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Sister chromatids of a metaphase chromosome animation

By: HWC, Views: 4717

At metaphase, the chromosomes are duplicated and are at their most condensed. In each chromosome. two identical sister chromatids are held together at a constricted region called the centromere. When a chromosome is condensed, interactions among chromosomal proteins keep loops of DNA tightly ...

Cardiac conductile cells

By: HWC, Views: 6896

• In order for the heart to function properly, all of its cells must contract in a specific sequence. This sequence is determined by a pathway known as the conduction system. • Cardiac muscle cells have two attributes that enable the conduction system to work: • Connective. Action pot...

Facilitated Diffusion - Glucose transport

By: HWC, Views: 6906

Transmembrane proteins help solutes that are too polar or too highly charged move through the lipid bilayer The processes involved are: Channel mediated facilitated diffusion Carrier mediated facilitated diffusion In facilitated diffusion, molecules only move with the aid of a protein i...

Buffers definition and the role of buffer in the body

By: HWC, Views: 6809

■ Too many H+ break hydrogen bonds and a protein comes apart. ■ Buffers react with excess H+ to protect proteins from breaking down. ■ Buffers consist of weak acid plus anions of that weak acid. This solution contains: • hydrogen ions • weak acid (H2CO3) • anions of we...

Plant Defense Mechanisms from Pathogens

By: HWC, Views: 6101

Plants and pathogens have coevolved such that pathogens can recognize plants by the sugars, or other molecules, they produce. Plants, in turn, can recognize pathogens by the molecules they produce. The ability to recognize pathogens allows plants to activate defense systems that can prevent wides...

Dietary Cholesterol & LDL

By: HWC, Views: 6046

LDL comprises 60–70% of total blood lipoproteins and is responsible for carrying cholesterol particles throughout your body. Having a lot of cholesterol carried by LDL lipoproteins is associated with an increased risk of heart disease. In fact, the higher the level, the greater the risk. ...

Muscle cell structures - actin, myosin and titin filaments

By: HWC, Views: 6780

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...

The pH scale - Strong acids and Weak acids

By: HWC, Views: 6720

The pH scale • Expresses concentration of H+. • range: 0-14. • 7 is neutral. • Less 7 is acid. • greater 7 is basic (alkaline). Strong acids - role in the body ■ In strong acids all molecules dissociate. ■ HC1 is highly acidic and found only in the stomach. • H...

Pores and Ion Channels

By: HWC, Views: 5885

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...