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Mendel's pea plant, Pisum sativum experimental

By: HWC, Views: 4535

Mendel chose the garden pea plant, Pisum sativum, for experimental tests of his ideas about inheritance. Under normal circumstances, the garden pea plant is self-fertilizing. This cross-section shows the gamete-forming structures. Sperm-producing pollen grains form in the stamens. Eggs deve...

Pores and Ion Channels

By: HWC, Views: 5894

Transmembrane channels, also called membrane channels, are pores within a lipid bilayer. The channels can be formed by protein complexes that run across the membrane or by peptides. They may cross the cell membrane, connecting the cytosol, or cytoplasm, to the extracellular matrix. Membrane po...

Fetal development - Weeks 9 to 38

By: HWC, Views: 6771

Weeks 9-12 • Fetal development during the third month includes: • A large head, about 1/2 the length of the fetus. • Visible eyes and ears. • A detectable heartbeat. • Kidneys that form urine. • Gender identification. • Weak, undetectable body movements. • By the e...

Embryonic development - week 1 and 2

By: HWC, Views: 6695

The first through eighth weeks after fertilization are called the embryonic. Week 1 • Within a day, the zygote begins mitotic cell division (cleavage) forming blastomeres. By the 4th day, the blastomeres have formed a solid ball called a morula. • The morula enters uterine cavity ar...

Gonorrhea

By: Administrator, Views: 255

Gonorrhea, colloquially known as the clap, is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. Infection may involve the genitals, mouth, or rectum. Infected men may experience pain or burning with urination, discharge from the penis, or testicular pain. Infec...

Introduction to Diabetes

By: Administrator, Views: 9820

Hyposecretion or inadequate use of insulin may result in diabetes mellitus (DM). Hypersecretion of insulin may result in hyperinsulinism. Diabetes mellitus is the most common endocrine system disorder of childhood. Symptoms include: Polyuria Polydipsia Polyphagia Management of DM durin...

Introduction to Insulin

By: Administrator, Views: 10337

The islets of Langerhans are composed of three major types of cells: Alpha cells secrete glucagon, elevating blood sugar. Beta cells secrete insulin, maintaining normal blood sugar. Delta cells secrete somatostatin, which suppresses release of glucagon and insulin. Hyposecretion or inadequa...

Proteins Defined, Hierarchy & Composition of Cells

By: HWC, Views: 6164

Proteins are long chains of amino acids linked together by peptide bonds. Together with the other three biological macromolecules—carbohydrates, lipids, and nucleic acids—proteins are the building blocks of cells. Proteins are the most complex and abundant biological macromolecules in cel...

Multiple Sclerosis Animation

By: Administrator, Views: 9910

Multiple sclerosis (MS) is a demyelinating disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. This damage disrupts the ability of parts of the nervous system to communicate, resulting in a range of signs and symptoms, including physical, mental, and so...