An inactivated X chromosome that appears as a dense mass of chromatin applied to the nuclear membrane of a nondividing cell
What is a sex chromatin body?
Spindle fibers pull chromatids apart.
Which of the following statements regarding mitosis is CORRECT?
A __________ is an arrangement of chromosomes from a single cell arrangement in pairs in descending order according to size of the chromosomes and the positions of the centromeres.
__________ are sausage-shaped organelles that have small amounts of DNA that contain genes necessary for the synthesis of energy-generating proteins.
Genes exist in pairs and the members of each pair are located at corresponding sites (gene loci) on homologous chromosomes.
A female carrying a defective X-linked gene may not manifest any clinical abnormalities related to the defective gene. T/F
The Human Genome Project has identified all the genes on the human chromosomes and has also determined the function of each gene that has been identified. T/F
Minor variations in the sequence of the nucleotides within the same genes of different individuals (gene polymorphism) may lead to differences in the way the genes are expressed. T/F
A gene inherited from a female parent does not always have the same effect as the identical gene inherited from the male parent. T/F
In the first meiotic division, the chromosomes of the daughter cells are exact duplicates of those in the parent cell. T/F
The process of spermatogenesis takes about 4 months, and sperm are being produced continually. T/F
During each reproductive cycle, several oocytes begin to mature, all of which are ovulated. T/F
1. Four spermatozoa are produced from each precursor cell in spermatogenesis, but only one ovum is formed from each precursor cell in oogenesis.
2. Spermatogenesis occurs continually and is carried through to completion in about 2 months, meaning that there is always "fresh" sperm. In contrast, the oocytes are all formed before birth and remain in a prolonged prophase of the first meiotic division from fetal life until they are ovulated.
What are two major differences between spermatogenesis and oogenesis?