History: When did stem cell research become known? Who discovered stem cells? What experiments or studies have been conducted so far?
Answer:
The stem cells was discovered by Ernest McCulloch and James Till in 1981. Studies conducted for stem cells can be used for bone marrow transplantation and to treat various diseases.
Explanation:
Stem cell are the cells that has the ability to differentiate into different cells of the body. In 1978 human cord blood discovered as stem cell. The stem cell research come to known in 1981.
Ernest McCulloch and James Till discovered the stem cell research while working on the mice bone marrow. He found that the different blood cells were formed by the single class of cells.
Experiments on mice and other animals have been conducted to study the stem cells so far. The study of stem cell is useful to cure the genetic defects, Cancer and other harmful diseases.
In 1963 James Edgar Till discovered that bone marrow transplanted cells in the spleen of mice self-replicated. With the research, Canadian scientist James Edgar Till discovered stem cells that have become a known and controversial subject ever since.
From this, stem cells have become the subject of numerous studies and experiments, and are the main subject of many debates. Experiments have already been performed that tested the influence of stem cells in cancer treatments, cloning, chronic disease treatments, experiments that evaluate the possibility of organ transplantation from animals to humans, tumor treatment, among others.
Several segments of the population have taken a position contrary to this type of research, as they claim that the good of society cannot be obtained from the death of some individuals, even if still in the embryonic stage. The Roman Catholic Church, as well as Protestant churches has defended this position, also accepted by many unrelated scientists and philosophers, that a person's life begins with fertilization, so there is no ethically adequate justification for such research. .
what are the two most abundant gases in the atmosphere
Answer:
The correct answer will be- Oxygen (21%) and Nitrogen (78%)
Explanation:
The atmosphere of Earth is composed of a mixture of the gases in different concentrations.
The major constituent gases of the atmosphere are the nitrogen which constitutes about 78% of the total gases present and the oxygen which constitutes the 21% of the total gases.
These gases exist in their divalent states in the atmosphere where the nitrogen is used by the organisms when it is fixed by the prokaryotic nitrogen-fixing bacteria whereas the oxygen is directly used by the organism.
Thus, Oxygen (21%) and Nitrogen (78%) is the correct answer.
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Which is not a year-round resident of the tundra?
polar bear
wolverine
jackrabbit
musk ox
Jackrabbit is not a year-round resident of the Tundra region. Polar bear, wolverine, musk ox all are year-round residents of the tundra region. Thus, the correct option is C.
What are the characteristics of Tundra region?
Tundra is the coldest of all the biomes on the globe. Tundra are the treeless plain regions. It has extremely low temperature, with a little precipitation, poor nutrient content of the soil, and short growing seasons. In these biomes, dead organic matter functions as nutrient pool.
Tundra wildlife includes mammals such as Norway lemmings, arctic hares, polar bear, wolverine, musk ox, and arctic ground squirrels. These animals build up stores of fat in their body to sustain and insulate themselves through the winter season.
Therefore, the correct option is C.
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Compare and contrast the lowry and bradford protein assays with regard to compatibility with various potential contaminating compounds.
During periods of intense activity, your body releases an antidiuretic hormone called vasopressin that causes the body to retain water (by decreasing the amount of water that is expelled in urine). why does this make endurance athletes particularly vulnerable to developing hyponatremia?
Final answer:
Endurance athletes are vulnerable to developing hyponatremia due to the release of antidiuretic hormone (ADH) which conserves water and decreases urine output, thereby diluting blood sodium levels without adequate sodium replacement.
Explanation:
During periods of intense activity, such as those experienced by endurance athletes, the body releases antidiuretic hormone (ADH) or vasopressin, which is secreted by the hypothalamus. This hormone plays a crucial role in conserving body water by causing the kidneys to excrete less water in urine, thereby conserving water when dehydration is a risk.
However, this mechanism makes endurance athletes particularly vulnerable to developing hyponatremia, a condition characterized by low sodium levels in the blood. This is because as water retention increases without adequate sodium intake to balance the increased fluid volume, the concentration of sodium in the blood drops. During long-duration activities, athletes often consume large volumes of water to stay hydrated but may not adequately replace lost sodium, exacerbating this imbalance.
Therefore, while ADH aids in water conservation, its effect on reducing urine output without compensatory sodium intake can lower blood sodium levels, leading to hyponatremia, which is particularly risky for endurance athletes engaged in prolonged physical activity.
Why is it incorrect to say that astronauts are weightless in space while orbiting Earth in a space shuttle?
In space, humans and their spaceship are still affected by Earth's gravity. Even though Earth's gravity is weaker in orbit, they still retain weight. They don't feel their weight since nobody pushes back.
What is weightlessness?Even though they are outside of Earth's gravitational pull, astronauts and their spacecraft continue to have mass and are subject to its effects. In this sense, they continue to have weight, despite the fact that the gravitational pull of the Earth is weaker in orbit than it is on the surface of the Earth. However, they are not aware of their own weight because there is no resistance being exerted on them.
The sense of having no weight at all, or almost none at all, is what is referred to as weightlessness. This phenomenon is often referred to as zero G-force or simply zero-G. A thing's weight can be thought of as a measurement of the force that gravity exerts on it while it's just sitting there doing nothing.
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Jimmy is riding in his car to the office. It is snowing heavily and he can see frost forming on the windowpane. Which type of water transition is this? A.evaporation B.precipitation C.condensation D.deposition
Answer:
D. Deposition
Explanation:
on edm
Phase transition of water is the process that involves the change in the state of the water. When a frost is formed on the windowpane due to the heavy snow, then it is called deposition. Thus, option D is correct.
What is the phase transition of water?Water transition is a series of processes where the water undergoes various phases to change its state of matter. Evaporation, condensation, deposition, and precipitation are some examples of water transitions.
In deposition is a phase transition where the water vapor of the sub-freezing air directly gets converted to ice or frost without entering the liquid phase.
Therefore, the frost formation on the window is an example of deposition.
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) in an atom, the nucleus is composed of _____________ and _____________, while the ____________ orbit very quickly around the nucleus.
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Permafrost remains throughout the summer because it is insulated by _____.
groundcover vegetation
thick sheets of ice
snow
topsoil
If I am correct, permafrost may last through the summer because of groundcover vegetation
Answer: groundcover vegetation
Explanation:
In humans, how many alleles of genes found on the x chromosome do male have?
Climbing to the top of mt. whitney in california, what would you expect to happen to the temperature on the mountain as you ascend?
Skin cells perform very different functions compared to brain cells. on the molecular level, what makes skin cells different from brain cells in the same organism? ph atp dna proteins
A garden has 80 pea plants. Of this total, 20 plants have short stems and 60 plants have tall stems. What percentage of the plants is short?
__________ is the conversion of acetyl coa into ketone bodies.
Final answer:
Ketogenesis is the conversion of surplus acetyl CoA into ketone bodies, such as acetoacetate, β-hydroxybutyrate, and acetone, when the Krebs cycle is overwhelmed. This process provides an alternative energy source for the body during periods of low glucose availability.
Explanation:
Ketogenesis is the conversion of acetyl CoA into ketone bodies. When there is an excess of acetyl CoA from the oxidation of fatty acids, and the Krebs cycle (citric acid cycle) cannot process it all, the liver converts this surplus acetyl CoA into ketone bodies through a pathway known as ketogenesis. The main ketone bodies produced are acetoacetate, β-hydroxybutyrate (B-hydroxybutyrate), and acetone. The process starts with two acetyl CoA molecules combining to form acetoacetyl-CoA. This is then converted into β-hydroxy-β-methylglutaryl-CoA (HMG CoA), which subsequently gets cleaved to form acetoacetate and acetyl CoA. Most of the acetoacetate is further reduced to β-hydroxybutyrate, and a smaller portion decarboxylates to form acetone and carbon dioxide.
Ketone bodies are useful as an alternative energy source when glucose is scarce, such as during prolonged fasting or uncontrolled diabetes. They can be transported from the liver to other tissues, where they are reconverted to acetyl CoA and enter the Krebs cycle to produce energy. This ensures organs like the brain can function even when glucose supply is low.
You have examined several body systems that rely and work with each other in order function properly. One very important task that amphibians and all living things need is to efficiently exchange gases in order to survive. Explain in a brief essay how the cardiovascular system and respiratory system work with each other based on your experience and observations from this virtual lab.
Predict what you think might happen if the respiratory membrane were instead composed of two layers of stratified squamous epithelium. Explain.
Final answer:
Switching the respiratory membrane to two layers of stratified squamous epithelium would impair gas exchange due to the increased thickness and protective nature of this type of tissue, leading to potentially decreased oxygen absorption and carbon dioxide removal.
Explanation:
The question asks, "Predict what you think might happen if the respiratory membrane were instead composed of two layers of stratified squamous epithelium." The respiratory membrane currently consists of a single layer of squamous epithelium, known for its thinness, which facilitates the efficient exchange of gases (oxygen and carbon dioxide) by diffusion. In sharp contrast, stratified squamous epithelium comprises multiple layers of cells, primarily designed for protection against abrasion and external damage, as seen in the skin, mouth, and vaginal tissues.
Replacing the current single-layered squamous epithelial structure with a stratified squamous epithelium would significantly impair the respiratory system's function. The increased thickness and the protective orientation of this layer would drastically reduce the efficiency of gas exchange. Instead of facilitating the transfer of oxygen and carbon dioxide, the thickened barrier would pose a formidable obstacle, potentially leading to decreased oxygen absorption into the bloodstream and impaired removal of carbon dioxide.
7. A system of stars orbiting a common center of gravity
A) solar system
B) universe
C) galaxy
D) biosphere
8. The group of eight planets and other matter that orbits the sun.
A) solar system
B) universe
C) galaxy
D) biosphere
9. Everything in outer space including stars,planets, and galaxies
A) solar system
B) universe
C) galaxy
D) biosphere
10. A planet that sustains life in its biosphere
A) mars
B) Venus
C) earth
D) Jupiter
The first stage of catabolic metabolism occurs in the
A. gallbladder.
B. stomach.
C. pancreas.
D. liver.
As you walk to your classes, your muscle cells are typically conducting _____.
Muscle cells are conducting depolarization waves to stimulate contraction, especially in the heart where a depolarization wave coordinates contractions and propels blood through the circulatory system.
Explanation:As you walk to your classes, your muscle cells are typically conducting depolarization waves that stimulate muscle contraction. In the case of the heart, a depolarization wave is sent across the heart to coordinate its rhythmic contractions and propel blood through the circulatory system. This wave starts at the sinoatrial (SA) node, the heart's natural pacemaker, and spreads through conductive cells across the heart.
The roots of many plants have a relationship with fungi called
Please help!!!!!!!! WIll give brainliest!!!!! One theme that connects all information in biology is “stability and change.” Describe one of the other themes that connects all the information in biology. Use an example to help explain the theme.
Structure and Function
Early in mitosis, the nucleus, nucleolus, and nuclear envelope begin to dissolve in preparation for cell division. In which stage of the cell cycle is this process reversed?
The correct answer is telophase.
The mitosis is divided into four phases, these are prophase, metaphase, anaphase and telophase.
The prophase is the first stage, in which the nuclear membrane, nucleolus begin to disappear and the genetic material is condensed in the form of chromosomes. The nuclear membbrane and nucleolus are absent till the late anaphase.
In the telophase, the nuclear envelope and the nucleolus begin to form again, teh chromosomes are decondensed and the nucleus is formed again. So, the process, which occur in the early mitosis is reversed in this phase.
Answer:
d. telophase
Explanation:
on edge
Compare coenzymes with substrates. how do they work together in enzyme catalysis
What is the role of restriction enzymes in studying the human genome?
Answer:
Restriction enzymes cut the large DNA of human cells into smaller fragments at specific regions called as restriction sites.
Explanation:
Restriction enzymes are endonucleases that cut the DNA into smaller fragments. These DNA fragments are separated from each other through gel electrophoresis and used to make the DNA profiles of individuals. Thus, restriction enzymes help in study of human genome by carrying out site specific digestion of human DNA.
disadvantages of silver fish and army ant?
An error that occurs when DNA is replicated is referred to as a ____. mutation migration splicing event genetic drift
An error that occurs when DNA is replicated is referred to as a mutation. The correct option is a.
What is mutation?A mutation is changing or modification in the nucleic acid or DNA sequence of a person. This is a natural process that occurs due to mutagens.
A mutation is now also artificial induced to bring out changes in the gene sequences for specific reasons.
There are different types of mutations; somatic mutation occurs in the body cell and chromosomal mutation occurs in the structure of chromosomes, point mutation changes the nucleotide.
The majority of non-neutral mutations are harmful. The effect of a mutation and its likelihood of being harmful increase generally with the number of base pairs that are changed by the mutation.
Therefore, the correct option is a. mutation.
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which molecule forms the bulk of a cell membrane?
which is the best definition of diffusion?
which substance is commonly found in a cell membrane?
what is the process whereby molecules in vesicles are exported out of a cell?
In a eukaryotic cell, where is most of the DNA located?
1. which molecule forms the bulk of a cell membrane?
answer: phospholipid
In terms of structure, a cell membrane (or plasma membrane)
consists mainly of a phospholipid bilayer (with associated proteins embedded in
it).
2. which is the best definition of diffusion?
answer: Diffusion is the bulk movement of particles from a region of higher concentration to a region of lower concentration
3. which substance is commonly found in a cell membrane?
answer: proteins
Proteins are enzymes which help transport things through the
membrane.
4. what is the process whereby molecules in vesicles are exported out of a cell?
answer: exocytosis
Actually there are 2 types of bulk transport and these are: exocytosis and endocytosis, and both require the spending of energy (ATP). In exocytosis, resources are excreted out of the cell via secretory vesicles.
5. In a eukaryotic cell, where is most of the DNA located?
answer: inside the nucleus
The nucleus is the main center of our cells. This contains our chromosomes and genetic information essential for the reproduction of life.
A client resides in a long-term care facility. which nursing intervention would promote increased dietary intake?
George is lost in the hot, dry desert. he has no water and he is sweating a lot. which of these blood components would be reduced or decrease?
I think plasma will decrease, because it is made by water (90%) and other components such as protein , vitamins, ...
In every energy transformation some energy is always "lost" __________ energy.
a.radiant
b.electrical
c.chemical
d.thermal
There is a loss of thermal energy during the process of energy transformation. Therefore, option "D" is correct.
What is thermal energy?The energy of the system which is controlled by its temperature is referred to as thermal energy. The term used for the flow of thermal energy is referred heat. The first law of thermodynamics explains how heat and work are transferred between systems, which is the subject of a whole branch of physics called thermodynamics.
There are different ways of energy transfer convection, conduction, and radiation. Thermal energy can be seen in the process of boiling water on a stove. These radiation transfer when come in contact.
Therefore, every material radiates energy which is transferred from one body to another.
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