<span>1. A neighbor is walking her dog to the park during her lunch break on a beautiful sunny day. explain how her skin is working to protect her from ultraviolet radiation due to intense sun exposure. be sure to discuss the specific structures and substances involved in this protection.
Ultraviolet light is dangerous as it could damage the skin. The skin will react by producing a dark granule called melanin which will absorb the light. Melanin is produced by the melanocyte in the epidermis. This will make the skin looks darker, especially people that frequently exposed to light.
2. mike is beginning his summer football camp today. the temperature high today is 85 degrees with moderate humidity. discuss two ways the skin's structures and functions are working to provide homeostasis and temperature regulation in this football player.
The sweat glands will produce sweat and sent it to the epidermis. This will make the epidermis wet. If the humidity is low, the water in epidermis will be evaporated and taking heat from the skin.
When the temperature is too high, the blood vessel in dermis part of the skin will dilate to make the body lose heat more.
3. this weekend you are going camping with your closest friends and family. thankfully, the layers of your skin will help protect you during this adventure. discuss at least two ways each layer, the epidermis and dermis, may protect you on this excursion.
When camping, you might need to interact with the wild plant directly. The epidermis is made of keratinized squamous cell that could protect the skin from any physical damage like a sharp branch. It also protects from bacteria and other microorganisms.
Wilderness has a fluctuating temperature. The dermis has a fat that will help insulating heat when faced with a cold environment. It also has sweat glands to reduce body heat in the hot environment.</span>
CD4 and CD 8 are molecules present on the surface of T cells where they interact with major histocompatibility (MHC) Molecules.
CD4 and CD8 improve T cell signalling by attaching to MHC class II (CD4) or MHC class I (CD8) molecules on APCs.
- The association of CD4 with MHC class II significantly decreases the number of antigenic peptides necessary for T cell activation (5) and significantly boosts cytokine output by helper T cells.
The MHC molecules' wide polymorphism is their distinguishing trait.
- This polymorphism is crucial for T cell antigen recognition.
- A T cell detects antigen as a peptide bound by a specific allelic variation of an MHC molecule and will not identify the identical peptide bound by other MHC molecules.
- This type of T cell activity is known as MHC limitation.
Hence, the correct answer is option C
Learn more about MHC here,
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Answer:
4.543 billion years
Explanation:
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Main components of plasma membrane are:
Plasma
Proteins
