Test 2 Lab Flashcards
the time period between cell division where the cell grows, uses energy and undergoes its normal, active life
interphase
The series of events that a cell undergoes throughout its life
cell cycle
what are the stages that interphase is broken into?
G1, S, G2
the most efficient growth period of the cell. Here the cell is using nutrients. lasts about 8-10 hours
G1
checkpoint that makes sure the cell is large enough to divide and has all of the nutrients present
G1 checkpoint
this is the phase that the cell is in most of the time
G1
where centrioles and centromeres begin replicating
late G1
This is the phase where DNA replication occurs and the amount of DNA doubles
S phase
how long does the S phase last
6-8 hours
what does the S phase checkpoint check for?
if DNA replicated properly
shortest stage. here the cell is still growing , metabolizing, and manufacturing proteins. cells move into mitosis from here
G2
how long does G2 last?
2-46 hours
what does the G2 checkpoint check for?
cell size and proper DNA replication
what are the two types of cells and what are the differences between them?
somatic cells - main body cells, undergo mitosis
gamete/sex/germ cells - sexual reproduction cells, undergo meiosis
genes that tell the cell to divide - “accelerator genes”
oncogenes
tell the cell not to divide - the “brakes” of the cell - give some examples
tumor suppressor genes
p53, p21, p27, p57
“suicide” genes
apoptosis genes
code for DNA repair enzymes
DNA repair genes
what is the difference between karyokinesis and cytokinesis?
karyokinesis is nuclear division while cytokinesis is cell division
in terms of karyokinesis and cytokinesis, what to multinucleate cells undergo and what don’t they?
they undergo karyokinesis, but not cytokinesis
division of somatic cells
mitosis
what does it mean that a cell is 2n?
it is diploid
2n -> 46
what does n stand for?
the number of sets of chromosomes
what is meiosis?
division in sex cells (sperm and egg)
what does meiosis produce?
a daughter cell with half the amount of DNA of the parent cell - DNA is reduced from 2 sets to 1
2n = 46 -> n=23
what does this represent?
meiosis
microtubules that radiate around each centriole at the end of each cell that hold the apparatus into place
astral microtubules
attach to the centromere on the chromosome and are involved in seperating and moving chromosomes. they are coated in kinetochore proteins
kinetochore microtubules
do not interact with the centriole, they attach the centriole to centriole and shorten the length of the cell
polar microtubules or non-kinetochore microtubules
identical strands of DNA pined at a centromere by DNA Replication
chromatids
when determining the amount of chromosomes, what should be counted?
the centromeres, not the chromatids
during which phase of the cell cycle does mitosis occur?
M phase
why is the chromosome number reduced by half in meiosis?
so that when the nuclei of gametes unite in fertilization, the diploid number is restored
charts that show an individuals chromosome number
karyotypes
chromosomes 1-22
autosomes
homologous chromosomes
chromosomes of the same size that contain the same genes
different molecular forms of a gene
alleles
segment of DNA that codes for 1 protein
gene
what are the two stages of meiosis?
stage 1 - Reduction Division - reduce the number of chromosomes
stage 2 - cell division
what occurs during prophase 1?
DNA is already replicated, sister chromatids are joined at the centromere and chromatin condenses. Synapsis occurs forming a tetrad, crossing over occurs
pairing of homologous chromosomes
synapsis
what occurs during metaphase 1?
the homologous chromosomes line up at the equator. This is facilitated by the spindle fibers and the centrioles
what occurs during anaphase 1?
the homologous chromosomes are pulled apart, separating the tetrad
what happens in telophase 1?
after the new nuclear membrane forms, cytokinesis occurs
what occurs in meiosis 2?
mitosis
what occurs in prophase of mitosis?
the nuclear membrane breaks down and chromatin condenses
what occurs in metaphase 2 of mitosis?
the chromosomes align at the metaphase plate (equator), the spindle fibers attach at the centromeres
what happens during anaphase of mitosis?
the centromere is replicated, the kinetochore shortens and pulls the sister chromatids towards the poles
what happens in telophase of mitosis?
each cell forms a new nuclear membrane and each cell goes through cytokinesis
the ability of heart muscles to contract on their own
automaticity
what do the special fibers in the myocardium do?
they rapidly conduct electricity across the muscle tissue and cause the heart to contract
why does the atria contract first and then the ventricles?
so that each chamber can fill completely before emptying into the next
what initiates all chamber contractions?
a single, common impulse that starts at the sinoatrial node
starts the sequence of depolarization and repolarization
sinoartrial node
how fast does the sinoatrial node cause the heart to beat?
60-80 beats per minute
the synchronization of the stimulation and contraction of the heart cells
syncytium
situated between the atrium and the venticle, it allows for a slightly slower transmission of the impulse to the ventricles
atrioventricular node
why does the AV node slow the transmpission of the impuls to the ventricles?
so that the atrium can empty and the ventricles can fill before the ventricles contract
how much does the AV node slow the electrical impulse from the SA node?
it slows it to 1/25 of the original signal or by about .2 seconds
what is the path of an electrical impulse in the heart?
SA node, AV node, AV bundle (bundle of His), Bundle branches, purkinje fibers
when ventricles start the relaxation phase
ventricular diastole
these produce electrical signals
rhythm generators
these spread the pacemakers signal
conductors
cells that mechanically pump the blood
contractile cells (myocardium)
what happens to the cells once the electrical signal of depolarization reaches them?
they contract
when the repolarization signal reaches the myocardial cells, what happens to them?
they relax
how does the sympathetic system effect the heart?
it speeds it up, increasing the contractile force when more oxygen is needed
how does the parasympathetic system effect the heart
it slows it, when you are relaxed, the parasympathetic system is in control
a straight line on the ECG that occurs before cardiac cycles of depolarization and reploarization
baseline/isoelectric line
represents atrial depolarization
P wave
result of ventricular depolarization and indicates the start of ventricular contraction
QRS complex
result of ventricular repolarization and signals the beginning of ventricular relaxation
T waves