Extinction of the Ordovician: This extinction was responsible for the disappearance of about 60-70% of the species of oceanic life, This is because in that period most of the life on Earth was in the ocean. This extinction is believed to have been caused by an intense glacial period, although short that froze most of the planet's water. It is believed that the species most affected were sponges, algae, jawless fish, molluscs and cephalopods.
Devonian Extinction: Responsible for the disappearance of about 75% of marine species. This extinction was caused by the depletion of oxygen in the ocean, making life impossible for all aerobic marine organisms. This depletion of oxygen was caused mainly by the variation in the level of the ocean and climatic changes that may have been caused by asteroids.
Permian Extinction: Responsible for the death of 95% of life on earth. This extinction is known as the "mother of all extinctions" due to its destructive character, which devastated life on land and in the ocean. It is believed that this extinction was caused by volcanic activities triggered by the impact of asteroids. Almost all living species on earth were affected, such as insects, trilobites, sharks, boneless fish, reptiles, among others.
Extinction of the Triassic: It is not known exactly what caused this extinction, but it is estimated that it had the power to decimate 70-80% of terrestrial life, mainly arcosaurs and amphibians. The most accepted theory today is that the extinction was caused by recurrent volcanic activities that influenced huge volumes of carbon dioxide in the atmosphere, generating intense heating.
Cretaceous extinction: It was caused by the impact of an asteroid with the earth. The impact had the power to exterminate 75% of terrestrial life. This is the most well-known extinction, since it was responsible for decimating dinosaurs, however, some animals survived this impact, such as most marine species, frogs, birds, reptile and mammals.
Which of the following accurately describes this element?
Answer:
Answer Expert Verified
The correct statements are: - Elements are made up of only one type of atom. - Each element has a unique chemical symbol. - Elements can be identified by their atomic number.
During the 1800's, what country was a leader of world exploration and placed at the center of most maps?
A. Britain
B. Spain
C. Morocco
D. USA
Answer:
B. Spain
Explanation:
Portugal and Spain are the western European nations that were the primary players in the age of discovery in 18th century. Under the leadership of prince henry the navigator. With the spread of missionary activities, Christianity becomes the world's largest religion. Exploration of the Americas and other nations started from this place.A response to an unconditioned stimulus that occurs naturally without learning is known as a(n) __________ response.
A. neutral
B. conditioned
C. reconditioned
D. unconditioned
Answer:
it is going o be B. conditioned
Answer:
D
Explanation:
edge
Which element provides strength to the exoskeletons of clams and oysters?
sulfur
oxygen
hydrogen
phosphorus
Phosphorus provides strength to the exoskeletons of clams and oysters. Thus, the correct option is D.
The exoskeleton of organisms including clams and oysters is made up of primarily calcium in the form of calcium phosphate and calcium carbonate.
Calcium phosphate is also present in the form of hydroxyapatite which is Ca₁₀(PO₄)₆(OH)₂ which provides invariable strength to the exoskeletal structure.
Thus, as phosphorus is a part of the exoskeleton, the correct option is D.
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A student hypothesized that EC growth might be affected by the DNA from circulating erythrocytes. Is this student’s hypothesis reasonable?
Answer:
Explanation:
It can be said that this hypothesis is actually not reasonable because circulating erythrocytes do not contain DNA. This can be proven by the Mammalian erythrocytes (rbcs) which ultimately loose their nuclei as well as many other organelles during their maturation process and they don't have nuclei or mitochondria meaning that they are not affected by the DNA.
if a person who is blood type O marries a person who is blood type A, what are the possible blood types their children could have
Answer:
The possible blood types their children could have are A or 0.
Explanation:
The I gene determines the blood type of a person. I is the dominant allele, while i is the recessive allele.
IA dominant over i. The person presents A type of antigens. IB dominant over i. The person presents B type of antigens. IA and IB are codominant. The person presents both types of antigens, A and B. i is the recessive allele. The person does not present any antigen.Cross: a person who is blood type O with a person who is blood type A
Parental) ii x IA-
Gametes) i i IA -
Punnet Square) IA -
i IAi -i
i IAi -i
The - symbol represents the possibility of either IA allele or i allele. This is, the parental with blood type A might have the genotype IAIA or IAi
F1) 2/4 = 1/2 IAi
2/4 = 1/2 -i (-i could be either IAi or ii, depending on the genotype of the parental with blood type A)
Option 1: ii x IAIAF1) 100% IAi (The whole progeny will have blood type A)
Option 2: ii x IAiF1) 50% IAi (Half of the progeny will have blood type A)
50% ii (Halfa of the progeny will have blood type 0)
The possible blood types their children could have are A or 0.
Which process involves a decrease in the dispersal of matter? Select the correct answer below: heat exchange between two solids
Answer:
The options are
A.heat exchange between two solids
B.the decomposition of a compound into its constituent elements
C.the precipitation of a solid
D.none of the above
The answer is
C.the precipitation of a solid
Dispersal of matter involves the process whereby there is more space occupied by the resulting element/compound than the initial one. For example the conversion of liquid to gas means that it has an increase in the dispersal of matter as the gas particles will contain more space when compared to a liquid.
Precipitation of a solid means conversion of a liquid to a solid. A liquid is known to contain more space which means there is a decrease in the dispersal of matter.
The process that involved the reduction in the dispersal of matter should be the precipitation of a solid
What is the dispersal of matter?It refers to the process in which it contains the additional space that should be occupied. Like the conversion of the liquid to gas represent there should be increment in the disperson of the matter since the particles of the gas comprise more space at the time when the comparison is to be done with the liquid. Here, precipitation of the solid represent the transformation of the liquid to the solid.
This question is incomplete. Please find the options below.
A.heat exchange between two solids
B.the decomposition of a compound into its constituent elements
C.the precipitation of a solid
D.none of the above
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Explain why it is necessary to include only one chain-terminating/synthesis-terminating nucleotide in each well of the electrophoresis instrument.
Answer:
Explanation:
Generally for the formation of phosphosdiester bond between two nucleotide molecules 3'-OH group is needed between the sugar molecule of one nucleotide and the OH group of the sugar present in the other nucleotide above it. However,in the single chain terminating molecule The 3'-OH is lacking.
Hence,DNA polymerace enzyme(which catalysis DNA replication) will not be able to elongate the DNA molecules, through replications with the addition of di-deoxynucleotidetriphosphates (ddNTP). Thus inhibiting replication and therefore chain terminations,
Which enzyme is used in gluconeogenesis, but NOT in glycolysis? Group of answer choices PEP carboxykinase enolase (interconverts 2-phosphoglycerate and phosphoenolpyruvate)
Answer:
PEP carboxykinase
Explanation:
PEP carboxykinase is also known as Phosphoenolpyruvate carboxykinase. It is an enzyme which is used for the production of glucose from non-carbohydrate carbon substrates. This enzyme is used only in gluconeogenesis not in glycolysis because this enzyme helps in the production of glucose while glycolysis is a process in which the glucose break down into pyruvate and ATP molecules.
a) There are three nucleotide in each codon, and each of these nucleotides can have one of four different bases. How many possible unique codons are there?
b) If DNA had only two types of bases instead of four, how long would codons need to be to specify all 20 amino acids?
Answer:
Explanation:
There are 64 possible codons to be specified for, If we have three nucleotides with 4 bases the set of all combinations can encode
4x4x4 = 64 amino acids
This will give 64 different combinations of four nucleotides
If we have 2 bases with 4 nucleotide we have a possibility of having 16 codons specifying for 20 amino acid.
If we have 2 nucleotides with 4 bases the set of combination is
4×4 = 16 amino acids of four nucleotides
The force of a muscle contraction is higher when the muscle is stimulated every 0.5 secs than when stimulated with the same voltage every 0.05 seconds.
a. True
b. False
Answer:
b. False
Explanation:
Increasing the frequency of muscle stimulation causes wave summation to occur, which causes an overlap of muscle twitch. When this muscle summation happens, the force generated in the muscle increases. This means that stimulating the muscle every 0.5 seconds will generate less muscle contraction force than when stimulated every 0.05 seconds
Please answer ASAP, the assignments in due really soon :) 30 Points!!! The image below shows the lac operon, which breaks down lactose in bacteria. Which statement correctly describes the expression of this gene?
Answer:
B. Gene expression is influenced by high lactose levels in the environment.
Explanation:
The lactose operon (lac operon) functions for the metabolism and transport of lactose in several bacteria.
Gene expression is influenced by high lactose levels in the environment as genes are expressed in the presence of high level lactose and absence of glucose. High level lactose carry an activator protein called catabolite activator protein (CAP), which let the RNA polymerase do transcription of the operon.
Hence, the correct option is "B".
Answer:
C
Explanation:
^he said it was right^
have an amazing day! :)
In humans, insulin is manufactured in the pancreas, insulin is a peptide hormone that causes the body’s cells to take up glucose. The blueprint for the polypeptide chain that is insulin is found in the — of specialized pancreatic cells.
Answer:
In type 1 diabetes the immune system erroneously attacks the beta cells that produce insulin in your pancreas. It causes permanent damage, leaving your pancreas unable to produce insulin. Exactly what triggers the immune system to do that isn't clear. Genetic and environmental factors may play a role.
Explanation:
Nucleic acids
Composed of Carbon, Hydrogen, Oxygen, Nitrogen and phosphorous.
DNA
The universal code that stores genetic information in all organisms
Semi
conservative-Bases in original strand split and new nucleotides complementary base pair to form two new strands
Mutations
Any change to the DNA sequence
Gene mutation
Permanent change in the DNA sequence that makes up a gene.
Transcription
The process of copying a nucleotide sequence of DNA to form a complementary strand of mRNA
Translation
Process by which mRNA is decoded and proteins are made.
Codon
Three nucleotide bases
tRNA
Reads the codon on the mRNA using anticodons and the complimentary base pair rules and delivers the amino acids
What would be the replicated DNA strand for the following DNA sequence?...GCGTATG
CGCATATC
What would be the mRNA and tRNA be for the following DNA sequence?...AGGTTA
mRNA...UCCAAU. tRNA...AGGUUA.
The process of converting the genetic message from DNA into ____ is called transcription.
mRNA
How many amino acids are in the human body and what do we call the bond that holds them together?
20; Peptide bond
A single strand of DNA contains the following nine nucleotides in order ACTTATGGA. What sequence of bases will be present on the complementary strand of DNA?
TGAATACCT
In humans, insulin is manufactured in the pancreas. Insulin is a peptide hormone that causes the body's cells to take up glucose. The blueprint for the polypeptide chain that is insulin is found in the __________ of specialized pancreatic cells.
DNA
Given the sequence of DNA nucleotide bases TTAGCCTTG, give the complementary mRNA produced during transcription.
AATCGGAAC
Identify the correct sequence of molecules, as a gene goes from coded information in the nucleus, to the product the cell wants to make.
DNA...messenger RNA...transfer RNA...Protein
Why is DNA replication considered semiconservative?
Each half of the old DNA strand serves as a template for the new growing strand causing the copied DNA to half new and half old.
who is the father of Genetic
Answer:
hey there
Explanation: answer is gregor mendal is the father of genetic in 19th century.
Answer:
Gregor Johann Mendel
List three protozoan infections of the circulatory system that are transmitted by arthropods. Include the disease name, specific organism (genus species), vector that is the intermediate between hosts, and disease progress in humans.
Answer:
List three protozoan infections of the circulatory system that are transmitted by arthropods:
Malaria
Toxoplasmosis
Chagas disease (American trypanosomiasis)
Explanation:
Malaria is a prozotoan infection, that can be produced by several protozoan, in the genus Plasmodium. This Plasmodium infect red blood cells and the vector that trasmites it is the Anopheles mosquitoe. In this disease, red blood cells can have severe damage in different organs because of the hemolysis.
Toxoplasmosis is a disease caused by the protozoan Toxoplasma gondii. The main vector of them are domestic cats. When cats are infected, T. gondii oocysts is found in their feces and it can spread to humans. This disease is generally asymptomatic, except when the patient has AIDS or in pregnancy, which can be very dangerous and fatal.
Chagas disease, or American trypanosomiasis is caused by protozoan Trypanosoma cruzi and is generally transmitted to people thanks to the feces of triatomine bugs. Some of the acute symptoms include fever, vomiting, headache, and in severe cases people can develop a chronic disease. In the worst cases it can produce flaccid cardiomegaly (enlargement of the heart) leading to heart failure and death.
Enzymes are protein molecules which are made up of long chains of
If a person had not drunk any water for 8 hours before collecting a sample, would you expect his/her urine to have a high or low specific gravity? Why?
Answer:
The person’s urine will have a high specific gravity
Explanation:
A high specific gravity is characterized by an increased concentration of solutes in the urine of am individual. A low specific gravity is characterized by a low or decreased concentration of the solutes.This is usually due to dehydration as a result of environmental conditions or tedious physical activities.
This explains why a person who had not drank any water for 8 hours and is dehydrated before collecting a sample is thought to have a urine with a high specific gravity
Which is/are possible genotypes for a person with straight little finger and brown eyes?
a. bbrr
b. bbRR
c. BbRr
d. bbRr
Answer:
The correct answer is b. bbRR.
Explanation:
Brown eyes color is dominant over blue eyes color. So, we can assign the letter R to the dominant allele that expresses brown eyes and r to the recessive allele that expresses the blue eyes. The phenotype bent little finger is dominant over the phenotype straight little finger. We can assign the letter B to the dominant allele, and b to the recessive allele.a. bbrr : This genotype belongs to a person with blue eyes and straight little finger
b. bbRR : This genotype belongs to a person with brown eyes and straight little finger
c. BbRr : This genotype belongs to a person with brown eyes and bent little finger
d. bbRr: This genotype belongs to a person with brown eyes and straight little finger.
explain the scientific theory of evolution and the evidence scientist found that proves it to be valid ?
Answer:
There are many theories
But main evidences are
Fossils of Plants animals and other organisms who lived on this planet at sometime. Oprain And Halden theory which suggests the chemical and biological evolution.what is a radical a group of ions
Answer:
A radical is a group of atoms of elements carrying a charge. radicals or ions are formed by gaining or loosing ions. positive radical ions are called radical cations whereas negative radical ions are called radical anions.
hope this helps you u :)
When brown iodine is exposed to starch it turns dark purple. In an experiment, you placed a cornstarch solution in a small plastic bag. Next, you placed the bag in a beaker of water containing 10 drops of iodine. If the solution in the plastic bag turned dark purple (Select all that apply)
a) the plastic bag was permeable to cornstarch.
b) the plastic bag was permeable to iodine.
c) the iodine moved into the plastic bag.
d) the cornstarch moved into the beaker.
e) the plastic bag was selectively permeable.
Answer:
b) the plastic bag was permeable to iodine
the plastic bag was selectively permeable
the iodine moved into the plastic bag.
the plastic bag was permeable to cornstarch.
Explanation:
The experimental set up represented the concept of osmosis.That is the movement of water molecules from the region of higher water potential to region of lower water potential through a semipermeable membrane(a cell membrane which only allows water and certain molecules to pass through,but restrain other molecules through its pores.
Generally potassium iodine test is the standard test for starch.
Therefore, in the question,water moves iodine molecules as iodine solution(from high water potential) to move across the paper bag(semi permeable membrane) to the reach the corn solution.(low water potential,high solute potential).This turns the starch in the corn solution blue-black/purple.
If the solution in the plastic bag turned dark purple:
the plastic bag was permeable to iodine. That is option (B)the iodine moved into the plastic bag. That is option (C)the plastic bag was selectively permeable. That is option (E)To test for the presence of starch in a solution, iodine solution is used. This gives a blue-black coloration which occurred due to the formation of a starch-iodine complex.
From the above experiment, the plastic bag which contains the corn starch solution, separates the solution from water containing 10 drops of iodine.
The turning of the solution, inside the plastic bag, into blue black signifies the formation of starch-iodine complex between the cornstarch solution the iodine water.
The reaction was able to occur because the plastic bag, which is selectively permeable to iodine, allowed the movement of iodine from the beaker of water into it. This is called diffusion.
Therefore, if the solution in the plastic bag turned dark purple it means that the plastic bag which is semi permeable allowed the movement of iodine into it.
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Vaccination is a process of injecting a dead or weakened form of a pathogen into the body. How does this help strengthen the immune system? It allows the body to increase its internal temperature. It allows the body to regulate the inflammatory response. It allows the body to keep pathogen information for future infections. It allows the body to increase its desire to eat healthy food.
Answer:
It allows the body to keep pathogen information for future infections.
Explanation:
Vaccination is the process whereby a substance called VACCINE is injected into body in order to prepare the immune system for resistance against infections. A vaccine contains the harmless or dead version of a pathogen called ANTIGEN, which functions to give the immune system defense mechanism against that form of pathogen in future.
The vaccine works by stimulating the immune system of the body to fight against the antigens in the same way it will fight against an actual pathogen in the future. Hence, the body keeps the information on how to combat such pathogens when there is an actual infection.
Answer
The answer is C edge 2020
Explanation:
Which is incorrect descriptions of the genetic event initiated by the HIV reverse transcriptase (RT) upon the HIV infection?
a. RT catalyzes initial synthesis of ssDNA using viral genomic RNA as the template.
b. The first RNA template is degraded after ssDNA synthesis.
c. The whole process is completed after synthesis of dsDNA.
d. tRNAs are adopted as the first primers.
e. None of these
Answer:
e. None of these
Explanation:
The immune deficiency viruses (HIV) are retroviruses that use a reverse transcriptase (RT) enzyme to produce a single-stranded DNA (ssDNA) from an RNA template. The reverse transcription allows retroviruses to replicate their genetic material, which is integrated into the host's genome as a double-stranded linear DNA molecule in a similar way to the mechanism of insertion used by endogenous retrotransposons. The synthesis of DNA is started by cellular tRNAs (tRNA3Lys) that are packaged into the virion. After reverse transcription, the HIV DNA enters the nucleus of CD4 immune cells (also known as CD4+ T cells), and then it integrates into the genome to coopt the host's cell machinery for its own replication.
The lactic acid generated in the body of a cricketer is first converted to glycogen in 1) Muscles 2) Liver 3) Blood 4) Both 2 and 3
Answer:
2) liver
Explanation:
the bloods transports the lactic acid to the liver to be converted into glycogen
Mitochondrial and chloroplast genomes typically Mitochondrial and chloroplast genomes typically encode some of the proteins needed for aerobic respiration and photosynthesis, respectively, as well as ribosomal and transfer RNA. encode for ribosomal and transfer RNAs. encode all of the proteins needed for aerobic respiration and photosynthesis, respectively. encode some of the proteins needed for aerobic respiration and photosynthesis, respectively. are composed of primarily noncoding DNA.
Answer:
The correct answer is "encode some of the proteins needed for aerobic respiration and photosynthesis, respectively, as well as ribosomal and transfer RNA".
Explanation:
Most organisms have a mitochondrial or a chloroplast genome in addition to the main genomic sequence located in the cell nucleus. The genes that are located in these organelles' genome include the genes that are used directly in the mitochondrion or chloroplast , including: proteins needed for aerobic respiration and photosynthesis (for instance genes involved in oxidative phosphorylation), respectively, as well as ribosomal and transfer RNA, which serve to the translation of proteins.
Where does cellular respiration get
the energy to make ATP? *
A. Chemical energy from sugars
B.Light energy from the Sun
C.Energy stored in the covalent bonds of
water molecules
D.Energy stored in the covalent bonds of
carbon dioxide molecules
Answer:
I believe A.
Explanation:
Cellular respiration gets energy to make ATP from the food you eat, so, A.
Given the gene sequence GGACCGTCGATCTTC, which of the following choices would represent an inversion mutation? A. GGACTCGATCTTC B. CCACCGTCGATCTTC C. GGACCGTCGATCTTC D. GGACCGTCGATCCTT
Answer:
D. GGACCGTCGATCCTT
Explanation:
Mutation refers to any change in the nucleotide sequence of a gene. Mutation can be of different types depending on how it occurs. According to the question, an INVERSION mutation is a type of mutation in which a segment of a gene gets broken off and reattached in another way on the same DNA. Hence, the only change in inversion mutation is the arrangement of the nucleotide bases on the gene.
Considering the nucleotide sequence: GGACCGTCGATCTTC, the sequence that describes an occurrence of inversion mutation is: GGACCGTCGATCCTT because the segment TTC in the original sequence has been rearranged as CTT in the mutated sequence.
Answer: GGACCGTCGATCCTT
Explanation: mutation means change and there is change in the gene sequence
Membrane-bounded vesicles that contain enzymes for oxidizing small organic molecules with the formation of hydrogen peroxide are Group of answer choices
Answer:
peroxisomes
Explanation:
The peroxisomes represent one of the organelles of the cell. They are usually small and characterized by membrane-bound vesicles that contain oxidative enzymes.
The enzymes in peroxisomes are involved in the oxidation of organic molecules - a process that leads to the formation of hydrogen peroxide. The later is further converted to water and oxygen by the constituent catalase enzyme of the peroxisomes. Fatty acids are also oxidized in peroxisomes but instead of hydrogen peroxide, acetyl groups that are utilized in other biosynthetic reactions are produced.
Which structures are highlighted? Which structures are highlighted? pulmonary arterioles alveoli bronchioles pulmonary capillaries
Hello. You forgot to put the image that complements this question. The image is attached below:
Answer:
pulmonary arterioles
Explanation:
Pulmonary arterioles are small blood vessels located in the lung. They appear as branches of the major arteries and have the main function of releasing blood from capillaries, in addition to regulating blood flow and peripheral blood pressure in capillaries.
It is important to note that arterioles are very small in size, which facilitates their functions to be performed efficiently and quickly.
_is a molecule that directs all of a cells activities
Answer:
[tex]\boxed{\mathrm{Nucleus}}[/tex]
Explanation:
The nucleus directs all cellular activities. The nucleus also contains genetic material of eukaryotic organisms.
