Chapter Three: Chromosomes Flashcards
the first human genetic disorder attributable to an abnormal number of chromosomes rather than a gene mutation
down syndrome
chromosomes transmit ___
genetic information
the ___ and ___ of genetic material is important for normal development
type and amount
genes reside in ___ in the ___
chromosomes
nucleus
the first observations of fertilization of nuclei occurred with ___ looking at ___
the naked eye
frog and sea urchin eggs and sperm
from observing the fusion of nuclei in frog and sea urchin eggs, scientists concluded that ___
something in the nucleus must contain hereditary material
in the 1880s, ___ and ___ were highly improved, and ___ could be visualized in the ___ and followed through ___
microscopy
staining techniques
chromosomes
nucleus
cell division
nuclear division that generates two daughter cells containing the same number and type of chromosomes as parent cell
mitosis
nuclear division that generates gametes (egg and sperm) containing half the number of chromosomes found in other cells
meiosis
body cells are ___and gametes are ___
diploid
haploid
diploid human cells have ___ chromosomes
46
haploid human cells have ___ chromosomes
23
the union of haploid gametes to produce diploid zygotes
fertilization
for each pair of chromosomes, zygotes have one from ___ and one from ___
mom
dad
how many cells are in an average adult human
100 trillion
to get from 1 to 100 trillion cells, ___ rounds of cell division are needed
60
metaphase chromosomes can be classified by ___, ___, and ___
size, banding pattern, and centromere position
location where sister chromatids are attached
centromere
centromere is in the middle of sister chromatids
metacentric chromosome
centromere is near one end of sister chromatids
Afrocentric chromosome
centromere is at the end of sister chromatids
telocentric chromosome
identical copies of a replicated chromosome
sister chromatids
chromosomes that contain the same set of genes, but can have different alleles for some genes
homologs/homologous chromosomes
chromosomes that carry completely unrelated sets of genes
nonhomologs/nonhmologous chromosomes
there are about ___ genes in the human genome, and about ___ genes per chromosome
20,000
1,000
___ of human DNA codes for something
1.5%
micrograph of stained chromosomes arranged in homologous pairs
karyotype
homologous chromosomes have the same ___, ___, and ___
size, shape (centromere location), and banding
the study of genetic anomalies
cytogenetics
every species has a characteristic number of ___
chromosomes
all chromosomes except X and Y
autosomes
unpaired X and Y
sex chromosomes
chromosomes are made of ___, ___, and ___
DNA, histone protein, and non-histone protein
a long thread primarily made of DNA with some protein scaffolding, what chromosomes usually exist as
chromatin
chromatin only duplicated and condenses into visible chromosomes when ___
cell division is about to occur
duplicated chromosomes (chromatids) are joined at the ___
centromere
a repeating pattern of cell growth and division
cell cycle
passes of the cell cycle
G1
S
G2
mitosis
cytokinesis