The structure of a typical antibody molecule
Antibodies are the secreted form of the B-cell receptor. An antibody is identical to the B-cell receptor of the cell that secretes it except for a small portion of the C-terminus of the heavy-chain constant region. In the case of the B-cell receptor the C-terminus is a hydrophobic membrane-anchoring sequence, and in the case of antibody it is a hydrophilic sequence that allows secretion. Since they are soluble, and secreted in large quantities, antibodies are easily obtainable and easily studied. For this reason, most of what we know about the B-cell receptor comes from the study of antibodies.
Antibody molecules are roughly Y-shaped molecules consisting of three equal-sized portions, loosely connected by a flexible tether. Three schematic representations of antibody structure, which has been determined by X-ray crystallography, are shown in Fig. 3.1. The aim of this part of the chapter is to explain how this structure is formed and how it allows antibody molecules to carry out their dual tasks—binding on the one hand to a wide variety of antigens, and on the other hand to a limited number of effector molecules and cells. As we will see, each of these tasks is carried out by separable parts of the molecule. The two arms of the Y end in regions that vary between different antibody molecules, the V regions. These are involved in antigen binding, whereas the stem of the Y, or the C region, is far less variable and is the part that interacts with effector cells and molecules.
Answer:
<h2>
Interphase : divided into three phases, i) G1 phase, ii) S phase and iii) G2 phase.</h2><h2>Mitotic phase: i) prophase, ii) metaphase, iii) anaphase and v) telophase.</h2>
Explanation:
interphase : divided into three phases, i) G1 phase, ii) S phase and iii) G2 phase.
G1 phase: cell decide whether to divide or not and prepare itself for replication of DNA and arrange replication machinery. otherwise it goes to G 0 phase.
S phase: DNA replication occurs in this phase.
G2 phase: cell duplicates all their contents and prepares for mitotic phase.
Mitotic phase:
i) prophase- chromosome condensation occurs,
ii) metaphase - chromosome arranges in meta-plate and spindle binds to each chromosomes at centromere.
iii) anaphase- chromosome separates from sister chromatids.
iv) telophase- chromosome moves to each ends and formation of nuclear membrane begins.
cytokinesis: there is division of cytoplasm and forming two daughter cells.
Answer:
I wanna say b
Explanation:
since the word "earth" is said twice
In recent molecular genetic studies, genes associated with the neurotransmitter Dopamine have been linked to ADHD.
ADHD stands for Attention Deficit Hyperactivity Disorder. People with ADHD have a hard time focusing on tasks. Scientists have found that the low levels of dopamine in the brain are associated with the symptoms of ADHD. It is because the neurons in the brain have a high amount of protein called the dopamine transporters. These proteins block the dopamine from passing between the neurons. This decreases the effect of dopamine.
Answer:
It is an environmental pollutant. It might disrupt sexual reproduction in marine organisms.
Explanation:
It is a pathogen. It might disrupt growth and development in marine organisms. - false. Estrogen and similar synthetic compounds cannot be classified as a pathogen. Pathogens are microorganisms that cause disease. Estrogen is a hormone, not a pathogen.
It is an environmental pollutant. It might disrupt sexual reproduction in marine organisms. - true. In this case, synthetic chemicals that mimic estrogen function have leaked into the <em>environment</em>, meaning it is an environmental pollutant. Because estrogen is a sex hormone that exists in all vertebrates (not just humans), its artificial existence in the environment will cause effects in marine life when exposed to it. This could interfere with sexual reproduction.
It is a genetic factor. It might be toxic to marine organisms and lead to death, changing the population structure - false. Although esrtogen can impact gene expression, it will not be considered a genetic factor. It would also unlikely be toxic to marine life, as they also possess estrogen.
It is both a pathogen and an environmental pollutant. It might lead to food shortages - false. Estrogen cannot be classified as a pathogen.
