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Hormonal feedback loop components

By: HWC, Views: 6806

The endocrine system maintains many body conditions within normal limits with feedback loops. Each endocrine feedback loop maintains homeostasis using the following components: ■ Stimulus - a change in a body condition. ■ Production cell - an endocrine cell that produces a hormone after b...

HIV Infection: Viral life cycle

By: HWC, Views: 6037

The series of steps that HIV follows to multiply in the body. The process begins when HIV encounters a CD4 cell. The seven steps in the HIV life cycle are: 1) binding; 2) fusion; 3) reverse transcription; 4) integration; 5) replication; 6) assembly; and 7) budding. Many viruses f...

Simple Diffusion - gases and nonpolar compounds transport

By: HWC, Views: 7004

Gases and some molecules can diffuse through the phospholipid bilayer because they are small or non-polar. Oxygen gas. Carbon dioxide gas. Lipid based hormones. Plasma membranes are selectively permeable: The lipid bilayer is always permeable to small, nonpolar, uncharged molecules ...

Leukemia

By: Administrator, Views: 10185

Leukemia is a type of cancer that affects the blood and bone marrow. Leukemia begins in a cell in the bone marrow. The cell undergoes a change and becomes a type of leukemia cell. Once the marrow cell undergoes a leukemic change, the leukemia cells may grow and survive better than normal cells.

Transferring genes into plants Animation

By: HWC, Views: 4055

Researchers extract DNA from an organism that has a trait they want to introduce into a plant. The genetic donor can be a bacterial cell, a plant cell. or even an animal cell. The desired gene will be transferred into a plasmid, a small circle of bacterial DNA. The gene is cut out of th...

Introduction to Sickle Cell Anemia

By: Administrator, Views: 10098

Sickle cell anemia (sickle cell disease) is a disorder of the blood caused by an inherited abnormal hemoglobin (the oxygen-carrying protein within the red blood cells). The abnormal hemoglobin causes distorted (sickled appearing under a microscope) red blood cells.

Cell mediated immune response to a viral infection Animation

By: HWC, Views: 2707

Intracellular pathogens are the targets of cell-mediated immune response. The process begins when a virus infects a macrophage. Another macrophage engulfs the same virus or an antigen from it. In both cells, enzymes cleave the viral antigens into small bits. The fragments move to the cell sur...

Endocytosis -Types and Phagocytosis

By: HWC, Views: 6696

Endocytosis is the process by which a substance is brought inside a cell without having to pass through the cell membrane. It is the opposite of endocytosis, the process by which substances exit the cell without having to pass through the cell membrane. Exocytosis – membrane-enclosed secret...

Phases of mitosis

By: HWC, Views: 4645

Prophase is the first step in the mitotic process. During prophase, the chromosomes condense. The centrosomes begin to form a spindle and move into position on opposite sides of the cell. Sister chromatids are held together by a protein called cohesin at the centromere. Prometaphase is the sec...