Bio Unit 4 Flashcards
Apoptosis
Uses Signals from checkpoint to commit programmed cell death; form apoptotic bodies cell shrinks with no inflammation
Necrosis
Accidental cell death; cell swells and ruptures releasing molecules
G1 Phase
cell growth- allows for rest period before S phase
S phase
DNA Synthesis
G2 Phase
DNA Repair and Growth
MPF
M phase promoting factor- CDK(kinase) binds to cyclin making it inactive but it begins to accumulate- CDK phosprylated at 2 sites inhibiting it- CDK dephosphorlated at inhibitory site creating active complex
Interphase
growth and metabolism
Prophase
chromosomes decondense and spindle apparats forms
Prometaphase
nuclear envelope breaks down and spindles connect to centromeres
Metaphase
chromosomes line up in the middle of the cell along the metaphase plate
Anaphase
Tension on microtubules pulls chromatids apart to opposite sides of the cell
Telophase
Nuclear envelopes reform and chromosome decondenses
Cytokinesis
cell splits into two daughter cells
M phase- Mitosis and Cytokinesis
Cell division
Kinetochore
protein complex associated with the DNA regions where copies of chromosomes are joined
Centromere
where chromosomes connect and spindle fibers attach
Microtubules
cytoskeletal component that separates sister chromatids during anaphase
What is separated in Meiosis 1?
Homologous Chromosomes
What is separated in Meiosis 2?
Sister Chromatids
Proto-oncogenes
normal gene that promotes growth and proliferation of health cells
Oncogenes
mutated gene that drives cancer growth and proliferation
Tumor Supressor
prevent division of cancer cells
Aneuploidy
Cell has abnormal number of cells
Crossing over
homologous chromosomes come together and exchange parts of themselves- creates diversity by making unique chromosomes
independent assortment
chromosomes randomly align and split into separate daughter cells so that they receive a random assortment of chromosomes from parents
random fertilization
alleles combine randomly
Growth Factor Checkpoint
signaling molecules to near by cells to grow
Ras
growth factor bunds and turns on cyclin D and inhibitors
E2F/Rb
transition form G1 to S; turn on Cyclin E to drive replication; binds to cage(Rb)
E2F
turns on genes for S phase
Ras- Growth Factor
Ras turns on Cyk/Cydk–> Phosphorylates Rb–> E2F released –> genes turned on
Rb
Acts as cage for E2F; releases E2F Cyk/Cdk phosphorylates it
P53
“Guardian of Genome”; take signals and transfers into cellular action; fix or die(self destruct)
Most commonly mutated in cancer cells…
P53
How does P53 work
turned on by DNA damage–> phosphorylation–> drives expression of Cdk/Cfk inhibitor –> prevents cell cycle–>MDM2 binds and destroys P53
Diploid
2 sets of chromosome
Haploid
1 set of chromosome
Ploidy
number of complete chromosome sets
polyploidy
many sets of chromosomes
autosomal chromosome
non sex chromosome
sex chromosome
produce sex/gender
karyotype
appearance of condensed chromosome; help determine abnormalities
homologous chromosome
same size/shape but not identical
non-homologous
not the same size/shape
sister chromatid
identical with the same alleles
gene
segment of DNA on chromosome that influences trait
allele
certain version of a gene
nondisjunction
chromosomes don’t split; one cell has to many chromosomes; worse in Meiosis 1
disjunction
chromosomes accurately seperate
trisomy
extra chromosome
monosomy
missing chromosome
Trisomy 21
Down syndrome- Autosomal
Trisomy 18
Edward Syndrome- Autosomal
Trisomy 13
Patau Syndrome- Autosomal
Turner Syndrome
monosomy(X,0)
Kinefelter Syndrome
XXY- trisomy- often undiagnosed
Mosaicism
partial aneuploidy- mitotic errors later in development that don’t affect all cells
Reasons for Nondisjunction
proteins that hold chromosomes together fail; microtubules don’t connect or operate properly
purifying selection
eliminate unfavorable mutations
changing environment
diversity of genes allow to survive changing enviorment
chromosomal theory of inheritance
genes on chromosome and how they move determines genotype
blending inheritance
parents traits blend together
acquired characters
acquired traits are passed to offspring
Why was Mendel lucky?
picked peas
polymorphic traits
result from more than one gene/allele
true/pure breeding
homozygous for genes
monohybrid cross
cross between homozygous but for different alleles
Reciprocal Cross
switch which trait came from mom vs dad; disproved
Particulate Inheritance
particles(chromosomes) that aren’t blended/modified. maintain integrity though generations
Principle of segregation
particles must seperate
dihybrid cross
mate between true breeding at two alleles
sex-linked genes
expressed on X and Y chromosome; phenotype depends on sex bc homologous not identical
hemizygous
only carries one; not on y
linkage
tendency of genes to be inherited together; close together and stay together during crossing over
loci
specific position on chromosome
P arm
short arm
Q arm
long arm
multiple allelism
more than two common alleles of the same gene
Complete Dominance
one allele is completely dominant over all others
Codominant
two versions of gene/allele are expressed equal; patched
Incomplete Dominance
phenotype is a blend of the parents
monogenic
one gene; one trait
pleiotropic
gene influences multiple traits; causes issues
polygenic
multiple genes influence single trait
discrete traits
grouped- eye color
quantitive trait
fall on continuum- height
mode of transmission
inheritance observed as a trait; inheritance influences traits
True or False: the M phase checkpoint is actually two checkpoints at the transition between metaphase and anaphase and at the transition between anaphase and telophase.
True
The extrinsic apoptosis pathway initiates apoptosis via _______ that initiates a signal cascade that eventually activates caspases.
binding to death receptors
Cells that fail the G1 checkpoint may
enter G0 phase or programmed death
G0
where cells go if they don’t pass G1 checkpoint to rest
Sub phases of interphase
G1; S; G2
Procaspases are inactive proteolytic enzymes that are activated by cleavage. This type of posttranslational modification is critical because
its irreversible
True or False: the nuclear envelope breaks down in metaphase and reforms in telophase.
false
The cyclin dependent kinase domain of MPF
phosphorylates mitosis proteins to promote entry into M phase
True or False: Cytokinesis is a part of M phase but it is not a part of mitosis.
True
True or False: Cells stalled at the G1 checkpoint must choose to proceed through cell cycle, enter into stasis, or enter into programmed cell death.
True
Rb is a tumor suppressor that functions by binding and inhibiting E2F until CDK ____.
hyperphosphorlyates Rb and causes it to release E2F
Cyclins are a subunit of MPF and
their expression fluctuates throughout the cell cycle
Nondisjunction that leads to problems in offspring can occur in
Meoisis 1/2 and mitosis
True or False: Crossing over occurs between sister chromatids
False
True or False: Sister chromatids are homologous chromosomes.
False
Genetic recombination?
the new combination of maternal and paternal chromosome segments that results when homologs cross over
True or False: A chiasma forms between two of the four molecules of double-stranded DNA on duplicated homologous chromosomes.
True
Chiasma
physical linkage of homologous chromosomes
True or False: A testcross is the breeding of an individual that expresses a dominant phenotype but unknown genotype with an individual having only dominant alleles for the gene of interest.
False
True or False: Linked genes are always inherited together.
False
The alleles found in haploid organisms cannot be dominant or recessive. Why?
because only one alley is present so its always dominant
True or false: The farther apart genes are on a chromosome, the more likely there is to be a crossover between these genes during meiosis.
True bc there are more opportunities for recombination
