Answer:
The correct answer is b. He determined that DNA contains four nitrogenous bases.
Explanation:
Levene was an American biochemist who studied the structure of DNA in the early 1900s and in 1920 he found that DNA consists of four nitrogenous bases that are Adenine, Guanine, Thymine, Cytosine.
He also found deoxyribose sugar and phosphate group and said that nucleotide is the basic unit of DNA which contains a ribose sugar with attached nitrogenous base and phosphate group.
He also concludes that an equal amount of adenine, guanine, thymine, and cytosine makes the DNA which is now known as tetranucleotide hypothesis. So the correct answer is b. He determined that DNA contains four nitrogenous bases.
Two of these options are correct (A & E)
So, the correct option is D.
<h3>About ADH/Vasopressin:</h3>
- Other name for ADH is arginine vasopressin.
- It is a hormone produced by the brain's hypothalamus and kept in the posterior pituitary gland.
- It instructs the kidneys on how much water to hold onto.
- The amount of water in your blood is continuously regulated and balanced by ADH.
- Your blood's volume and pressure increase with higher water concentration.
- ADH helps to sustain water metabolism along with osmotic sensors and baroreceptors.
- The concentration of particles in your blood causes osmotic sensors in the hypothalamus to respond.
- Carbon dioxide, sodium, potassium, chloride, and other chemicals are among these particles.
- These sensors and baroreceptors tell your kidneys to store or release water to maintain a healthy range of these substances when particle concentration is out of balance or blood pressure is too low.
- They also control how thirsty your body feels.
- The particular nerve cells that make anti-diuretic hormone are located in the hypothalamus, a region at the base of the brain.
- The hormone is sent by the nerve cells to the posterior pituitary gland, where it is released into the bloodstream, via their nerve fibers (axons).
- By influencing the kidneys and blood arteries, anti-diuretic hormone aids in maintaining blood pressure.
- Its primary function is to decrease the volume of water excreted in the urine, so conserving your body's fluid volume.
- This is achieved by permitting a specific region of the kidney to enable water from the urine to be reabsorbed into the body.
- As a result, the bloodstream is replenished with more water, urine concentration increases, and water loss is decreased.
<h3> Aquaporins and ADH:</h3>
- Antidiuretic hormone levels above a certain threshold narrow (constrict) blood arteries, raising blood pressure.
- The only way to fully recover from a lack of bodily fluid (dehydration) is by drinking more water.
- The aquaporin 2 protein is made according to instructions from the AQP2 gene.
- The water molecules are transported across cell membranes by this protein, which creates a channel.
- Collecting ducts, a network of tiny tubes that reabsorb water from the kidneys into the bloodstream, are found in the kidneys where it is discovered.
- In order to keep the body's water balance in check, the aquaporin 2 water channel is crucial.
- A hormone known as vasopressin or antidiuretic hormone regulates the positioning of these channels (ADH).
- The body creates more ADH when the amount of fluid consumed is low or when there is a lot of fluid loss (for instance, through sweating).
- Aquaporin 2 water channels are ultimately inserted into the membrane of collecting duct cells by this hormone, which sets off chemical events.
- Due to the re-absorption of water into the bloodstream made possible by these channels, the urine is more concentrated.
- Less ADH is created when fluid intake is sufficient. Aquaporin 2 water channels are taken out of the collecting duct cells' membrane in the absence of signals from ADH.
- During these times, the urine is more diluted and less water is reabsorbed into the bloodstream.
Disclaimer: The given question was incomplete on the portal. Here is the complete question.
Question: ADH or Vasopressin...
A. Promotes the insertion of aquaporins (specifically AQP2) into the apical membrane of the collecting duct cells
B. Promotes the insertion of aquaporins (specifically AQP3 and AQP4) into the basolateral membrane of the collecting duct cells
C. All of these options are correct
D. Two of these options are correct
E. When released, increases the osmolarity of the excreted urine
Learn more about "ADH" :
brainly.com/question/25921436
#SPJ4
Explanation:
<u>the Paleozoic Era </u>
The Precambrian era describes a period of time that pre-dates Cambrian. This time typically references the entire period of the history of earth before the formation of rocks containing identifiable fossils occurred. It covers the majority of Earth’s history and is divided into the Hadean, Archean and the Proterozoic era.
Just before the Cambrian eruption, in the Paleozoic Era the environment was oxygenated, culminating in an explosion of new life in the Proteozoic Eon (2500-541 million years ago) in the form of primitive blue-green algae named cyanobacteria and oxygen based species. Multicellular species followed later, along with structure at higher levels, and complex life. Oxygen levels grew gradually over this period of time, from low levels.
Learn more about cellular life at brainly.com/question/11259903
#LearnWithBrainly
It is Codominance. Examples for this phenomenon is ABO blood groups.
