Answer:
All of the statements are correct except 6. (Deacetylation of histone tails in chromatin loosens the association between nucleosomes and DNA)
Explanation:
Chromatin structure and its modifications can change the package of the DNA and consequently, alter the gene expression. The most common modifications of the chromatin are covalent modifications such as acetylation/deacetylation (by acetyltransferases and eacetylases), methylation (by methyltransferases), and phosphorylation (by kinases). This is the way of gene expression regulation.
The effects of modifications are different, for example methylation promotes condensation of the chromatin and as a consequence, prevents binding of transcription factors to the DNA (transcription is repressed).
Acetylation loosens the association between nucleosomes and DNA (because it neutralizes the positive charge of histones) and consequently promotes transcription. Deacetylation is a process opposite to acetylation.
True statements about the modification of chromatin structure in eukaryotes include the inhibition of transcription when chromatin is condensed, the possibility of inheriting some chromatin modifications by future generations, and that acetylation of histone tails allows transcription while being reversible. In contrast, methylation can promote condensation, and deacetylation actually increases, not decreases, DNA-histone binding.
The modification of chromatin structure in eukaryotes involves several processes that affect gene expression. The statements that are true are:
DNA is not transcribed when chromatin is packaged tightly in a condensed form.Some forms of chromatin modification can be passed on to future generations of cells.Acetylation of histone tails in chromatin allows access to DNA for transcription.Acetylation of histone tails is a reversible process.Methylation of histone tails in chromatin can promote condensation of the chromatin.Deacetylation of histone tails in chromatin does not loosen the association between nucleosomes and DNA; rather, it promotes condensation, thereby making it harder for the DNA to be transcribed due to lessened accessibility to transcription machinery.When DNA is tightly wrapped around histones in a condensed chromatin state, transcription factors and RNA polymerase cannot access the DNA, hence, transcription is inhibited. Chemical modifications, like acetylation and methylation of histone tails, determine the packing level of chromatin and influence gene expression. These processes are part of a broader regulatory system known as the histone code, which can be inherited through cell divisions and potentially across generations, contributing to epigenetic inheritance.
As a ribosome translocates along an mRNA molecule by one codon, which of the following occurs? The tRNA that was in the A site moves into the P site. The tRNA that was in the P site moves into the A site. The tRNA that was in the P site moves to the E site and is released. The tRNA that was in the A site departs from the ribosome Both A and Care correct.
Answer:
The tRNA that was in the A site moves into the P Site, and the tRNA that was in the P site moves to the E site and is released.
In protein translation, tRNA moves through the A, P, and E sites of the ribosome, catalyzing peptide bond formation and translocating along mRNA. The ribosome proceeds to next codon after each tRNA moves from the A site to the P site, and then from the P site to the E site.
Explanation:During the elongation phase of protein translation, charged tRNAs move through the A, P, and E sites of the ribosome. This process allows the polypeptide chain to form and grow. Specifically, a charged tRNA first binds to the mRNA in the A site of the ribosome and a peptide bond is formed between two adjacent amino acids, catalyzed by an RNA-based enzyme, peptidyl transferase. Subsequently, the ribosome moves one codon along the mRNA, causing the tRNA that was in the A site to move into the P site.
Next, the tRNA that was in the P site moves to the E site, and it is released from the ribosomal complex. This sequence of tRNA movements-- from the A site to the P site, and then from the P site to the E site-- occurs with each translocation event, that is, each single-codon 'step' of the ribosome. Amazingly, the E. coli translation apparatus takes only 0.05 seconds to add each amino acid, meaning that a 200 amino acid protein can translate in just 10 seconds.
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Thymine dimers can be repaired by Photoreactivation Repair or Nucleotide Excision Repair. - true or false?
Answer:True
Explanation:Basically thymine diamers are mismatched pairs (thymine binds with another thymine instead of binding with adenine) and may lead to unwanted results so the mismatching can be repaired by using two methods which are as follows :
1-the PRE enzyme activated by blue light breaks the thymine diamer and some of the surrounding bonds the strand is cut and DNA polymerase then restores the normal base pairing
2-UVR system breaks dimer creating a gap when a gap is created and the molecules appear unpaired it is filled by proof readers hence restoring normal base pairing.
The claim that thymine dimers can be repaired through both Photoreactivation Repair and Nucleotide Excision Repair is true. These mechanisms are crucial for DNA repair in cells that have been exposed to UV light, as they help maintain the integrity of the genetic material.
Explanation:The statement that thymine dimers can be repaired by Photoreactivation Repair or Nucleotide Excision Repair is true. Thymine dimers are formed when DNA is exposed to ultraviolet (UV) light, causing adjacent thymine bases to bond together improperly. In bacteria, nucleotide excision repair operates by recognizing the distortion in the DNA around the thymine dimer. An enzyme complex then excises the affected strand, and DNA polymerase and DNA ligase fill in and seal the gap with correct nucleotides. In addition, photoreactivation repair specifically reverses thymine dimers with the help of the enzyme photolyase, which binds to the dimers and, in the presence of visible light, breaks them apart, thus restoring the normal base pairing.
Which of the following would be an example of an organism creating a positive feedback interaction with its environment?Tamarisk shrubs are highly salt-tolerant; they take up salty water, but have special glands that secrete excess salt onto their waxy leaf surfaces, thus storing it out of the way where it can’t harm their cells. When the foliage falls, the salts wash into the soil, increasing the soil salinity. Over time, the salinity increases to a level that is toxic to almost any plant other than the tamarisks, which allows their offspring to grow where other plants have died.Unlike most organisms, nitrogen-fixing bacteria can grow well in soils with very low levels of available nitrogen, because they can convert N2 into a biologically-available form, which they can use to support their own growth. As numbers of N-fixing bacteria increase, more nitrogen becomes available in the soil, in part because some usable nitrogen “leaks” into the environment, and in part because the cells eventually die, releasing all of their usable nitrogen into the soil. As the levels of usable nitrogen increase, other organisms can grow near the N-fixing bacteria, competing with them for other resources, like carbon and water.
Answer:
Tamarisk shrubs
Explanation:
Positive feedback is a system in which component A produces more of component B which increases the production of A. In the example above, Tamarisk shrubs increase the soil salinity, which increase the growth and reproduction of more Tamarisk shrubs. So, Tamarisk shrubs is component A, environmental salinity is component B.
Cells require energy to perform tasks such as movement, active transport, and the construction of large molecules. This energy comes from...
It comes from the nucleus
Cells get the energy needed for various tasks from the breakdown of nutrients and molecules. This energy is utilized for activities such as molecule synthesis, transport, and cell movement. The process of obtaining and using this energy is known as metabolism.
Cells require energy to perform various tasks, including movement, active transport, and the construction of large molecules.
This energy comes from the breakdown of nutrients and other molecules imported into the cell. Energy is particularly needed for:
The synthesis and breakdown of moleculesThe transport of molecules into and out of cellsIngesting and breaking down foodExporting wastes and toxinsMovement of the cellCells obtain this energy through a process known as metabolism, which involves step-wise chemical reactions that can either release or consume energy.
Specifically, complex carbohydrates are broken down into simple sugars, proteins are built from amino acids, and fats are broken down into fatty acids, all of which provide the necessary energy for cellular functions.
A worm that is solid from the gut epithelium to the outermost epithelium would be considered A) coelomate. B) acoelomate. C) pseudocoelomate. D) diploblastic
If by solid meaning there is no cavity in the body, then it would be acoelomate. The wording is sort of throwing me off
(B.) Acoelomate is possibly correct if i'm wrong then i'm sorry . . Only a 10Th grader
Two important natural processes that release carbon into our atmosphere are
A) combustion and decomposition
B) decomposition and respiration
C) photosynthesis and respiration
D) deforestation and decomposition
Two important natural processes that release carbon into our atmosphere are photosynthesis and respiration.
C) photosynthesis and respiration
Both plants and animals play a critical part of balancing oxygen levels and cleaning air.
What innate immune component is directly responsible for the lysis of the cell membrane of invading microorganisms?
Answer:
The name of the innate immune component is MEMBRANE ATTACK COMPLEX.
Explanation:
The membrane attack complex is a type of structure that is usually formed on the surface of the cell membrane of invading pathogens due to the activation of the immune system. Membrane attack complex is also known as terminal complement complex. Individuals that lack this immune component due to mutations usually experience recurrent infections.
Which of the following is true of the structure of typical transcriptional activators?
A.They contain only one type of motif.
B.The regulatory domain contains the DNA-binding motif.
C.The DNA-binding domain always binds to the coactivator.
D.They contain a regulatory domain that is functional when removed from the DNA-binding domain.
Answer:
D.They contain a regulatory domain that is functional when removed from the DNA-binding domain.
Explanation:
Transcriptional activators are transcriptional factors that positively regulate transcription of the gene (increase gene transcription). They usually contain two functional domains:
DNA-binding domain which interacts with DNAActivation domain which interacts with other proteins.Mechanism of action of activators includes their binding to the enhancers (DNA sequences) and recruitment of RNA polymerase II to the promoter.
What is commonly chewed at the end of the meal in india to aid in digestion and freshen the breath??
Answer:
Paan
Explanation:
Snapdragons show co-dominance for red and white flower color. which of these would you expect to have dark red flowers?
a flower homozygous for the red flower allele
Why are skeletal muscle fibers multinucleated
Answer:
It is because large skeletal muscle fibers form by the fusion of thousands of individual muscle cells
Explanation:
During the developments of muscle fibers, multinucleated arrangment is formed and it is also known as syncytium (syncytium is defined as multiple cell fusions of uninuclear cells).
Multinucleated arrangment of muscle fibers makes the muscles efficient, because many nuclei can control the contractions of long cell better.
Skeletal muscle fibers are multinucleated due to their development from multiple smaller cells known as myoblasts, each with its nucleus. The multiple nuclei allow for increased production of proteins and enzymes, enabling quick recovery from damage, and the ability to adapt to physical exercise.
Explanation:Skeletal muscle fibers are referred to as multinucleated because they contain many nuclei. This unique characteristic is a result of their development process, in which numerous smaller cells, known as myoblasts, fuse to form a mature muscle fiber. Each myoblast has its nucleus and when they fuse, their nuclei are retained in the final muscle fiber. This generates mature muscle cells with multiple nuclei dispersed within them.
Unlike cardiac and smooth muscle cells, skeletal muscle fibers are long and cylindrical. They can be quite large, with diameters up to 100 μm and lengths up to 30 cm. These unique cells functionally contract through signaling from the nervous system and perform a significant role in various body movements and functions.
The presence of multiple nuclei in skeletal muscle fibers provides multiple copies of genes, enabling the production of large amounts of proteins and enzymes essential for muscle contraction and relaxation. This property equips skeletal muscles with the ability to recover quickly from damage and adapt to physical exercise by synthesizing more protein in response. Therefore, the multinucleated nature of skeletal muscle is essential to their function and adaptability in the human body.
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The kidneys are stimulated to produce renin ________.
Answer: C) by a decrease in the blood pressure
The kidneys are stimulated to produce renin when the blood pressure drops.
What are the conditions during which renin is produced by kidneys?The kidney is stimulated to produce renin under 3 conditions majorly.
Increase in sympathetic nerve activityDecrease in blood pressureDecrease in sodium delivery to the distal tubules.When any of these conditions are present, kidneys are stimulated to produce renin.Renin in the presence of angiotensinogen releases aldosterone and this helps kidneys to increase sodium levels and in turn, helps fluid retention.Similarly, by certain changes, the blood pressure and nerve activity are brought back to the normal range.To learn more about the function of kidneys, refer to:
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The most important renal mechanism for regulating acid-base balance of the blood involves __________.
Answer:
the kidneys
Explanation:
The kidneys help maintain the acid–base balance by excreting hydrogen ions into the urine and reabsorbing bicarbonate from the urine.
why would different populations of the same species have different gene pools?
Gene pool is defined as: the stock of different genes in an interbreeding population.
So different populations of the same species have different gene pools as long as they are not interbreeding.
Muscles move bones by _[blank]_.
pulling them
stretching them back and forth
pushing them
relaxing against them
Answer:
stretching them back and forth
Explanation:
Muscles move bones by pulling them.
Muscles pull on the joints, allowing us to move. They also help the body do such thing as chewing food and then moving it through the digestive.
During which phase of the cell cycle is dna replicated?
Anaphase, they line up at the equator during the previous phase, Metaphase
Sexual reproduction involves the joining of two sex cells to form a new organism. Describe how when the sexual reproduction occurs genetic material from both parents is passed on and combined to form the genetic code for the new organism.
Sexual reproduction involves two parents producing offspring that are genetically unique in that two haploid gametes join in the process of fertilization to produce a diploid zygote.
What is Sexual reproduction?Sexual reproduction is defined as the type of reproduction that involves a complex life cycle in which a gamete with one set of chromosomes fuses with another gamete to form a zygote that develops into an organism that has the same set of chromosomes.
Zygote develops into a new individual whereas sexual reproduction is explained as the major form of reproduction in living beings. Sexual reproduction has the advantage over asexual reproduction as it increases the genetic variation which expands the gene pool.
Thus, Sexual reproduction involves two parents producing offspring that are genetically unique in that two haploid gametes join in the process of fertilization to produce a diploid zygote.
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Final answer:
Sexual reproduction involves the combination of genetic material from two parents through the processes of meiosis and fertilization, resulting in a genetically unique offspring. Gametes merge to form a diploid zygote, which develops into a new individual with a genetic code derived from both parents. This process introduces genetic diversity, crucial for species adaptation and evolution.
Explanation:
Sexual reproduction involves two parents contributing their genetic material to produce a genetically unique offspring. This process starts with the production of gametes, which are haploid cells meaning they carry half the number of chromosomes typical for the species. Gametes are formed through a special type of cell division called meiosis, ensuring diversity and a reduced chromosome number.
When gametes from two individuals unite during fertilization, they form a zygote. This zygote is a diploid cell, which means it contains a complete set of chromosomes - half from each parent. The genetic material from both parents is thus combined, forming the genetic code for the new organism. This combination introduces genetic diversity, which is crucial for adaptation and evolution. The zygote will then undergo multiple rounds of cell division and develop into a new individual through a process guided by this genetic code.
The success of sexual reproduction largely depends on this blending of genetic material, which provides a mechanism for increased variation within a species. This variation is essential for the survival and adaptation of species in changing environments.
Which organ system produces the most heat?
Answer:
Muscular System
It helps to move the body and move materials through the body and also creates most body heat.
Hope this helps and have a great day!!!
[tex]Sofia[/tex]
The three general guidelines to control pollution are
~Reuse
~Reduce
~Recycle
Hope this helps:)
Answer:
Management, Prevention, and Cure
Which of the following structures consists mainly of white matter?
Corpus callosumCerebral cortexThalamusCaudate nucleusBroca area
Answer:
The corpus callosum
Explanation:
The corpus callosum is the largest white matter structure in the brain. It is located beneath the cerebral cortex and it connects the left and right cerebral hemispheres thus enabling communication between them. The corpus callosum is a bundle of nerve fibers, (axon projections) which transmits neural signals.
The corpus callosum mainly consists of white matter and connects the two hemispheres of the brain.
Explanation:The structure that consists mainly of white matter is the corpus callosum. The corpus callosum is a large bundle of nerve fibers that connects the two hemispheres of the brain, allowing communication between them. It is mainly made up of myelinated axons, which give it a white appearance.
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Brainliest if correct!!
During which moon phase do spring tides occur?
new moon and full moon
first quarter and third quarter
waxing gibbous and waning gibbous
waxing crescent and waning crescent
Answer:
new moon and full moon
Explanation:
Tides occur due to gravitational force of the sun and the moon. During New moon and Full moon, the Sun and the Moon are aligned in a straight line. This alignment leads to strong effect of gravity on tides and highest high tides and lowest low tides occur. These tides are referred as spring tides.
Neap tides occur when the sun and the moon are aligned at right angles. Effect of gravity is minimum and low tidal range is observed.
The answer is A
New moon and full moon
Compare and contrast human respiration and cellular respiration.
Breathing involves inhale of oxygen from the atmosphere into the lungs and exhale of carbon dioxide from the lungs into the atmosphere ; whereas cellular respiration involves breakdown of glucose into carbon dioxide and water in living cells, releasing energy.
During breathing, termed as external respiration, air from the atmosphere enters into the lungs. Exchange of oxygen and carbon dioxide occurs between the blood present in the capillaries and the air entering the lungs.
The R.B.C. in the blood present in capillaries pick up oxygen from the air entering the lungs and the hemoglobin molecule is converted into oxy-hemoglobin. Carbon dioxide from the deoxygenated blood is released into the air. The air carrying carbon dioxide is exhaled out of the lungs.
Thus breathing involves intake of oxygen from the atmosphere into the lungs and exit of carbon dioxide from the lungs into the atmosphere.
Cellular respiration, also termed as internal respiration, occurs in living cells. The oxygenated blood is carried to all living cells in the body of an organism through blood circulatory.
Cellular respiration involves breakdown of glucose into carbon dioxide and water in presence of oxygen, releasing energy. Oxygen carried by blood is used in cellular respiration and carbon dioxide released combines with hemoglobin in RBCs.
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Human Respiration involves oxygen and carbon dioxide exchange, while cellular respiration is about cells producing energy through glucose. The processes differ in scale and purpose.
Human Respiration involves the exchange of oxygen and carbon dioxide, while cellular respiration is the process where cells generate energy by reacting oxygen with glucose. The main difference lies in the levels at which these processes occur.
In respiration, oxygen is inhaled to supply the body with oxygen and expel carbon dioxide, whereas in cellular respiration, cells break down glucose to produce ATP, water, and carbon dioxide.
What processes can change weathered rock particles into solid rock?
Lithification is compacting and cementation of sediments into sedimentary rock
A city grid of Anytown, U.S.A is shown on the grid below. The fire department is represented by quadrilateral RSTU. Another fire department is opening in a different part of the city to maximize fire protection. The size of the new department's property must be congruent to the older department. Vertices A and B are plotted on the grid to represent two vertices of the new fire department quadrilateral ABCD.. . . . What could be the ordered pairs representing vertices C and D of quadrilateral ABCD so that the new fire department is congruent to the old fire department?
Answer:
b
Explanation:
The human body maintains a temperature of around 98.6 degrees at all times. Enzymes are involved in almost every chemical reaction in the body. Which of the following describes the connection between these two statements? A. Enzymes function best at a specific temperature.B. The body needs to be warm to prevent hypothermia.C. The body is kept relatively warm to prevent too much enzyme action. D. There is no connection between the two statements.
Answer:
A. Enzymes function best at a specific temperature.
Explanation:
One of the factors that determinate the enzyme activity is temperature. Each enzyme has a temperature optimum (the temperature at which its activity is the highest) and it corresponds to the normal body temperature for humans (around 98.6 degrees Fahrenheit or 37 degrees Celsius). Some of them can work on lower temperatures while some of them can increase their activity with the increase in temperature. But, since enzymes are usually proteins, high temperature (above 40 degrees Celsius) might denature them and consequently enzymes lose their activity.
The four major categories of tissues are _____.
The 4 major categories of tissues are the muscle tissue, nervous tissue, connective tissue, and the epithelial tissue.
Describe how the nervous system helps different parts of your body communicate with one another the moment you begin to pet a dog.
Answer:
Your hand movement sends signals to the brain which tells you what you want to do and directs you to doing that.
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Petting a dog leads to the releases of oxytocin that keeps your hand muscles petting the dog.
What is te nervous system?The nervous system is the system of the body that coordinates electrical impulses to the brain. The sense organs are directly connected to the nervous system.
If you start petting a dog, oxytocin is realeased that enhances your conection to the dog causing the muscles in your hand to continiue pettining the dog.
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Which trophic level is most vulnerable to extinction?A.tertiary consumer levelB.producer levelC.secondary consumer levelD.primary consumer level
Answer:
a. Tertiary consumer level
Kelley weighs her self before and after exercising. after exercising she weighs 1 pound less. how many oz of water should she drink to regain the fluid that must have been lost
Answer:
At least 10
Explanation:
What is the effect of norepinephrine on the heart?
Answer:
It increases the heart rate
Explanation:
Norepinephrine or noradrenalin is a neurontransmitter that controls many body functions as part of the sympathetic nervous system. This means that its role is to increase body movement and to prepare organism for "fight and flight" reactions. Its functions are:
alertness, arousal and attention (in the brain) increase of the heart rate and blood pressure, release of glucose from energy stores, inhibition of voiding of the bladder and gastrointestinal motility etc.Norepinephrine achieves its function by binding to its cell membrane receptors-alpha and beta adrenergic G protein-coupled receptors.