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29 terms

Nailah Test Bank Ch 3

Human Health & Disease
STUDY
PLAY
genome
The sum total of all the genes contained in a cell's chromosomes is called its __________.
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?
An X-linked gene occurs only in females.
Which of the following statements is INCORRECT?
Spindle fibers pull chromatids apart.
Which of the following statements regarding mitosis is CORRECT?
Gametes
__________ are mature germ cells.
polar bodie
The daughter cells that are discarded during oogenesis are called __________
karyotype
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.
locus
Each gene occupies a specific site on the chromosome, called a(n) __________.
the alleles are different.
An individual is heterozygous for a gene if:
recessive
A __________ gene is one that produces an effect only in the homozygous state.
dominant
A __________ gene expresses itself in either the heterozygous or the homozygous state.
recessive
Genes carried on sex chromosomes are called __________ genes.
Mitochondria
__________ are sausage-shaped organelles that have small amounts of DNA that contain genes necessary for the synthesis of energy-generating proteins.
True
Chromosomes exist in pairs called homologous chromosomes. T/F
False
Human beings normally have 22 pairs of autosomes and 2 pairs of sex chromosomes. T/F
True
Genes exist in pairs and the members of each pair are located at corresponding sites (gene loci) on homologous chromosomes.
False
An X-linked gene occurs in only females. T/F
True
A female carrying a defective X-linked gene may not manifest any clinical abnormalities related to the defective gene. T/F
False
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
True
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
True
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
True
Genetic sex is determined by the composition of X and Y chromosomes. T/F
False
All mature somatic cells are able to divide through mitosis. T/F
False
In the first meiotic division, the chromosomes of the daughter cells are exact duplicates of those in the parent cell. T/F
True
Gametogenesis is the process by which gametes are formed. T/F
False
The process of spermatogenesis takes about 4 months, and sperm are being produced continually. T/F
True
During each reproductive cycle, several oocytes begin to mature, all of which are ovulated. T/F
False
Any one chromosome can carry multiple alleles at a given locus. 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?