Particles or molecules that are too big to fit through regular pores in the cell membrane, or have to big an electric charge, against the current of passive transport ( lower to higher ).
Answer:
A. The Cell Wall
Explanation:
The cell wall holds and supports the shape of the cell.
Answer:
In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells.
The three tenets to the cell theory are as described below: All living organisms are composed of one or more cells. The cell is the basic unit of structure and organization in organisms. Cells arise from pre-existing cells.
Explanation:
In biology, cell theory is the historic scientific theory, now universally accepted, that living organisms are made up of cells, that they are the basic structural/organizational unit of all organisms, and that all cells come from pre-existing cells. Cells are the basic unit of structure in all organisms and also the basic unit of reproduction. With continual improvements made to microscopes over time, magnification technology advanced enough to discover cells in the 17th century. This discovery is largely attributed to Robert Hooke, and began the scientific study of cells, also known as cell biology. Over a century later, many debates about cells began amongst scientists. Most of these debates involved the nature of cellular regeneration, and the idea of cells as a fundamental unit of life. Cell theory was eventually formulated in 1839.
Answer:
Cancer is a malignant cellular disorder caused by the abnormal growth of cells and has potential to spread to different parts of the body.
Explanation:
Cancer is a malignancy caused by uncontrolled cellular development due to genetic changes, such as mutations in DNA. These genetic changes can be inherited from the parents or arise as a result of errors that occur during cell division or due to DNA damage caused by certain environmental exposures such as the chemicals (tobacco smoke), radiation (ultraviolet rays from the sun), etc.
Normally, when human cells become old or damaged, they die and new cells take their place by controlled cell division. When cancer develops, some of the body cells begin to divide without stopping. Due to this uncontrolled cell division, more and more abnormal cells are formed. This causes the old or damaged cells to survive and new cells to form when they are not needed. These abnormal cells form growths called tumors, which have the ability to spread into surrounding tissues and travel to distant places in the body through the blood or the lymph system. This results in the formation of new tumors far from the original tumor.
Different types of cancer based on where it begins include carcinomas, sarcomas, leukemias, lymphomas, etc. Carcinomas include prostate cancer, breast cancer, lung cancer, colorectal cancer, etc. Leukemia is a cancer of the blood which begins when blood cells grow uncontrollably. Examples include acute and chronic lymphocytic leukemia, acute and chronic myeloid leukemia. Sarcomas develop in cartilage, bone, fat, muscles, nerves, etc and lymphoma starts in the lymphatic system (Hodgkin lymphoma and non-Hodgkin lymphoma).
Answer: To stay alive, to not starve, and to stay healthy.