Answer:
Semi-conservative replication
Explanation:
After the double-helix discovery of Watson and Crick, there were three possible models about the DNI replication:
The Conservative model stated that the two strands of DNI together were the template of another new molecule. The final product was the original double-stranded molecule and the new molecule. The semi-conservative model stated that the original DNI molecule separated into two strands, and each of them served as a template for the synthesis of a new complementary strand. The replication product would be two double-stranded DNA molecules, each carrying an original strand a new one. The Dispersive moles stated that the replication product would be two molecules made by a mixture of segments of the original and the new molecules.Meselson and Stahl joined to discover which of the models was the correct one. To do it they used E. coli and Nitrogen isotopes.
First, they extracted DNI from bacteria grown in a medium with N¹⁴ and got its density band by centrifugation. Then they grew bacteria in a medium with N¹⁵, extracted their DNI molecules, centrifugated them, and got the density band, which was heavier than the firsts ones. The researchers then transferred bacteria grown in medium with N¹⁵ to a medium with N¹⁴, and they allowed only one replication process to occur. DNI was extracted and centrifugated again, and a new band appeared. This band was an intermediate form between bands of DNI-N¹⁵ and DNI-N¹⁴.This event eliminated the conservative model. If this model were correct, the expected result would be to get two bands: one corresponding to the density DNI-N¹⁵ and the other corresponding to the density DNI-N¹⁴.
Bacteria grown in a medium with N¹⁵ and then transferred to a medium with N¹⁴ were finally allowed to replicate twice. Their DNI was extracted and centrifugated. The result was two bands: one of them coincided with the intermediate band, and the other one with the DNI-N¹⁴.This result was conclusive because if the dispersal model were correct, these two bands should not appear, as all the DNI strands would have part of the original molecule.
With this experiment, Meselson and Stahl proved that the correct replication model was the semi-conservative one.
Write out RNA strand that would be transcribed from following DNA sequence:
TTC AGC CAG
Why is Global warming occurring?
Answer:
Global warming occurs when carbon dioxide (CO2) and other air pollutants collect in the atmosphere and absorb sunlight and solar radiation.
Explanation: do you want one?
What part did undeveloped and developing countries play in the Industrial
Revolution
Answer:
Explanation:
A girl holds her breath for 30 seconds, breathes out, and then breathes in. Compared with the air she breathes out, the air she breathes in contains less
A) carbon dioxide and water vapour
B) nitrogen and water vapour.
C) oxygen and carbon dioxide.
D) oxygen and nitrogen.
HELP!
Beginning around 1750,the global human population began to grow at much faster then it had in the years before this time.What caused this to change in the population growth rate?
Answer:
The cartogram is made up of squares, each of which represents half a million people of a country’s population. The 11.5 million Belgians are represented by 23 squares; the 49.5 million Colombians are represented by 99 squares; the 1.415 billion people in China are represented by 2830 squares; and the entire world population of 7.633 billion people in 2018 is represented by the total sum of 15,266 squares. It started in 1798, to the 1800. This period is when the human population began to grow at a faster rate then any other time in history. The answer is 300 years ago.
Explanation : Births - usually measured using the birth rate (number of live births per 1,000 of the population per year). Deaths - usually measured using the death rate (number of deaths per 1,000 of the population per year). Migration - the movement of people in and out of an area.
please help me
An ecosystem that develops from barren rock is known as?
The rebuilding of an ecosystem after a natural disaster
is known as?
Explain why secondary succession is a faster process than primary succession.
Answer:
Ecological succession happens when new life takes over an environment. ... Primary succession begins in barren areas, such as on bare rock exposed by a retreating glacier. The first inhabitants are lichens or plants—those that can survive in such an environment
Ecological restoration aims to recreate, initiate, or accelerate the recovery of an ecosystem that has been disturbed. Disturbances are environmental changes that alter ecosystem structure and function. Common disturbances include logging, damming rivers, intense grazing, hurricanes, floods, and fire
Secondary succession is usually faster than primary succession because soil and nutrients are already present due to 'normalization' by previous pioneer species, and because roots, seeds and other biotic organisms may still be present within the substrate
PLEASE HELP ILL GIVE 50 POINTS AND BRAINLIEST.
23.How are lungs a benefit over simple diffusion for getting oxygen?
24.What is the relationship between the alveoli and capillaries?
25.Make an argument that the heart is the most important part of the circulatory system.
26.Make an argument that the blood is the most important part of the circulatory system.
Answer:
23.oxygen diffuses through alveoli walls to the blood capillaries
24.blood capillaries surround alveoli
25. pumps blood which carry all the body minerals all over the body from the lungs and to all body parts
The atoms of certain element each contain 36 protons and 8 valence electrons. Which statement correctly identifies this element and describes its chmical reactivity?
Answer:
This question lacks options, the options are:
A The element is krypton, Kr, and it is not very reactive.
B The element is chlorine, Cl, and it is highly reactive.
C The element is krypton, Kr, and it is highly reactive.
D The element is chlorine, Cl, and it is not very reactive.
The correct answer is A
Explanation:
An atom is identified by its atomic number, which is the number of protons it contains. In this question, it is said that the atoms of a certain element each contain 36 protons. Using the periodic table, the element with atomic no. 36 is KRYPTON.
Also, Krypton posseses 8 valence electrons in its outer shell. In accordance to the octet rule, Krypton has no further need to engage in any chemical reaction to fill its electron shell because it is already filled (8 valence electrons). This accounts for the reason Krypton belongs to "Noble gases" and very unreactive.
HELP PLEASE I GIVE YOU BRAINLIEST I NEED HELP WITH 2
Answer:
C. makes the most sense so I hope I'm right
Explanation:
If this isn't correct I am so so so sorry!
Select the true statement.
Cells, tissues, and organs all work together to make up
organ systems.
The smallest and simplest systems within organ systems
are the organs.
Organ systems work independently from the rest of the
body.
PLEASE HELP ILL GIVE BRAINLEST
The diagram shows a nephron.
A nephron. W points to branch of renal artery. X points to branch of renal vein. Y points to tubular point of nephron. Z points to collecting duct.
Where is the blood first filtered?
W
X
Y
Z
I hope this helps A nephron. W points to branch of renal artery. X points to branch of renal vein. Y points to tubular point of nephron. Z points to collecting duct.
Where is the blood first filtered?
W
X
Y
Z
Answer: A
Answer:
W
Explanation:
I just did the quiz
What happened to animals are producers are not available to photosynthesize?
Answer:
They will find another food source or starve
If brown hair is represented by the allele "B" and blond hair is represented by the allele "b" then what must the genotype(s) be of someone who has brown hair?
Answer:
Bb or BB
Explanation:
since brown hair was the dominant allele it only has to have one big B to serve as a heterozygous dominant trait. Therefore, the person has brown hair. If you were looking for blond hair it would have to be bb because it is a recessive trait and you need two recessive traits to make up a certain genetic trait.
Which graph below represents the amount of potassium-40 and the amount of argon-40 and calcium-40 over four half-lives?
Answer: b
Explanation: i got it right
If only one species is considered the 'fittest', why do we still have so many variation among species?
Answer:
Variation occurs in species with the genes resulting in the traits and physical characteristics that make it possible for them to be among the fittest for a number of reasons:
1. Mutation
2. Recombination and
3. Migration
Explanation:
Mutations: A mutation is a deviation from the norm in a DNA sequence. It can be stimulated by errors during the DNA replication process which happens as the cell is dividing, or by exposure to ionizing radiation, chemicals, or viral infection (whether artificial or natural).
It is noteworthy that naturally, without any human intervention, the possibility of a spontaneous mutation is very low.
Recombination: This refers to the creation of new fusion of genes in the offspring that did not occur in the parents by the processes of crossing-over and independent assortment. Independent assortment meaning that the allele the gamete received for one gene was not influenced by the allele received for another gene.
Migration: Variation by migration here refers to the introduction of new genes from into one population by another. This could happen when a new population arrives at an existing one or when an existing one migrates to another population.
We can say for example that, genes from Americans have “migrated” into the population of African origin in America given the continuous immigration of Africans into America.
So in both populations, there are very fit species, but when their genes are mixed during cross-reproduction, variation arises.
Cheers
FRAMESHIFT mutation. Explain what this means and how it affects the
protein
Explanation:
frameshift mutation is a type of mutation involving the insertion or deletion of a nucleotide in which the number of deleted base pairs is not divisible by three. ... Each group of three bases corresponds to one of 20 different amino acids used to build a protein.
genome dot gov
Chromosomes are SMALLER than genes and are found in DNA.
True
False
Answer:True
Explanation:
In a given population of plants there is variation in the time of day when flowers open. Those individual plants with flowers that open at night would be more likely to pass on this trait in an environment
dominated by what?
A Solar radiation
B. Nocturnal pollinators
c. Moist sol
D. Grazing animals
Answer: B is the answer. Hope this helps!
no links! pls help
What process is occurring in the illustration?
a) classic ecosystem
b) climax community
c) primary succession
d) secondary succession
classic ecosystem
Explanation:
because i love
Answer: D
Secondary Succession
Explanation:
I took the quiz.
Exposure to certain environmental toxins, such as pesticides, may reduce fertility in males by interfering with their ability to produce gam
toxins are most likely having an effect on the
testes and progesterone
2.
ovaries and testosterone
3.
ovaries and estrogen
4
testes and testosterone
Answer:4
Explanation: i’m smart
)Winds occur
because of convection currents the troposphere. How do you think winds affect
air pollution?
Question 6 help me answer 6
Answer:
the first one or the last one
Explanation:
Question 23 (6 points)
Sea Urchins are aquatic mammals that dive down to catch and eat sea urchins. Sea
urchins hunt the sea floor to catch and eat starfish. Starfish feed off of kelp forests
under the sea.
When sea otters overpopulate they clean out the sea urchins very quickly. This
allows the starfish to overpopulate and eat too much of the kelp forests.
Answer the following questions for 2 points each:
1. Name the TWO organisms that act as Carnivores in the ecosystem described
above.
2. Identify the ecological roles of the other TWO organisms.
3. Identify which of the four organisms above would be considered a keystone
species. Explain why.
Answer: 1. Sea urchins and sea otters
2. They are prey for carnivores.
3. Sea otters, star fish
Explanation:
Sea urchins and sea otters are carnivores as they eat on the flesh of starfish and sea urchins respectively.
Starfish feed on the kelp forests which are the producers in the food chain and the starfish is the primary consumer and prey for sea urchins. So, starfish and kelp forests are the prey in the marine ecosystem.
Keystone species is the one which controls the population of other inferior species in an ecosystem. Here, sea otters consume sea urchins so the population of sea urchins remained in control Starfish controls the population of kelp forest.
How do cancer cells differ from normal cells? Select all that apply.
A
they do not stop at checkpoints
B
they condense their DNA into chromosomes for cell division
C
they have uncontrolled growth
D
they go through the S phase
Answer: A and B
Explanation:
Cancers cells differ from normal cells because they do not stop at checkpoints and they have uncontrolled growth. So, options A and C are correct.
What do you mean by Cancerous cells?Cancerous cells may be defined as an abnormal cell that doesn't follow the regulations of the cell cycle. They get multiply at a rapid speed.
Normal cells follow a typical cell cycle. They grow, divide and finally die. But cancer cells do not follow the cell cycle, they do not undergo apoptosis, and they continuously multiply at a rapid pace.
Therefore, Cancers cells differ from normal cells because they do not stop at checkpoints and they have uncontrolled growth.
To learn more about Cancerous cells, refer to the link:
https://brainly.com/question/373177
NO LINKS I WILL REPORT U
Answer:
Both of these are correct
moves constantly between Earth's surface and the atmosphere
and it is matter that is essential for life
Answer:
Water is matter is essential for life
Explanation:
Cual es el componente gaseoso que faltaba en la atmosfera primitiva y que hoy es escencial para la vida?
Answer:
El componente gaseoso que faltaba en la atmósfera primitiva y que hoy es esencial para la vida es:
El oxigeno [tex]O_{2}[/tex]Explanation:
Se tiene constancia de que en sus inicios, la atmósfera de la Tierra estaba compuesta por los gases resultantes de las diferentes erupciones volcánicas (ya que la actividad volcánica de dicha era fue demasiado alta), por lo tanto, era normal tener una atmósfera compuesta por azufre, dióxido de carbono, nitrógeno (que hoy en día es más del 70% del aire que respiramos) e incluso agua en estado gaseoso, sin embargo, la presencia del oxígeno [tex]O_{2}[/tex] era sumamente baja, casi inexistente, actualmente su presencia en el aire es de un poco más del 20% y es sumamente importante para diferentes funciones en los seres vivos, incluso los seres vivos acuáticos que se abastecen del oxígeno disuelto en el agua, esta es la razón por la cual, si tienes una pecera con peces en tu casa, debes instalarle un sistema que abastezca de oxígeno constantemente a tu peces mascota.
ANSWER PLS DONT PUT LINKS
Answer: C!! :)
Explanation:
Why is Carbon important?
Answer:
Carbon is an important constituent of living beings. Along with Nitrogen and oxygen, carbon is one of the essential building blocks of organic life. Carbon forms about 18% of the human body. By organic here I want to stress the fact that it includes every living thing in the world including substances that are produced by living beings. Organic Chemistry, which deals with the study of carbon compounds is a vast repository of information on such compounds. Carbon is integral because of its unique ability to form four different bonds with other elements. This makes it possible for carbon to react with many other elements and form a vast array of compounds.
Hydrocarbons which again is primarily a compound of hydrogen and carbon are the source of all our fossil fuels. ( Fossil Fuels as these fuels are literally formed by fossilized organic matter)
CO2 which again is a carbon compound is responsible for keeping our earth warm and habitable by aiding the greenhouse effect. There are many other such compounds of carbon that are very useful to the earth and living beings.
To conclude carbon in itself is not as essential as its ability to form numerous compounds that are essential for life to exist.
Explanation:
Hope this helps
Every ____ has a specific _____
• cell membrane
• function
• cell wall
• chloroplast
• mitochondria
• nucleus
• cytoplasm
• organelle
Answer:
Every organelle has a specific function
What do you think the color of the pea plants has to do with genes?
Answer:
According to Mendel Gregor, he analyzed two plants can make a different offspring. It depends on the alleles. I hope this helped!
Explanation:
Answer:
The instructions for making a pea plant are found in its genes. Each gene has the instructions for one small part of the pea plant. There is a gene that determines the color of the peas the plant will produce. These genes can come in all different versions.