Answer:
44
Explanation:
A somatic cell is diploid - it has 46 chromosomes. Half of these are from the mother, so there are 23 maternal chromosomes
A sex cell (gamete) is haploid - it has 23 chromosomes. There are (usually) two sex chromosomes in a diploid genome, either XX or XY, so there is one 1 in a haploid cell, giving a total of 22 autosomes
Barr bodies are inactive X chromosomes in a female somatic cell. This occurs to control dosage compensation (otherwise all the genes on the X in females would be expressed twice as much as they are in males). In a healthy female, there is normally one Barr body
A person with Kleinfelter's syndrome has two X chromosomes and one Y (XXY). They are biologically male, but have two X chromosomes. Therefore, one of these becomes a Barr body, as in females.
23 + 22 - 1 = 44
Pattern formation in plant embryos involves several morphogenetic steps, during which cell type specification, asymmetric cell division, and cell–cell communication play critical roles.
Answer:
d. Estrogen will bind to a receptor protein that enters the nucleus and activates specific genes.
Explanation:
Estrogens are small lipophilic molecules synthesized from cholesterol. This steroid hormone (estrogen) is able to directly enter into the cell nucleus to bind with their corresponding receptors. Subsequently, estrogen-receptor binding stimulates these receptors to form dimeric structures that bind to DNA and thus activate gene expression. Estrogen receptors interact with DNA and activate gene expression through zinc finger domains composed of four (4) cysteine residues surrounding a zinc atom.
Cells provide structure for the body. They take in nutrients and convert it to energy as well.
