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Mendel's Principles of Inheritance (Father of Genetics)

By: HWC, Views: 7339

Gregory Johann Mendel, a monk living in the mid-1800's, is known as the "Father of Genetics" for his experiments with pea plants in the abbey garden. These experiments led him to deduce the fundamental law of genetics. Mendel was an Augustinian friar who entered, in 1843, the Abbey of St. Thom...

Coaductile pathway, Timing of contraction signal & Conduction system and ECG

By: HWC, Views: 7926

• When the system is healthy, the signal to contract the entire conduction system originates in the SA node - known as the heart's pacemaker. • The SA node triggers contraction because it depolarizes at a faster rate than other parts of the conduction system. • The wave of excitation fr...

The primary factors that affect circulation - MABP, CO and SVR

By: HWC, Views: 8047

Introduction Blood flow is determined by the relative intensities of factors that drive and resist moving blood. • Cardiac output (CO) equals the mean arterial blood pressure (MABP, a driving force) divided by systemic vascular resistance (SVR, a resisting force). • Hormones and the cen...

Darwin's Observation (Fossils, Galapagos Islands & Africa ) and Natural Selection (Adaptive Traits)

By: HWC, Views: 7615

Along Darwin's voyage, he made many observations. Each one added to his understanding of how organisms change over time. Darwin was already familiar with fossils and knew that many fossils were very different from living organisms. But, also there were some fossils that were very similar to li...

Diversity of Living Creatures - Charles Darwin & the Beagle's Voyage

By: HWC, Views: 7463

As we look around at the living creatures on Earth, we see a great amount of diversity. In some cases, the differences are quite noticeable, like the differences between plants and animals. Some differences are not as easy to see, like the differences between two species of lizard. How did all...

Predator- prey competition and symbiosis

By: HWC, Views: 7526

Predator-prey relationships occur when one species, the predator, kills and eats an organism of another species, the prey. This graph shows the cyclical nature of predator-prey relationships, in this case among populations of Canada lynx and snowshoe rabbits. If predation is without some li...

Erythropoietin (EPO)

By: HWC, Views: 7223

■ Secreted by kidney cells when blood oxygen is low. ■ Targets cells in red bone marrow that will become red blood cells. ■ Promotes increased numbers of mature red blood cells. ■ More mature red blood cells carry more oxygen so blood oxygen level is restored to normal.

T cell receptors

By: HWC, Views: 7402

• T cells are responsible for cell-mediated immunity. • Each T cell contains a unique form of T cell receptor (TCR) on its membrane. • These T cell receptors are produced through a process of genetic recombination which is able to produce millions of different variations. • Each T ce...

Cytotoxic T cell receptors, activation, proliferation, differentiation & action

By: HWC, Views: 8034

• Most cells which have CD8 on their surface become cytotoxic T cells (Tc cells). • CD8 T cells recognize a foreign antigen when it is presented in conjunction with the protein, MHC-I. • Nearly all nucleated cells in the body express MHC-I molecules. • T cells that recognize self-pe...