Answer:
E. are found in nitrogen-fixing cyanobacteria AND are used to protect nitrogenase.
Explanation:
Heterocysts are specialized cellular compartments found in nitrogen fixing cyanobacteria. They provide the ideal anaerobic environment for nitrogen fixation since nitrogenase enzyme cant work in presence of oxygen. Hence, in a cyanobacteria both the oxygen requiring photosynthesis process and the oxygen sensitive nitrogen fixation process takes place simultaneously.
Heterocysts have an additional cell wall made of glycolipid that provides a hydrophobic barrier to oxygen. They are involved in production of nitrogenase and other proteins that are required for nitrogen fixation. They also degrade photosystem II which is responsible for producing oxygen and produce proteins which remove any remaining oxygen.
Answer:
The question lacks options, the options are:
A) All cells contain a nucleus.
B) All cells come from other living cells
C) All living organisms are made of one or more cells.
D) Cells are the basic unit of structure and function of all living things.
The answer is A
Explanation:
In 1830's, three scientists named; Mattias Schleiden, Theodor Schwann and Rudolph Virchow contributed to describing the basic properties of the cell, which they proposed in their so named CELL THEORY. This widely accepted cell theory has three components:
All living organisms are made up of one or more cells.
Cells are the basic and fundamental unit of life
All existing cells come from cells that have previously existed.
It was not proposed that all cells have a nucleus
An example of ATMOSPHERE affecting the BIOSPHERE. Atmosphere because it is AIR pollution and biosphere because it causes LUNG TISSUE damage.
Answer:
Mitosis is the process in which the nucleus of a eukaryotic cell divides. During this process, sister chromatids separate from each other and move to opposite poles of the cell. This happens in four phases, called prophase, metaphase, anaphase, and telophase.
Explanation:
