Search results for: 'food molecules'

Watch Later 2:59

Bond in biological molecules (Ionic, Covalent and Hydrogen bonds)/ How atoms bond?

By: HWC, Views: 3982

Sodium atoms and chloride atoms have unfilled orbitals in their outer shells. The lone electron in the outermost shell of a sodium atom can be pulled or knocked out. This ionizes the atom. It is now a positively charged sodium ion. A chlorine atom has an electron vacancy in its outer shell and...

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What are the Parts of a Plant Cell?

By: HWC, Views: 5690

Every chloroplast in a plant cell is packed with stacks of flattened sacs called thylakoids. The thylakoid membranes contain chlorophyll, as well as most of the other components required for the light reactions of photosynthesis. The chlorophyll-containing structures within the membranes are c...

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How does an animal choose what food to eat?

By: HWC, Views: 6130

One might assume that natural selection has influenced the foraging behaviors of animals, and that most animals forage efficiently, spending the least energy to gain the most nutrients. This is the underlying assumption of optimality modeling, a scientific approach to studying foraging behavior. ...

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Contraction cycle of a sarcomere

By: HWC, Views: 7163

• A single nervous signal releases Ca2+ ions into the sarcoplasm and initiates the contraction cycle. step 1. ATP hydrolysis • ATP provides the to move myosin molecules back into the energized configuration necessary to perform the power stroke. Step 2. Crossbridge attachment • Myosin...

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Hydrogen bonds - role in the body

By: HWC, Views: 7010

A hydrogen bond is the electromagnetic attraction between polar molecules in which hydrogen is bound to a larger atom, such as oxygen or nitrogen. This is not a sharing of electrons, as in a covalent bond. Instead, this is an attraction between the positive and negative poles of charged atoms. ...

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Type of Cell Junctions - Desmosome, Hemidesmosomes and Gap Junctions

By: HWC, Views: 6999

Cell Junctions: Cell junctions are found in some multi-cellular organisms. They exist of complexes and are found between cells and between cells and other structures. The junctions provide a way for cells to connect and exchange signals. What are tight junctions, desmosomes, and gap junctions...

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Barriers - eye structures, digestive mucosa, respiratory mucosa & genitourinary mucosa

By: HWC, Views: 6879

• Eyebrows, eyelids, eyelashes and conjunctiva serve to trap microbes preventing their invasion. • Tearing (lacrimation) is a protective mechanism that washes away microbes that attempt to enter the eyes. • Salts, mucus, and lysozymes in tears neutralize substances and bacteria. �...

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

By: HWC, Views: 6554

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...

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Role of transport in a cell

By: HWC, Views: 6804

Transport of chemicals across the plasma membrane provides the following functions: Importing molecules for the maintenance of metabolic processes. Exporting chemicals produced by the cell or waste products. Communicating with other cells, allowing for the generation and conduction of a...

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