List four types of control on cell cycle rate
telomere length, checkpoints, crowding, outside signals (hormones, growth factors)
What role does the plasma membrane play in signal transduction?
The plasma membrane holds many of the molecules that intercept incoming signals and it acts in ways that spread the message.
Embryonic cells
totipotent, taken from inner cell mass of a blastocyst, very potent, undifferentiated, there can be ethical problems with using these for therapy
Induced pluripotent stem cells (iPSC)
cell is able to "go back in time" to become a stem cell (less differentiated state), is engineered, their full potential for therapy is not yet know
Adult stem cells
multipotent or unipotent, can self renew or form a progenitor cell (ex: multi potent: blood cell, ex: unipotent: liver cell), originate from ESC, if used for therapy there are potential risks for cancer or rejection of cells
What abnormalities can lead to cancer?
lack of cellular adhesion can speed migration of cancer cells, impaired signal transduction can block a signal to cease dividing, blocking apoptosis can lead to excess mitosis and uncontrolled cell growth, lack of control of cell cycle can lead to too man
Why wouldn't a cell in an embryo likely be in G0 phase?
it has to divide frequently to support the tremendous growth rate
What is a sodium channel and in which cell structure is it located?
a sodium channel is a protein lined opening in the plasma membrane that regulates the movement of sodium into and out of the cell
Autosomal recessive
the trait needs two recessive alleles to be passed down
Autosomal dominant
the trait needs at least one dominant allele to be passed down
Mendel's first law
The law of segregation: each member of a pair of homologous chromosomes separates during metaphase 1 of meiosis and are distributed to different gametes
Mendel's second law
The law of independent assortment: chromosomes line up randomly along the metaphase plate (occurs during metaphase 1
Homozygote
organism with identical pairs of genes (or alleles) for a specific trait
Heterozygote
organism with different pairs of genes (or alleles) for a specific trait
Monohybrid cross
mating between a pair of individuals who have different alleles at one genetic locus of interest
Dihybrid cross
mating between F1 generation who differ in two traits of particular interest
Punnet square
determines alleles of offspring from those of its parents; one generational
Pedigree
spans multiple generations, showcases which individuals are affected by certain traits and which are not
Cell membrane
keeps things in and out of cell
Chromosomes
organized structure containing DNA, RNA, proteins
Differentiated
very specialized (ex: unipotent adult stem cells -> liver cells)
G0
resting" or quiescent stage, cell does not divide but is metabolically active; can either start division process, remain specialized, or apoptize
G1
growth 1", build more cytoplasm, prepare DNA for replication
S
Synthesis", DNA replication (1 chromosome -> 2 sister chromatids/ 1 chromosome)
G2
growth 2" build more cytoplasm and membranes, prepare to divide
What is the purpose of mitosis?
to replicate a cell (1 diploid -> 2 diploid identical daughter cells)
Four applications of stem cells
use to test drugs, grow in cultures to observe earliest signs of disease, create tissues/ organs for use in transplants or study, iPSCs
Diploid
two sets of chromosomes
Haploid
one set of chromosomes
Progenitor cell
pushed by stem cell to differentiate into its target cell
Centromere
part of chromosome that links sister chromatids
Telomere
located at the ends of chromatids, signals cell to divide, gets shorter every time a cell divides, once too short it signals for apoptosis
Spermatogonium
an un-differentiated cell that can become primary spermatocyte-> secondary spermatocyte-> spermatids -> sperm
Oogonium
an un-differentiated cell that can become primary oocyte & polar body -> secondary oocyte & polar bodies -> ovum and polar bodies
Homologous chromosomes
chromosomes with the same gene sequence
Assisted Reproductive Technologies
provide innovative ways to conceive offspring, ex IVF
Why are egg donors paid more than sperm donors?
more invasive, limited amount of eggs
What type of diseases can Preimplantation genetic diagnosis test for?
cystic fibrosis, sickle cell anemia, hemophilia
What stage of embryonic development is tested for PGD?
8 cell embryos
Criteria for autosomal dominant traits
males and females can be affected, male to male transmission can occur, successive generations affected, males and females transmit the trait with equal frequency, transmission stops after a generation in which no one is affected
Criteria for autosomal recessive traits
males and females can be affected and can transmit the gene if it doesn't kill them, the trait can skip generations, parents of an affected individual are heterozygous or have the trait
Allele
one of a number of alternative forms of the same gene
Conditional probability
measures the probability of an event given that another event has occurred