1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
andreyandreev [35.5K]
3 years ago
12

The nitrogen cycle could not exsist without

Biology
2 answers:
Jet001 [13]3 years ago
4 0

Answer:

Nitrogen is your answer

IRISSAK [1]3 years ago
3 0

Answer:

The nitrogen cycle could not exist without first nitrogen. The cycle is about this specific element which goes to show that if this element is not present then, there will not be any nitrogen cycle. Also, an important factor for the cycle is the presence of the bacteria and other microorganism which are needed for the fixation.

You might be interested in
A gene is involved in promoting limb development in humans. The gene is initially weakly activated during the limb induction pha
Anna [14]

Answer:

1. If the gene is weakly activated, it likely lacks repressive histone modifications, but may also lack the presence of histone marks associated with strong transcriptional activation such as acetylation.

When the gene is strongly activated, it likely lacks repressive marks (such as H3K9me2/3 and H3K27me3 - both examples of repressive histone methylation) and might possess some activating histone acetylation marks, such as H3K4ac, and active histone methylation such as H3K4me3

<em>An aside: The pattern and presence of different histone modifications would depend on the gene, but based on the fact that it is a developmental gene, I would assume that H3K27me3 and H3K4me3 are at play (these are part of the Polycomb/Trithorax system)</em>

<em />

After limb growth is complete, the gene is turned off. Repressive histone methylation marks would be associated with this state, such as the aforementioned H3K9me2/3 or H3K27me3.

2. Histone modifications are tightly linked to genome organisation. Histone methylation marks associated with repression such as H3K27me3 and H3K9me3 are associated with compact chromatin structures, which restrict the access of transcriptional machinery and other positive regulators. Conversely, histone marks associated with gene activation are associated with a more permissive chromatin environment that facilitates the binding of factors associated with gene expression. In the case of histone acetylation, the acetyl mark directly removes the positive charge of chromatin, relaxing its interaction with negatively charged DNA.

3. If the inappropriate activation of this gene caused a cancerous tumor, this gene would be referred to as an oncogene (or a proto-oncogene for the term before it is inappropriately activated).

Typically, there are two classes of genes that lead to cancer: tumor-suppressor genes and oncogenes. Tumor suppressor genes lead to cancer when their protective activity is reduced or demolished, leading to the production of cancer cells. Oncogenes lead to cancer when they become over active. Oncogenes are often genes associated positively with growth and proliferation, consistent with the gene in this example.

8 0
3 years ago
Three organelles found in cells?
Katen [24]

Answer:

1.Plasma membrane

The plasma membrane surrounds the cell to create a barrier between the cytosol and the extracellular matrix. Plasma membranes also enclose lumens of some cellular organelles.

2.Endoplasmic reticulum

The endoplasmic reticulum (ER) is a large network of membranes responsible for the production of proteins, metabolism and transportation of lipids, and detoxification of poisons. There are two types of endoplasmic reticulum with separate functions: smooth endoplasmic reticulum and rough endoplasmic reticulum. The presence or absence of ribosomes in the ER’s plasma membrane determines whether it is classified as smooth or rough ER.

3.Golgi apparatus

The Golgi apparatus appears as a series of flattened, membranous sacs, or cisternae, that resemble a stack of pancakes just off the rough endoplasmic reticulum. It receives vesicles containing proteins recently produced by the rER. The Golgi apparatus can be compared to a warehouse or post office for newly formed proteins. Here the proteins are further modified, packaged, and sent off to their final destinations in the cell or body.

6 0
2 years ago
Read 2 more answers
An example of a low energy electromagnetic wave is
Natasha2012 [34]
An example is a radio wave
3 0
3 years ago
A 100%<br> B. 25%<br> c. 50%<br> D.75%
tekilochka [14]
Hey there what is your question?
3 0
3 years ago
How many solutions can an equation have?​
gayaneshka [121]

Answer:

It depends entirely on an equation, certain equations are meant to confuse you with numerous answers so taht you have to narrow it down, some only have one or a few. It really depends on the type of problem

3 0
3 years ago
Other questions:
  • What is the main purpose of the organ system shown below?
    14·2 answers
  • Explain how human insulin can be produced using gene splicing.​
    10·2 answers
  • What are the three domains into which all living organisms are placed?
    8·1 answer
  • Should we put animals to unnatural and painful situations in the pursuit of knowledge
    5·1 answer
  • Which part of the government has authority to enforce the Clean Water Act?
    12·2 answers
  • The frequency of a lethal allele in a population is greatest when it is: Group of answer choices dominant manifested in infancy
    14·1 answer
  • THIS IS NOT A QUESTION. I JUST HAVE THE ANSWERS.
    14·1 answer
  • Which structure controls how much light passes through the specimen? (please help)
    14·2 answers
  • Which group includes ALL renewable resources?
    13·1 answer
  • What is the maximum number of white blood cells allowed in a leukocyte-reduced unit of red blood cells?
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!