Cellular Process unit
*the spindle fibers shorten pulling the sister chromatids. *the centromeres split as the sister chromatids are pulled away from each other towards opposite sides of the cells
2 things that happen in anaphase
*spindle fibers attach to the centromeres of chromosomes aka sister chromatids *the chromosomes are lined up around the middle/ equator of a cell
2 things that happen in metaphase
*G1 phase: normal metabolic activity: the cell grows, makes protein, acquires and uses energy etc *S phase: all the pieces of chromatin replicate-make a copy of themselves DNA replication *G2 phase: final growth phase, organelles and cell parts needed for division are made/ 2 sets of furniture
3 things that happen in interphase
*a triploid cell with three copies of each chromosomes *the n equals the number of copies of each type of chromosome
3n
*the duplicated chromatin now coils up into chromosomes and pairs with its identical copy aka it makes sister chromatids and they are joined by a centromere *the nuclear membrane and nucleus disappear *centrioles, which are cylindrical structures made out of microtubules, begin to move towards the opposite ends of the cell *spindle fivers, a network of microtubules, begin to form between the centrioles and smaller fibers called asters from behind the centrioles
4 things that happen in prophase
*the spindle breaks down because its no longer needed *chromosomes begin to uncoil aka turn back into chromatin *2 new nuclei begin to form around the 2 groups of chromatin *cytokinesis occurs aka the cells begin to divide into 2 cells -animal cells cleavage furrow -plant cells a cell plate forms along the equator of a cell
4 things that happen in telophase
the requirement that to divide a cell must be attached to the substratum
Anchorage dependence
*cyclin dependent kinases that depend on cyclins--> these kinases that drive the cycle are present at a constant concentration but they are invective unless they are attached to a cyclin that fluctuates the concentration *Cyclin-dependent kinases. A protein kinase that is active only when attached to a particular cyclin. Activity rises and falls depending on the concentration of the cyclin partner. *speeds up actions in a cell *are homologous through evolution *depend on cyclin because they re activated when attache to cyclin *MPF is a type of cdk that breaks the nucleus
CDK
because they depend on cycle ins they are called cyclin dependent kinases or cdks the activity of a cdm rises and falls with changes in the concentration of its cyclin partner
CDKs
*serves as a master regulator of apoptosis acting as a break in the absence of a signal promoting apoptosis. When death signal is received by the cell, it overrides the brake and the apoptotic pathway activates protases and nucleases, enzymes that cut up the protein and the dan of the cell *as long as fed-9 located in the outer mitochondrial membrane is active apoptosis is inhibited and the cell remains alive *when the cell receives death signal ced-9 is inactivated, relieving its inhibition of ced-3 and ced-4. Active ced-3 a protease triggers a cascade of reactions leading to activation of nucleases and other proteases the action of these enzymes causes the changes seen in apoptotic cells and eventual cell death *reception --> transduction--> response
Ced 9
instructions on how to build protein
DNA has...
DNA replication happens in interphase because it saves time
Dna replication happens in ____ because...
it is in interphase and it is normal metabolic activity; the cell grows, makes protein, acquires and uses energy, etc --> the cell grows
G1 phase
*it is in interphase *final growth phase; organelles and cell parts needed for division are made *has 2 sets of furniture *the cell grows some more *a nuclear envelope bounds the nucleus *two centrosomes have formed y replication of a singe centrosome *in animals there are two centrioles *chromosomes were duplicated in the s phase but they are not yet condensed
G2 phase
*fluctuating activity of the cyclin CDK complex: maturation promoting factor *A cyclin-Cdk complex that causes the cell to move from interphase into mitosis *Maturation-promoting factor (M-phase-promoting factor); a protein complex required for a cell to progress from late interphase to mitosis. The active form consists of cyclin and a protein kinase. *is a kind of CDK that breaks the nucleus *m phase promoting factor/ maturation promoting factor cause it riggers the cells passage past the g2 checkpoint into m phase *mpf acts both directly as a kinase and indirectly by activating other kinases
MPF
*growth factor made by blood cells called platelets--> it is required for division of fibroblasts in culture *Platelet-derived growth factor *Platelet derived Growth Factor; brain and breast cancer; plays a critical role in cellular proliferation and development; active to a differing degree depending on which dimer is formed; a dimer and can form from the combination of the alpha and beta chains in any order
PDGF
genes control enzymes wich control the cell cycle
____ control _____ which control ______
this organism must be a fungus or a pro tis perhaps an alga
a certain eukaryote lives as a unicellular organism but during environmental stress its cell pro due hamlets. the gametes fuse and the resulting zygote undergoes meiosis. generating new single cells. what type of organism could this be.
39, 39,78
a chicken has 78 chr in its somatic cells how many chromosomes did the chicken inherit from each pattern. how many are in the chickens gametes. who many chromosomes are in each cell of the chickens offspring
animal cells
a cleavage furrow is only in
meiosis is distinguished from mitosis b the three events: *prophase one in which each of the homologous pair undergoes synapsis and crossing over between non sister chromatids *metaphase one : chromosomes line up as homologous pairs on the metaphase plate aka tetrads line up *anaphase one:h homologs separate frome ach other and sited chromatids remain joined at the centromere
a comparisons of meiosis and mitosis
less
a gene that is located close to the centromere is more or less likely to cross over than one located far away from the centromere
she should clone it breeding would generate offspring that have additional variation which she no longer desires now that she has obtained her ideal orchid
a horticulturalist breeds orchids tyring to obtian a plant with a unique combination of desirable traits. after many years she finally succeeds to produce more plants like this one, should she breed it or clone it ? why
sperm
a human cell containing 22 autosomes and a y chromosomes is called a
g1
a particular cell has half as much dna as some other cells in a miotically active tissue the cell in question is most limey in
aneuplody can result form nondisjuction during meiosis when normal gamete unites with one containing two com pies of no com pies os a particular chr resulting zygote and its descendant cells either have one extra copy in a trisomy or are missing a copy in a monosomy. polyploidy aka more than 2 complete set of chr can result fro complete nondisjuction during gamete formation
abnormal chr number
the replication is followed y 2 cell division which includes mitosis and cytokinesis each time but skips interphase between the divisions the first division is called meiosis I while the second division is called meiosis II
after chromosome replication in mitosis
*one of them can be a death signaling molecule that leads to the deactivation of ced-9 an the activation of protases and nucleases such as the caspase ced-3 *two other types of alarm signals originate from inside the cell. one comes from the nucleus generated when the DNA has suffered irreparable damage and the second comes from the er when excessive protein misfiling occurs
alarm signals for apoptosis
chromosome breakage can result in selections, inversions, duplications and translocations
alterations of chr structure
*the spindle fibers shorten pulling on the sister chromatids *anaphase is the shortest stage of mitosis often lasting only a few minutes *anaphase begins when the cohesion proteins are cleaved this allow stye two sister chromatids to become a full fledged chromosome *the centimes split as the chromatids are pulled away *sister chromatids come apart at the centromere and each is now considered a daughter chromosomes --> each then moves towards an opposite pole, being pulled by spindle fibers *the cell elongates as the nonkinetochore microtubules lengthen *by the end of anaphase the two ends of the cell have equivalent and complete collections of chromosomes
anaphase
*breakdown of proteins responsible for sitter chromatid cohesion along chromatid arms allows homologs to separate *the homologs move toward opposite poles guided but the spindle apparatus *sister chromatid cohesion persist at the centromere accusing chromatids to move as a unit toward the same pole
anaphase 1
*break down of proteins holding the sister chromatids together at the centromere allows the chromatids to separate. the chromatids move toward opposite poles as individual chromosomes
anaphase 2
anaphase is the action phase where the chromosomes separate
anaphase is the ____
the aberrant gamete units with a normal one inf reutilization the zygote will also have an abnormal number of chr known as a n aneuploydy
aneuploidy
*programmed cell death *it integrates multiple cell signaling pathways *cells that are infected or damaged or that have simply reached the end of their functional life span often enter a program controlled cell suicide called apoptosis meaning falling off *apoptosis in a human white blood cell *during this process cellular agents chop up the DNA fragment of the organelle and together cytoplasmic components--> the cell shrinks and becomes lobed aka blabbing occurs and the cells parts are packaged up in vesicles that are engulfed and digested by specialized scavenger cells leaving no trace *apoptosis protects neighboring cells from damage that they would otherwise suffer if a dying cell merely leaked out all its contents, including its many digestive and other enzymes
apoptosis
in formation of the hand or paw in mammals cells in the regions between the fingers are programmed to undergo apoptosis. this serves to shape the digits of the hand or paws so that they are not webbed
apoptosis and webbed hands
apoptosis occurs at defined times during embryonic development of c elegant. a protein called ced-9 in the mitochondrial membrane acts as a break and when released by a death signal it allows activation of caspases that carry out apoptosis
apoptosis in caenohabditis elegans
*fragmentation of the DNA *cell signaling pathways *activation of cellular enzymes *digestion of cellular contents by scavenger cells
apoptosis includes
several apoptotic pathways exist in the ells of humans and other mammals and these pathways may be triggered in different ways. a major pathway involves pore formation in the outer mitochondrial membrane which leads to release of factors that activate caspases. signals can originate from outside or inside the cell
apoptotic pathway and the signals that rigger them
* no mate needed *saves energy not finding mate and for mating cycles *more babies formed *less genetic variation leads to specialization as organisms in the population look and act similar *is beneficial in a constant and not changing environment
asexual reproduction advantages
*more risk of extinction due to lack of variation--> in an unstable environment *decreased potential for adaptation *more likelihood for predators and parasites to be able to fix on the one type
asexual reproduction disadvantages
*budding *parthenogenesis: unfertilized egg develops *vegetative propagation *binary fission
asexual reproduction examples
smaller fibers called asters form behind the centrioles
asters
anaphase
at what point does a sitter chromatid become its own chromosome
telophase
at what point in mitosis do 2 new nuclear membranes begin to form and chromatin unwinds
anaphase
at what point in the cell cycle does each sitter chromatid become its own chr
*the chromosomes replicate forming 2 sister chromatids that are held together by the centromere/kinetochore *this type of chromosome has two exact copies of each DNA strand held together is called a big chromosomes or a bivalent chromosome and only is seen in the G2 phase and early mitosis
before a cell divides
chromosomes replicate themselves just like in mitosis
before cells divide in meiosis
at sexual maturity ovaries and testes produce haploid gametes by meiosis each gamete containing a single set of 23 chr during fertilization a zygote that is diploid is formed and it will develop into a full grown organism by mitosis
behavior of chr sets in the human life cycle
*there are moments in an animals life when their biological activity slows down, they are generally known as dormant period *they know when the is period are though cues in their environment
behaviors in animals are triggered by environmental cues and are vital to reproduction, natural selection, and survival
*hibernation: is the used mainly by mammals in the winter to escape the cold and survive through food shortage *diapause: is mostly in insects who use it during the autumn and winter to survive unfavorable conditions. diapause can happen at any time *estivation is almost the opposite of hibernation its purpose is to survive through hot periods of time
behaviors in animals are triggered by environmental cues and are vital to reproduction, natural selection, and survival: hibernation/estivation/diapause
*the division of bacterial cells resulting in 2 daughter cells that are exactly alike --> e coli replication *asexual reproduction of single celled eukaryotes such as amoeba *diring binary fission in bacteria the chromosome replicates and the two daughter chromosome actively move apart.
binary fission
*before a cell divides the chromosomes replicate forming 2 sister chromatids that are held together by the centromere/kinetochore this type of chromosome has two exact copies of each DNA strand held together is called a big chromosomes or a bivalent chromosome and only is seen in the G2 phase and early mitosis
bivalent chromosome
*asexual reproduction where a small outgrowth on an animal occurs and then breaks off to become a new organism
budding
*cancer is the uncontrollable growth of cells where they often divide before doing interphase. This leads to a tumor of undifferentiated cells that are smaller than normal individually as they have not had a change to grow before dividing *often the cell checkpoints that would normally stop the cell cycle is changed and this is why the cells are not regulated in the same way
cancer
*the uncontrolled division of cells *cancers do not respond to cyclin signals that regulate cell growth resulting in tumors
cancer
the cancer cells might even divide in the absence of pdgf in which case they would not stop when the surface of the culture vessel was covered and they would pile onto of one another because they do not respond to contact inhibition
cancer cells and pdgf
*are the main proteases of apoptosis *the chief cascade is Ced-3
caspases
*faulty or mutated genes/ DNA *environmental factors *radiation:UV rays, X-rays, nuclear rays or gamma rays *certain chemicals like carcinogen or cigarette smoke *genetic factors like bad genes inherited from parents *some viruses
causes of Cancer/ mutation of DNA
*a culture of cells grown together * group of cells grown in a nutrient solution from a single original cell
cell culture
*allows organisms to grow and develop as well as allowing for replacement of dead of damaged cells *it is made up of mitosis and cytokinesis
cell division
mitosis and cytokinesis
cell division aka
it forms the cell wall to divide the cytoplasm in the cytokenises of plants
cell plate
*cell plate: vesicles from golgi move along microtubules to the middle of the cell where they make a cell plate *cleavage furrow: actin filaments interact with myosin causing the ring to contract -> the cleavage furrow deepens until the cell is pinched in two
cell plate vs cleavage furrow
dna is partitioned among chromosomes. eukaryotic chromosomes consist of chromatin a complex of dna and proteins that condenses s during mitosis. in animal cells gametes have one set of chr and somatic cells have two sets
cellular organiation of genetic material
cylindrical structures made out of microtubules
centrioles
*the center of an x that joins the sister chromatids aka the identical pairs of chromosomes
centromere
*the assembly of spindle microtubules stars here, a sub cellular region containing material that functions throughout the cell cycle to organize the cells microtubules *they replicate in interphase and then stay by the nucleus until prophase when they start moving apart and in pro metaphase the spindle microtubules grow out from them and during pro metaphase some of the spindle microtubules will attach to a structure of proteins associated with specific sections of chromosomal dna at the centromere called kinetochore
centrosome
*is a control point where stop and go ahead signals can regulate the cycle. The signals are transmitted within the cell by the kinds of signal transduction pathways *checkpoints also register signals from out side the cell as we will discuss later. Three major checkpoints are found in G1 G2 and M phases *for many cells the G1 dubbed the restriction point in mammalian cells seems to be the most important. If a cell receives a go ahead signal at the G1 checkpoint it will usually complete the rest and then divide and if it does not receive the go ahead signal it will go into a non dividing phase of G0
check poinT
*is a critical control point where stop and go ahead signals can regulate the cycle *is a control point where stop and go ahead signals can regulate the cell cycle --> these signals are transmuted thorough transduction pathway *checkpoints also register signals from outside the cell --> there are 3 major check points *if fails check point then goes into G0
checkpoints
it states that something is wrong and your results are significantly different that we would expect
chi square test alternative hypothesis
it is the sum of the ((O-E)^2 )/E
chi square test: equation
it states that the results are no different from what we would expect under normal circumstances
chi square test: null hypothesis
*a p value of 0.02 means that 98% chance that the results are really different *so for a p value less or equal to 0.05 you reject the null because you are really really sure that there is a difference thus you accept the alternative that says that there is a difference
chi square test: p value
*all the new DNA in a cell *chromatin is a thin threadlike pieces of DNA during interphase DNA is in chromatin form *chromosomes are made of chromatin a complex of dna and associated protein molecules
chromatin
*during mitosis the chromatin coils up into distinct, tightly packed rod-like structures called chromosomes *the DNA is manageable because it is packaged into chromosomes
chromosomes
*the pinches on the cells *in animal cells a cleavage furrow forms as the cell divides while in plants a cell plate is formed by vesicles lining up on the medial line of the cell and secreting the new cell wall. Plant cells do not have centriole but they still use spindle fibers
cleavage furrow
both types pof tumors consist on the ambormal cells. a benign tumor stays at the original site and can usually be surgically removed. cancer cells fro ta malignant tumor spread fro the original site by metastasis and may impair the function of one or more organs
compare and contras benign tumor and malignant tumor
*cytokinesis results in two genetically identical daughter cells in both plant cells and animal cells bu the mechanism of dividing the cytoplasm is different in animals and plants. in animals cells cytokinesis occurs by cleavage which divides the parent cell in two with a contractile ring of actin filaments. in a plant cell the cell plate forms in the middle of the cell and grows until its membrane fusses iwht the plasma membrane of the parent cell. a new cell wall grow sin side the plate
compare cytokineses in animal cells and plant cells
during eukaryotic cell division tubulin is involved in spindle formation and cur movement while actin functions during cytokinesis. in binary fission its the opposite: tubulin like molecules are thought to act in daughter cell separation and actin like molecules are thought to move the daughter bacterial chromosomes to opposite ends of the cell
compare the roles of tubulin and actin during eukaryotic cell division with the role of tubulin like and actin like proteins during bacterial binary fission
in asexual reproduction a single parent reproduces genetically identical offspring by mitosis in sexual reproduction combines sets of genes from two different parents forming genetically diverse offspring due to sex, independent assortment of the chr, crossing over, and random fertilization
comparison of asexual and sexual reproduction
a cell phenomenon where cells chemically communicate with each other and stop dividing/ multiplying when there is no more room/ space to divide
contact inhibition
crossing over produces recombinant chromosomes in prophase one at the chiasma aka the site of crossing over
crossing over
*a type of enzyme, which is a protein. *this enzyme can either trigger the start or stop of mitosis *kinases must be attached to a cyclin for the cell clock to work--> cyclin is a protein which cyclically fluctuates concentration in a cell *a protein that gets its name because it cyclically fluctuating concentration in the cell--> cyclin levels rise during the s and g2 phases and then falls abruptly during the m phase
cyclins
mpf
cyclins bind to cdk to start the process of mitosis by forming what
*apoptotic proteins can form molecular pores in the mitochondrial outer membrane causing it to leak and release protein that promote apoptosis. Surprisingly these include cytochrome c which functions in mitochondrial electron transport in healthy cells but acts as a cell death factor when released from mitochondria
cytochrome c
*it occurs in the cell and it begins to divide into 2 cells *animal cells- the membrane begins to pinch in by forming a cleavage furrow *plant cells-a cell plate the start of a new cell wall, forms in the equator of a cell *completes just after the competition of mitts tus completing cell division *division of the cytoplasm
cytokineis
is the division of the cytoplasm
cytokinesis
the results of fusing a g1 cell with a cell in the s or m phase of the cell cycle suggest that molecules present in the cytoplasm during the s or m phase control the progression to those phases
cytoplasmic singals
removes a chromosomal segment
deletion
*this is what went wrong in tumors *a phenomenon observed in normal animal cells that causes them to stop dividing when they come in contact with one another
density dependent inhibition
in preparing for cell division chromosomes replicate each one then consisting of two didactical sister chromatids joined along their lengths by sister chromatid cohesion when this cohesion is broken the chromatids separate during cell division becoming the chromosomes of the new daughter cells. eukaryotic cell division consists of mitosis
distribution of cur during eukaryotic cells ividsion
nucleus
dna is located in the
trisomy 21
down sysndrom
repeats a segment
duplication
during telophase
during what phase do chromosomes turn back into chromatin
during prophase in mitosis
during what phase does chromatin coil up into distinct tightly packed rod like structures called chromosomes
during interphase to save time
during what phase does dna replicate
interphase
during what phase is DNA in chromatin form
prophase
during what phase of mitosis do chromosomes condense and become visible
prophase
during what phase of mitosis do the chr condense and become visible
metaphase
during what phase of mitosis do we take cells for a karyotype
metaphase
during what phase to we take cells for a karyotypes
S
during what sub phase of interphase does DNA replicate
s
during what sub phase of interphase does the DNA replicate
2nd
during which round of meiotic division do the sister chromatids separate
from the end of s phase in interphase through the end of metaphase in mitosis
during which stages of of the cell cycle does a chromosome consist of two identical chromatids
the haploid dumber is 7 the diploid number is 14
each sperm a pea plant contains seven chromosomes. what are the haploid and diploid numbers for peas
*embryonic development is a period during which apoptosis is widespread and plays a crucial role. The molecular mechanisms underlying apoptosis were worked out in detail by researches studying embryonic development of a small soil worm nematode called caenorhabditis
embryonic development and apoptosis
*organisms with a more desirable trait will survive better than other organisms that have traits that are to suited to the chaining environment --> natural selection s determines plants response to the environment and global climate change affects gene activation and expression of traits such as flowering timing *members within a population who have a favorable characteristic are more likely to survive than those with out it--> as environment changes some phenotypes/characteristics/genes become more favorable
environmental change and act as selective mechanisms on populations
*as the climate warms -due to co2 levels rising leading to higher temperatures-plats flower sooner (phenology) as a result pollination of crops and the onset of spring and the health of ecosystems are all affected
environmental change and act as selective mechanisms on populations: flowering in time in relation to global climate change
*England in the industrial revolution trees were light colored so the moths were like this to camouflage but after the industrial revolution dark colored trees and lichees of the pollution lead to the growth in the favorable pattern of the moth so it could camouflage and avoid being eaten
environmental change and act as selective mechanisms on populations: peppered moth example
*our phenotype depends on the environment in which our genotype is expressed *the environment can cause changes in organisms phenotype which causes differences to be seen among organisms
environmental factors influence many traits both directly and indirectly
*cholesterol levels in humans can be affected by the environment, for example diet, exercise, and tobacco smoking strongly influence the amount of cholesterol in a persons blood and not just their heredity
environmental factors influence many traits both directly and indirectly : blood cholesterol levels in humans
*if the genotype of the flowers is expressed in a low ph then the flower will be unable to obtain nutrients such as aluminum thus the flower will be blue but in higher ph's the aluminum and other nutrients are more available so the flower color will be pink
environmental factors influence many traits both directly and indirectly : flower color based on pH of soil
*sex determination is a biological system that distinguishes the gender of an organism *temperature dependent sex determination (TSD)--> the temperature condition directly influences sex determination of reptiles (males at intermediate temperature, females at extremes)
environmental factors influence many traits both directly and indirectly: sex determination in sea turtles
molecules present in the cytoplasm regulate progress through the cell cycle
evidence for cytoplasmic signals
such organisms reproduce by mitosis which generates offspring whose genomes are exact copies of the presents genome
explain how asexually reproducing organisms produce offspring that are genetically identical to each other and to their parents
in a given number of time there is higher probability to find a cell tin the phase that takes more than that to find it in a charter phase thus the appearance of a phase is proportional to the time it takes. So by multiplying the ration of cells in a phase: the number of all cells one is able to find the percent of cells in a phase and when multiplied boy the time one finds the total amount per phase (direct proportion --> + number of cells in phase= + time 2 complete phase)
explain how counting the number o cells can be used to determine how much time each phase takes
a state of no division and normal cell activity --> most cells are within this phase
g0 phase
*have 23 chromosomes and are haploid n *the n equals the number of copies of each type of chromosome
gametes
we would not want a baby to start with shortened telomeres. when cloning the sheep dolly, she started with shortened telomeres as they used adult cells. stem cells have long telomeres and would be better for cloning. gametes need the full length of telomere. cancer cells are dividing crazy fast, so if they didn't have the ability to add telomere they would quickly age out. for this reason they have cancer cells that have been around in cultures for years.
gametes and cancer cells are two types of cells where telomerase is working. why would these cells need telomerase?
*a segment/short section of DNA along a chromosome that codes for the production of one protein, for example: an enzyme
gene
recomcombinant offspring exhibit new combinations of traits inherited from two parents because of the independent assortment of the chromosomes, unlike genes exhibit a 50% frequency of recombination in gametes. for linked genes crossing ver between non sister chromatids sduring meiosis 1 accounts for the observed recombinant always less than 50% of the total
genetic recombination and lincage
a cells endowment of DNA
genome
a cells endowment of DNA its genetic info
genome
if crossing over did not occur the two homologous would not be associated in and in a way this might result in incorrect arrangement of homologs during metaphase 1 band ultimately in formation of games with an abnormal number of chr--> aneuplody
given the synaptonemal complex is appears by the end of prophase how would the two homologous chr associated if crossing over did not occur? what effect might this ultimately have on gamete formation
diploid cells in the gonads aka the ovaries and testes undergo meiosis to form gametes
gonads --> gametes
is a protein released by certain cells that stimulates other cells to divide
growth factor
*is a protein released by certain body cells that stimulate other cells to divide
growth factor in general
the greater distance between two genes the more points there are between them where crossing over can occur
he predicted that the farther pap art to genes are the higher the probability that a crossover will occur between them and therefore the higher recombination frequency because ...
meiosis 1
homologous chr move toward opposite poses of a dividing cell during
*the two chromosomes that from each type of chromosome are called homologous chromosomes and have the same length, centromere position, and stating pattern *they would contain the same genes but the alleles for each gene would be different *a pair that cary genes for the same characteristics
homologous chromosomes
the chr are similar in the each is composed o two sitter chromatids and the individual chromosomes are positioned similarly on the metaphase plate. the chr differ in that in a mitotically dividing cell sited chromatids of each chr are genetically identical but in a meiotically dividing cell sister chromatids are genetically distinct because of crossing over in meiosis 1 prophase1 moreover the chr in metaphase of mitosis can be diploid set of haploid set but the chr in metaphase of meiosis 2 will alway she a haploid set
how are the chromosomes in a cell at the metaphase of mitosis similar and different from chromosome in a cell at the metaphase of meiosis 2
parents pass genes to their offspring; genes program cells to make specific enzymes and other proteins whose cumulative action produces an individuals inherited traits
how are the traits of parents transmitted to their offspring
It has 1/2 the DNA of the mother cell
how does the DNA of a gamete compare the DNA of its mother cell
in meiosis the chromosome count is reduced from diploid to haploid and the union of two haploid in fertilization resorts the diploid chromosome count through a zygote
how does the alternation of meiosis and fertilization in the life cycles of sexuality reproducing organisms maintain the normal cur count for each species
22: 1 sex chromosome
how many autosomes are in a sperm
44
how many autosomes in a skin cell of a human
23
how many chr are present in a human gamete
2
how many chromatids are in a duplicated chromosome
46 typically : 23 pairs
how many chromosomes are found in a diploid human cell
46
how many chromosomes are present in a human cell after the first round of meiosis
23
how many chromosomes are present in a human gamete
46
how many chromosomes are present in a human somatic cell
46 big ones
how many chromosomes are present in a human somatic cell just after the synthesis stage of interphase
46 daughter/single copy type chromosomes
how many chromosomes are there in a nucleus of a cell that just completed mitosis and cytokinesis
92: 46 per nuclei as the 46 bivalent chromosomes were pulled apart
how many chromosomes in a cell that just completed mitosis but has not yet done cytokinesis
one
how many copies of each chromosomes are present in a haploid cell
16
how many different combinations of maternal and paternal chr chn be packaged in gametes made by an organism with a diploid number of 8
2
how many divisions are involved in meiosis
1 (1 egg and 2 polar bodies)
how many gametes are formed when meiosis takes place in a female cell
4
how many gametes are formed when meiosis takes place in a male cell
2
how many nuclear divisions are needed to create an egg
5.75 (6) 23 of mom 11.5 of each of her parents and 5.75 of each her grandparents
how many of your chromosomes are identical to your great grandmother assuming you are a girl and there was no crossing over
1
how many poies of each chromosome are present in a haploid cell
2
how many rounds of nuclear division occur in meiosis
4
how many sister chromatids are present in a tetrad
4
how many sisters chromatids are present in a tetrad for crossing over
*each cell has two copies of each type of chromosome with one coming in the egg of the mother and the other coming in the sperm of the father and they fuse to form a zygote which is diploid
how zygotes are formed
*have 46 chromosomes and are diploid (2n) *the n equals the number of copies of each type of chromosome
human somatic cells
*humans change the natural world with technology --> other species are forced to adapt
humans impact on variation in other species
*r plasmids: carry resistance genes --> r plasmid is in some bacterias *natural selection: non resistant bacteria die --> resistant bacteria reproduce *overuse of antibiotics leads to more natural selection which leads to amplified antibiotic resistance
humans impact on variation in other species: overuse of antibiotics
*humans instead of nature decide which organisms reproduce such as GMOS changing them *artificial selection in GMO's may lead to organisms being more homogenous. Leading to a loss of genetic diversity
humans impact on variation in other species:artificial selection and loss of genetic diversity within a crop species
each type of cur consists of a single molecule of many times longer than the cells in which they reside. during cell division the tow copies of each type of cur actively move apart and one copy ends up in each of the two doughtier cells. chromosome movement in both types of cells may provide similar cytoskeletal proteins
identify three similarities between bacterial and chromosomes and eukaryotic chromosomes considering both structure and behavior during cell division
2x
if the dna content of diploid cell in the g1 phase of the cell cycle is x then the dna content of the same cell at metaphase of meiosis one would be
x
if the dna content of diploid cell in the g1 phase of the cell cycle is x then the dna content of the same cell at metaphase of meiosis one would be--> if we contented to follow this cell lineage then the dna content of a single cell at metaphase of meiosis 2 would be
roots and shoot tips (meristems)
in a plant where do you find cells dividing rapidly
proteins
in is used for
iroot timp/ shoot tip: apical meristem
in plant where do you ding cells dividing rapidly
cells with more than one nucleus
in the cells of some organisms mitosis occurs without cytokinesis this will result in
in anaphase
in what stage of mitosis do do the sister chromatids separate
in telophase
in what stage of mitosis do the chromosomes uncoil
in telophase
in what stage of mitosis does the mitotic spindle disappear
monosomy
in what type of nondisjuction does the individual have one chromosome instead of a pair
trisomy
in what type of nondisjunction does the individual have 3 chromosomes instead of a pair
map units
in what units do we measure distance of genes front eh centromere of a chromosome
*because each homologous pari of chromosomes is positioned independently of the other pairs at metaphase 1 the first meiotic division results in each pair sorting its maternal and paternal homologs into daughter cells independently of every other pair. This is called independent assortment in which each tdayghter cellar epresents one outcome of a possible combination of maternal and paternal chromosome
independent assortment of the chromosomes
each gene in an organisms dna exist as a specific locus on a certain chromosome. she inherit one set of chromosomes from our mother and one sent from our fateher
inheritance of genes
* G1 Phase: Normal metabolic activity; the cell grows, makes proteins, acquires and uses energy etc --> cells grow *S Phase: all the pieces of chromatin replicate-make a copy of themselves aka DNA replication --> chromosomes are duplicated *G2 phase: final growth phase; organelles and cell parts needed for division are made --> more cell growth * this is when the cell grows duplicates its organelle and replicates its chromosomes
interphase
reverses a segment within a chr
inversion
genetic research on C elegant has revealed two key apoptosis genes called ced-3 and ced-4 in which fed stands for cell death
key apoptosis genes
lobsters don't die of old age. some live to be 200 years old. they die due to disease or mishap or being put into a pot. what if humans could add telomere and not age???????
lobsters have telomerase in all of their cells. what is true of lobsters that is not true of almost all other animals?
cancer cells elude normal regulations and divide out of control forming tumors. malignant tumors invade surrounding tissue and can metastasize exporting cancer cells to other part of the body where they may form secondary tumors since cancer does not need anchorage dependence of density dependent inhibition
loss of cell cycle controls in cancer
tumor
lump of undifferentiated cells
*benign: if lump of cells remain at the original site they can be removed and they don't cause as much problem as a malignant tumor that becomes invasive through incapacitation function of 1 or more organs
malignant vs benign
distance between genes
map units
the order of genes on a chromosome and the relative distances between them can be deduced form recombination frequencies observed in genetic crosses the farther apart the genes are the more likely that their alleles combinations will be recombined during crossing over
mapping the distance between genes using recombination data: scientific inquiry
sister chromatids separate during anaphase
meiosis 2 is similar to mitosis in that
*spindle fibers attach to centromeres of the sister chromatids --> centromeres are now at opposite poles of the cell *the chromosomes are lined up in the middle (equator) of the cell--> the chromosomes convene on the metaphase plate an imaginary plate that is equidistant between the spindles two poles. the chromosomes centromeres lie on the metaphase plate *for each chromosome the kinetochores of the sister chromatids are attached to kinetochore microtubules coming from opposite poles *all chromosomes are attached to microtubules of the spindle *each sister chromatid has a kinetochore that is attached to a microtubule from an opposite pole *longest phase of mitosis lasting about 20 min
metaphase
*pairs of homologous chromosomes are now arranged on the metaphase plate with one cur in each pari facing the pole *both chromatids of one homolog are attached to kinetohchore microtubules from one pole those of the other homolog are attached to microtubules from the opposite pole
metaphase 1
*the chromosomes are positioned on the metaphase plate as in mitosis *because of crossing over in meiosis one the two sister chromatids of each cur are not identical *kinetochores of sister chromatids are attached to microtubules extending from opposite poles
metaphase 2
the spread of cancer cell to new locations distant from their original site
metastasis
includes both mitosis and cytokinesis
miotic m phase
forms in the cytoplasm during prophase
miotic spindle
*the period of cell division *mitosis is the division of the nucleus
mitosis
the mitotic spindle is an apparatus of microtubules that controls the cur movement during mitosis. in animal cells the spindle arises from the centrosomes and includes spindle microtubules and asters. some spindle microtubules attach to the kinetocores of chromosomes and move the chromosomes to the metaphase plate. in anaphase sister chromatids separate and motor proteins move them along the kinetochore microtubules toward opposite ends of the cell. meanwhile motor protein s push nonkinetochore microtubules from opposite poles away from each other elongating the cell. in telophase genetically didactical daughter nuclei form at opposite ends of the cell
mitotic spindle a closer look
fertilization involving a gamete that has not copy of a particular chr will lead to a missing chr in the zygote to that the cell has 2n-1 chr and this aneyploydi is called monosomic
monosomic
*gene duplication-allows organisms to have multiple copies of a gene but the original copy stays the same and the second copy can mutate leading to new phenotypes and natural selection
multiple copies of genes may provide new phenotypes
*gene that coded for digestive enzymes was copied *duplicated genes mutated *natural selection led to the evolution of the function of the protein the ten codes for : cold arctic temperatures, need to prevent blood from freezing, antifreeze gene evolved
multiple copies of genes may provide new phenotypes: antifreeze gene in fish
*growth of multicellular organisms *to repair damage or replace dead cells *reproduction- it is how unicellular organisms reproduce
name three reasons of cel division
error in meiosis in which homologous chromosomes fail to separate
nondisjuction
can produce things like kinefleter syndrome with XXY or turner syndrome with a monosomy of x, or XYY and XXX which are not as dangerous
nondisjuction in sex chr
*44 are outcomes *the other 2 are sex chromosomes either XX or XY
of the 46 human chromosomes in each diploid cell
*Oncogene is a gene associated with the development of cancer. It is derived from a mutated form of a normal cellular gene. Protooncogene is the normal un mutated version of the oncogene *oncogene is a gene found in viruses or as part of the normal genomes that is involved in triggering cancerous characteristics *protooncogene: a normal cellular gene corresponding to an oncogene; a gene with a potential to cause cancer but that requirers the same alteration to become an oncogene
oncogene vs protooncogene
continue to divide even when they are tightly packed together
one difference between cancer cells and normal cells is that cancer cells
*organisms have to react if they want to survive : they might move towards a stimulus or they might respond to their environment for matin g, avoiding danger, or finding food *to survive organisms must respond to external stimuli in a positive or negative way --> often leads to evolution
organisms respond to changes in their external environment
*a mechanism in which plants grow towards or away from the light--> auxins in the stem away from the light cause the cells to elongate which will cause it to bend --> good for surviving cause plants need light
organisms respond to changes in their external environment: phototropism in plants
*thermoregulation is the homeostatic maintenance of internal body temperatures, ectotherms gain most of their heat from external stimuli, low metabolic activity and most dominant in cold conditions, most invertebrates are ectotherms *may adjust body temperature by behavioral means such as seeking shade or basking in sun
organisms respond to changes in their external environment: thermoregulation in ectotherms
*bacteria's reaction to the stimulus of a population density *microfibers *they secrete chemicals thus attracting more bacteria which will secrete more chemicals which will attract more bacteria... *coordinates gene expression and can result in things like antibiotic resistance
organisms respond to changes in their external environment:quorum sensing in bacteria
three event in sexual reproduction contribute to genetic variation in a population:independent assortment of the chr during meiosis, cross ing over during prophase1, and random fertilization of egg cell shy sperm and sex. due to sister chromatid cohesion cross in over leads to chiasmata which hold homologs together until anaphase1
origins of genetic variation among offspring
*a tumor-suppressor gene that codes for a specific transcription factor that promotes the synthesis of cell cycle-inhibiting proteins *the guardian angel of the genome that is expressed when cells DNA is damaged. Its product the 53 protein functions as a transcription factor for several genes
p53 gene
between divisions cells are in interphase. the cell grows throughout interphase but dna is replicated only during the synthesis phase. mitosis and cytogeneses make up the mitotic m phase of the cell cycle
phases of the cell cycle
some organisms have more than two complete chromosome dents in all somatic cells. the general term for this chr alteration is polyployi
polyploidy
*genetic diversity: the biodiversity refers to the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability which describes the tendency of genetic characteristics to vary genetic diversity *species with little genetic diversity are tat risk for extinction because this does not allow for one species to be affected by an ill or other outside factor without affecting the whole species
population ability to respond to changes in the environment is affected by genetic diversity. Species and populations with little genetic diversity are at risk for extinction
*the chicken is loosing its habitat so it has been forced to adapt
population ability to respond to changes in the environment is affected by genetic diversity. Species and populations with little genetic diversity are at risk for extinction: prairie chickens
*the nuclear membrane breaks apart, the spindle pushes through the cytosol, and microtubules of the spindle begin to attach to the kinetochore of chromosomes *the nuclear envelope fragments *the microtubules extending from ach centrosome can now invite the nuclear area *the cur have become even more condensed *each of the two chromatids of each chromosome now has a kinetochore, a specialized protein located at the centromere *some of the microtubules attach to the kinetochores becoming kinetochore microtubules ; these jerk the cur back and forth *non kinetochore microtubules interact with those from opposite pole of the spindle
pro metaphase
*prokaryotes reproduce by a type of cell division called binary fission where the chromosome duplicates, each duplicate chromosome attaches to the plasma membrane and grows until it separates
prokaryotinc reproduction
*the duplicated chromatin now coils up into chromosomes and pairs with its identical copy. this pairing is now called sister chromatids and they are joined by a centromere *the nuclear membrane, nucleolus and the nucleus disappear *each duplicated chromosome appears as two identical sister chromatids joined at their centromeres and all along their arms by cohesins *miotic spindle begins to form *the centrosomes move away from each other *the centrioles begin to move towards the opposite ends of the cell *spindle fibers, a network of microtubules, begin to form between the centrioles. Smaller fibers called asters form behind the centrioles *during prophase the spindle apparatus forms, chromatin coils into dense chromosomes , the nucleoli disappear, and centrosomes move to opposite poles
prophase
*during prophase one chromosomes pair with their homologous pairs which form the tetrad *within a tetrad portions of the chromatids of the two homologous may cross over exchanging genetic information. The x that is formed by the crossed over regions is called chiasma (usually one or more) and the process that formed the x is called synapsis--> synapsis ends in mid prophase and the chromosomes in each parer move apart slightly *chromosomes begin to condense and homologous loosely pair along their lengths alined gene by gene *centrosome movement spindle formation and nuclear envelope breack down occur as in mitosis * in late prophase one the microtubules from the pole or the other attach to the two kinetochore protein structures at the centromeres of the two homologs and the homologous pairs tun move to metaphase plate for metaphase 1
prophase 1
*a spindle apparatus forms *in late prophase 2 chromosomes each still composed of two chromatics associated at the centromere move tower the metaphase 2p plate
prophase 2
prophase is the prep time where the cell makes initial preparations
prophase is the ___
*enzymes in apoptosis that cut up other proteins and dna of a cell *when a signal occurs ced-9 is inactivated and then an apoptotic pathway activates protases and nucleases
protases
*are enzymes that activate or inactivate other proteins by phosphorilating them. particular protein kinases give the go ahead signals at the G1 and G2 checkpoints
protein kinases
it is in the S phase in interphase when the pieces of chromatin replicate making a copy of themselves because thy are getting ready to reproduce but they are not reproducing yet.
puberty of a cell
the random nature of fertilization adds to the genetic variation arising from meiosis. in humans each male and female gamete represents one of about 8.4 million possible chromosome combinations due to independent assortment. the fusion of the male gamete with a female gamete during fertilization will produce a zygote with about 70 trillion diploid combinations.
random fertilization
* A gene that codes for Ras, a G protein that relays a growth signal from a growth factor receptor on the plasma membrane to a cascade of protein kinases, ultimately resulting in stimulation of the cell cycle. *This gene codes for Ras protein, a G protein that relays a growth signal from a growth-factor receptor on the plasma membrane to a cascade of protein kinases that ultimately results in the stimulation of the cell cycle. Many ras oncogenes have a point mutation that leads to a hyperactive version of the Ras protein that can lead to excessive cell division.
ras gene
*growth of multicellular organisms *to repair damage or replace dead cells *reproduction-it is how unicellular organisms asexually reproduce
reasons for cell division
is not asexual reproduction as it only replaces lost cells and the lost cells do not become a new organism
regeneration
*2 diploid cells with identical 46 single copy chromosomes
result of mitosis
*4 haploid cells with 23 single copy chromosomes that are one of each kind *males: all four are viable cells in the form of sperm *females: of the four cells created only one will become an egg and the other three becoming polar bodies with little cytoplasm yet having the full 23 chromosomes
results of meiosis
2 daughter cells with identical genetic material
results of mitosis
*signal transduction is a mechanism linking a mechanical or chemical stimulator to a specific cellular response
role of signal transduction in cancer
normal numan somatic cells are diploid they have 46 chr made up of two dents of 23 - one sent from each parent. in a human diploid cells there are 22 homologous pairs of autosomes each with a maternal and parental homologous the 23rd pair the sex chr determines the sex of a person
sets of chr in a human cells
*more variation fro natural selection/ adaptation--> beneficial in a changing environment *decreased risk of extinction due to variation
sexual reproduction advantages
*energy lost for mating and mating cycles *if no mate is available then reproduction is impossible *changes in population may lead to eventual troubles *recessive disorders are more likely to show up
sexual reproduction disadvantages
two organisms contribute genetically
sexual reproduction examples
crossing over
she the tetrad forms what process occurs where pieces of homologous chromosomes are traded
*signal transmission role: hormones or neurotransmitters bind to a receptor and send a signal into the cell to conduct a specific function
signal transmission within and between cells mediates cell function and gene expression
*p53 a protein which regulates the cell cycle repairs damaged DNA and initiates apoptosis --> DNA damage and stress signals trigger p53 proteins and if the p53 gene is damage d mutated or deleted then the protein can not function
signal transmission within and between cells mediates cell function and gene expression : changes in p53 activity can result in cancer
*cytokinin: protein hormones that are released by cells *gene expression: precess wehre genes encode proteins to regulate cell function *cell differentiation: process where cells become more specialized
signal transmission within and between cells mediates cell function and gene expression : cytokinesis regulation gene expression to allow for cell replication and division in plants
*the production of ethylene is regulated by internal signals during development and in response to the environmental stimuli from biotic and abiotic stresses *ethylene signals make enzymes because ethylene turns on genes that are then transcribed and translated to make these enzymes
signal transmission within and between cells mediates cell function and gene expression : ethylene levels cause changes in the production of different enzymes
*the chromosome identical pairs each duplicated chromosomes has two sister chromatids. the two chromatids each containing an identical dna molecule are initially attached all along their lengths by protein complexes called cohesins --> sited chromatid cohesion
sister chromatids
all body cells except for reproductive cells that have 46 chromosomes
somatic cells
*phenotypic variations:variations in traits or characteristics *fitness: ability of an individual measured by the number of its offspring that survive and reproduce with the phenotype-> variations can either help produce offspring or not *variations in natural selection can help a population flourish as well as cause a population to be more susceptible to extinction--t his is a part of evolution within species
some phenotypic variations significantly increase or decrease fitness in organisms and the population
*DDT is a colorless synthetic compound used as a pesticide for insect control --> insects have evolved resistance to it due to natural selection in a mutation in a gene which makes insects break down DDT until its no longer toxic to them *this phenotypic variations is advantageous to insist because it saves them from being killed
some phenotypic variations significantly increase or decrease fitness in organisms and the population: DDT resistance
*allele is a result of a point mutation in hemoglobin *codominance *harmful recessive alleles can persist in populations because they can hide behind dominant alleles due to heterozygous advantage *regions where malaria is common the resistance against malaria outweighs the disadvantage of having heterozygous sickle cell anemia --> aa is not advantageous bc hemoglobin cannot cary oxygen though you have protection against malaria
some phenotypic variations significantly increase or decrease fitness in organisms and the population:sickle cell anemia and the heterozygote advantage
*independent assortment of the chromosomes *recombination through sexual reproduction: each combination of mom and dad DNA is different *crossing over during meiosis: chromosome inherited is part from mom and dad *mutation: DNA changes: chromosomal rearrangements and nucleotide changes *random fertilization: not picking mate abased on characteristic leads to variation
sources for genetic variation that eventually could lead to changes in populations via evolution
32--> 2^5
starting with a fertilized egg/zygote a series of five cell division would produce an early embryo with how many cells
*the spindle breaks down because it is no longer needed *the chromosomes begin to uncoil and turn back into chromatin *the nuclei begin to form around the 2 groups of chromatin --> two daughter nuclei form in the cell and nuclear envelopes arise from the fragments of the parents cells nuclear envelope and other portions of the endomembrane system *nucleoli reappear *daughter nuclei from the 2 poles and chromatin unwinds *mitosis is now complete
telophase
*at the begging of telophase one each half of the cell has a complete haploid set of replicated chromosomes. ash cur is composed of two sitter chromatids one or both include reins of non registered chormatid dna *cytokinesis usually occurs simultaneously with telophase one forming to haploid daughter cells *in animal cells a cleavage furrow forms *in some species chromosomes decadence and the nuclear envelop e reforms *nor explication occurs between meiosis one and two
telophase 1 and citokinesis
*nuclei form the chromosomes begin decondensing and cytokenises occurs *the meiotic division of one parent cell produces four daughter cells each with a haploid set of genetically distinct chromosomes --> each of the 4 daughter cells is distinct from tother daughter cells and parent cells
telophase 2 and cytokenises
4n
tetraploidy
F
tf apoptosis includes lysis of the cell
cyclic changes rin regulatory proteins work as a cell cycle clock. the clock has specific checkpoints where the cell cycle stops until a go ahead signal is received. the key molecules are cyclins and cyclin dependent kinases aka cdks. cell culture has enabled researches to study the molecular detail of cell division both internal signals and eternal signals control the cell cycle checkpoints via transduction pathways. most cells exhibit density dependent inhibition of cell division and well as anchorage dependence
the cell cycle control system
interphase
the cell spends most of the time in what phase of the cell cycle
interphase
the cells spend most of the time in what phase of the cell cycle
the degradation of cylin
the decline of mpf activity at the end of mitosis is due to
without crossing over, indp assortment of the ch during meiosis 1 theoretically can create d^# of chr possible haploid gametes and fertilization can produce d^# x d^# possible diploid cellos because the haploid number of the grasshoppers ins 223 and that of fruit flies is 4 two grasshoppers would be expected to produce a greater variety of zygotes than two fruit flies
the diploid huber of fruit fliers is 8 while that of a grasshopper is 46 if no crossing over took place would the genetic variation among the offspring from a given pari of parents be greater in the fruit flies or grasshoppers
cleavage furrow formation
the drug cytochalasin b blocks the function of action which of the following aspects of the cell cycle would be disrupted by this drug
since prokaryotes preceded eukaryotes by more than billion years it is likely that mitosis evolved from prokaryotic cell division. certain protest exhibit types of cell division that seem intermediate between binary fission and the process of mitosis of eukaryotic cells
the evolution of mitosis
genetic variation is the raw material for evolution by natural selection. mutations are the original source of this variation the production of new combinations of variant genes in sexual reproduction generates additional genetic diversity
the evolutionary significance of genetic variation within populations
*46 chromosomes split into 2 nuclei with 23 chromosomes (one chromosome of each kind) *cytokines follows both division s but interphase only follows the sectioned division *in meiosis one homologous chromosomes line up together to form a tetrad then separate to form two new cells each with a double copy of one chromosome *during prophase one chromosomes pair with their homologous pairs which form the tetrad *within a tetrad portions of the chromatids of the two homologous may cross over exchanging genetic information. The x that is formed by the crossed over regions is called chiasma and the process that formed the x is called synapsis
the first nuclear division of meiosis
the nucleus is still visible in interphase
the nucleus and interphase
metasis
the process of cancer spreading
*23 chromosomes split into 2 nuclei with 23 single copy chromosomes *cytokines follows both division s but interphase only follows the sectioned division *in meiosis II the homologous chromosomes separate just like in mitosis leaving four cells with a single copy of each of the kinds of chromosomes, 23 in human cells
the second nuclear division of meiosis
the two cell division s of meiosis produce four haploid daughter cells. the number of chr is reduced from diploid to haploid during meiosis 1 the reductional division
the stages of meiosis
sexual life cycles differ in the timing g of meiosis relative to fertilization and in the points of the cycle at which a multicellular organism is produced by mitosis
the variety of sexual life cycles
a plant cell in the process of cytokinesis
though a microscope you can see a cell plate begin gin to develop across the middle of the cell and nuclei reforming on tier of the cell plate. this cell is most likely
moves a segment from one chr to a non homologous chr. in a reciprocal translocation the most common type non homologous chr exchange fragments in a non reciprocal translocation which is less common a chr transfers a fragment without receiving a fragment in return
translocation
3n
triploidy
if a chr is present in the triplicate in the zygote so that the cell has 2n +1 chr it is called trisomic--> trisomy 21 = down
trisomic
false-brain cells, muscle cells rarely divide after maturity
true or false: all human body cells are constantly dividing
a gene whose protein products inhibit cell divisions thereby preventing uncontrolled cell growth
tumor suppressor gene
if the segments of the maternal and parental chromatids undergo crossing over are genetically identical and thus have the same two alleles for every gene then the recombinant chromosomes will be genetically equivalents to the parents chr. crossing over contributes to genetic variation only when it involves the rearrangement of different alleles
under what circumstances would crossing over during meiosis not contribute to genetic variation among daughter cells
*gametophyte *alternation of generations *sporophyte--> spores
variety of sexual life cycles
*asexual reproduction where a small cutting of a plant can grow into a new plant
vegetative propagation
disruption of mitotic spindle formation
vinbastine is a standard chemotherapeutic drug used to treat cancer because it interferes with the assembly of microtubules its effectiveness must be related to
*coil up - chromatin becomes chromosomes *pair up into sister chromatids
what 2 things does the DNA do in prophase
autosomes
what are 22 non sex chromosomes called
replacing dead cells and growth and development periods
what are 3 scenarios where mitosis is common
they are a network of microtubules that begin to form between the centrioles
what are spindle fibers and where do they occur
salinity ph heat
what are the 3 ways to denature an enzyme
interphase, prophase, metaphase, anaphase, telophase
what are the 5 phases of cell reproduction in order
prohase, pro metaphase, metaphase, anaphase, telophase
what are the 5 phases of mitosis
muscles, neurons, organs that are fully formed (no growth/development) although some cells are replacing damaged cells in some organs
what are the cells that are in G0 pahse called
sister chromatids
what are the identical strands of DNA that are held together to tom bivalent chromosomes
spindle fibers
what are the microtubules that shorten to move chromosomes to opposite sides of the cell during mitosis
XX
what are the sex chromosomes of a female
budding, vegetative propagation/ cuttings, binary fission
what are the three examples of asexual reproduction
interphase, mitosis, cytokinesis
what are the three stages of the cell cycle
G1, S, G2
what are the three sub phases of inter phase
all life in males, 4 gamers in males, egg: unequal cytoplasm in females starts, stops, starts, stops
what are the tree differences between meiosis in females and males
rna and protein
what are the two primary components of a ribosome
transpiration /cohesion
what are the two processes tha tallow most water to move up a tall tree
*mutations *sexual reproduction:two sources *random fertilization: sperm egg choice *crossing over: mixes chromosomes more *independent assortment of the chromosomes
what are the ways to increase viration
homologous chromosomes: same genes but different alleles for those genes
what are two chromosomes called that are the same type with one coming from each parent
*repaire damage *growth/development *reproduction
what are two reasons that the cells divide
*they may make too much of a certain enzyme or have failure to produce a certain enzyme *they can use up all of the resources or space, they can due this due to their uncontrollable mitosis/spread
what can mutated cells/ cancer cells do
crossing over
what can occur during prophase I of meiosis that increases genetic variation
cell division, when replicating dna, the cell can't get all the way to the end of the dna molecule so some is lost each time
what causes telomeres to shorten?
homologous pair, homologues
what do we call a pair of the same chromosomes
homologous chr
what do we call a pair of the same type of chr
karyotype
what do we call a picture of a smooched metaphase cell that shows all of the chromosomes
metaphase plate
what do we call the line of chromosomes formed in the middle of the cell during metaphase
chiasma
what do we call the x that is formed by the tips of chromosomes when why are crossed over
cancer
what do we call uncontrolled cell division
it keeps the chromosomes number exactly the same in the daughter cells 46-46 & 46
what does mitosis do
it is a normal cell division that creates all of our somatic body cells
what does mitosis do for us
cell plate
what forms in the middle of a dividing plant cell to from the new cell wall
synapsis- homologous chromosomes find each other
what happens during prophase I of meiosis that is different from what happens in prophase of mitosis
cell grows and normal cell activity
what happens during the G1 and G2 sub phases of interphase
centromere/kinetochore
what holds sister chromatids together
centromere
what holds two sister chromatids together
growth
what ihappens during the g1 and g2 sub phases of interphase
they elongate the cell during anaphase
what is a function of non kinetochore microtubules
gene
what is a short section of dna that codes for a protein
protective cap on the end of chromosomes that shortens after each cell division until it is gone and genes are actually effeccted.
what is a telomere?
tumor
what is any mass of abnormal cells
tumor
what is any mass of abnormal undifferentiated cells
in meiosis I they line up in homologous pairs in mitosis they like up singly
what is different about how chromosomes line up in metaphase 1 meiosis and metaphase of mitosis
*it is when all the pieces of chromatin replicate- make a copy of themselves *happens during the S phase in interphase
what is dna replication and when does it occur
metastasis
what is it called when cancer cells enter the blood stream and start dividing in a new location
metastasis
what is it called when cancer cells enter the bloodstream and start dividing in a new location
contact inhibition
what is it called when cells stop dividing when they run out of space
enzyme that adds telomere to the chromosome making it more protected
what is telomerase?
cytokinesis
what is the division of the cytoplasm
egg/ovum
what is the female gamete
oxygen
what is the final e acceptor in etc in aerobic cellular respiration
a sufficient amount of mpg has to build up for a cell to pass the g2 check point
what is the go ahead signal for a cell to pass the g2 phase check point and enter mitosis
sperm
what is the male gamete
nondisjunction
what is the name for any chromosomal mutation where the individual does not have a pair of each of the 23 chromosomes
mutations in a gene lead to the different versions alleles of that gene
what is the original source of all the different alleles of a gene
cleavage furrow
what is the place where protein belts accomplish cytokinesis in animal cells
cell plate
what is the place where the golgi bodies line up and make a new cell wall during cytokenises for plant cells
increased variation
what is the purpose of crossing over
to make gametes for sexual reproduction
what is the purpose of meiosis
centromere
what is the region of the chromosomes where 2 sister chromatids are joined
fermentation
what is the second stage of anaerobic respiration
2n
what is the symbol for diploid
ion
what is the term for an atom that has a charge
telophase
what is the undoing of prophase
chromatin
what is the unwound form of the DNA /protein combination
chromosomes
what is the wound up form of the DNA/ protein combination
benign
what kind of tumors are not spreading
malignant
what kind of tumors are spreading
cyclins
what molecule builds up during g2 to trigger the beginning of mitosis
centrioles
what organelle helps with cell division but is absent in plant cells
g0--> a non dividing phase
what phase are most of your body cells in
prophase 1
what phase of meiosis is when crossing over occurs
kinetochore
what portion o the sister chromatin's attaches to spindle fibers
kinetochore/centromere
what portion of the sister chromatids attach to the spindle fibers
amniocentesis
what procedure is used to harvest cells for karyotyping from a baby still in the womb
growth factors
what proteins directly stimulate the cell to divide
interphase
what stage is this in
it is in anaphase
what stage is this in
it is the results of mitosis where there are 2 identical sets
what stage is this in
metaphase
what stage is this in
it is in prophase 1) centriole 2)centromere 3)spindle fiber 4)one of the sister chromatids 5)aster
what stage is this in and label all the parts
it is in telophase 1)cleavage furrow in animal cells
what stage is this in and label the parts
interphase
what stage of the cell cycle takes the longest
Anchorage dependence
what term describes the concept that cells will only divide when anchored into a substrate such as a tissue
density dependent inhibition
what term describes the concept that cells will stop dividing when they are crowded
angiogenesis
what term describes the formation of new blood vessels that will grow toward a cancerous tumor
XX
what two sex chromosomes does a female have
XY
what two sex chromosomes does a male have
cancer cells
what type of cells do not exhibit density dependent inhibition and anchorage dependence
meiosis
what type of nuclear division is involved when cell division creates haploid cells from diploid cells
cyclins
what type of proteins are sometimes needed to activate kinases
kinases
what type of proteins transfer a P from ATP to other proteins to activate them to start the next phase of cell division
kinases
what type of proteins transfer a p form atp to other proteins to activate them to start the next phase of cell division
benign
what type of tumor remains at its original site
neuron muscle and organs
what types of adult cells generally are in g0 as a teenager
*if a receptor protein for death signaling molecule was defective so that it was activated for signaling even in the absence of the death signal this would lead to apoptosis when it wouldn't normally happen
what would lead to apoptosis when it wouldn't normally occur
daughter chromosomes
when a centromere is pulled apart during the separation of a bivalent chromosome what is the resulting chromosome called
*the pulling away of the chromatids splits the centromeres in anaphase
when and what causes the centromeres to split
*in the gonads, the germ cells give rise to the gametes *females: begins before two years old then starts again during puberty with one egg made each month, menopause is when eggs are no longer formed *males: happens through life from puberty to death
when and where does meiosis occur
only during mitosis/ meiosis
when are chromosomes present in the cell cycle
in metaphase
when are the chromosomes lined up in the middle of the cell
during prophase
when do centrioles begin to move to opposite ends of the cell
in telophase
when do chromosomes begin to uncoil and turn back into chromatin
during prophase
when do chromosomes pair with its identical copy to create sister chromatids
during anaphase
when do sister chromatids split from each other
during metaphase
when do sister chromatids stay as sister chromatids
during metaphase
when do spindle fibers attach to centromeres
in telophase
when do spindle fibers break down
during prophase
when do the membrane, nucleolus, and the nucleus disappear
during anaphase
when do the spindle fibers shorten and begin pulling on the sister chromatin's
during prophase
when does chromatin coil up into chromosomes
in telophase
when does the nuclei form
tetrad (4)
when the two homologous bivalent chromosomes line up during meiosis I what is the combination called
*any cell not in g0 phase, except in the gonads *throughout the life in some cells but cell division stops in nerve cells and muscle cells in early life like 2-3 years old
where and when does mitosis occur
gonads
where are gametes made in humans
ovaries
where does meiosis in females occur
fame gonads: ovaries
where does meiosis occur in females
gonads
where does meiosis occur in humans
male gonads: testes
where does meiosis occur in males
the gonads- the ovaries (oocytes), testes (spermatocytes)
where in the human body does meiosis take place
mulicelluar haploid
which life cycle stage is found in plants but not animals
s: synthesis
which sub phase of interphase doubles/replicaties the DNA
mitosis, cytokinesis
which two stages of the cell cycle are involved in cell division
a female xx while a make has xy
who does the karyotype of a human female differs from that of a human male
*because each daughter cell receives an exact copy of the genetic material of dna
why do cells duplicate their genetic material before they divide
so each nucleus has its own exact copy of chromosomes
why does replication have to happen before mitosis
skin cells are constantly dividing muscle cells are not
why is it worse to damage a muscle cell than a skin cell
mucle cell they don't divide any more
why is it worse to damage a muslce cell than a skin cell
increases genetic variation by chr begin mixed so more potential possibilities
wwhy is crossing over important
