In the respiratory system, a specialized type of simple columnar cells, called goblet cells, produce mucus for the mucous membrane to catch or transport foreign objects out of the system. Microcilia is also present at the apical portion of the cell and serves to trap foreign bodies that enter the respiratory tract.

A mutation occurs in a germ cell of a pure-breeding, wild-type male mouse prior to DNA replication. The mutation is not corrected, and the cell undergoes DNA replication and a normal meiosis produces four gametes. How many of these gametes will carry the mutation?

Answers

Answer: 2

Explanation:

A germ cell is a cell that gives rise to gametes. This is through meiosis, a type of cell division that reduces the chromosome number by half. In this way, four haploid cells are created, each genetically different from the parent cell.

During meiosis I, crossing over takes place. It consists on the exchange of genetic material between two homologous chromosomes to create recombinant chromosomes. Then, if there is a mutation not corrected, it would end up only in one of those two chromosomes. At the end of meiosis I, these homologous chromosomes are separated into two daughter cells. During meiosis I, the sister chromatids of each chromosome within the two daughter cells are separated, creating four daughter gametes.

So, the mutation that was only on one chromosome ended up in one of the two cells created in meiosis I. Then that cell with the mutation divided again during meiosis II, creating two more cells. So, here we have two gametes with one mutation each. On the other hand, the cell that did not receive the mutation also created two daughter cells in meiosis I but with their normal genes. And that same one created two other cells during meiosis II, also normal. The total is 4 cells, only 2 affected by the mutation.

Final answer:

All four gametes produced by meiosis from the mutated germ cell in a male mouse will carry the mutation, as germ-line mutations are passed on to every gamete formed post-mutation.

Explanation:

The question revolves around the consequences of a mutation in the germ cell of a wild-type male mouse, specifically how many gametes will carry the mutation if it occurs prior to DNA replication and is not corrected. Germinal or germ-line mutations, like the one described, occur in reproductive cells (gametes) and are significant because they can be passed to offspring, with every future somatic and germ-line cell of the offspring containing this mutation.

Given that mutations in germ cells are transmitted to all gametes formed from that cell post-DNA replication and subsequent meiosis, and considering that meiosis typically produces four gametes from each germ cell, all four gametes from the mutated germ cell would carry the mutation.

[HELP ASAP]
Proteins are made up of long chains of which of these building blocks?

a. saccharides
b. nucleotides
c. fatty acids
d. amino acids

Answers

Answer:

amino acids

Explanation:

Saccharides are for polysaccharides

Nucleotides are for DNA

Fatty acids are for lipids

Amino acids line up in a chain during translation into a protein.

Final answer:

Proteins are made up of long chains of building blocks called amino acids. There are 20 different amino acids that can be combined to create a protein. The sequence of these amino acids determines the protein's structure and function.

Explanation:

Proteins, which are integral to bodily processes, are composed of long chains of building blocks known as amino acids. There are 20 different types of amino acids that can be combined to make a protein. The sequence of the amino acids determines the structure and function of each protein. Unlike saccharides, which make up carbohydrates, nucleotides that build up nucleic acids, and fatty acids which are the building blocks of lipids; amino acids are unique in their role as the building blocks of proteins.

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The four main categories of large biological molecules present in living systems are _____.

A. RNA, DNA, proteins, and carbohydrates
B. monosaccharides, lipids, polysaccharides, and proteins
C. nucleic acids, carbohydrates, monosaccharides, and proteins
D. proteins, nucleic acids, carbohydrates, and lipids
E. proteins, DNA, RNA, and steroids

Answers

Answer: D. Proteins, Nucleic Acids, Carbohydrates, and Lipids

Explanation: Living systems have important macromolecules that act as structural blocks or participate in metabolism.

Proteins. These macromolecules are composed by aminoacids and can be structural like collagen, act as enzymes as oxidases, act as a receptors as tyrosin kinase receptors, among other functions.Nucleic acids. These macromolecules are composed by nucleotides and acts a inheritance molecules: DNA and RNA.Carbohydrates. These macromolecules are composed by monosaccharides and can be structural as cellulose or participate in metabolism like glycogen and glucose.Lipids. These macromolecules are composed by carbon, hydrogen and oxygen atoms. Participate in metabolism as energy reserve and structural in biological membranes.

Final answer:

The four main biological macromolecules in living organisms are proteins, carbohydrates, lipids, and nucleic acids, each with essential roles in bodily functions.

Explanation:

The four main categories of large biological molecules present in living systems are proteins, carbohydrates, lipids, and nucleic acids. These macromolecules are essential to life, each playing unique and critical roles in the structure, function, and regulation of the body's cells, tissues, and organs. Proteins are made from amino acids and perform a variety of functions including catalyzing metabolic reactions, DNA replication, and transporting molecules. Carbohydrates include sugars and starches that are vital for energy storage and supply. Lipids are fats and oils that store energy, insulate the body, and make up cell membranes. Nucleic acids, which encompass DNA and RNA, contain the genetic instructions for the development and function of living organisms.

If a cell culture contains 400 cells/ml at time = 0 and it has a generation time of 30 minutes, how many cells (cells/ml) will be present after 2 hours of incubation?
2400 cells/ml
1600 cells/ml
1200 cells/ml
6400 cells/ml
3200 cells/ml

Answers

Answer:

The answer to your question is: after two hours there will be 6400 cell/ ml

Explanation:

Data

Bacteria t = 0; 400 cells/ml

generation time = 30 minutes

# cells after two hours = ?

                                 # of bacteria               time

                                     400                            0

                                      800                         30 min

                                   1600                           60 min

                                   3200                           90 min

                                   6400                          120 min

What will happen if a bacterial cell is placed in 10% NaCl with penicillin? The cell will undergo osmotic lysis. Penicillin will diffuse into the cell. Water will enter the cell. The cell will plasmolyze. No change will result; the solution is isotonic.

Answers

Answer:

The cell will plasmolyze

Explanation:

Plamolysis is a process that cells suffer and that is characterized by a loss of water.

By placing the bacterial cell in a solution of 10% NaCl with penicillin we will be facing different situations.

First, penicillin is an antibiotic that affects the cell wall by destroying it. By not having the cell wall, the bacteria is more vulnerable to everything outside.

When deposited in a hypertonic medium, this means that the concentration of solutes from outside is greater than that of the protoplast (cytoplasm). The water in the protoplast will start to flow out of it and the cell will shrink. This decrease in size causes the plasma membrane to separate from the cell wall.

Final answer:

A bacterial cell placed in a 10% NaCl solution would undergo plasmolysis due to the hypertonic environment. Penicillin would inhibit the repair of the bacterial cell wall, leading to cell death. The cell wall's peptidoglycan is crucial for preventing lysis in hypotonic environments and counteracting hypertonic stress.

Explanation:

When a bacterial cell is placed in a 10% NaCl solution, the environment becomes hypertonic relative to the interior of the bacterial cell. As a result, water will move out of the cell, causing the cell to shrink and the plasma membrane to pull away from the cell wall, a process known as plasmolysis. This process is distinct from osmotic lysis, which occurs in a hypotonic environment where water enters a cell, leading it to swell and potentially burst. Penicillin targets bacterial cells by inhibiting the formation of peptidoglycan cross-links in the bacterial cell wall. Due to the hypertonic environment and the action of penicillin, a bacterial cell would likely undergo plasmolysis and be prevented from repairing its cell wall, leaving the cell unable to counteract the osmotic effects and likely leading to cell death.

Penicillin works by disrupting the cell wall construction, leading to the eventual death of the bacteria through cell wall damage. In a hypertonic solution like one with 10% NaCl, penicillin would further prevent the weakened cell from counteracting the osmotic stress. Gram-positive bacteria stain purple after Gram staining while Gram-negative bacteria stain pink. The presence of a strong cell wall containing peptidoglycan in bacteria prevents them from bursting in a hypotonic environment, while in a hypertonic environment they experience plasmolysis.

The female I-1 and her mate, male I-2, had four children, one of whom has albinism. What is the probability that they could have had a total of four children with any other outcome except one child with albinism and three with normal pigmentation?

Answers

Answer:

75% chance of having four normal phenotype children without albinism.

50% chance of having four children who are carriers of the gene with normal phenotype.

Explanation:

Albinism results from an autosomal recessive gene.  In order to solve this problem we have to draw a punnet square and figure out the genotypes of the parents.  So with the genotype of the parents both parents have to be carriers of the trait since it is an autosomal recessive trait.

Genotype of female I-1 = Aa

Genotype of male I-1 = Aa

 

PARENTS A a

A                AA  Aa

a                Aa  aa

75% chance of having four normal phenotype children without albinism.

50% chance of having four children who are carriers of the gene with normal phenotype.

25% chance of having children with albinism.

Final answer:

The probability of the parents having any other outcome except for one child with albinism and three with normal pigmentation is approximately 32%, based on the principals of Mendelian genetics.

Explanation:

The probability of I-1 and I-2 having an outcome of four children without at least one child being albino is based on Mendelian genetics principles. Albinism is a recessive genetic disorder, meaning that both parents must contribute an albino allele for a child to exhibit albinism. Assuming both parents are heterozygous for albinism (each carries one albino allele and one normal allele), the probability of them having a child with albinism is 25%, or 1 in 4. However, probability applies independently to each child they have, and is not influenced by the outcomes of previous offspring.

In this scenario, the possible genetic combinations for the children are: two normal pigmentation alleles (NN), one normal and one albino allele resulting in normal pigmentation (Nn or nN), or two albino alleles (nn). The probability for each child to be NN or Nn/nN (normal pigmentation) is 75%, while the probability for a child to be nn (albino) is 25%. Therefore, the probability of having four consecutive children without albinism (NN or Nn/nN) is (0.75)^4 = 0.3164 or approximately 32%. So, there is a 32% chance of them having an outcome of four children all with normal pigmentation.

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While discussing the various chemical properties of nutrients in the body, the class discusses that differences between anions and cations. What mineral is the major anion in the extracellular fluid?

Answers

Answer:

Within the extracellular fluid, the major cation is sodium and the major anion is chloride.

Chloride is a major contributor to the osmotic pressure gradient between the ICF and ECF, and plays an important role in maintaining proper hydration. It functions to balance cations in the ECF, maintaining the electrical neutrality of this fluid.

Chloride is by large the major anion in the extracellular fluid.

Its concentration in blood plasma is around 98.00–107.00 (mM), in  cerebrospinal fluid (CSF) around 118.00–132.00 (mM) and in urine around 110.00–250.00 (mM); while the concentrations of bicarbonate (HCO3-), the second most abundant anion in blood is 22.00–29.00 (mM).

Chloride is the predominant extracellular anion. Chloride is a major contributor to the osmotic pressure gradient between the ICF and ECF, and plays an important role in maintaining proper hydration. Chloride functions to balance cations in the ECF, maintaining the electrical neutrality of this fluid.

*ICF = intracellular fluid

ECF = extracellular fluid

Final answer:

Chloride (Cl⁻) is the major anion present in the extracellular fluid (ECF), which helps in maintaining the balance and neutrality of the body fluids.

Explanation:

The major anion found in the extracellular fluid of the body is chloride (Cl). In the extracellular fluid (ECF), the balance of electrolytes is essential to maintain a neutral charge, with various cations such as sodium (Na⁺), potassium (K⁺), calcium (Ca²⁺), and magnesium (Mg²⁺) being neutralized by anions like chloride.

Chloride ions serve to balance the charge of the cations, playing a critical role in maintaining fluid balance, pH, and electrical neutrality.

When the size of a cell increases, the surface area/volume ratio:
- decreases initially and then begins to increase.
- remains the same.
- increases.
- decreases.
- increases initially and then begins to decrease.

Answers

Answer: B membrane bonded nucleus

Explanation:

Match each neural component with its role in synaptic transmission. Drag each item on the left to its matching item on the right. a. neurotransmitters presynaptic b. neuron postsynaptic c. neuron dendrites postsynaptic d. neuron cell body 1. receiving information 2. chemicals that are released into the synapse 3. integrating information 4. sending information

Answers

Following are the functions of neural components in synaptic transmission pathway -

a. neurotransmitter pre-synaptic – 2. Chemicals that are released into the synapse.

b. neuron post-synaptic – 4. Sending information.

c. neuron dendrites post-synaptic – 1. Receiving information.

d. neuron cell body – 3. Integrating information.

The neurons release the neurotransmitter, which act as a messenger and carry the signal from one neuron to another.

The synaptic transmission pathway is as follows -

The synaptic vesicles release their neurotransmitter content when the electrical impulse (action potential) reaches them.The signal is subsequently transferred across the synaptic gap by neurotransmitters. They complete synaptic transmission by attaching to receptor sites on the post-synaptic cell.

Therefore, the synaptic transmission pathway starts with the neurotransmitters, which are chemical messengers. They give information to dendrites, which further receives and transmit the information to cell body, where it's processed and transmitted to another neuron.

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Final answer:

Neurotransmitters in the presynaptic neuron are chemicals that are released into the synapse. The presynaptic neuron sends the information while the postsynaptic neuron dendrites receive this information. The neuron cell body integrates the received information.

Explanation:

In the process of synaptic transmission, several neural components play specific roles. These include:

Neurotransmitters (presynaptic): These are chemicals that are released from the presynaptic neuron, specifically from the axon terminals, into the synapse. This process is also known as exocytosis. Neuron (presynaptic): This neuron is responsible for sending information. It gives off an electric potential which triggers the release of neurotransmitters from its axon terminal.Neuron dendrites (postsynaptic): These structures are found on the postsynaptic neuron and are responsible for receiving information. They capture the neurotransmitters from the synaptic cleft and transmit the signal further into the neuron.Neuron cell body: The main role of the cell body involves integrating information received from the dendrites and deciding whether the neuron will fire an action potential or not. It is here that synaptic signals may be summed and modulated.

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Select one FALSE statement regarding diffusion: Diffusion is the movement of particles from high to low concentration Substance A (molecular weight 120) will diffuse faster than substance B (molecular weight 240) Solute in solution will diffuse faster if the solution is heated The source of energy for diffusion comes from cellular ATP All of the above are true

Answers

Answer:

The source of energy for diffusion comes from cellular ATP

Explanation:

Diffusion is the net movement of particles against concentration gradient. Particles move from higher concentration to lower concentration on their own without requirement of external energy source. Hence no ATP is required for the process. ATP provides energy for movement of particles against the concentration gradient.

Rate of diffusion increases with increase in temperature as kinetic energy of particles increases; also lighter the particles, faster they will move. Hence, a substance with less molecular weight will diffuse faster than heavier substance.

All living things are made up of carbon. This is because
A: carbon has the ability to form single bonds, double bonds, triple bonds, and rings and form large macromolecules.
B: carbon forms very unstable bonds with all elements except for itself.
C: carbon can only form small chains of macromolecules.
D :carbon likes to make 6 bonds with many other kinds of elements and form large macromolecules.

Answers

Final answer:

All living things are made up of carbon primarily because carbon atoms can form diverse stable covalent bonds, including single, double, and triple bonds, as well as rings, which enables the formation of complex and large macromolecules necessary for life.

Explanation:

All living things are made up of carbon because it has unique properties that are crucial for forming the complex molecules of life. The correct answer to why carbon is so basic to life is A: carbon has the ability to form single bonds, double bonds, triple bonds, and rings and form large macromolecules. Carbon atoms can form covalent bonds with up to four different atoms. This versatility allows carbon to form the backbone of macromolecules such as proteins, nucleic acids (DNA and RNA), carbohydrates, and lipids. Carbon's bonding capabilities enable it to form stable and diverse molecular structures, including straight chains, branched chains, and rings, which in turn are responsible for the variety of functions of biological macromolecules.

Final answer:

Carbon is fundamental to life because it can form single, double, triple bonds, and rings to create large macromolecules. It's the bonding versatility of carbon that enables it to serve as the backbone for crucial biological compounds. Carbon's unique capacity to bond in multiple ways underpins the structural diversity and complexity of life’s molecules.

Explanation:

All living things are made up of carbon because of option A: carbon has the ability to form single bonds, double bonds, triple bonds, and rings and form large macromolecules. Carbon is a unique element with the capacity to form stable covalent bonds with up to four different atoms, enabling the construction of complex molecules essential for life. These can range from simple organic molecules to the polymers that make up life's crucial macromolecules like proteins and carbohydrates.

Carbon's versatility is due to its four valence electrons, allowing for a variety of stable bonding patterns, including chains, branching chains, and rings—structures foundational to biological macromolecules. This bond diversity is the reason why carbon can form a vast array of organic compounds, making it indispensable to life's chemical processes.

The carbon atoms may form large macromolecular structures by bonding with other carbon atoms or with other elements like nitrogen, oxygen, and phosphorus. These formations underlie the structural and functional diversity of organic molecules in living systems. Unlike other elements, carbon's ability to form an extensive range of varying sized and shaped molecules contributes to its fundamental role in biology.

Lance Armstrong just finished third (by about 5 minutes) in the 2009 Tour de France cycling race. This was an incredible feat for the 37-year-old father of 4. First and second-place winners, Alberto Contador (age 27) and Andy Schleck (age 24), respectively, have no children. Which of these three men shows the greatest evolutionary fitness?

Answers

Answer:

Lance Armstrong showed the greatest evolutionary fitness.

Explanation:

Because of this age and his 4 kids. It requires a really fit body to achieve that goal.

Meiosis reduces chromosome number and rearranges genetic information.

a.Explain how the reduction and rearrangement are accomplished in meiosis
b.Several human disorders occur as a result of defects in the meiotic process.Identify ONE such chromosomal abnormality; what effects does it have on the phenotype of people with the disorder?Describe how this abnormality could result from a defect in meiosis.
c.Production of offspring by parthenogenesis or cloning bypasses the typical meiotic process. Describe either parthenogenesis or cloning and compare the genomes of the offspring with those of the parents.

Answers

Answer:

a- Rearrangement occurs during meiosis as the chromosomes line up in pairs during meta phase 1 & 2. Then afterwards in anaphase 1 & 2 these chromosomes are separated and each gamete receives one of each type of chromosome.

b- Examples of chromosomal abnormality include Down syndrome which is identified by a third copy of chromosome 21 and Turner syndrome which is characterized by the presence of only one X chromosome in women instead of two. Down syndrome cause phenotypic variability including cognitive impairment,muscle hypotonia at birth.

c- Parthenogenesis is a reproductive strategy that involves development of a female (rarely a male) gamete without fertilization. It can occur in plant and animals without invertebrate and rarely among higher vertebrates.

Final answer:

Meiosis is a unique type of cell division that reduces the chromosome number by half and rearranges genetic information to ensure genetic diversity. Abnormalities such as Down Syndrome can occur due to errors in this process. Parthenogenesis or cloning bypass meiosis, resulting in offspring identical to the parent.

Explanation:

Meiosis is the process by which cells divide to produce sex cells, or gametes. This process is unique because it results in four daughter cells, each with half the number of chromosomes as the parent cell. This reduction in chromosome number is accomplished through two rounds of cell division, known as Meiosis I and Meiosis II.

During Meiosis I, homologous chromosomes pair up and exchange genetic material, a process known as crossing over. This 'rearrangement' ensures genetic diversity in offspring. Also, an error in this phase can lead to chromosomal abnormalities. One such abnormality is Down Syndrome, where an individual has an extra 21st chromosome. This abnormality can result from nondisjunction, a defect in meiosis where chromosomes fail to separate properly.

The production of offspring bypassing meiosis can be seen in cloning or parthenogenesis. Parthenogenesis, for instance, is a form of asexual reproduction that involves the development of a female gamete without fertilization. The offspring's genomes in these cases would be identical to the parent's genome, lacking the genetic diversity provided by meiosis.

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In a repeated-measures experiment, each individual participates in one treatment condition and then moves on to a second treatment condition. One of the major concerns in this type of study is that participation in the first treatment may influence the participant's score in the second treatment. This problem is referred to as _________.
a. individual differences
b. homogeneity of variance
c. bi-treatment effect
d. order effects

Answers

Answer:

Explanation:

a

Why isn’t the Gram stain used on Acid fast bacteria? If you did Gram stain acid-fast bacteria, what would their Gram reaction be? What is the Gram reaction of non-acid-fast bacteria?

Answers

Answer:

Acid fast bacteria are stain by the gram process but it retains the red color like the gram negative. The result will show a false positive to a negative gram bacteria.

Explanation:

The acid fast bacteria are 4 groups of bacteria ( Mycobacterium, Nocardia, Corynebacterium, Clostridium) that have the characteristic that they posses a high concentration of micolic acid. This characteristic is sensible to be dye by the gramm process, because the chemicals are not attract among them. To be dye, this kind of bacteria, is necessary used heat and the presence of phenol.

Final answer:

The Gram stain is not used on acid-fast bacteria due to their unique cell wall structure with a layer of waxy mycolic acids, making them retain the acid-fast stain instead. Non-acid-fast bacteria can be identified by Gram stain procedure, showing up as either gram-positive or gram-negative.

Explanation:

The Gram stain isn't used on acid-fast bacteria because it wouldn't accurately identify them due to their unique cell wall structure. Acid-fast bacteria, such as members of the Mycobacteriaceae family, have an extra layer of waxy mycolic acids in their cell walls, which resists the decolorizing process of the Gram stain procedure.

If you attempted to Gram stain acid-fast bacteria, the result would be inconclusive as they may not properly retain the stain due to their special cell wall structure. Therefore, the acid-fast staining protocol, which uses carbolfuchsin as the primary stain, is necessary. In this process, acid-fast cells retain the carbolfuchsin dye even after a decolorizing agent is applied.

Normal (non-acid-fast) bacteria do not have the waxy mycolic acid layer. They can be correctly identified by the Gram stain procedure. These could show gram-positive or gram-negative reaction based on their cell wall structure. Gram-positive bacteria have a thicker peptidoglycan layer which retains the purple crystal-violet stain, while Gram-negative bacteria have a thinner peptidoglycan layer and do not retain the crystal-violet stain but take up the red counterstain, safranin.

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Simple epithelia have more layers for protection, whereas stratified epithelia allow materials to move across them and are less protective. True False

Answers

Answer: False.

Explanation:

Epithelial tissue is found in the linings of many structures throughout the body. There are two kinds of epithelial tissue: simple and stratified. And they  perform different functions and are structured differently.

The simple epithelium consists of one single layer of cells. In this way, all cells are in direct contact with the basement membrane and are separated from the connective tissue. The main function of this epithelium is absorption and filtration.

The stratified epithelium is composed of many layers of cells that are stacked together. In this way, this epithelium has the function of protecting against physical and chemical damage.

The difference between simple diffusion and facilitated diffusion is that facilitated diffusion Can move materials from a higher to a lower concentration. Doesn't require ATP. Can move materials from a lower to a higher concentration. Requires ATP. Requires transporter proteins.

Answers

Answer:

Requires transporter proteins.

Explanation:

Facilitated diffusion is similar to simple diffusion because both the methods carry molecules from higher to lower concentration. Since the movement is along the concentration gradient there is no requirement of energy or ATP. The difference between them lies in the use of transporter proteins. Polar molecules and large ions are not able to diffuse across the semi permeable membrane despite the concentration gradient because the membrane's hydrophobic nature repels them. Transporter proteins are embedded in the membrane and the molecules can pass through them to other side avoiding the hydrophobic membrane. Hence, facilitated diffusion requires transporter proteins.

Final answer:

Facilitated diffusion requires transporter proteins to assist the movement of substances down their concentration gradient, while simple diffusion does not involve such proteins and relies purely on concentration gradient. Both processes are forms of passive transport and do not require ATP.

Explanation:

The difference between simple diffusion and facilitated diffusion lies in their mechanisms of transport across cell membranes. Simple diffusion moves substances from a higher to a lower concentration without the need for energy or transport proteins, relying solely on the concentration gradient. Facilitated diffusion, on the other hand, requires specific transporter proteins such as channel proteins or carrier proteins to assist in the movement of substances. Unlike active transport, facilitated diffusion does not require ATP because it also moves substances down their concentration gradient, but it enables substances that are not able to pass through the cell membrane easily, such as glucose and certain ions, to do so with the help of transport proteins.

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identify the process used to form the covalent peptide bonds that join amino acids into a polypeptide.

Answers

Final answer:

A peptide bond is the covalent bond that joins amino acids together into a polypeptide through dehydration synthesis.

Explanation:

A peptide bond is the covalent bond that joins amino acids together into a polypeptide. This bond is formed through a process called dehydration synthesis, where two amino acids combine and a molecule of water is released. The carboxyl group of one amino acid reacts with the amino group of the incoming amino acid, resulting in the formation of a peptide bond.

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Final answer:

Amino acids form polypeptides through a process called dehydration synthesis, creating a peptide bond, a type of covalent bond. The chain formed is known as the polypeptide. The sequence and number of these amino acids can influence the protein's final characteristics.

Explanation:

Amino acids come together to form polypeptides through the formation of peptide bonds, a type of covalent bond. This process is known as dehydration synthesis. Here, the carboxyl group (COOH) of one amino acid and the amino group (NH2) of another amino acid combine. This combination leads to the release of a water molecule, forming the peptide bond.

The resulting chain of amino acids is known as a polypeptide. If the chain contains fewer than 100 amino acids, it is referred to as a polypeptide rather than a protein. The sequence and number of amino acids in the polypeptide can dictate the protein's shape, size, and function.

It's worth noting that after the process of protein synthesis, there may be post-translational modifications to make the protein fully functional. These modifications could include cleavage, phosphorylation, or the addition of other chemical groups to the polypeptide.

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QUESTION 4


A substance that produces OH– ions in solution is a(n)_____.


A)acid


B)salt


C)base


D)alcohol

Answers

Answer: acid

Explanation:

In this reaction, sodium hydroxide (NaOH) disassociates into sodium (Na+) and hydroxide (OH-) ions when dissolved in water, thereby releasing OH- ions into solution.

Answer:

Bases are the chemical compounds which give out [tex]\bold{OH^-}[/tex] ions when dissolved in aqueous solution or water.

Explanation:

In science, bases are substances that show the following characteristic:

In watery arrangement, discharge hydroxide [tex]\bold{(OH^-)}[/tex] particles.It is elusive/slippery to the touch.It has bitter taste.It changes the shade of litmus paper (e.g., turn red litmus paper blue).It responds with acids to shape salts.It advances certain compound responses (base catalysis).It receives protons from any proton contributor or contain totally or halfway displaceable [tex]OH^-[/tex] particles.

You are setting up your own lab, where you plan to study proteobacteria. You have narrowed your research focus and decided that you are most interested in the role of proteobacteria in the global nitrogen cycle. Which species of proteobacteria should your researchers study?
Check all that apply.
a. Alphab. Betac. Epsilond. Deltae. Gamma

Answers

Answer:

-Alphaproteobacteria

-Betaproteobacteria

Explanation:

Proteobacteria are gram-negative bacteria that can either be pathogenic or free-living parasitic in nature. Several classes fall under the category of proteobacteria, and two of them are alphaproteobacteria and beta proteobacteria. Both Alphaproteobacteria and Betaproteobacteriaare are the ones that play an important role in nitrogen fixation and since according to the question the research is focused studying the role of proteobacteria in the global nitrogen cycle, it is wise to choose these two bacterial classes.

Final answer:

For studying the role of proteobacteria in the global nitrogen cycle, Beta Proteobacteria is the correct option to focus on, as they play a significant role in this biochemical process.

Explanation:

If you are setting up your own lab to study the role of proteobacteria in the global nitrogen cycle, focusing on specific classes within the proteobacteria phylum is crucial. Based on the information provided, Beta Proteobacteria play a significant role in the nitrogen cycle. These bacteria are diverse and include species fundamentally involved in nitrogen transformations. Therefore, your research should include studying Beta Proteobacteria.

While other classes of proteobacteria, such as Delta and Epsilon, have notable roles in other environmental or health-related aspects, they are not primarily noted for their involvement in the nitrogen cycle in the provided context. Thus, the correct option for your research focus should be:

Beta Proteobacteria

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