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Major Elements in Biological Molecules: Proteins

By: HWC, Views: 6036

Proteins are chains of amino acids linked by peptide bonds. The 20 different amino acids used to make all proteins differ only in their side chains, and the properties of these side chains account for the great diversity of protein structure and function. Collagen is an example of how a prote...

Male Reproductive System - Testosterone

By: HWC, Views: 7201

• Under the influence of FSH and testosterone, Sertoli cells produce androgen-binding protein (ABP) that binds to testosterone and maintains high levels of the hormone near spermatogenic cells. • Testosterone stimulates the final stages of spermatogenesis. • In addition, testosterone is...

ACTH/Cortisol (glycogenolysis, protein catabolism, lipolysis and gluconeogenesis)

By: HWC, Views: 6502

• A decline in blood glucose concentration stimulates corticotropic cells in the anterior pituitary to produce adrenocorticotropic hormone (ACTH). • ACTH binds with cells in the zona fasciculata of the adrenal cortex. • Increased ACTH promotes the production of cortisol, the major gluco...

The life cycle of protein

By: HWC, Views: 6198

The life cycle of a typical protein begins with its synthesis on a ribosome. As the polypeptide chain grows, molecules of a chaperone protein bind along its length. This prevents misfolding of the nascent polypeptide. ATP binding causes chaperone release. For most proteins, the polypeptide th...

Peptide Bond Formation Animation

By: HWC, Views: 481

During protein synthesis, peptide bonds link amino acids together in the order specified by DNA instructions. In this case, the first two amino acids in the protein are methionine and alanine. Here are ball-and-stick models of these amino acids. Peptide bond formation is a type of condensatio...

Hormonal regulation of pregnancy - weeks 17 through 38

By: HWC, Views: 6885

• Estrogens increase uterine blood flow, maintaining the endometrium during pregnancy. • High levels of estrogen and progesterone inhibit the synthesis of milk. Progesterone inhibits myometrial contractions of the uterus to prevent premature birth. • Relaxin inhibits myometrial contract...

Molecules, Membrane Permeability and Structure

By: HWC, Views: 6133

Organisms are not isolated system at equilibrium and need to intake nutrients and electrolytes as remove wastes. Similarly Cells within an organism must also exchange compound by passing them through membrane. The permeability of a membrane is the rate of passive diffusion of molecules th...

hGH (protein synthesis, growth and development)

By: HWC, Views: 7096

• Increased GHRH, a hypothalamic releasing hormone stimulated by low blood glucose, physical exertion, and increased sympathetic stimulation, stimulates the production of human growth hormone (hGH) from the somatotrophic cells of the anterior pituitary. • Human growth hormone targets cartil...

Subunits of DNA And Semi Conservative Replication

By: HWC, Views: 3034

Adenine is a purine with a double-ring structure. In double-stranded DNA, adenine base-pairs with thymine. Guanine is a purine with a double-ring structure. In double-stranded DNA, guanine base-pairs with cytosine. Thymine is a pyrimidine with a single-ring structure. In double-stranded DNA, th...