QUIZ 2: GENETICS: GOD'S PLAN OF INHERITANCE
Humans have _____ pairs of autosomes and and __ pair of sex chromosomes
22, 1
crossing over
A condition where non-sister chromatid of homologous chromosomes exchange genes.
chromatid
A double-stranded chromosome following replication attached by a centromere.
spindle fibers
A number of threadlike filaments formed between poles of the cell during cell division to which the centromeres of chromosomes attach; used to pull chromosomes apart and segregate them during anaphase.
hypothesis
A proposed explanation for an observation which has not been experimentally tested.
Y chromosome
A sex chromosome found in males; also a Y chro. present in males (one of each), hook-shaped chromosome
X chromosome
A sex chromosome; in human males ONLY one is present and in females two are present, rod-shaped chromosome
centromere
A structure on the chromosome that holds a pair of chromatids together during replication.
law
An explanation for events which is supported by the results on many experiments by a large number of investigations.
autosome
Any pair of chromosomes other than the sex chromosome.
diploid
Both members of a pair of chromosomes are present.
somatic cells
Cells with diploid chromosomes
tetrad
During metaphase I the two pairs of chromatids of the homologous pair of chromosomes comes together; crossing-over can occur at this time.
white eyed male, red eyes female F1: ________ F2: _________
F1: all red eyes F2: 3/4 red & 1/4 white eyes
haploid
One member of a pair of homologous chromosomes is present, such as in a gamete.
polar body
One of three small cells produced during oogenesis, each contain the haploid number of chromosomes.
oogenesis
Process of development of haploid female gametes.
chromosome theory
The behavior of chromosomes explains the inheritance of genes.
theory
The form of the hypothesis after it has been tested and found to be supported by the data collected as the explanation for the observation.
linkage
The presence of different genes on the same chromosome.
spermatogenesis
The production of haploid male gametes by the male parent
Prophase I
The stage in the first meiotic division where the doubled chromosomes become visible and nuclear membrane disappears.
Anaphase II
The stage in the second meiotic division where sister chromatids of a chromosome split and migrate to opposite poles.
Metaphase II
The stage in the second meiotic division where the chromatid pair lines up at the equator of the cell.
Telophase I
The stage of the first meiotic division where the cell divides into two cells each containing one member of each pair of homologous chromosomes.
Telophase II
The stage of the second meiotic division when the cell divides into two cells with each being haploid; these cells become the gametes.
If the sperm has an X chromosome it can only fertilize an egg with the
X chromosome (offspring will be XX or female)
autosomes
any of the numbered chromosomes (X & Y)
centromere
attaches the two chromatids, horizontal part of DNA
A gene is located on the
chromosome
chromatid
doubled chromosome attached in the midsection, the vertical part of DNA
color-blindness occurs in men ______________ times as often as in women
eight to ten
nondisjunction
failure of chromosomes to separate during crossing, resulting in extra or a shortage of chromosomes in the gamete, abnormal chromosome number (having 2 of something)
Metaphase I
first meiotic division stage, forming a tetrad, centromeres being attached to spindle fibers
Anaphase I
first meiotic division when the homo. chromosomes separate and move to opposite sides of the cell,
Drosophila melanogaster
fruit fly
sex-linked
genes that are located in the sex chromosome
chromatin
genetic material
W.S. Sutton
his theory that the Mendelian laws of inheritance could be applied to chromosomes
chromosomes that come in pairs
homologous chromosomes
If the sperm has a Y chromosome it will form
male (XY) offspring
C. B. Bridges
observed that once in two thousand flies, a vermillion-eyed daughter was produced
sex-chromosome
one of the chromosomes which determine the sex of the individual
T. H. Morgan
raised thousands of flies,
Spermatogenesis
reducing the chromosome number in both plant and animal cells
X^R is for
the red-eye condition, red-eyed female (X^RX^R)
the sex of the offspring is dependent upon
the sperm that produced the egg
X^r is for
the white-eye condition, white-eyed male (X^rY)
Sutton's chromosome theory
theory which identifies chromosomes as the carriers of genetic material
chromosomes in the vermillion female
two X chromosomes (XX) and a Y chromosome (XrXrY)
Very few hypotheses are proved
with a single or even a few experiments