Answer:
False.
Explanation:
Among the organic macromolecules , enzymes belong in the category of proteins. Proteins are distinct from carbohydrates, nucleic acids and lipids in that a protein is made of amino acids. Amino acids link together into a chain that can fold into a three-dimensional shape.
Answer:
peptide and protein hormone
Explanation:
Peptide and protein hormones are composed of amino acids with latter being longer in length. They are synthesized in rough endoplasmic reticulum where they undergo various modifications like N terminal signal sequence removal and glycosylation to form prohormones. These prohormones are sent to golgi apparatus where they are packaged in secretory vesicles. In response to a stimulus the appropriate vesicle is released via exocytosis.
They can show regulated secretion where the hormone is stored in vesicles for a long time and then released in large amount in bursts for a proper stimulus. Sometimes they also show constitutive secretion where they are released slowly and steadily by the vesicles.
Answer:
The three-chambered hearts of amphibians and nonbird reptiles are facultative, allowing variation in blood flow through the heart.
Explanation:
In Anatomy, cardiac cycle can be defined as a complete heartbeat of the human heart which comprises of sequential alternating contraction and relaxation of the atria and ventricles, therefore causing blood to flow unidirectionally (one direction) throughout the human body.
Generally, the cardiac cycle occurs in two (2) stages;
I. Diastole : in this stage, the ventricles is relaxed and would be filled with blood.
II. Systole: at this stage, the muscles contracts and thus, allow blood to be pushed through the atria.
All amphibians and reptiles except for crocodiles (having four-chambered heart) have three-chambered hearts, which typically comprises of a partially divided ventricle and two atria.
Hence, the correct statement about the three-chambered hearts of amphibians and nonbird reptiles is that, the three-chambered hearts of amphibians and nonbird reptiles are facultative, allowing variation in blood flow through the heart due to the partially divided ventricle.
Answer:
a process where green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water
Explanation:
hope this helps
Answer:
The answer is <em><u>D.
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Explanation:
Viruses can evade the processing and presentation of antigens, for example by interfering with the expression of MHC class I proteins, although this increases their susceptibility to be detected by natural killer cells (NK). However, some members of the herpesvirus, papillomavirus, retrovirus, poxvirus and flavivirus families have also developed strategies to escape the attack of NK cells and promote their survival, inhibiting cell apoptosis. Finally, some pathogens often change surface antigens frequently, as in the case of influenza viruses (orthomyxovirus).
The human immunodeficiency virus (HIV) affects CD4 + T cells and degrades the host's ability to counterattack with a strong cell-mediated immune response. There are so many tactics of immune evasion used by HIV, which have so far hindered the development of an effective vaccine.
