Biology Kaplan Book Flashcards
viroids
small pathogens consisting of a very short circular single-stranded RNA that infect plants
brings large number of RNA sequences and silences genes in plant genome
prions
infectious proteins
cause disease by triggering misfolding of other proteins
positive sense RNA viruses
genome may be directly translated to functional proteins by the ribosomes of host cell, like mRNA
Negative sense RNA viruses
require synthesis of an RNA strand complementary to the negative-sense strand, which can then be used as a template for protein synthesis
must carry an RNA replicase in virion to ensure synthesis
extrusion
the process in which a virus leaves the cell by fusing with the plasma membrane, allowing the survival of the host cell and continued use of host cell by virus
- a productive cycle
p53
the main protein in control of stopping the cell cycle (going into arrest at the checkpoints) until the DNA has been repaired if damaged
damage/mutation to the gene that produces p53 can lead to cancer
what molecules are responsible for the cell cycle?
cyclins and cyclin-dependent kinases (CDK)
CDK must be activated by the right cyclins
synaptonemal complex
a group of proteins that holds homologous chromosomes together
Mendel’s second law (of independent assortment)
states that the inheritance of one allele has no effect on the likelihood of inheriting certain alleles for other genes
Mendel’s first law (of segregation)
the distribution of homologous chromosomes to the two intermediate daughter cells is random with respect to parental origin
What is the pathway of sperm through the male reproductive system?
SEVE(N) UP
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Seminiferous tubules
Epididymis
Vas deferens
Ejactulatory duct
Nothing
Urethra
Penis
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deuterostomes
develops into anus from blastopore
“deu” = 2 = “number two” = doo doo
protostomes
develops into mouth from blastopore
ectoderm
“attracto”derm (things that attracts us to others, such as cosmetic features and “smarts”)
outer layer of germ layers; gives rise to the integument (epidermis, hair, nails, and epithelia of nose, mouth, and lower anal canal), the lens of the eye, nervous system (w/ adrenal medulla) and inner ear
mesoderm
“means”oderm = means of getting around as an organism, such as bones and muscle; means of getting around in the body, such as the circulatory system; means of “getting around” wink wink (such as gonads)
middle layer; develops into several different systems including musculoskeletal, circulatory, and most of the excretory systems; also gives rise to gonads and muscular/connective tissue layers of digestive and respiratory systems and adrenal cortex
endoderm
linings of “endernal” (internal) organs
- the digestive and respiratory tract, including lungs, and accessory organs attached to these systems
- pancreas, thyroid, bladder, and distal urinary tracts, as well as parts of liver
What happens after penetration of the sperm through the cell membrane of the secondary oocyte (the cortical reaction)?
Calcium ions are released, depolarizing the membrane of ovum, serving 2 purposes:
- depolarization prevents fertilization by multiple sperm cells
- increased Ca2+ concentration increases the metabolic rate of the newly formed diploid zygote
what tissues do the neural crest cells develop into?
the PNS
what does it mean for a cell to be determined?
it is committed to a particular cell lineage, but not yet actually produced the products it needs to carry out the functions of that cell type
what does it mean for a cell to differentiate?
it assumes the structure, function, and biochemistry of that cell type. Goal is to produce products it needs to carry out the function of that cell type
what determines how many different cell types a stem cell can become?
potency
explain the different types of potency
totipotent: ultimately can differentiate into any cell type (either in fetus or in placental structures); has greatest potency
pluripotent: cells can differentiate into any cell type except for those found in placental structures (differentiate into the three germ cell layers ecto, meso, endo)
multipotent: can differentiate into multiple types of cells within a particular group (like how hematopoietic stem cells can differentiate into all cells only found in blood like WBC, RBC, platelets)
what molecules cause determination of cells
morphogens
examples: transforming growth factor beta (TGF-B), sonic hedgehog (Shh), and epidermal growth factor (EGF)
Where does oxygenation occur in fetal circulation?
at the placenta
