Chap 12 Inheritance patterns Flashcards
Meiosis separates homologous pairs of
chromosomes so that a gamete receives
only one.
Law of Segregation
Which homologue a zygote (offspring)
receives is random based on the
alignment of tetrads
Law of Independent Assortment
Which homologue a zygote (offspring)
receives is random based on the
alignment of tetrads DURING
Metaphase I
Meiosis separates homologous pairs of
chromosomes so that a gamete receives
only one DURING
Anaphase I
alternative versions of genes
Alleles
account for variations of inherited traits
Alleles
heterozygous for both characters
dihybrids
Two dominant alleles affect the phenotype in
separate, distinguishable way
Codominance
The phenotype of F1 hybrids is somewhere between the phenotypes
of the two parental varietie
Incomplete dominance
gene has multiple phenotypic
effects
pleiotropy
Seemingly unrelated character traits controlled by one
gene
pleiotropy
gene at one locus alters the
phenotypic expression of a gene at a second locus
epistasis
An additive effect
of two or more genes
on a single phenotype
polygenic
inheritance
Recessively inherited disorders show up only in
individuals
homozygous
heterozygous individuals who
carry the recessive allele but are phenotypically
normal
Carriers
Thick mucus builds up in some internal organs
Cystic Fibrosis
Abnormal absorption of nutrients, chronic bronchitis,
infections
Cystic Fibrosis
Cystic Fibrosis is
Pleiotropic
Insufficient oxygen exchange to tissues
Sickle-cell disease
Sickle-cell disease is
Incomplete and Codominance
more likely to produce homozygous recessive genotypes.
consanguineous
liquid that bathes the fetus is removed
and tested
amniocentesis
A sample of the placenta is removed and
tested
chorionic villus sampling
separates tetrad
Anaphase 1
segregates homologues
Cytokineisi
are genes on the same
chromosome
Linked genes
chromosome has hundreds or thousands of
Genes
Incomplete linkage is due to
Crosssing over
The mechanism that occasionally breaks the
physical connection between genes on the
same chromosome
Crossing over
The point of
disconnect
Chiasmata
The farther apart genes are on a chromosome the
more likely they are to be
Seperated during crossing over
Color blindness
– Duchene muscular dystrophy
– Hemophilia
ressesive alleles on x chromosome
Sex-linked disorders appear in males more
frequently than in females because
A single ressesive gene on the x will be expressed
One of the two X chromosomes in each cell is
_________during embryonic
developmen
randomly inactivated
Inactivated X becomes
Barr Body
Pairs of homologous chromosomes or sister chromatids
do not separate normally during meiosi
Non disgunction
Nondisjunction occurs during
Meiosisi
A - Meiotic ‘failure’ to separate ———-
chromosomes (during Anaphase I)
or
B -Meiotic ‘failure’ to separate sister chromatids
(during Anaphase II)
A , Homologoes B Sister Chromatids
Result of Nondisjunction
n organism with n = 2 chromosomes)
if zygote is ——- it has
three copies of a particular
chromosom
Trisomic
Down syndrome
Autosomes - Trisomy 21
s a condition in which there are more
than two complete sets of
chromosomes in an organis
Polyploidy
result of an extra
chromosome in a male,
producing XXY individuals
Klinefelter
Is the result of monosomy X,
producing an X
Turner Sydrome
Defects in — —— Prevent cells from making enough ATP
– Cause diseases affecting the muscular and
nervous system
Mitochondrial Genes
The phosphate is bonded
to the
5 end
The phosphate of one
nucleotide bonds to the
#3 carbon of the adjacent
nucleotide
backbone’ or ‘rails’ of
ladder formed by
Sugar Phosphate
connect purine to
pyrimidin
Hydrogen bonds
add nucleotides to the 3 end
of a growing strand
DNA polymerase
catalyzes
formation of covalent bond
DNA polymerase III
nucleotide inserted as a starting point is made of
RNA.
The primwer is Rna
RNA primer must be removed from strand by another enzyme
dna polymerese 1
The ends of the DNA molecules have
sequences called
Telomeres
These serve to postpone the erosion of genes
found at the ends of chromosomes
Telomeres
