B. Mesozoic and Paleozoic eras ended with mass extinctions.
What is Mass extinctions?Mass extinctions are periods in Earth's history when a significant proportion of the planet's biodiversity is wiped out in a relatively short period of time.
These events have occurred several times throughout Earth's history, and they are typically associated with major geological and environmental changes.
The Mesozoic era, which lasted from about 252 to 66 million years ago, ended with the Cretaceous-Paleogene extinction event. This event was likely caused by the impact of a large asteroid or comet, which triggered a range of environmental changes, including wildfires, acid rain, and a nuclear winter-like effect.
The event is most famous for wiping out the dinosaurs, but it also resulted in the extinction of many other species, both on land and in the oceans.
The Mesozoic era ended with the Cretaceous-Paleogene extinction event, which wiped out the dinosaurs and many other species.
The Paleozoic era ended with the Permian-Triassic extinction event, which was the largest mass extinction in Earth's history, and resulted in the loss of approximately 96% of all marine species and 70% of land species.
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Regulation of expression of genes is important because: Group of answer choices A. some genes function in opposition to other genes. B. it is energetically wasteful to produce all possible genes. C. multicellular bacteria need specialized cell types. A and B. All of the above
Answer:
All of the above.
Explanation:
Regulation of the expression of genes refers to different processes tge cells use to increase or decrease the production of some gene content. It involve Turing gene on and off so as to ensure that appropriate genes are expressed at the right times. This allow organism to respond to changes in their environment.
which feature of a membrane describes wether molecules can cross the membrane
Answer:
Permeability
Explanation:
Membranes are semi-permeable that only certain things can come cross on its own. This feature of permeability describes whether molecules can cross the membrane
Which of followings are true?
a. Most people accept that the characteristics within a population--say pesticide resistance in lice--can change over time.
b. Some refer to the theory of evolution as "just a theory" with other competing and equally likely alternatives.
c. Some people want "special creation"--the idea that living things were created by a supernatural agent--to be considered as an alternative hypothesis alongside the theory of evolution in science education.
d. Science has rejected a hypothesis that different groups of organisms can show relationships without sharing one common ancestor.
e. Fossils are the direct evidence we have to test the theory of evolution.
f. The theory of evolution is accepted by scientists as the correct explanation for the origin of humans.
Answer:
A) True
John Marshall Clark a pesticide toxicologist recently discovered in one his studies at the University of Massachusetts that about 67% to 75% of lice are no longer affected adversly by insecticides.
B) True
An alternative to the theory of evolution is the Theistic Evolution.
C) True
Creationism or Special Creation is one of the ideas of evolutions which tries to offer a better explanation to the origin of the universe.
D) False
An example would be the winds of Bees, Bats and Birds. They all use wings (with similar structure) to fly however, their origins as explained by evolution are quite different taking into conginsance how they are formed at the embryo stage.
E) True
To understand evolution, we have to study and obtain as much as possible, all the information that a fossil can provide. Many times, these information provide substantial elements which support the theory.
F) False
Evolution is a theory which scientists have accepted as ONE of the several explanations of the origins of the human species. There are other competing theories.
Cheers!
Consider a simplified metabolic model to describe nitrogen metabolism in the body. Nitrogen is ingested in the food (F), a fraction of which is actually absorbed (A), the remainder being lost in the feces (W). The absorbed nitrogen is taken up by the muscle to make protein. At small fraction of the stored muscle protein undergoes degradation and the liberated nitrogen (L) is released from the muscle. Of the liberated nitrogen, a fraction is recycled back to the muscle (R), while the rest is lost to excretion (E) in the urine
The given question is incomplete, the complete question is:
Consider a simplified metabolic model to describe nitrogen metabolism in the body. Nitrogen is ingested in the food (F), a fraction of which is actually absorbed (A), the remainder being lost in the feces (W). The absorbed nitrogen is taken up by the muscle to make protein. At small fraction of the stored muscle protein undergoes degradation and the liberated nitrogen (L) is released from the muscle. Of the liberated nitrogen, a fraction is recycled back to the muscle (R), while the rest is lost to excretion (E) in the urine. If the nitrogen ingested in food is 100 g/day, but only 80% of the food is actually absorbed, while the rest goes to waste, what is the amount of nitrogen lost by excretion? Assume steady-state. Of the nitrogen liberated from muscle, 90% is excreted, while the rest is recycled, what fraction of the nitrogen entering the muscle is from the absorbed food? (In other words, what is the ratio A/(A+R)). Again, assume steady-state
Answer:
The amount of nitrogen lost in the process is 20 grams in a day and the fraction of nitrogen entering the muscle is 0.909.
Explanation:
Based on the given question, the amount of nitrogen absorbed is 80 percent of 100 grams, that is,
100*(80/100) = 80 grams in a day.
The concentration of nitrogen lost in the process is,
Nitrogen ingested-nitrogen absorbed = 100-80 = 20 grams in a day.
Let us assume that all the ingested nitrogen is liberated from the muscle. Therefore, 80 grams of nitrogen is liberated. If 90 percent of the nitrogen liberated from the muscle get excreted, then the value of excreted nitrogen will be,
90% of 80 grams = 90/100*80 = 72 grams
Now the nitrogen recycled will be,
Liberated nitrogen - excreted nitrogen = 80-72 = 8 grams
From the absorbed food, the fraction of the nitrogen entering the muscle will be,
80/(80+8) = 80/88 = 0.909.
what is is a specific version of a gene on a homologous chromosome that has a corresponding version of a similar gene on a homologous chromosome. For example, hair color gene (ie. red from mom) will be on one homologous chromosome and a possibly different version of hair color gene (ie. black from dad) will be on the other corresponding homologous chromosome.
Answer:
This statement is partially true.
Explanation:
There are many phenotypic features that display a quantitative mode of inheritance and exhibit a continuous range of variation. Hair color is controlled by different genes that work together to express this trait. In consequence, this trait has a polygenic mode of inheritance, where a particular phenotype depends on both additive and dominance genetic effects. The most important gene associated with the hair color is Melanocortin 1 Receptor (MC1R), which is involved in the biosynthesis pathway that controls the synthesis of melanin.
Which of the following is an example of protein denaturation?
Choose 1 answer:
A) Amino acids fold into repeating patterns due to hydrogen bonding of the peptide backbone.
B) Several amino acids are joined together via peptide bonds.
C) A protein binds with a substrate, lowering the activation energy of a reaction.
D) A protein is exposed to extremely high heat, causing it to lose its secondary structure and be
left with only its primary structure.
Answer:
D
Explanation:
Denaturation occurs when the protein deforms and loses its structure.
According to the question, A protein is exposed to extremely high heat, causing it to lose its secondary structure and be left with only its primary structure.
What is protein denaturation and how does it happen?A protein becomes denatured when its normal shape gets deformed because some of the hydrogen bonds are broken.
Weak hydrogen bonds break when too much heat is applied or when they are exposed to an acid.
Thus, option "D" is correct.
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Different protists use cilia, _______, or pseudopodia to move.
Answer:
Different protists use cilia, flagella , or pseudopodia to move.
Why use needle loop to prepare fungi slide??
Answer:
The needle loop is use to transfer fungi to a soft agar and this will cause or create more fungal growth to occur in the slide.
Explanation:
Needle loop is a tool or device use in microbiology to inoculate microorganisms like bacteria and fungi in media to boost their growth. It is use for sampling and transferring specimens or microorganisms into a media for further analysis, examination and serial dilution.
You have isolated a new mutation in the T4 bacteriophage rII A gene and you map its location within the gene by recombination frequency. You find that this new mutation fails to give wild type recombinants with several different adjacent mutations located in the same gene. What type of mutation is this new one you just isolated
Answer:
A lethal mutation, thereby the resulting phenotype is not observed .
Explanation:
Lethal mutations are the result of genomic changes that may be lethal in certain conditions. In genetic research, this type of mutation has shown to be very useful in analyzing gene function (i.e., genes whose protein products are key for the survival of the organism in question), and they are perfect gene markers. In bacteriophages, for example, temperature-sensitive mutants of phage T4 that can not grow at temperatures higher 42°C have been identified (Edgar & Lielausis 1964).
Citation:
R. S. Edgar, & I. Lielausis (1964). Temperature-sensitive mutants of bacteriophage T4D: their isolation and genetic characterization. Genetics, 49(4), 649.
. What was Sharon’s experience with the experimental drug?
a) she suffered severe side effects b) she had few side effects c) it made her very sick
Answer:
imagine being on brainly
Explanation:
. If Haily is analyzing samples of chromosomes under a microscope which feature would help her categorize the different samples? A. Genetic makeup B. Arm length C. Shape D. Centromere placement E. None of the above
Answer:
B. Arm length
C. Shape
D. Centromere placement
Explanation:
Cytogenetics is a discipline that study the structure and number of chromosomes including their morphology, position of the centromere, arm length, staining bands, etc. These features can be observed by microscope and enable us to identify different genome rearrangements (i.e., translocations, deletions, centric fusion, chromosome duplications, etc.) by ilustrating chromosomes in defined pictures referred to as karyotypes. In consequence, they are chromosome features that can be used in order to categorize different samples.
Mendel used monohybrid crosses to study the inheritance of pea plant characteristics. In one of his classic experiments, Mendel crossed a purple-flowered plant with a white-flowered plant. All of the offspring plants produced purple flowers.
1. Using the symbols P for the purple allele and p for the white allele, provide the following information:
A. What the genotypes of the Parental Generation plants?
Purple parent: White parent:
B. What is the genotype of the F1 generation?
C. Organisms with two copies of the same allele are called
D. Organisms with two different alleles are called
2. When is it necessary to perform a test cross?
3. In rabbits, brown coat (B) is dominant to white coat (b). A rabbit breeder wants to know the genotype of his best looking male brown rabbit using a test cross. He has brown females and white females available to conduct his breeding experiments.
A. What should be the coat color of the female he must use in this test cross?
B. If the test cross produces seven (7) brown rabbits and one (1) white rabbit, what is the genotype of the brown male rabbit?
4. How is Mendel's Law of Independent related to the events of Meiosis?
5. In your own words, state the Law of Segregation
There are other patterns of inheritance that require explanations beyond the predictions of Mendel's Law of Dominance and Segregation. These patterns are known in biology as non-Mendelian inheritance and include:______.
A. Incomplete dominance
B. Codominance
C. Multiple Alleles
D. Pleiotropy (explained in the first assigned video)
E. X-linked inheritance
F. Epistasis
6. Write in the space provided the type of non-Mendelian inheritance from the list above that matches the descriptions or the examples listed below:
1. When a gene has more than two allele variants.(Example)
2. When a single gene or allele controls the expression of 2 or more traits.
3. When offspring show a blended phenotype, a physical appearance intermediate to the phenotype of both parents
4. When an allele is carried in the X chromosome.
Answer:
Explanation:
A. To produce all purple flowers from a cross between purple and white flowers, it means the parents genotype are dominant homozygous purple and the recessive homozygous white ( PP and pp)
B. The F1 generation will possess a phenotype of purple colour with genotype ( Pp )- heterozygous
C. Organisms with two copies of the same allele are called homozygotes
D. Organisms with two different alleles are called heterozygotes
2. When is it necessary to perform a test cross?
This test is only perform when the identity/genotype of one of the parents is unknown then a testcross is carried out.
3.A The coat color of the female he must use is white...a testcross is done with the recessive parents
B. The genotype of the male brown rabbit is Bb to produce a white rabbit.
4. The law of independent assortment amd meiosis relates in that the independent assortment law talks about independent separatíon of gens from each other and in meiosis, it takes into account the independent separation of homologous chromosomes.
5. The law of segregation of genes takes into account that an individual that is diploid possessing 2 copies of a gene/alleles on each homologous chromosome, that each of these alleles segregation or separate into each gametes, as one allele per gamete.
5. Non-Mendelian inheritance includes all listed below
6.
1. When a gene has more than two allele variants - multiple alleles
2. When a single gene or allele controls the expression of 2 or more traits - Pleitropy e.g. as in the ABO blood group
3. When offspring show a blended phenotype, a physical appearance intermediate to the phenotype of both parents: incomplete dominance
4. When an allele is carried in the X chromosome - X linked inheritance
Answer: the biological
Explanation: the biological
You have decided to examine the dynamic properties of a flagellum. After having isolated flagella from sea urchin sperms, you placed them into an aqueous buffer with a pH of 7.0. Very rapidly, however, you observed that the movement of the isolated flagella stopped. Which hypothesis are you likely to propose to explain that result?
Answer:
Osmosis
Explanation:
In this case, osmosis has occurred, and that is why the movement of the flagellum stops.
It should be understood that osmosis is the movement of substances from the region of lower concentration to the region of lower concentration through a semi- permeable membrane.
Why do rocks on the ocean floor form a pattern of magnetized stripes?
Answer: D trust me on this
Explanation:
the rocks contain iron that points in different directions depending on earths polarity
The polarity of Earth affects the iron in the rocks, which points in various ways, so rocks on the ocean floor form a pattern of magnetized stripes.
How form a pattern of magnetized stripes?The idea of paleomagnetism, according to which the arrangement of the earth's tectonic plates depends on the iron present in magma, is one of the theories explaining seafloor spreading. The positive and negatively charged ions are represented by the stripes.
The magnetic strips, also known as magnetic anomalies, are identified by white and black strip patterns. They have ions that are positively and negatively charged. As a result, the magma magnetizes with the Earth's magnetic field when it emerges from the ridges.
Therefore, the polarity of Earth affects the iron in the rocks, which points in various ways.
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Which statement about enzymes is true?
An enzyme functions to increase the activation energy in a reacton.
Enzymes are proteins that function as catalysts in nonliving things.
Each enzyme can catalyze many different biochemical reactions.
Enzymes and substrates fit together like a lock and key.
Answer:
Enzymes and substrates fit together like a lock and key since, in one enzymatic reaction, only the correct substrate (i.e., the key) binds to its corresponding enzyme (i.e. the lock).
Explanation:
An enzyme (or catalyst) is one protein that has catalytic functions, being therefore capable of accelerating chemical reactions. The enzymes are known to control the rate of these chemical reactions (i.e., catalysis) without suffering alterations during these processes. Thus, the enzymes are proteins that catalyze chemical reactions that are not favored under normal conditions. Moreover, one enzyme may catalyze more than one chemical transformation, as well as the same reaction may be catalyzed by two or more enzymes.
what is 9 + 10??? VERY IMPORTANT
Answer:
9 + 10 = 19
the answer is = 19
What is the function of the seed coat ?
• it protects the new plant.
• it contains food.
• it performs respiration.
• it attracts animals.
Answer:
It protects the new plant.
Plants combine carbon dioxide and water to make what
substance?
O A. Glucose
O B. Ammonia
O C. Peptide
O D. Nitrogen
SUBMIT
Answer:
A. glucose right good brilliant
The genetics of a-thalassemia are similar to narrow sense heritability in that there is a gradation of phenotype, with each allele seeming to contribute equally to the trait. However, there are also differences from narrow sense heritability. In particular, as you can see from your answers above, it is difficult to predict offspring phenotype based only on parental phenotype. What two aspects of HBA1 and HBA2 combine to offset what would otherwise appear to be narrow sense heritability of a-thalassemia?
Answer:
In strict mode, the narrow-sense heritability is the proportion of the additive genetic variance that contributes to the total of the phenotypic variance. This value can be associated with the inheritance of the a-thalassemia .
Explanation:
A-thalassemia is a genetic disorder caused by mutations affecting four different genes that encode alpha-globin, thus affecting the hemoglobin production process and, consequently, oxygen transport. The mode of inheritance of the a-thalassemia may be associated with narrow sense heritability since the phenotype is manifested by gradation, i.e., each allele might contribute in similar mode to this genetic condition.
A negative control is a sample that you know will give you a negative result. You are testing for the presence of proteins, reducing sugars, starch, and lipids in various foods. What would be the best negative control for this experiment
Answer:
Starch and water will be the best negative control
Explanation:
Negative control sample is a sample that will not give change in an experiment.
Starch and water will be the best negative control. This is because, starch is broken down by HCl to monosaccharides in the Benedict test which is the test for reducing sugar
Distilled water remain a negative control because it remain blue which means it does not reduce sugar with starch solution.
Water plus us a negative control for Buiret test (protein) and Benedict(reducing sugar) because it does not indicate the presence of protein and reducing sugar.
5. Find the LC.M of XX,X-1,X-X
Answer:
-1 I believe
Explanation:
Why do you find glucose in the filtrate but not formed elements of the blood (erythrocytes, leukocytes, and
platelets)?
Answer:
Formed elements of the blood are too large to fit through the filtration slits of the filtration membrane. ... Nephron tubules cannot reabsorb large proteins and cells that enter the filtrate.
After a volcanic eruption, lava flows on the surface of the Earth. After the lava has time to cool, scientists notice that plants are starting to grow on the lava surface. What kind of ecological process could you infer is happening and why?
Answer:
The correct answer is ecological succession.
Explanation:
For the growth and development of an ecosystem, the phenomenon of ecological succession plays an essential role. A slow procedure by which the ecosystems modify and develop with time is termed as the ecological succession. There are prime two kinds of succession, that is, primary succession and secondary succession.
The phenomenon of ecological succession helps in the colonization of the novel areas, and in the recolonization of the destructed ecosystems, this helps the species to get amend with the modifications taking place in the surroundings and helps them to thrive. The given case is an illustration of ecological succession as the flowing of lava creates barren land, which further helps in the establishment of the pioneer plants. These pioneer species of plants helps in the development of a new ecosystem.
In the lab, metabolic poisons can be used to study ATP synthesis and oxygen consumption. Many of these poisons have – or have had – other uses, from diet aids to animal poisons to antibiotics. Poison Action oligomycin binds to F0F0 and blocks the proton channel cyanide inhibits cytochrome oxidase by reacting with heme a3 trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP) increases membrane proton permeability rotenone blocks electron transfer at NADHNADH dehydrogenase (NAD−Q(NAD−Q oxidoreductase) bongkrekic acid binds to inward‑facing site of ATP‑ADP translocase Classify the metabolic poisons as electron transport inhibitors, uncoupling agents, ATP synthase inhibitors, or transport inhibitors.
Answer:
Electron transport inhibitors: Cyanide, Rotenone
Uncoupling agents: trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP)
ATP synthase inhibitors: Oligomycin
Transport inhibitors: Bongkrekic acid
Explanation:
Electron transport inhibitors: Cyanide, Rotenone
Cytochrome oxidase also known as complex IV in the electron transport chain, carries electrons from cytochrome c to oxygen. It is a large enzyme having 13 subunits. Subunit 1 contains two heme groups , a and a3. Electrons are tranferred from heme a to oxygen bound to heme a3. The reaction of cyanide with heme a3 blocks this process of eleron transport
.Rotenone blocks electron transfer at NADH dehydrogenase (NAD−Q(NAD−Q oxidoreductase) by preventing electron transfer from Fe-S center to ubiquinone.
Uncoupling agents: trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP)
The transfer of electrons from NADH through the respiratory chain to molecularoxygen is coupled to proton pumping from the inner mitochondrial matrix to the intermembrane space. This generates a proton motive force which is utilized in ATP synthesis. Trifluorocarbonylcyanide phenylhydrazone (FCCP)(FCCP) increases membrane proton permeability, causing protons to leak back into the mitochondrial matrix, thereby uncoupling the processs of ATP synthesis and proton flux.
ATP synthase inhibitors: Oligomycin
ATP synthase is the enzyme rensponsible for ATP synthesis. It has two functional domains,: F₁ and F₀. Oligomycin binds to F₀ and blocks the proton channel preventing rotation of the F₁ subuni, thus, preventing ATP synthesis from ADP.
Transport inhibitors: Bongkrekic acid
Adenine nucleotide translocase is a transport protein that transports free ADP from the cytoplasm into the mitochondrial matrix, while ATP produced from oxidative phosphorylation is transported from the mitochondrial matrix to the cytoplasm o the cell.
Bongkrekic acid inhibits Adenine nucleotide translocase, thus preventing ATP from leaving the mitochondria and starving cells of needed energy.
What causes an ecosystem to move from a primary successional stage towards a relatively-stable mature ecosystem?
Answer:
The correct answer is "secondary succession, an ecological succession step where an area previously occupied by living beings is disrupted".
Explanation:
In ecological succession, an ecosystem changes and develops through a series of steps. The first step, is the primary successional stage where rocks or other sedimentary structures are colonized by microorganisms. The second step, where the ecosystems changes towards a relatively-stable mature stage, occurs when an area previously occupied by living beings is disrupted. This step is named secondary succession, and the most clear example of this phenomena occurs when wildfire clears oak and hickory forests.
A scientist analyzed a segment of DNA from a human chromosome and found that the percentage of thymine molecular bases (T) was 35%. Which
row in the chart below contains the correct percentages of the other molecular bases in the DNA segment?
Row
Guanine (G) Cytosine (C) Adenine (A)
15%
25%
25%
A.
25%
25%
15%
B.
15%
15%
35%
C.
35%
15%
15%
D
Answer:
C. 15% 15% 35%
Explanation:
This follows the rules of base pairing. The amount of thymine (T) equals the amount of adenine (A), and the amount of guanine (G) equals the amount of cytosine (C).
Since thymine is equal to adenine and 35% of the bases is thymine, 35% of the bases is also adenine. This gives you a total of 70%.
35% + 35% = 70%
Now you need to figure out how much cytosine and guanine are in the bases. Since 70% of the bases are adenine and thymine, 30% will be cytosine and guanine.
100% - 70% = 30%
Since the amount of cytosine and guanine are equal, divide 30% by 2 to figure out how much each base takes of the total.
30/2 = 15%
Cytosine and guanine each take up 15% of the molecular bases.
Which process is the First step of protein synthesis
Answer:
transcription
Explanation:
transcription of DNA by tRNA is the first step of protein synthesis
Answer:
Transcription.
Explanation:
The
called the pleura.
are enclosed in a membrane
The
are branch-like extensions
found in the lower respiratory system.
Identify the structures labeled in the diagram to
the right
Label A
A
In the 1930s, medical journal
articles linked asbestos to cancer.
Answer:
Lungs
bronchioles
alveoli
positive impact
Explanation:
Answer:
The -lungs- are enclosed in a membrane called the pleura.
The -bronchioles- are branch-like extensions found in the lower respiratory system.
-alveoli- Label A
-positive impact- In the 1930s, medical journal articles linked asbestos to cancer.
Explanation:
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In humans, oculocutaneous (OCA) albinism is a collection of autosomal recessive disorders characterized by an absence of the pigment melanin in skin, hair, and eyes. That is, normal pigmentation (A) is dominant over albinism (a). For this question, assume it is a single gene with two alleles. Assume it is a single gene with two alleles. If two people have normal pigmentation, what possible phenotypes may be observed in their offspring?
Answer:
The definition of the problem is listed in the explanation segment below.
Explanation:
The parent phenotype is an albino on every one of them. Albino gene seems to be located primarily while it has its whole genotypes in such a recessive state called "aa". When this trait becomes autosomal, it does have an equivalent amount of alleles across both parent members. The gametes including its albino genotypes.⇒ [tex]Mother \ aa\times Father \ aa[/tex]
⇒ [tex]a\times a[/tex]
Genotype including its offspring - albino. Well, all offspring will also have albino phenotypes.So that the above is the right answer.
how do plant get nutrients
Answer:
Processes. Plants take up essential elements from the soil through their roots and from the air through their leaves. Nutrient uptake in the soil is achieved by cation exchange, where in root hairs pump hydrogen ions (H+) into the soil through proton pumps
hope i helped !!
Answer:
water, sun, soil
Explanation:
Plants absorb nutrients and water through their roots, but photosynthesis occurs in the leaves. So, plants need to get fluids and nutrients from the ground up through their stems to their parts that are above ground level.
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