Bio Test #7 Flashcards
CVS
sample of Chorion is obtained with a catheter inserted through the vagina; done at 8 weeks; cells can be cultured and grown
Nuchal Transluency Scan
scan (ultasound), non-invasive, look for presence of nuchal fluid, can indicate down syndrome, farther tests are recommended
trimosy
have an extra chromosome on a pair and has the number of the pair that is in
What are the examples of trimosies?
Trimosy 21 (down syndrome), Trisomy 18 (Edwards Syndrome)
What are trimosy of sex chromosomes?
Triple X Syndrome (female) Turner Syndrome (female) Kleinefelter Syndrome (female) Syndrome XYY (male)
What are risks of Amniocentesis and CVS?
it could result in termination of pregnancy
meiosis
a form of cell division that produces Gametes
gametes
general name for all sex cells
What is another name for meiosis?
reduction division
reduction division
a diploid nucleus (2n) forms an haploid nucleus
diploid
each cell has 2 sets of chromosomes for each pair (2n)
haploid
cell with only 1 chromosome for each pair (n)
What happens in meiosis?
a diploid cell generates 4 haploid cells different from the starting cell
What are the 2 main phases of meiosis?
Meiosis I
Meiosis II
Meiosis I
homologous chromosomes separate
Meiosis II
sister chromatids separate
Homologous Chromosomes
chromosomes that control the same characteristics; have same shape, length, and carry same genes, or same loci
What are the phases in Meiosis I?
prophase I
metaphase I
anaphase I
telophase I
What are the phases in Meiosis II?
prophase II
metaphase II
anaphase II
telophase II
What occurs in Prophase I?
nuclear membrane disappears, centrioles migrate to opposite poles, spindle starts forming & organizing, chromosomes finish condensing, spindle attaches to chromosomes at centromere (spindle attaches to only 1 side of chromosome)
What occurs in Metaphase I?
homologous chromosomes line up in the middle of the cell; spindle fibers move them to align them
What occurs in Anaphase I?
spindle fibers contract & homologous chromosomes are pulled apart
What occurs in Telophase I?
spindle fibers disappear, chromosome arrive at opposite poles; sometimes nuclear membrane reappear (sometimes it moves straight into Prophase II); chromosomes uncoil
What occurs in Prophase II?
nuclear envelope disappears; chromosomes recoil; spindle reforms; centrioles migrate to opposite poles (spindle each chromosomes on both sides)
What occurs in Metaphase II?
chromosomes alighn along equator of cell
What occurs in Anaphase II?
sisters chromatids spearate as the spindle contracts
What occurs in Telophase II?
chromosomes arrive at opposite poles; spindle disappears; nuclear membrane reappears; cells prepare for cytokinesis
What occurs in cytokinesis of meiosis?
cytoplasm is divided; there are now 4 qhaploid cells
genotype
the alleles possessed by an organism
phenotype
the characteristic observed in an organism
homozygous
having 2 identical alleles
heterozygous
having 2 different alleles
dominant
a trait that affects the phenotype whether it is in homozygous or heterozygous form
recessive
a trait that affects the phenotype only when it is in homozygous form
carrier
an individual that has the recessive allele of a gene but does not show any affect
co-dominance
both traits have an effect on phenotype
What are the two types of co-dominance?
co-dominant
incomplete dominance
co-dominant
both traits show up on the phenotype. one is not stronger than the other
incomplete dominance
the two traits blend & create an intermediate trait; generally creates extra phenotype
monohybrid crosses
two organisms are “crossed” (mating) and 1 trait is observed
test cross
breeding an unknown organism with a homozygous recessive
When is a trait sex-linked?
A trait is sex-linked when it is on the non-homologous region of the x-chromosomes
HOw many alleles will a male have in the non-homologous?
For any gene in this region a male will only have one allele
What are males genotype stipulations?
males cannot be carriers (it either has it or not); male will pass a trait to his daughters (not his sons); males with conditions always inherit them from their mothers
What are the 4 possible blood types?
A, B, AB, & 0
What blood type alleles are co-dominant with each other, but dominant over 0?
A & B
Antigen
protein on a surface of cell
characteristics of blood type A
has red blood cells with Antigen A and produces antibodies for blood type B
characteristics of blood type B
has antigen B on blood cells and produces antibodies for type A
characteristics of blood type AB
has both A & B antigens and does not produce antibodies
characteristics of blood type 0
does not have antigens, but produces both antibodies A & B
What blood type is a universal acceptor?
AB
What blood type is a universal donor?
0
Rh Factor
an antigen on blood cells
What are the characteristics of Rh-?
produces antibodies for Rh+, and can donate to Rh+ AND Rh- patients
What are the characteristics of Rh+?
does not produce antibodies for Rh. It can only donate to Rh+
pedigree
diagrams used by geneticists to collect info on human families.
