Midterm 1 Current Troubles Flashcards
When the centromere of a chromosome is at the very end
Telocentric
When the centromere is very off Center but there is still parts on each side
Acrocentric
When a centromere is a little off center
Submetacentric
When a centromere is directly in the middle
Metacentric
What is the purpose of PAR
Behave like autosomes and recombine during meiosis
What is MSY
Non recombining section of DnA only on Y chromosome
What is SRY
Region that codes for testis determining factor
What is testis determining factor
What causes the formation of the testis which then release MIF hormones to degrade female organs and produce testosterone to develop male sex characteristics
Examples of age dependent expression
Male pattern baldness (androgenic alopecia), huntingtons disease
Example of sex limited gene expression
Hen or rooster feathering
Example of sex linked
Color blindness
Example of sex influenced
Male pattern baldness
Example of temp-dependent gene expression
Himalayan rabbits where the pigment producing enzyme works from 15-25 degrees but not at 35 or above
Why did Mendel study pea plants
They have short generation time, have different observable traits, controllable mating, cheap and available, grow fast
Example of environmental impact on phenotype
Hydrangea flowers blue in ph 5.5 or lower pink in 6.5 or higher or purple 5.5-6.5
Penetrance vs Expressivity
Penetrance is the proportion of individuals with a genotype who express the phenotype
Expressivity is the variation in expression between people with an allele
Penetrance can be
Complete or incomplete
Expressivity can be
Narrow or broad
What is incomplete linkage
Two genes typically passed on with one another due to being close together on the chromosome
What is unlinked genes
Genes far apart on a chromosome so are typically passed on independently of each other
What is incomplete linkage
Genes close enough to be passed together normally but far enough to be independent sometimes
What is a recombinant phenotype
A phenotype which arises due to crossing over
What is Duchenne muscular dystrophy the result of
Lack of seek linked gene for muscle protein called dystrophin (recessive)
Some sex linked disorders are
Hemophilia, duchenne muscular dystrophy, hypertrichosis
Is someone has lots of hair all over their body they have
Hypertricosis
Diseases caused by non-disjunction are
Down syndrome
Klinefelter syndrome (XXY)
Monopsony x (Turner’s syndrome)
Trisomy x
Jacob’s syndrome (XYY)
What is a diseases which results in structural alterations of a chromosome
Cri du chat
Cri du chat is a result of
A deletion of part of chromosome 5
Results in high pitch cat like cries
What is Marfans symptoms and name for the genetic thing this results from
Pleiotropy
Tall
Disproportionate arms and legs
Dislocation of lens of eye
Heart issues
Due to less of a protein which creates elastic fibrils being created
Difference between plieotropy and polygenic inheritance
One gene many traits
Many genes one trait
Intra versus intergenic interaction
Intragenic is interactions between alleles on the same gene locus producing non Mendelian results
Co dominance, incomplete dominance, multiple alleles
Intergenic interaction is between different gene loci
Epistasis or polygenic inheritance
Example of dominant epistasis
Squash color
Example of complimentary epistasis
Sweet pea flower color
The genes of sweet pea flower color code for
Anthocyanin
Duplicate dominant epi eg
Fruit shape of capsella bursa pastoris
Triangle or oval
Polymeric gene interaction epi eg
Squash fruit shape
A genome is
All the dna in a cell
A centrosome is the
Microtubule organizing center
G1 checkpoint looks for
Cell size, nutrients, social signals, undamaged dna
The G2 checkpoint checks if
Chromosomes are replicated, dna undamaged, active MPF present
M checkpoints info
Checkpoint 3 and 4
Between metaphase and anaphase
-apc active and that whole thing has happened
Between anaphase and telophase
- everything properly separated
When does cyclin synthesis begin
S phase
Tell me about the main internal signal we need to know
APC activates when kinetochore microtubules connect to all kinetochores, this causes the degradation of securin which is inhibiting seperase, now that seperase is uninhibited it separates chromatids by degrading cohesin proteins
What are the 3 examples of external signals
Growth factors
Density dependent inhibition
Anchorage dependence
What are the types of mutants
Weak, stronger, strongest
Difference between homomorphic and homogametic sex
Homomorphic refers to two morphologically identical chromosomes where homogametic sex refers to the production of alike sex chromosomes eg XX
What is hemizygous
Having one of a type of chromosome in an otherwise diploid organism
X and y in xy
What are all of the parts we need to know on a Y chromosome
PAR 1 and 2, MSY, SRY
What is a Barr body
A compacted inactive form of an X chromosome
When do Barr bodies form
Randomly in embryonic cells during x inactivation
What gene initiates x inactivation
XIST gene
How does XIST work
Produces copies of RNA which cover the chromosome and initiate X inactivation
A fertilized egg is called a
Diploid zygote
What is added to a karyotype to stop the cell cycle
Colchicine
What part of the cell cycle does colchicine stop
Meiosis so chromosomes most condensed
