Answer:
The DNA of the baby shares the DNA of both father and mother, and hence a cross link between an O type mother (Taylor) and an AB type father (Tyler) will produce children with blood groups A and B. It will be impossible to give birth to a child with blood group O.
Animal cell shrinks in a hypotonic solution as content in it moves from higher concentration to lower concentration
Hope this helps!
<span>To break a protein down into its amino acids you will need enzymes. Enzymes
are biological molecules (proteins) that act as catalysts and help
complex reactions occur everywhere in life. Let's say you ate a piece of
meat. Proteases would go to work and help break down the peptide bonds between the amino acids.
</span>
Answer: The model, which is air tight, represents the thorax, and air is only able to enter via the glass tube which represents the trachea.
As the rubber sheet is pulled down the volume of the jar increases, the pressure therefore decreases and air is drawn in through the glass tube inflating the balloons, which represent the lungs.
There are a number of similarities and differences between the model and the actual respiratory system.
Glass tube/tracheaAllows air to pass through, splits into twoGlass is rigid and inflexible unlike the cartilage bound trachea
Bell jar/chest cavityAir tightUnable to move, the ribs can move up and out to increase the volume of the thorax
Balloons/lungsCan inflate and deflate, are elastic like the alveoliThe balloons are large open spaces whereas the lungs are made up of millions of individual elastic alveoli
Rubber sheet/diaphragmCan be domed up to decrease the volume in the jarThe diaphragm only flattens, it is not pulled downwards like the rubber sheet.
Answer:
Explanation:
The transformation of a zygote into an embryo adheres both to nature and to nurture: not only genetics but also environment determines the outcome. This idea has assumed many forms. A territory in the early sea urchin blastula contains clones of founder cells, and each clone contributes exclusively to one territory (Cameron & Davidson, 1991). Both the lineage of a founder cell, i.e. its nature, and the position of a founder cell, which determines how it is nurtured, contribute to its fate. Fertilisation, the topic of the first Forum, fixes the genes; interblastomere communication, the topic here, regulates gene expression. Blastomeres communicate like any other cell – via ligand-receptor interactions and through gap junctions. Saxe and DeHaan review these mechanisms. The definition of ligands and receptors becomes broadened in this context, and cell adhesions as well as gap junctions enter into the story. In spite of these entanglements, it appears that nature uses the same sorts of mechanisms to get cells to specialise that she uses to keep them talking. Thus, neurons and glial cells signal to one another via glutamate receptors and gap junctions (Nedergaard, 1994). Likewise, we expect neurotransmitters (and neurotransmitter transporters) to help signal differentiation. The biophysicist may ask whether electrical properties also play a role, but that we reserve for another Forum. If gap junctions figure in development as fusion pores that pass small molecules and electrical signals between blastomeres, another parallel suggests itself. Brian Dale asked in the first Forum: How does a spermatozoon activate an oocyte? This question, which concerns gamete communication, has produced two schools of thought and remains controversial (Shilling et al., 1994). Do sperm activate oocytes via contact-mediated mechanisms or through fusionmediated mechanisms? Or do both mechanisms occur, as they appear to in development?
