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Mitosis step-by-step

By: HWC, Views: 5737

During interphase, the chromosomes will be duplicated in preparation for mitosis, which divides the chromosomes, and cytokinesis, which divides the cell's cytoplasm. In early prophase, the duplicated chromosomes begin to condense. Each chromosome consists of two sister chromatids joined at the...

Second Messengers in the Inositol-lipid Signaling Pathway

By: HWC, Views: 7017

Extracellular signals produce specific responses in target cells through the action of intracellular second messengers. Here, we focus on three second messengers, IP3, DAG, and Ca2+, all involved in the inositol-lipid signaling pathway. A hormone-receptor signal on the cell surface leads to the a...

Introduction to C-Section

By: Administrator, Views: 334

Caesarean section, also known as C-section, or caesarean delivery, is the use of surgery to deliver babies. A caesarean section is often necessary when a vaginal delivery would put the baby or mother at risk. This may include obstructed labor, twin pregnancy, high blood pressure in the mother, br...

Bone elongation - processes at the epiphyseal plate

By: HWC, Views: 7995

• Interstitial lengthening occurs in only certain bones, primarily those of the appendages. • Such lengthening takes place at the epiphyseal plate, a layer of hyaline cartilage in the metaphysis of a growing bone. 1. Zone of resting cartilage. • Consisting of a hyaline cartilage pa...

Fermentation - When Oxygen Is Absent, Pyruvate to Lactate & Pyruvate to Ethanol

By: HWC, Views: 7305

Pyruvate is the end product of glycolysis. If oxygen is present, pyruvate enters the mitochondrion where further energy yielding reactions of the Krebs cycle will take place. However, if oxygen is not present, pyruvate will enter a pathway called fermentation. This pathway regenerates NAD+ fro...

Lactation and Breast Feeding

By: HWC, Views: 8550

Regulation of lactation - breast preparation • Pregnancy hormones trigger breast changes to prepare for feeding the new baby. • The amount of the hormone prolactin, essential to the initiation of lactation, increases steadily throughout pregnancy. • However, high levels of both estroge...

Endocytosis - pinocytosis, receptor mediated and Transcytosis

By: HWC, Views: 7626

Pinocytosis is the process in which a cell "drinks" a tiny droplet Of extracellular fluid, including its solutes. Pinocytosis (Cell Drinking) is the process by which the cell takes in fluids (as well as any small molecules dissolved in those fluids). • The plasma membrane folds inward to...

Stages of Mitosis - Prophase, Prometaphase, Metaphase, Anaphase & Telophase

By: HWC, Views: 7449

In mitosis, the nucleus divides to produce two nuclei that are genetically identical to each other and to the parent nucleus. To prepare for division, the DNA replicates in the preceding interphase. Although the chromosomes are not yet compacted and visible as discrete bodies, we illustrate them ...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 7895

Once the muscle cell has been excited it will contract. • A muscle action potential will trigger the release Of Ca2+ ions into the sarcoplasm. • The Ca2+ ions bind to the regulatory proteins and trigger contraction. • Within skeletal muscle cells are structures that provide the ability...