1875
1900
1925
1869 Friedrich Mlescher
Identifies a substance that
will later be known as DNA.
1919 Phoebus Levene publishes a paper on nucleic
acids. His research helps scientists determine that
DNA is made up of sugars, phosphate groups, and four
nitrogen-containing bases: adenine, thymine, guanine,
and cytosine. Bases are often referred to by their first
letter: A, T, C, or G. Each base has a different shape.
6 Analyze In this model, what do P, S, and A bases
represent?
S
A
base
Wedwo dostigny LION CHO
148 Unit 2 Reproduction and Heredity
Answers
Answer:
In 1869, Friedrich Miescher isolated "nuclein," DNA with associated proteins, from cell nuclei. He was the first to identify DNA as a distinct molecule. Phoebus Levene was an organic chemist in the early 1900's. He is perhaps best known for his incorrect tetranucleotide hypothesis of DNA.
Explanation:
Phoebus Aaron Theodor Levene was born in Sagor in Russia. He grew up in St. Petersburg and studied medicine at the Imperial Military Medical Academy. As a student he worked in the laboratory of his organic chemistry professor where he likely developed an interest in biochemistry.
In 1891, because of growing anti-Semitism in Russia, Levene and his family emigrated to the U.S. They arrived on the symbolic day of July 4. Levene went back to Russia almost immediately to finish his medical degree, but by 1892, he was in New York and practicing medicine on the Lower East Side.
Levene did not give up research. He enrolled as a special student at Columbia University and he split his time between his medical practice and research in the department of physiology. By 1894, he began publishing papers on the chemical structure of sugars. Two years later, Levene received his first appointment as an Associate in the Pathological Institute of the New York State Hospitals. Unfortunately, around this time, Levene contracted tuberculosis and was forced to take time off to recuperate.
Levene used the time between 1896 and 1905 to regain his health and to work with a number of well-known chemists, including Albrecht Kossel and Emil Fischer, the nucleic acid and protein experts of the time. In 1905, Levene was hired by the newly established Rockefeller Institute of Medical Research to head the biochemical laboratory. Levene did most of his nucleic acid work at the Rockefeller and stayed there until his death.
Levene was a cultured man, an art lover and a collector. The walls of his house were lined with either prints and paintings or overflowing bookshelves. Levene was extremely well-read and was fluent in Russian, English, French and German. He also spoke passable Spanish and Italian. His experience, knowledge and his generosity made him a favorite with colleagues and friends. He was also said to be a great teacher, enthusiastic and supportive.
Although mostly remembered now for his incorrect tetranucleotide theory of DNA, Levene published over 700 original papers and articles on the chemical structures of many biochemicals. Levene died in 1940, before the true significance of DNA became clear.
Explanation:
Related Questions
What is the change in entropy (AS) when sodium chloride dissolves in water?
Answers
D. Greater than 0
Explanation:
Sodium chloride(NaCl) in water is a endothermic reaction, which means the heat is absorbed.
How many moles of carbon dioxide molecules
are there in 50g of carbon dioxide?
Answers
Answer:
3.011×1023 individual carbon dioxide molecules
how can you use these materials to test whether land or water heats faster?
Materials:
sand
water
heat lamps
thermometers
cups
Answers
Answer:
Put sand in one cup and water in the other. Put two heat lamps at equal height and under each one put the water and sand, this must be done at the same exact time. Set a timer for 5, then 10, then 15, and so forth minutes. Each time measure the temperature of each with the thermometers and write the down. Have a certain temperature you want them to get to and see which gets to it quicker. Then set a new temp 3 times to see if the answer is consistent.
Explanation:
Doing this would test whether land or water heats quicker.
Answer:
heat lamps
Explanation:
can someone solve this plz
βeta decay
carbon atomic mass 14
atomic # 6
Answers
Answer:
14/6C your welcome
Explanation:
what is atomic?................................................
Answers
Answer:
oh I'm here thanks for your points
Answer:
thanx for the points
Explanation:
A 23.7 g piece of iron at 54.9°C is cooled and releases 338 J of heat. The specific heat of iron is 0.450 J/g°C.
Answers
Answer:
The heat capacity and the specific heat are related by C=cm or c=C/m. The mass m, specific heat c, change in temperature ΔT, and heat added (or subtracted) Q are related by the equation: Q=mcΔT. Values of specific heat are dependent on the properties and phase of a given substance.
Explanation:
Answer:
23.2 degrees c
Explanation:
Metals react by losing valence electrons. Which of the alkali metals loses its valence electrons most easily? Explain.
Answers
Answer:
lol you have an aot profile pic
need helpppppp hurry pls, i just really need help
Answers
Answer:
6.8 mole of O₂
Explanation:
Given expression:
2H₂ + O₂ → 2H₂O
Number of moles of H₂ = 13.6moles
Unknown:
Number of moles of O₂ = ?
Solution:
In the given problem, we are to find the number of moles of oxygen gas that will use up 13.6mole of hydrogen gas;
From the reaction equation;
2 mole of H₂ will completely react with 1 mole of O₂
13.6 moles of H₂ will completely be used up by [tex]\frac{13.6}{2}[/tex] mole of O₂
= 6.8 mole of O₂
Carbon makes up part of all life forms on Earth. The human body, for example, is about blank % carbon.
Answers
Which element wants to gain valence electrons while bonding?
a. Neon (Ne)
b. Fluorine (FI)
c. Lithium (Li)
d. Magnesium (Mg)
Answers
Answer:
b. Fluorine (FI)
Explanation:
From the given choices, only fluorine wants to gain valence electrons while bonding.
This is because fluorine is the most electronegative specie from the given choices. An electronegative substance have a high tendency to attract electrons to itself in a bond.
Neon is a noble gas and it is stable. Lithium and Magnesium are metals that are electropositive. They prefer to lose electrons than to gain electrons.
If you have 100 particles of hydrogen and 100 particles of oxygen, how many units of water can you form? Will you use all the particles of both
elements? If not, what will remain?
Answers
Answer:
82
Explanation:
i took the assingment
the diagram below shows three containers of gas.
Which list correctly describes the gases in containers R, S, and T?
a R= element s = compound t = mixture
b R= compound s = element T= mixture
cR= element s = mixture t= compound
d r = mixture s= emelem t = compound
ASAP
Answers
Answer:
d
Explanation:
The correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
What are gases?Gases are defined as the state of matter where particles often travel very swiftly, far apart from one another, and with little or no attraction to one another. They take up much more space than the liquids or solids from which they are formed, are simple to compress, and expand to fill their containers.
Particles make up all matter; these particles can be single atoms or atoms that have been chemically combined to form molecules. This fact allows us to divide matter into three general categories: elements, compounds, and mixtures. All the atoms in an element are of the same kind. A compound is created when more than one kind of atom is chemically bonded.
Thus, the correctly describes the gases in containers R, S, and T is R = mixture S = element and T = compound. Hence option d is correct.
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1. Which of these is not one of the main 6 forms of energy?
O a. Nuclear energy
O b. Chemical energy
O c. Light energy
O d. Electromagnetic energy
Answers
Answer:
Chemical energy
Explanation:
Chemical Energy
Calculate the percent composition of C6H12O6
Answers
Answer:
Did you just let your cat walk on your keyboard? XD
Could you explain this a bit better please?
I'll answer the question in the replies of this comment if you can give me a bit more information.
Explanation:
May I have brainliest please? :)
3. IDENTIFY the following reactions as Oxidation / Reduction reactions ?
a) PbO + H2 --> Pb + H2O
b) ZnO + C --> Zn + CO
c) H2S + Cl2--> 2HCl + S
d) Fe203 + 3C0 --> 2Fe + 3CO2
e) PbS + 4H202 --- PbSO4 + 4H2O
Answers
[ Reduction: since there is a loss of oxygen in Pb]
[Oxidation: since there is a gain of oxygen in H2O]
b) Reduction AND oxidation
[Reduction: since there is a loss of oxygen in Zn]
[Oxidation: since there is gain of oxygen in CO]
c) Oxidisation AND reduction
[Oxidisation: since there is a loss of electrons in S]
[Reduction: since there is a gain of electrons in Cl^-1]
d)Reduction AND oxidation
[Reduction: since there is a loss of oxygen in 2Fe]
[Oxidation: since there is a gain of oxygen in 3CO2]
e) Oxidation AND Reduction
[Oxidation: since there is a gain of oxygen in PbSO4]
[Reduction: since there is a loss of oxygen in 4H2O]
( Hope this was helpful... And I apologize if any of the answers are incorrect.... I just did this chapter as well!)
Remember: Oxidation requires—Gain of O2
—Loss of H2
—Loss of elections
Reduction requires—loss of O2
—Gain of H2
—gain of electrons
When the moon is between the earth and the sun what moon phase will this be
Answers
Answer: New Moon Phase
Explanation:
Answer:
The New Moon phase
Explanation:
The moon in between the earth and the sun will cause it being a new moon because the sun's light doesn't reach the side of the moon thats facing the earth
Help pls!! Due in 30 mins!
Which equation represents a single replacement reaction?
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g)
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
Answers
2. 2Al(s) + 6HCl(aq) + 2AlCl3(aq) + 3H2(g) represents a single replacement reaction
Further explanationA single replacement reaction is a chemical reaction in which one element replaces the other elements of a compound to produce new elements and compounds
Not all of these reactions can occur. We can use the activity series(voltaic series), which is a list of elements that can replace other elements below / to the right of them in a single replacement reaction.
1. 2Al(s) + 3Cl2(g) → 2AlCl3(s)
Syntesis/combination reaction
2. 2Al(s) + 6HCl(aq) ⇒2AlCl3(aq) + 3H2(g)
Single replacement reaction
3. 2AlCl3(s) → 2Al(s) + Cl2(g)
Decomposition reaction
4. AlCl3(aq) + 3KOH(aq) + Al(OH)3(s) + 3KCl(aq)
Double replacement reaction
In a single replacement reaction, one element replaces another one. The reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
Single replacement reaction:It is a chemical reaction in which one element of the reactant compound replaces the other elements of another compound to form a new molecule.In these reactions, a more active element replaces the less active element.
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
In the given reaction, aluminum replaces the hydrogen from hydrochloric acid to form Aluminum chloride.
Therefore, the reaction that shows the single replacement reaction is:
[tex]\bold { 2Al(s) + 6HCl(aq) \rightarrow 2AlCl_3(aq) + 3H_2(g)}[/tex]
Learn more about Single replacement reaction:
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Analyze how friction can be both a positive and negative aspect in our everyday lives. Use examples to support your statements.
Answers
Answer:
For example, friction between our shoes and the floor stop us from slipping and friction between tyres and the road stop cars from skidding. Friction is sometimes unhelpful. For example, if you don't lubricate your bike regularly with oil, the friction in the chain and axles increases.
Explanation:
As the frequency decreases the wavelength...
Answers
Answer:
Increase
Explanation:
Assuming a sinusoidal wave moving at a fixed wave speed, wavelength is inversely proportional to frequency of the wave: waves with higher frequencies have shorter wavelengths, and lower frequencies have longer wavelengths.
For the water, what color is the hydrogen molecule?
Answers
Answer:
White is the color of a hydrogen molecule
Answer:
green. It is white when separate, but it turns green when it's formed into water.
Explanation:
the first 5 elements (in increasing order) that are found in group 18
Answers
Answer:
Today, I will present the first eighteen elements which are Hydrogen, Helium, Lithium, Beryllium, Boron, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Sodium, Magnesium, Aluminum, Silicon, Phosphorus, Sulfur, Chlorine, and Argon.
First 5: Hydrogen. The first and simplest element on the periodic table.
Helium. a very light colorless element that is one of the six inert gasses.
Lithium. A very soft, light metal.
Beryllium. A very light metal; although it is 3 1/2 times the density of Lithium.
Boron. The fifth element in the periodic table.
Explanation:
Is cell membrane a plant or animals cell
Answers
Answer:
They both have a cell membrane, however a plant also has a cell wall.
Explanation:
Butane and methyl propane are an example of a pair of
Answers
The Environmental Protection Agency and health officials nationwide are concerned about the levels
of Radon gas in homes. The half-life of Radon-222 isotope is 3.8 days. If a sample of gas taken from
basement contains 4.38 ug of Radon-222, how long will it be until 0.55 ug will remain? How many half lives?
Answers
It takes 11.4 days⇒three half-lives
Further explanationGeneral formulas used in decay:
[tex]\large{\boxed{\bold{N_t=N_0(\dfrac{1}{2})^{t/t\frac{1}{2} }}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
t1/2=3.8 days
No=4.38 μg
Nt=0.55 μg
[tex]\tt 0.55=4.38\dfrac{1}{2}^{t/3.8}\\\\0.125=\dfrac{1}{2}^{t/3.8}\\\\\dfrac{1}{2}^3=\dfrac{1}{2}^{t/3.8}\\\\3=t/3.8\rightarrow t=3.8\times 3=11.4~days[/tex]
Explain what occurs when an electron is given energy from an outside source.
Answers
Answer:
An electron can become excited if it is given extra energy, such as if it absorbs a photon, or packet of light, or collides with a nearby atom or particle.
Explanation:
Mark me brainliest.
The chemical equation below shows the amount of the reactants used and the amount of only one of the products formed. How much water (H2O) should be formed in this chemical reaction? CH4 mass 4 + 2O2 mass 16 CO2 11 + 2h2O mass ?
Answers
Answer:
CH4 + 2O2 → CO2 + 2H2O
Explanation:
This is all i could come up with im sorry.
The amount of water formed in the given chemical reaction is 9 grams.
What is Stoichiometry?Stoichiometry is the calculation for the determination of the relative amount of reactants and products in chemical reactions. Stoichiometry is based on the law of conservation of mass where the total mass of the reactants in reaction equals the total mass of the products.
If the quantity of one reactant is known and the quantity of the product can be determined empirically, then the quantity of the other reactants can be calculated.
Given chemical equation is:
CH₄ + 2O₂ [tex]\longrightarrow[/tex] CO₂ + 2H₂O
16g 32g 44g 32g (from their molecular masses)
The amount of methane, oxygen, and carbon dioxide is 4g, 16g, and 32 g respectively.
16g of methane react with oxygen = 32g
4g of methane will react with oxygen = 8g
It means here methane is the limiting reagent as the given amount of oxygen is more than reacted one. So CH₄ will decide the amount of water.
16g of methane produces water = 32g
Then 4g of methane will produce water = (32/16) × 4 = 9 g
Therefore, 9 grams of water should be formed in this reaction.
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Time Period Duration (Millions of Years ago)
Cenozoic 66-0
Mesozoic 252-66
Paleozoic 541-252
Trilobites appeared approximately 521 years ago and disappeared approximately 250 million years ago. During which era did the trilobites live?
a
Cenozoic
b
Mesozoic
c
Paleozoic
d
None of These
Answers
Answer:
B
Explanation:
What is the role of CdKs? to create enzymes that produce chemical changes to signal the cell to move to the next phase of the cell cycle to build structural components of DNA and energy-rich substances to activate the cyclins that cause progression of the cell cycle
Answers
Answer:
It’s b
Explanation:
Answer:
Regulation of the cell cycle is carried out by which of the following? Check all that apply.
CdKs
cyclins
What is the role of CdKs?
to signal the cell to move to the next phase of the cell cycle
Explanation:
Benzoic acid, C6H5COOH, is another derivative of benzene. The pH of an aqueous solution of benzoic acid at 298 K is 2.95. Determine the concentration of hydroxide ions in the solution,
Answers
Answer:
[OH⁻] = 8.91x10⁻¹²M
Explanation:
In aqueous solutions, the [OH] and [H⁺] are associated in the equation of hydrolisis of water:
1x10⁻¹⁴ = [OH⁻] [H⁺]
With pH, we can solve for [H⁺] and obtain, the [OH⁻] using this equation:
pH = -log [H⁺]
[H⁺]= 10^-pH
[H⁺] = 1.122x10⁻³M
1x10⁻¹⁴ = [OH⁻] [1.122x10⁻³M]
[OH⁻] = 8.91x10⁻¹²MHELP DUE TOMMOROW! FAILING CLASS!!! When it would be appropriate to use Radiocarbon dating, Rubidium-Strontium dating, Uranium-Lead dating, and Potassium-Argon dating. Include if the types of dating are used for organic or inorganic things and the time range they are useful for.
Answers
Answer:
Uhm if you're failing the class why are you still using brainly to get answers... Where's your momma boy?
Explanation:
It izzz what it izzz