A vein in a leaf has what important function?

Meselson and Stahl used density labeling of DNA to show that DNA replication occurs via a semiconservative mechanism. In their e

cricket20 [7]

Answer:

The organism previously used 15N for replication so all the DNA molecules were of 15N15N type. Then the organism is shifted to a medium where only 14N is available for replication.
According to semi conservative mode of replication, a newly synthesised DNA molecule consists of one new strand and one parental strand. So after the first round of replication, All the 15N strands will synthesise new DNA strands using 14N resulting into intermediate 15N14N DNA molecules. Hence, only one band would be observed (15N14N) above the original 15N15N band since 15N14N has lighter isotope too so it will be lighter than 15N15N molecules and will lie above it.
After second round of replication, 15N strand from 15N14N would synthesise another 14N strand. 14N strand from 15N14N molecules will also synthesise another 14N strand. So now, 50% of the DNA molecules will be of 15N14N intermediate type and 50% of them will be of 14N14N type.Two bands will be observed above the original 15N15N band. One band of 15N14N molecules will be right above it and other band of 14N14N molecules will be even higher because it is the lightest band since it has only the lighter isotope of nitrogen.

8 0

3 years ago

Consider the parts of the digestive system, particularly the place where water is removed before feces are excreted. Which organ

Phoenix [80]

Answer:

The colon.

Explanation:

The colon, also known as the large intestine is one of the major organs of the digestive system and plays a vital role in the processing of food and excretion of waste. It is divided into the ascending colon, transverse colon, descending colon and sigmoid colon.

The colon has a large surface area and plays a major role in the reabsorption of fluids and the processing and formation of waste which it pushes towards the rectum to be expelled.

Diarrhea is a condition which is characterized by frequency of bowel movements and passage of loose and watery stools. It has various causes most of which affects the normal functionality of the colon thereby limiting it's ability to reabsorb water and fluids. Such causes which affect the colon include; Bacterial infections, laxative abuse, diseases of the colon such as ulcerative colitis and Crohn's disease etc.

8 0

3 years ago

Which geometric solid is the best model for the cell in the bottom two layers of cells?

nevsk [136]

Answer:

The correct answer is option D. cube.

Explanation:

The image represent the cells similar to the epithelial cells whcih is found in various tissues such as muscle, nervous and many more. These cells are found in cuboidal, columnar and squamous sha[es which found in normally double layer or in multiple layers.

These cells are cube like in structure with a spherical nucleus present in the center of the cell known in assocation of various cells.

6 0

3 years ago

Read 2 more answers

What process recharges this molecules so that it can become ATP again

alexdok [17]

<span>By rebonding with another phosphate molecule through oxidative phosphorylation, it becomes recharged and the ADP to ATP process can be restarted. This allows for more cellular energy to be produced, and more metabolic actions to be undertaken. This is the major aspect of cell respiration.</span>

7 0

3 years ago

Amino acids with hydrophobic r groups are most often found buried in the interior of folded proteins. true or false

pentagon [3]

Answer:

True

Explanation:

Hydrophobicity is the aversion to the water of a molecule (or part of it). Amino acids with a hydrophobic R group (glycine, alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, and tryptophan) <em>will fold with the R groups in the interior to avoid water. This behavior is one of the most important forces in protein folding. </em>You can see it exemplified in the image I added.

I hope you fidn this information useful and interesting! Good luck!

7 0

3 years ago