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Nucleic acid digestion - brush border enzymes, end products & transport mechanism

By: HWC, Views: 7510

• Further digestion occurs at the microvilli (brush border) of the epithelial cells of the villi in the small intestine. • Two brush border enzymes complete nucleic acid digestion: • Phosphatases, which catalyze the cleavage of a phosphate to form a nucleoside (nitrogenous base and pent...

DNA close up Animation

By: HWC, Views: 1657

A section from a DNA double helix The backbone of each DNA strand consists of alternating deoxyribose sugars and phosphate groups. The two strands run in opposite directions. One runs from the 5' to 3' direction, the other in the 3' to 5' direction. Think of the deoxyribose units o...

What are Strong & Weak Acids and How they're different?

By: HWC, Views: 6516

Let's consider the changes that take place when hydrogen chloride, HCI, is added to water. You will need to recognize space-filling models of HCI molecules, hydronium ions (H30+), chloride ions (C11, and water molecules (H20). They are shown at the right. When HC1 molecules dissolve in water, ...

The Lac Operon in E. Coli

By: Administrator, Views: 11790

The lac operon (lactose operon) is an operon required for the transport and metabolism of lactose in Escherichia coli and many other enteric bacteria. Although glucose is the preferred carbon source for most bacteria, the lac operon allows for the effective digestion of lactose when glucose is no...

Hydrogen bonds vs. Ionic bond

By: HWC, Views: 6510

The slight positive charge of a hydrogen atom in a water molecule can attract an atom with a slight negative charge, such as the nitrogen in a molecule of ammonia. This forms a hydrogen bond between the two atoms. Hydrogen bonds join the two strands of a DNA molecule. Although hydrogen bo...

Hormonal regulation of pregnancy - weeks 17 through 38

By: HWC, Views: 7975

• 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...

Bone cells and tissues - tissue composition and cells

By: HWC, Views: 8556

Bone tissue consists of bone cells secreting bone matrix. • The extracellular bone matrix is a connective tissue that is hard, yet flexible. • Collagen fibers provide flexibility. • Inorganic mineral salts (primarily calcium phosphate, or hydroxyapatite) provide hardness. • Togethe...

hGH, Thyroid hormones & Aldosterone

By: HWC, Views: 7753

Glycogenolysis and lipolysis • Stressors stimulate production of a hypothalamic releasing hormone (GHRH). • The releasing hormone stimulates somatotroph cells of anterior pituitary to secrete human growth hormone. • Human growth hormone targets liver cells and fat cells. hGH (glycog...

Replication of DNA and Chromosomes/ How do cells replicate their DNA? (Animation) no Audio

By: HWC, Views: 7463

DNA replication in E. coil begins at a site called oriC where a replication bubble forms. At either end of this bubble is a replication fork. Since DNA polymerase Ill can read its DNA template strand only in the 3' to 5' direction this means that one strand (leading) can be read continuously b...