Answer:
Macrophages are part of your innate immune system, which is antigen-independent and does not require activation.
Explanation:
Macrophages phagocytize (internalize) all non-self pathogens it encounters. These do their job without activation. Other cells in the innate immune system include basophils, neutrophils, eosinophils (these cells are polymorphonuclear leukocytes), mast cells, and dendritic cells, which act as the bridge between your innate and adaptive immune system.
All of the other entities listed above are part of your adaptive immune system. The adaptive immune system is antigen-dependent and requires activation. This section of your immune system responds differently to different pathogens, and has the bonus of having immunologic memory, the ability to remember pathogens after infection and respond much quicker upon secondary and tertiary encounters.
Note: All lymphocyte types begin as naïve cells, which then differentiate into their fully matured form upon activation.
Helper T cells are a type of CD4+ T cell that has the job of activating B and T lymphocytes. There are two different types of T helper cells: Th1 and Th2. Th1 cells secrete the cytokine interferon-gamma (IFNγ), and is primarily involved with the stimulation and activation of cytotoxic T cells, while Th2 cells secrete a variety of cytokines and are responsible for activating and assisting with B cells to make antibodies. To make a long story short, Th cells interact with APC (Antigen Presenting Cells), specifically their Class II MHC (a group of genes that present exogenous proteins). The Th cells then proliferate and gain the ability to activate these APC cells and provide the necessary signals to activate B and T cells and make them proliferate and do their specific function.
Cell-wall inhibiting antimicrobial drugs be less effective on gram-negative bacteria compared to gram-positive bacteria because the outer membrane of the gram-negative bacteria inhibits penetration of the drug and the peptidoglycan found in gram-positive bacteria is structurally different from that in gram-negative bacteria.
Answer: Option B & C
<u>Explanation:</u>
Antimicrobial drugs are induced into a body to act on that particular selective bacterium which causes disease. When antimicrobial drugs are injected they act efficiently on the gram positive bacteria inhibiting the proliferation of the cells by acting on the cell wall so that cell multiplication doesn’t happen.
On the other hand it is hard to act on the gram-negative bacteria as it has a cell membrane that inhibits drug penetration into it. Both cell walls contain peptidoglycan but in the gram-positive is more assembled and layered while in the gram-negative it is just a thin layer. As gram-positive is thick layered it provides place for another molecule to attach to it but the thin layer in gram-negative inhibits it.
Answer:
1. Leads to mixing of genetic materials hence variation within species
2. Leads to offspring with hybrid viguor that tend to show high and adaptability to environmental conditions.
3. Variations due to sexual reproduction leads to improvement of species hence evolutionary changes that may bring about specialisation
Ans.
Steroids are defined as active organic bio-molecules, having four rings with a specific molecular configuration. Steroids play role in two major functions: as hormones or signaling molecules and as structural components of plasma membrane.
Examples of steroid hormones are estrogen, progesterone, and cortisol. Thus, the correct answer is 'option b). they serve as chemical messengers.'
