When water from the oceans/seas evaporate up into the atmosphere.
Absence of oxygen means anaerobic respiration ; which has 2 different pathways.
First Pathway ; Alcoholic fermentation which takes place in yeast.
Pyruvate is decarboxylated into ethanal releasing co2 as waste product.
Ethanal is toxic , so its reduced by help of NADH to ethanol in presence of alcohol dehydrogenase enzyme , and Free NAD is released to continue glycolysis.
2) The second pathway is Lactic fermentation which takes place in mammalian muscles.
Pyruvate accepts hydrogen and is converted to lactate by the help of enzyme lactate dehydrogenase , again free NAD is released to continue glycolysis.
Hope I made it clear enough :)
Answer:
1. Weaker
2. Continuous
Explanation:
A tumor suppressor gene codes for retinoblastoma protein (pRb). The retinoblastoma protein binds to transcription factor E2F when DNA damage is detected. The E2F bound to pRb can not stimulate expression of genes that code for proteins required during the process of DNA synthesis. The cell can not enter the S phase.
On the other hand, when the retinoblastoma protein is phosphorylated by cyclin E-CDK2, E2F transcription factor is free to stimulate the expression of genes required for DNA synthesis and the cell proceeds from G1 to S phase.
When the mutated retinoblastoma gene code for a protein that serves as phosphorylated protein, it will not be able to bind strongly with E2F and there would be continuous expression of genes required for S phase.
Answer:
English:
RNA and DNA are polymers made up of long chains of nucleotides . A nucleotide is made up of a sugar molecule (ribose in RNA or deoxyribose in DNA) attached to a phosphate group and a nitrogen base. The bases used in DNA are adenine (A), cytosine (C), guanine (G), and thymine (T).
Spanish:
El ARN y el ADN son polímeros formados por largas cadenas de nucleótidos. Un nucleótido está formado por una molécula de azúcar (ribosa en el ARN o desoxirribosa en el ADN) unido a un grupo fosfato y una base nitrogenada. Las bases utilizadas en el ADN son la adenina (A), citosina (C), guanina (G) y timina (T).
