What process allows the amount of DNA in an organism's cells to be kept constant in sexually reproducing species?
Meiosis is the process through which sexually reproducing organisms maintain their particular chromosomal numbers from generation to generation. In humans, meiosis generates sperm and eggs, each having 23 chromosomes. By fertilizing sperm and ova, the chromosome number is restored in the zygote (46 chromosomes).
The sperm and egg carry half as many chromosomes as body cells since they are haploid (n) (in humans, 23 in each sperm and egg).
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what part of the brain does not fully develop until people are in their mid-20s?
Answer:
the prefrontal cortex
Explanation:
When did cancer study start?.
Answer:
The modern era of cancer research really began in the 19th century and led to the current concept developed by several investigators, notably Rudolf Virchow, that cancer is a disease of cells.
Explanation:
Why is heating a first step in pcr amplification of extracted dna?
Heating is the first step of PCR amplification because it is necessary to denature the double-stranded DNA template so that it can be used by the polymerase enzyme.
This process involves breaking the hydrogen bonds that hold the two strands together, which allows the primers to bind to the single-stranded DNA. Heating is also necessary to bthe polymerase enzyme, as it is not active at room temperature.
Additionally, the high temperature denaturation step also helps to increase the efficiency of the polymerase enzyme by increasing its activity and allowing it to bind more tightly to the primer. This makes it more likely that the primer will anneal and that the polymerase will be able to initiate DNA synthesis.
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describe the temperature, moisture and air pressure associated with a continental polar air mass.
Surface high pressure, frigid temperatures, and low dew points are characteristics of coastal polar or colonial arctic air masses. Air masses in the maritime polar region (mP) are cold, humid, and unstable.
In biology, what does a temperature mean?The degree to which an individual or environment is hot or chilly . the physical experience of warmth or cold. The amount of heat or cold in a specific location, typically expressed in degrees Fahrenheit (F), Celsius (C), or Kelvin (K).
What role does temperature have in biology?The reaction rates enzyme enzymes, which control processes that appear of any kind levels of a organism's organization, are greatly influenced by temperature.
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What are the possible abnormal gametes The male can produce with non disjunction?.
Humans will create two gametes with additional chromosomes and two gametes without a chromosome if nondisjunction happens during Meiosis I.
50 percent of the gametes produced by meiosis II nondisjunction are normal. 50 percent of the gametes produced during meiosis I are normal due to nondisjunction.
They are brought on by nondisjunction, which takes place when sister chromatids or homologous pairs of chromosomes fail to separate during meiosis. The chance of nondisjunction increases with parent age.
The most frequent cause of abnormal chromosomes is a mistake made during cell division. Chromosome abnormalities frequently result from 1 or more of the following: errors that occur as sex cells divide (meiosis) errors that occur when other cells divide (mitosis).
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darwin’s theories were interpreted by social darwinists to indicate that
Social Darwinists subscribe to the idea that some people achieve prominence in society due to their innate excellence. This idea is known as "survival of the fittest."
Many social evils like racism, eugenics, imperialism, and socioeconomic inequality have been defended with the help of social Darwinism. Darwin claimed that all species share a common origin, that species can change through time, and that new species develop from existing ones. According to this theory, each species has a distinct set of heritable (genetic) differences from the common ancestor that have developed gradually over extremely long time periods. A multi-level "tree" connecting all living things is created through repeated branching events, in which new species split off from a common ancestor. Darwin called this process of heritable trait alteration in groups of animals over generations "descent with modification." We now refer to it as evolution.
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Why are leaves green and not black?.
The leaves are green and not black because leaves аbsorb light in the blue аnd red spectrа, but not green light which аctuаlly more the sun's light.
Plаnts cаn broаdly be divided into four mаin components: roots, stem, flowers аnd leаves. The leаves mаke the plаnt’s energy, or food in, аs every GCSE student knows, the process cаlled photosynthesis.
Plаnts (plus аlgаe аnd certаin bаcteriа) аbsorb light to mаke sugаrs, providing the plаnt with energy аnd some other useful biochemicаl products which the plаnt requires to grow successfully.
Plаnts аnd their leаves look green becаuse the “speciаl pаir” of chlorophyll molecules uses the red end of the visible light spectrum to power reаctions inside eаch cell. The unused green light is reflected from the leаf аnd we see thаt light. The chemicаl reаctions of photosynthesis turn cаrbon dioxide from the аir into sugаrs to feed the plаnt, аnd аs а by-product the plаnt produces oxygen.
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What are the main features of scientific research Mcq?.
The main features of scientific research include:
Empiricism: The reliance on empirical evidence, or evidence obtained through observation or experimentation, to support or refute hypotheses and theories.
Objectivity: The use of unbiased and impartial methods to conduct research, in order to minimize the influence of personal opinions and beliefs on the outcome.
Replicability: The ability of other researchers to replicate the study and obtain similar results, in order to confirm the validity of the findings.
Parsimony: The use of the simplest explanation that fits the evidence, rather than invoking complex or unlikely explanations.
Self-correction: The ability of the scientific community to identify and correct errors or inaccuracies in the research, through peer review and replication.
In conclusion, scientific research is characterized by its use of empirical evidence, objective methods, replicability, parsimony, and self-correction, which together help to ensure the validity and reliability of the findings.
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the protein rda for adults is ________ grams per kilogram.
The protein RDA for adults is 0.8 grams per kilogram.
How does the protein RDA for adults compare to the protein needs of athletes?
The protein RDA for adults is 0.8 grams per kilogram, which is a general guideline for the average daily protein intake for healthy individuals. However, the protein needs of athletes may be higher due to their increased muscle mass and activity level. Athletes may require 1.2 to 2.0 grams of protein per kilogram of body weight per day to help support muscle growth and recovery. However, it's important to consult with a sports nutritionist or a healthcare professional to determine specific protein needs for individual athletes.
The protein RDA (Recommended Dietary Allowance) for adults is 0.8 grams per kilogram. This means that for an adult with a body weight of 68 kg, the recommended daily intake of protein is 54.4 grams. However, it's worth noting that this is just a general guideline and individual protein needs may vary depending on factors such as age, sex, muscle mass, activity level, and overall health.
It's important to note that the RDA is the average daily level of intake sufficient to meet the nutrient requirements of nearly all (97-98%) healthy individuals in each life-stage and gender group, however for athletes or people with specific health conditions, the protein needs may differ.
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One gene has several different forms, resulting in more than two phenotypes.a. Trueb. False
One gene has several different forms, resulting in more than two phenotypes is True.
A gene can have multiple forms, also known as alleles, which can result in more than two phenotypes.
A phenotype is the observable characteristic or trait of an organism, which is determined by the combination of its genetic makeup (genotype) and the environment.
For example, the gene for eye color in humans can have multiple alleles, such as brown, blue, and green. The presence of different alleles can result in different eye colors, such as brown eyes, blue eyes, and green eyes.
Another example is the gene for height in humans. Height is a polygenic trait, which means it is influenced by multiple genes, each with different alleles. The combination of different alleles of these genes can result in a wide range of heights in humans.
In conclusion, the presence of multiple alleles of a gene can result in more than two phenotypes, and this is known as polygenic inheritance. This is because a trait can be influenced by multiple genes, each with different alleles, which can result in a wide range of variations of that trait.
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What is the study of cancer known as?.
Answer:
Listen to pronunciation. (on-KAH-loh-jee) A branch of medicine that specializes in the diagnosis and treatment of cancer.
13. The synthesis of ATP from ADP results in:
a. ADP released
b. ADP storage
C.energy released
D. energy storage
Answer:
C
Explanation:
Energy is released because the bonds are broken.
those that carry impulses from the cns out to the muscles and glands.
Motor nerves are those that carry impulses from the CNS out to the muscles and glands.
Muscle cells get impulses from the central nervous system through motor nerves. The nerves that send messages from the brain and spinal cord to all of the glands, organs, and muscles in the human body are known as motor nerves. All muscle-related movements are directly under the control of these motor neurons.
The CNS receives impulses from peripheral sense receptors through afferent, or sensory, neurons. They often have relatively short axons and lengthy dendrites. The CNS sends impulses via efferent, or motor, neurons to effector organs like muscles and glands.
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after one division of the nucleus, a new spindle forms around each group of chromosomes.
During mitosis, the nucleus of a cell divides into two identical nuclei, each containing the same number of chromosomes as the original cell.
How do chromosomes get separated during mitosis?During mitosis, chromosomes are separated by the formation of a structure called the spindle, which is composed of microtubules that extend from opposite poles of the cell. The spindle fibers attach to the chromosomes and pull them apart, separating the identical copies of each chromosome into the two new nuclei. The spindle fibers also help to align the chromosomes in the middle of the cell before they are pulled apart. After the chromosomes have been separated, the cell then divides into two daughter cells, each with a complete set of chromosomes.
During mitosis, the nucleus of a cell divide process is controlled by the formation of a structure called the spindle, which is composed of microtubules that extend from opposite poles of the cell.
The spindle fibers attach to the chromosomes and pull them apart, separating the identical copies of each chromosome into the two new nuclei. The spindle fibers also help to align the chromosomes in the middle of the cell before they are pulled apart. After the chromosomes have been separated, the cell then divides into two daughter cells, each with a complete set of chromosomes. The new spindle will form around each group of chromosomes in each daughter cell to ensure that all chromosomes are properly separated and distributed during the cell division.
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List the parts of a visceral reflex arc .
A reflex arc consists of five components that, when combined, form a reflex loop:
Receptor for sensory information.Sensory neuron is a type of neuron.Center for integration.The motor neuron.The effector's target.The output of a visceral reflex is a two-step pathway that begins with a preganglionic fiber emerging from a lateral horn neuron in the spinal cord or a cranial nucleus neuron in the brain stem to a ganglion, followed by a postganglionic fiber projecting to a target effector.
The viscerosomatic reflex arc begins after visceral dysfunction (i.e., myocardial ischemia), which increases the propagation of action potentials along visceral afferent fibers that terminate in the dorsal gray matter of the spinal cord.
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Dye injected into a plant cell might be able to enter an adjacent cell through ..
a. Microtubule
b. Microfilament
c. Plasmodesmata
d. Tight Junction
Answer:
The cell wall of the cells has very small pores which are known as the plasmodesmata, they act like a bridge between the two cells. So, if we inject ink into the cell then it will get transferred to the other cell via these pores called plasmodesmata.
nervous system subdivision that is composed of the brain and spinal cord
The brain and spinal cord are the two components of the central nervous system. The peripheral nervous system is composed of nerves that emerge from the spinal cord and cover the entire body.
What division are the brain and spinal cord?The peripheral nervous system (PNS) and the central nervous system (CNS) are two components of the human nervous system (PNS). The brain and spinal cord are two components of the CNS that are located in the cranial cavity of the skull and the vertebral canal, respectively.The peripheral nervous system (PNS) and the central nervous system (CNS) make up the entire nervous system (PNS).The term "peripheral nervous system" describes the portions of the nervous system that are not located in the brain and spinal cord. It contains the neuromuscular connections, peripheral nerves, spinal nerves, their roots, and branches.The cervical, thoracic, lumbar, and sacral portions of the spinal cord are the four distinct divisions.To learn more about spinal cord refer to:
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Which list shows only SECONDARY consumers according to this photo?
a) penguins, other seals, phytoplankton
b) fish, carnivorous zooplankton, birds
c) krill, leopard seal, smaller toothed whales
d) elephant seal, fish, other herbivorous zooplankton
Which tatement i correct about the difference between theorie and law?
A Unlike theorie, law are baed on obervation obtained through experimentation. BWhile both law and theorie are developed on the bai of experimentation, theorie are not explanation. C Unlike theorie, law cannot be changed or replaced becaue they are tatement of fact. D While both law and theorie are tatement, theorie are not widely accepted
The correct statement about the difference between law and theory is Option (C) : Unlike theory, law cannot be changed or replaced because they are statement of fact.
Science defines a law as a generalization made following a number of observations. When a law is drafted, it is without exceptions or justifications. It is an undeniable reality that was observed and documented. Gravity could serve as a nice illustration of this. On the Earth's surface, an apple has been seen to fall. It cannot be disputed. There are also no exceptions to this statement. A reverse or alternate phenomenon has never been seen. Consequently, it is regarded as a law.
A theory is a proposed law that provides an explanation for the observed facts. A theory is, to put it simply, the justification for a law. It might also be described as a sophisticated or evolved theory. Any observation has a "hypothesis" that is a likely explanation for it. A theory must pass several tests. A hypothesis might be recognized as a theory if it stands up well under many circumstances.
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How did algae photosynthesis cause coral bleaching?.
Two things induce coral bleaching: the first is the acidification of the water, which is strongly related to the carbon dioxide in the water dissolving to generate carbonic acid, which kills the coral polyps.
Carbon dioxide levels that are too high will always result in the creation of carbonic acid. The second factor is the rising temperature and intense sunlight, which has the effect of speeding up photosynthesis and increasing the rate at which oxygen is produced. According to another theory, too much oxygen in the water is detrimental and can even kill polyps. Therefore, the process of coral reef-forming reef bleaching involves algae photosynthesis to a significant extent. The gradual warming of the planet causes an increase in temperature.
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T/F a peripheral nerve passes from the spinal cord into the limbs
True. A peripheral nerve passes from the spinal cord into the limbs.
What do you mean by spinal cord?
The spinal cord is a long, thin bundle of nerves that runs from the base of the brain down to the lower back. It is the main conduit for information between the brain and the rest of the body. It carries nerve signals to and from the brain and is responsible for relaying information about sensation and movement. It also plays a role in controlling involuntary body processes such as breathing, heart rate, and digestion.
Peripheral nerves are the nerves that connect the central nervous system (CNS) to the limbs and organs of the body. They pass from the spinal cord, which is part of the CNS, into the limbs and organs. These nerves carry both sensory and motor signals from the CNS to the limbs and organs, and vice versa. This allows the CNS to control movement, sense touch, and regulate organ functions.
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the process by which cells grow and divide to produce more cells. this is to help cells grow, repair and replace other cells.
Mitosis is the process by which cells grow and divide to produce more cells. This is to help cells grow, repair and replace other cells.
Mitosis is an essential process for cells to grow and divide, enabling them to produce more cells. This process helps cells grow, repair, and replace other cells, ultimately aiding in the maintenance of healthy cells in the body.
Mitosis is a complex process, beginning with the duplication of the cell’s DNA, followed by the splitting of the cell into two daughter cells. During the process, the daughter cells are identical to the parent cell, carrying the exact same genetic material.
The process of mitosis is essential for the growth and development of living organisms.
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Hormones are released into the _______ ______surrounding endocrine cells. From there, they diffuse into bloodstream and are carried to all parts of the body
Hormones are released into the Extracellular spaces surrounding endocrine cells. From there, they diffuse into bloodstream and are carried to all parts of the body.
Hormones are chemicals that are secreted by an endocrine gland and carried through the bloodstream. Hormones are secreted into the extracellular areas that surround endocrine cells. They then diffuse into the bloodstream, where they are delivered to all regions of the body. Hormones are released into the bloodstream by endocrine glands. This allows hormones to flow to cells throughout the body. Endocrine hormones regulate mood, growth and development, organ function, metabolism, and reproduction. The endocrine system controls the amount of each hormone released. Hormones are chemical messengers in your body. They circulate through the circulation to tissues or organs.
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fragile x syndrome is a chromosomal disorder in which
Fragile x syndrome is a chromosomal disorder in which FXS is caused by changes in a gene called Fragile X Messenger Ribonucleoprotein 1 (FMR1).
FXS is a hereditary condition known as fragile X syndrome. A gene called Fragile X Messenger Ribonucleoprotein 1 alterations lead to FXS (FMR1). A protein termed FMRP that is required for brain development is typically produced by FMR1. FXS patients cannot produce this protein. Although the FMR1 gene has changed in people with fragile X diseases, they typically still produce part of the protein.
Males and females are both impacted by FXS. However, compared to men, women frequently exhibit milder symptoms. Although the precise number of FXS patients is unknown, a review of research papers estimated that approximately 1 in 7,000 males and 1 in 11,000 females have the condition.
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spindle fibers attach to the homologous chromosome pairs
The centromeres are where the spindle fibres connect to homologous chromosomal pairs. The chromosomes can move because the nuclear membrane has broken down.
The chromosomes are subsequently positioned along the cell's equatorial plane by the spindle fibres. Eukaryotic cells have spindle fibres, which are a part of the cytoskeleton as well as cilia and flagella. During mitosis and meiosis, chromosomes are moved by a spindle machinery to guarantee uniform chromosomal distribution amongst daughter cells.
The cell lengthens and elongates due to spindle fibres that are not attached to chromatids. The spindle fibres scatter during telophase as the chromosomes divide and move into separate new nuclei. Two daughter cells are created at the conclusion of mitosis and cytokinesis, each with the appropriate size of the chromosomes.
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which organelle is the site where energy is made in an animal cell
The majority of the chemical energy required to drive a cell's metabolic operations is produced by mitochondria, which are membrane-bound cell organelles (mitochondrion, singular).
Adenosine triphosphate, a tiny molecule, serves as a storage container for the chemical energy generated by the mitochondria (ATP). Complete response: The Golgi complex is a cell organelle. The Golgi complex is the name of the organelle found in cells that is responsible for moving proteins across the cytoplasm. By using the process of aerobic respiration, the mitochondria's primary job is to supply energy for cellular activities. In this procedure, glucose is converted to pyruvic acid in the cytoplasm of the cell and then transferred into the mitochondrion.
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Which cells are involved in bone growth?
Bone morphogenetic proteins (BMPs), which are secreted and deposited into the extracellular matrix during bone formation, are the work of osteoblasts.
What kind of cells contribute to bone growth?terms in this group (9) The secretion of an organic matrix and mineral salts by osteoblasts contributes to the development of new bone. are established bone tissue cells that have reached maturity.
Which two cells are crucial to bone remodeling?Osteoclasts, multinucleated cells that break down the bone matrix, and osteoblasts, which have osteogenic functions, are the two main bone tissue cells that must operate properly for bone remodeling to occur.
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Baed on the information in the twin tudie, what can we predict about the likelihood of identical twin inheriting Alzheimer' dieae?
Even identical twins with identical inheriting genes have different levels of susceptibility. For identical male couples, the study only showed a concordance rate of 45%.
What are the heritability implications of twin studies?Twin research enables the separation of the genetic and environmental components that contribute to the desired trait. Researchers can calculate how much of the diversity in a trait is due to genetic variation and how much is due to shared or unshared environments.
What are some overarching conclusions drawn from research on identical and fraternal twins?Fraternal twins only share half of their genes with each other while identical twins share 100%. A trait may have genetic roots if identical twins exhibit it more frequently than fraternal twins.
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use the enlargements in the figure to rank the following structures and molecules from largest to smallest.
The following organelles and cellular components are found in the cytoplasm: nucleolus ,nucleus ribosome ,vesicle ,rough endoplasmic reticulum.
What are the 12 organelles in a cell?The cytoplasm contains the following organelles and cellular parts:the nucleolus, the nucleus, the ribosome, the vesicle, the rough endoplasmic reticulum, the Golgi apparatus, the cytoskeleton, the mitochondria, the vacuole, the cytosol, the lysosome, and the centriole. One can only see the nucleus with a light microscope, which is the largest cellular organelle.The sole pathways for tiny polar molecules, ions, and macromolecules (such proteins and RNAs) to move between the nucleus and cytoplasm are the nuclear pore complexes. The only positively charged nucleus in an atom is surrounded by a cloud of negatively charged electrons.The electron clouds interact with each other and with the nuclei as atoms come close to one another.To learn more about cellular components refer
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What muscle separates the thoracic cavity from the abdominal cavity?
The diaphragm separates the thoracic cavity from the abdominal cavity.
It is involved in respiration, drawing downward in the chest on inhalation, and pushing upward in exhalation.
What is thoracic cavity and abdominal cavity?
The region of the body commonly referred to as the chest is called the thoracic cavity. It is where the heart and lungs are located.
The stomach, intestines, female reproductive organs, liver, gallbladder, spleen, and pancreas are all housed in the abdominal cavity, which is below the thoracic cavity.
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