A species can only be declared extinct today if there is "no reasonable doubt that the last individual member has perished," according to updated 1990s regulations. For each species under consideration, scientists today take into account information on the population size, number of breeding adults, geographic range, and habitat degradation.
It was proposed in the 1980s that an extinction should be declared if a species went 50 years without being seen. Although it seemed like a lot of time, it wasn't enough. After decades or even centuries since their previous observation, many species have been found again. For the first time in 170 years, the black-browed babbler, for instance, was just discovered in Borneo's jungles!
In fact, some recently found species had already been officially declared extinct, proving that extinction need not be permanent. These species are known as Lazarus species; for example, the Miles' robber frog was revived after being discovered in a cloud forest in Honduras in 2008.
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Aseptic technique means that that you perform the preparation of media or the transfer of living microbes__
A. uniformly and consistently
B. without introducing contamination
C. only with pathogens
D. under completely sterile conditions
Aseptic method refers to the uniform and consistent preparation of media as well as transfer of living microorganisms without adding contamination other than pathogen contamination under entirely sterile conditions.
Safety and Aseptic Techniques. To decrease contamination from germs, aseptic technique uses target-specific practises and procedures under adequately controlled settings. To perform laboratory research in the area of microbiology, you must have certain skills.Aseptic method refers to the uniform and consistent preparation of media as well as transfer of living microorganisms without adding contamination other than pathogen contamination under entirely sterile conditions. By using aseptic method, you can prepare media or transfer living bacteria reliably and consistently without introducing contamination. only with pathogens.
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Although the cells of some prokaryotic species may adhere to one another within a matrix or form filaments, prokaryotes are fundamentally unicellular
Although cells of some prokaryotic species may adhere to one another within a matrix or form filaments, prokaryotes are fundamentally: unicellular.
What are prokaryotes?Prokaryotes are simple and single-celled organisms that lack nucleus and other membrane-bound organelles. They are among the earliest forms of life on the Earth and are hence characterized by their small size and simple structure.
Prokaryotic cells perform all cellular functions on their own and do not depend on specialized organelles to carry out these functions and they are also capable of reproducing asexually, making identical copies of themselves.
Prokaryotic cells may form clusters or chains, but they will still be considered unicellular organisms.
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the small bulge at the end of the axon that sends messages to other neurons are called
It moves nerve impulses from the cell and toward surrounding cells. The axon hillock is a little hump seen at the base of motor neuron axons. Every positive feedback loop or action potential starts at the axon hillock. The axon branches, creating the axon terminal.
What function do tiny message-sending terminals that are presently at the axon's end serve?Axon terminals are swellings or little knobs on the extremities of both the thinner fibers that branch out from the axon and are responsible for making connections with other nerve cells. They are termed as nerve endings, ending buttons, or synaptic knobs.
What does the transmission that the axon sends have a name?Action potentials are communication packets that are used to transfer data. When an action potential passes through a single neuron cell, an electrochemical cascade occurs, allowing a budget surplus more positively charged substances into the axon.
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What are the 2 types of transport in and out of cells?
Answer: passive diffusion and active transport
Explanation: Hope this helps!
How is dsrna different in function from other types of rna?
Answer: dsRNA, or double-stranded RNA, is different from other types of RNA in its structure and function. Unlike single-stranded RNA, such as messenger RNA (mRNA), dsRNA has a double-stranded structure, meaning that it has two complementary RNA chains that are bound together. This unique structure of dsRNA makes it an important molecule in the regulation of gene expression and the response to viral infections.
In the context of gene regulation, dsRNA can trigger the RNA interference (RNAi) pathway, which is a mechanism that helps cells to regulate gene expression. RNAi works by using dsRNA as a trigger to destroy specific mRNA molecules, thereby reducing the production of the corresponding proteins. This is an important mechanism that helps cells to regulate the expression of genes and respond to changes in their environment.
In the context of viral infections, dsRNA is often produced by RNA viruses as a result of replication. This dsRNA is recognized by the host cell's antiviral defense mechanisms as a sign of a viral infection and triggers an immune response. This response helps to prevent the spread of the virus and protects the host cell from further damage.
In conclusion, the double-stranded structure of dsRNA makes it an important molecule in the regulation of gene expression and the response to viral infections, and sets it apart from other types of RNA.
Explanation:
Frederick Griffith studied two strains of pneumococci
bacteria: the S strain and the R strain. He wanted to know
whether each strain was deadly to mice. The diagram
below shows Griffith's experimental setup.
Frederick Griffith studied two strains of pneumococci bacteria: the S strain and the R strain. He was trying to study the process of transformation through his experiment. Therefore, the correct option is A.
What is transformation?Transformation refers to the conversion in the genetic constitution of an organism by picking up genes present in the remains of different organisms in its surrounding.
By the experiment that was performed by Fredrick Griffith by 2 strains of diplococcus pneumonia-The S strain which is the smooth virulent strain while the R strain which is the rough non-virulent strain. When he injected the S strain, the mice died, but when he injected the R strain, the mice survived.
In the remaining experiment when he injected the heat killed S strain the mice survived but when he injected the mixture of heat killed S strain with the live R strain the mice died. This confirmed that the living bacteria was able to transform by heritable substance from the dead bacteria. Therefore, the correct option is A.
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The question is incomplete, but most probably the complete question is,
Frederick Griffith studied two strains of pneumococci bacteria: the S strain and the R strain. He wanted to know whether, which strain was deadly to mice. The diagram below shows Griffith's experimental setup. Find the strain which is deadly to the mice?
a. S strain.
b. R strain.
c. Heat killed S strain.
d. Heat killed R strain.
Answer: A, D
Explanation:
the double helix of dna is composed of building blocks called
The double helix of DNA is composed of building blocks called nucleotides.
How can it be explained in detail?The double helix of DNA is composed of building blocks called nucleotides. Each nucleotide is made up of a sugar molecule (deoxyribose), a phosphate group, and one of four nitrogenous bases: adenine (A), guanine (G), cytosine (C), or thymine (T). The nucleotides are joined together by covalent bonds between the sugar of one nucleotide and the phosphate of the next, forming a sugar-phosphate backbone. The nitrogenous bases are attached to the sugar molecules and extend inward, pairing in a complementary fashion (A with T and C with G) to form the rungs of the DNA ladder.
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During photosynthesis, the sunlight energy is converted into which form of chemical energy and how?
During photosynthesis, the sunlight energy is converted into chemical energy in the form of glucose molecules through a series of complex biochemical reactions.
This process occurs in the chloroplasts of plant cells and involves two stages: light-dependent reactions and light-independent reactions.
In light-dependent reactions, light energy is absorbed by pigments such as chlorophyll, and this energy is used to create ATP, which is a molecule that stores energy. Additionally, water is split into oxygen and hydrogen ions, with the hydrogen ions being used to generate another energy-rich molecule called NADPH.
In the light-independent reactions, also known as the Calvin cycle, the ATP and NADPH produced in the light-dependent reactions are used to fix carbon dioxide into glucose. This process involves a series of enzyme-catalyzed reactions that ultimately produce glucose molecules. The glucose is then either used by the plant for energy or stored as starch for later use.
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reasoning. Compare the evidence and reasoning
used to support the geocentric model with the evidence
and reasoning used to support the modern model of the
solar system.
The evidence and reasoning used to support the geocentric model relied on observations and mathematical calculations, while the evidence and reasoning used to support the modern model of the solar system relied on empirical data from telescopes, spacecraft, and other advanced technologies.
What is the geocentric model?The geocentric model is a cosmological model that places the Earth at the center of the universe with all other celestial bodies revolving around it. This model was the predominant view of the universe for over a thousand years, from ancient Greek times until the 16th century.
The geocentric model was based on observations of the apparent motion of the Sun, Moon, and planets, as well as on mathematical calculations and philosophical assumptions.
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You question is incomplete, but most probably your full question was,
Compare the evidence and reasoning used to support the geocentric model with the evidence and reasoning used to support the modern model of the solar system.
Explain the general process of nuclear fission. What is created from fission?
Answer:
Fission occurs when a neutron slams into a larger atom, forcing it to excite and split into two smaller particles—also known as fission products. Additional neutrons are also released that can initiate a chain reaction. When each atom splits, a tremendous amount of energy is released.
Explanation:
Hope it helps:)
ozone is a natural gas that is also found in the troposphere.
Three oxygen molecules combine to form the odorless, colorless gas known as ozone, which occurs naturally in the atmosphere. It happens in the troposphere, the lower atmosphere, and the upper atmosphere of the planet.
What makes up the atmosphere of Earth?We reside in the bottom of the air, a layer of chemicals that envelops our planet. Ninety-nine percent of a gases in dry air are nitrogen and oxygen, with a very little amount of argon, dioxide, helium, neon, or other gases.
Why is atmosphere essential?It not only provides us with the oxygen i need to survive, but it also shields us from dangerous UV solar radiation. Without it, the pressure needed for liquid water to exist on the surface of our globe wouldn't exist.
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The complete question is: What is Ozone and where is it found in the troposphere?
This substance is produced in the liver, but is stored in and secreted by the gallbladder is called?
A physiological aqueous fluid called bile is created or secreted by the liver.
Digestion is aided by bile. Bile, commonly known as gall, is a greenish yellow fluid that the liver produces and sends to the gall for storage, concentration, or transportation into the duodenum, the first part of the small intestine. Its purpose is to facilitate the duodenum's ability to digest lipids. The two main functions of bile secretion are (1) to transport bile acids to aid in the breakdown of lipids and (2) to eliminate various compounds such bilirubin, certain medications, and poisons. The digestion dietary fat is aided by bile salts. Additionally, they aid in the body's absorption of fat-soluble vitamins like A, D, E, and K. The liver produces bile and bile salts, which are then kept in the gall between meals.
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true or false statement, an egg has 23 chromosomes is it haploid or diploid
Human gametes (egg and sperm cells), however, contain a single set of chromosomes and are said to be haploid.
What are the 23 chromosomes called?Chromosome pairs are numbered from one to 22, with the 23rd pair denoted as either X or Y based on the configuration. The homologous structures are the initial 22 sets of chromosomes. The 23rd chromosome pair sometimes referred as the y chromosome, decides whether such an individual will be born male or female.
What is chromosome and its function?The thread-like chromosomes that transmit genetic data from cell to cell are composed of protein and a single - stranded DNA molecule. Chromatids are found in the cell's nuclei in both plants and animals, including humans.
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The crust is the inner of the the earth true or false
Answer:
False.
The crust is the outermost shell of the earth.
Explanation:
Hope it helps! =D
Answer:
False
Explanation:
The crust is the outermost covering/layer of the earth.
5. What causes a water molecule to be polar?
Answer:The unequal sharing of electrons between the atoms and the unsymmetrical shape of the molecule means that a water molecule has two poles - a positive charge on the hydrogen pole (side) and a negative charge on the oxygen pole (side). We say that the water molecule is electrically polar.
Explanation:
What are the consequences of lipid bilayers forming two-dimensional sheets, the edges of which close on each other and undergo self-sealing to form vesicles (liposomes) for the structure of the biological membrane?
This characteristic of the lipid bilayer is due to the phospholipids' amphibathic nature.
Vesicles form where?Vesicles are constantly forming, especially near the lipid bilayer, ER, and hence the Golgi. Once they are formed, vesicles carry their contents to sites on or in the cell. A vesicle forms is when membrane extends and pinches off.
Phospholipids, which have two hydrophobic tails and a hydrophillic head (phosphor group), make up the majority of the membrane lipid bilayers (fatty acids). While the phenolic hydroxyl groups of both films are exposed out, the fatty acid tailed of one top interact only with fatty tails with another layer through hydrophobic interactions.
The hydrophobic group is thereby hidden inside the lipid bilayer while the hydrophilic group remains out to interact with the aqueous cell environment.
Lipid bilayers can surround cells, cellular organelles, etc. thanks to this characteristic.
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The complete question is-
Lipid bilayers formed between two aqueous phases have this important property : they form two-dimensional sheet, the edges of which close upon each other and undergo self-sealing to form vesicles ( liposomes). what properties of lipids are responsible for this property of bilayers? Explain what are the consequences of this property for the structure of biological membranes?
What links amino acids together to make protein?
Peptide bonds link amino acids together to make proteins.
Amino acids are the monomers that make up proteins. A protein is made up of one or more polypeptides made up of amino acids. Twenty different types of amino acids are typically present in proteins. The core carbon atom, also referred to as the alpha (α) carbon, is joined to an amino group ([tex]NH_{2}[/tex]), a carboxyl group (COOH), and a hydrogen atom in the fundamental structure that all amino acids share.
A molecule of water is produced during the process of protein synthesis when the carboxyl group of the amino acid at the end of the expanding polypeptide chain combines with the amino group of an incoming amino acid. Peptide bonds, the resultant bond between amino acids. Thus, it is a peptide bond that links amino acids together to make proteins.
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Which of the following are examples of growth factors? A. Amino acids. B. Phospholipids C. Cholesterol D. Vitamins E. Nucleotides F. Polysaccharides G. Water
In this following question, Among the provided alternatives for growth factors are: A. Amino acids, D. Vitamins, and E. Nucleotides.
How can it be explained in detail?Amino acids are the basic building blocks of proteins, which are required for tissue development and repair. Vitamins are chemical molecules that are needed in minute amounts for a variety of metabolic functions, including growth and development. Nucleotides are the fundamental components of DNA and RNA, both of which are required for cell development and replication.
Phospholipids, cholesterol, polysaccharides, and water are not commonly considered growth factors, despite the fact that they play key roles in a variety of physiological processes.
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"Phagocytosis, pinocytosis, and receptor-mediated endocytosis all involve
A. the export of macromolecules.
B. invagination of the plasma membrane.
C. the intake of large particles.
D. the intake of specific fluids by the cell.
E. the presence of receptor proteins."
Phagocytosis, pinocytosis, and receptor-mediated endocytosis are all types of endocytosis, a process by which cells take up material from the extracellular environment by invagination of the plasma membrane, making option B the correct answer.
What is Phagocytosis?In all three forms of endocytosis, the plasma membrane of the cell invaginates or folds inward, forming a vesicle or sac that encloses the material to be taken up. Phagocytosis involves the intake of large particles such as bacteria or other cells, while pinocytosis involves the intake of fluid or small solutes. Receptor-mediated endocytosis is a more specific form of endocytosis in which the cell takes up specific molecules that have bound to receptor proteins on the surface of the plasma membrane. So, all three forms of endocytosis involve invagination of the plasma membrane to form a vesicle or sac that encloses the material being taken up.
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______ microscopes bounce electrons off the outside of a metal-coated three-dimensional object to observe the exterior texture.
Scanning electron microscopes bounce electrons off the outside of a metal-coated three-dimensional object to observe the exterior texture.
The definition of scanning electron microscopes (SEM).In contrast to visible light, electrons are used in electron microscopes to produce images. The electron beam must be focused, and a vacuum is required to employ electrons for microscopy. A three-dimensional image of the sample's surface is produced once the beam bounces off the sample. Higher resolution is achieved because the electrons' wavelength is significantly less than that of light coming from a lamp or a laser. Your sample must be electrically conductive to allow the electrons to bounce off of it while using a scanning electron microscope. A thin covering of gold or another metal is frequently applied to samples before being examined using scanning electron microscopes.
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Renewal or modification of the cell membrane is a function of the
a. microtubules.
b. mitochondria.
c. rough endoplasmic reticulum.
d. ribosomes.
e. Golgi apparatus.
Renewal or modification of the cell membrane is a function of the Golgi apparatus.
What is the main function of Golgi apparatus?The Golgi apparatus, or Golgi complex, functions as a factory in which proteins received from the ER are further processed and sorted for transport to their eventual destinations: lysosomes, the plasma membrane, or secretion. In addition, as noted earlier, glycolipids and sphingomyelin are synthesized within the Golgi.
What is the function and structure of Golgi apparatus?The Golgi apparatus is a central intracellular membrane-bound organelle with key functions in trafficking, processing, and sorting of newly synthesized membrane and secretory proteins and lipids. To best perform these functions, Golgi membranes form a unique stacked structure.
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what rule did chargaff develop based on his study of dna?
Answer:
The number of guanine units equals the number of cytosine units and the number of adenine units equals the number of thymine units.
Explanation:
This strongly hinted towards the base pair makeup of the DNA.
The sarcolemma of the cardiac muscle cells have fast voltage-gated ______ channels that participate in the depolarization of the cell membrane.
The sarcolemma of the cardiac muscle cells have fast voltage-gated sodium channels that participate in the depolarization of the cell membrane.
Every striated muscle fiber is covered by a thin, translucent, and extensible membrane called a sarcolemma. Its structure and layout are crucial for conducting and receiving impulses. Muscle tendons are created by the fusion of tendon fibers with the sarcolemma's outer layer at each end of a muscle fiber.
The muscle cell membrane depolarizes as a result of the inflow of cations (sodium and calcium) brought on by the activation of the nAChR. An action potential is produced as a result of the muscle membrane's high density of voltage-gated sodium channels being activated by this depolarization.
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Question:
What caused mass extinctions to occur at the end of the Permian and Cretaceous Periods, and how does this explain current worldwide reduction in biodiversity?
Extinction
Extinction is the phenomenon in which the last member of a species dies, and the species no longer exists. This extinction is a natural part of evolution and occurs when a species is no longer able to survive in their habitat. Sometimes extinction occurs as the result of large events that cause huge amounts of extinctions. These extinction events are referred to as mass extinctions and over 75% of the species on the earth will die during these.
The mass extinctions at the end of the Permian and Cretaceous Periods occurred due to widespread volcanic activities that lead to worldwide global warming. This created an anoxic environment which suffocated the living organisms and hence lead to reduction in biodiversity.
Extinction is the phenomenon of loss of all the individuals of a species. A species is said to be extinct when the last living organism of a species dies out. The extinction can be due to various reasons like loss of habitat, competition, etc.
Biodiversity is the different types of species present over a region. A region is said to be rich in biodiversity when a large number of different species are present together in that area.
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A man with a specific unusual genetic trait marries an unaffected woman and they have 4 children. Pedigrees of this family are shown in parts a) through e), but the presence or absence of the trait in the children is not indicated. For each type of inheritance indicate how many children of each sex are expected to express the trait by filling in the appropriate circles and squares. Assume that the trait is rare and fully penetrant.a) Autosomal recessive traitb) Autosomal dominant traitc) X-linked recessive traitd) X-linked dominant traite) Y-linked trait
A) Recessive autosomal trait. A family's pedigree might reveal how diseases are passed down through the generations.
One of parents must possess the trait for it to be dominant. No generation will be spared from dominant features. If a trait is recessive, either parent needs to have it in order for it to be present because they can both be heterozygous. Every time the appropriate gene is present, the trait also exists (generally). The parents both are heterozygous ("carriers") of the recessive phenotype if they share the trait but none of their children do. An autosomal recessive condition known as with cf (CF) is brought on by a change in the CFTR gene on chromosome 7. A family's pedigree might reveal how diseases are passed down through the generations. standard nomenclature for pedigrees. Simple symbols are employed.
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What are 3 parts of cellular respiration?
Answer: Glycolysis, Krebs Cycle (Citric Acid Cycle), Oxidative Phosporylation
Explanation:
Glycolysis is first, followed by the Krebs Cycle. At this point, it moves to oxidative phosphorylation (which involves the electron transport chain).
____ is a developmental stage of an embryo in which a single layer of cells is surrounded by a space filled with fluid
Blastula stage is a developmental stage of an embryo in which a single layer of cells is surrounded by a space filled with fluid.
What is the blastula stage of an embryo?The blastula stage is a developmental stage of an embryo characterized by a single layer of cells surrounding a fluid-filled space.
What is the significance of the blastula stage in embryonic development?The blastula stage is a critical stage in embryonic development as it marks the formation of the blastocyst, which will eventually give rise to the three germ layers and all the tissues and organs of the embryo.
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villi are the tiny fingerlike projections inside the walls of which organ of the gi tract?
Villi are the tiny finger-like projections that protrude from the walls of the small intestine, which is a part of the gastrointestinal (GI) tract.
What is villi?The small intestine is a long, narrow tube that is located between the stomach and the large intestine, and it is the primary site of nutrient absorption in the digestive system. The walls of the small intestine are lined with millions of tiny villi that increase the surface area available for the absorption of nutrients from the food we eat. Each villus contains a network of blood vessels and a lymphatic vessel called a lacteal, which help to transport nutrients from the small intestine to the rest of the body. The villi also contain specialized cells called enterocytes, which are responsible for absorbing nutrients from the food we eat and transporting them across the epithelial lining of the small intestine. Overall, the villi in the small intestine play a crucial role in the digestion and absorption of nutrients from our food, making them an important structure in the GI tract.
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in a biochemical pathway, the product released by the first enzyme becomes the substrate for the second enzyme. True/False
The end result of the first enzyme in a biological reaction serves as the second enzyme's substrate. A biochemical pathway's other reactions' rates won't change if one of its steps is blocked, and vice versa.
What are the four categories of enzymes?Enzymes can be divided into six different groups: oxidoreductases, transferases, lipases, lyases, isomerases, & ligases. Within its own category, each category performs a single general kind of reaction while also catalyzing a wide range of particular ones.
Why do we use enzymes?Proteins known as enzymes assist our bodies' chemical reactions, or metabolism, to move more quickly. Others are broken down while others are built. Enzymes exist in every living thing. Enzymes are created in our bodies by nature.
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what is the same about two species that are isoelectronic with each other
The same about two species that are isoelectronic with each other are mentioned below.
What is isoelectronic?
Isoelectronic describes atoms and ions with identical electron configurations. N3-, O2-, F-, Ne, Na+, Mg2+, and Al3+ are a few isoelectronic species examples (1s22s22p6). The isoelectron series P3-, S2-, Cl-, Ar, K+, Ca2+, and Sc3+ is another one ([Ne]3s23p6).
What is species ?
A group of people who actually or possibly interbreed in nature is commonly understood to be a species. The largest gene pool attainable in the wild is, in this sense, a species.
A group of atoms or ions with the same amount of electrons is referred to as an isoelectronic series. There are 10 electrons in each of these series.
Therefore, same about two species that are isoelectronic with each other are mentioned above.
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