Answer:
1-The respiratory system is the network of organs and tissues that help you breathe. It includes your airways, lungs and blood vessels. The muscles that power your lungs are also part of the respiratory system. These parts work together to move oxygen throughout the body and clean out waste gases like carbon dioxide.
2-The fluid represents the outermost layer of the alveolar surface that is directly exposed to air and thus to the environment. Alveolar fluid prevents desiccation of the epithelial cells and also functions as a physical protection barrier against inhaled particles and irritants.
3-The main function of surfactant is to lower the surface tension at the air/liquid interface within the alveoli of the lung. This is needed to lower the work of breathing and to prevent alveolar collapse at end-expiration.
4-The trachea (windpipe) conducts inhaled air into the lungs through its tubular branches, called bronchi. The bronchi then divide into smaller and smaller branches (bronchioles), finally becoming microscopic. The bronchioles eventually end in clusters of microscopic air sacs called alveoli.
5- i havent seen the video then how can i answer q5
sabre-toothed cats, cave bears, giant deer, etc..
In biochemistry, aligand is a substance that forms a complex with a biomolecule to serve abiological purpose. In protein-ligandbinding, the ligand is usually a molecule which produces a signal by binding to a site on a target protein.
Receptor mediated endocytosis is an endocytotic mechanism in which specific molecules are ingested into the cell. The specificity results from a receptor-ligand interaction. Receptors on the plasma membrane of the target tissue will specifically bind to ligands on the outside of the cell. An endocytotic process occurs and the ligand is ingested.
A very well studied example of receptor mediated endocytosis involves the metabolism of cholesterol.
Answer:
by binding to an ion channel
Explanation:
The neurotransmitters are chemical messengers capable of transmitting a signal from a given nerve cell across biological junctions named 'synapses' to target cells such as, for example, other nerve cells (e.g., neurons). In the cell, the neurotransmitters are transported into internal vesicles that are fused with the cell membrane to release them in the synaptic cleft by the process of exocytosis. Subsequently, the neurotransmitters bind to cell receptors localized on the postsynaptic membrane and thus trigger responses in postsynaptic cells. For example, glutamate is a neurotransmitter capable of exciting nerve cells by binding to a transmitter-gated ion channel called N-methyl-D-aspartate (NMDA).
