Chapters 9, 10, 11, 12

Question 1

mitosis terms
genome
chromosome
somatic
diploid
gametes
haploid
zygote
cohesions
centromere
mitosis 
cytokinesis

Answer 1

genome- all organisms genetic info
chromosome-contains very long strand of NDA with specific genes for organism (histones also present)
somatic cell- body cell, 2n diploid cell, pair of homologous chromosomes
gametes-n (23) one set of homologous chromosomes, their haploid
zygote-first body cell
cohesions- two sister chromatids genetically identical held together by cohesions- protein complexes known as sister chromatid cohesion
centromere-connects sister chromatids that contain specific DNA sequences where chromatids attached closely
mitosis- division of nucleus
cytokinesis-division of cytoplasm

Question 2

interphase

Answer 2

90% of cell cycle

• synapses ( s phase ) DNA replicated (chromosomes duplicated) cell growth continues
• G1 phase - first gap, , growth of cell, occurs first
• G2 phase- second gap after s phase cell prepares for division
• order G1, S G2 then mitosis or G0
• G0 cells that are not dividing go into phase G 0 the cells have left the cell cycle and are doing their job ex;nerve cells sending impulses

Question 3

mitotic spindle

Answer 3

forms during prophase, fibres made of microtubules. when spindle assembles, other microtubules disassemble to provide material for the spindle. the spindle elongate or polymerize by incorporating subunits of the protein tubular.
CENTROSOME assemble spindle and are composed of two centrioles, the centrioles duplicate during during interphase MOVE DURING PROPHASE - start to move to opposite poles
-prometaphase- microtubules polymerize from centrioles and there is a centrosome at each pole
-aster- radial array of short microtubules expanding from each centrosome
-kinetochore-specific regions of DNA on centromere one facing each way that attach to spindle (they are made of proteins) microtubules attach to kinetochores on each sister chromatid during PROMETAPHASE THE ONES THAT ATTACH ARE CALLED KINETOCHORE MICROTUBULES
—sister chromatid linked to kinetochore microtubules will move toward the pole it extended from , kinetochore connected from each side and align chromosomes in the centre ( METAPHASE) metaphase plate.
-microtubules with out kinetochore overlap and interact they are called polar microtubules that push against each other to elongate the cell

Question 4

chromosome movement

Answer 4

• motor proteins on kinetochore walk along microtubule which depolymerizes at their kinetochore ends after the motor proteins walk across
• motor proteins walk away from one another shortening the over lapped region and elongating the cell (polar microtubules)

Question 5

stages of mitosis / interphase

Answer 5

G2- nuclear envelope and nucleolus present, 2 centrosomes formed
**prophase- chromosomes condense and become visible. nucleoli disappear and each chromosome appears as two identical sister chromatids joined at the centromere.- mitotic spindle begins to form and microtubules extend from centrosome and move away from each other
**prometaphase- nuclear envelope fragments -microtubules enter nucleus -chromosomes very condensed- each sister chromatid has a kinetochore -microtubules attache to kinetochore and they move chromosomes back and forth. -non kinetochore microtubules interact with ones opposite
** metaphase- centrosomes at opposite poles -chromosomes at metaphase plate -each chromosome has two sister chromatids kinetochores attached to kinetochore microtubules
**anaphase- shortest stage -cohesion proteins are cleaved and chromosomes part -chromosomes move to opposite poles ( as kinetochore proteins shorten) cell elongates as nonkinetochore microtubules lengthen, end of cell has complete set of chromosomes
telophase- daughter nuclei form and nuclear envelop. nucleoli reappear and chromosomes decondense and microtubules depolymerize mitosis is complete

Question 6

cytokinesis

Answer 6

division of cytoplasm, it can overlap with telophase.

• animal cell-cleavage-process –cleavage furrow-groove near metaphase plate, contractile ring of actin filaments that work with protein myosin, their interaction causes ring to contract like a draw string, and cell pinched into two
• plant cell no cleavage furrow -vesicles carry cell wall material, vesicles from golgi move to middle of the cell and join together to produce the cell plate which enlarges until surrounding membrane from vesicles fuse with plasma membrane

Question 7

binary fission

Answer 7

asexual - cell doubles in size and divides no mitosis because there is no nucleus -bacterial chromosome, genes in singular ring. ecolie- cell division begins when bacterial chromosome begins to replicate at the origin of replication
dinoflagellates -chromosomes attach to nuclear envelop and remain intact, microtubules go thru cytoplasmic tunnels into nucleus

Question 8

evolution of mitosis

Answer 8

evolved from simple eukaryote - binary fission gave way to mitosis – intermediate stages -dinoflagelates, diatoms, yeast nuclear envelope stays intact

Question 9

checkpoints and cell cycle control

Answer 9

cell is regulated at check points
checkpoint- stop and go signals regulate the cell cycle -determine if cell should continue and they register signals outside of the cell
G1- most important- no go enter G0-nondividing (can reenter G1 if growth factor received)
-cell regulated by regulatory proteins-kinases and cyclins
M phase- separation does not occur in anaphase until all chromosomes are at metaphase plate during metaphase

Question 10

physical signalling

Answer 10

density dependance inhibition– crowded cells stop dividing
anchorage dependance-cells must be attached to ecm to divide and this is involved with membrane proteins (cancerous cells do not have these signals )

Question 11

homologous chromosomes

Answer 11

one from mom and one from dad same genes different alleles

Question 12

review sexual life cycles before final

Answer 12

do it

Question 13

meiosis 1

Answer 13

p1- chromosomes condense homologs pair up and align along the lengths with the same genes and they attach by proteins called synaptonemar complex, synapsis crossing over occurs
mid prophase- disassembly of synaptonemal complex at the end of the synapse chromosomes move apart slightly (chiasmata is the x shaped region where crossing over occurred) nuclear envelop breaks and spindle begins to move
late prophase- microtubules attach to kinetochore
m1- pairs of duplicated homologs lie up at metaphase plate INDEPENDENT ASSORTMENT
a1- break down of siterchromatid cohesion proteins. homologs move to opposite poles but SISTER CHROMATID COHESION IS STILL AT CENTROMERE
t1 each side has complete set of duplicated chromosomes cytokinesis occurs

Question 14

meiosis 2

Answer 14

no dna replication occurs before (does in m1)
p2-spindle forms sister chromatids that aren’t genetically identical due to crossing over move to metaphase plate
m2chromosomes at metaphase plate
a2- break down of proteins holding sister chromatids together at centromere the chromatids separate and move to opposite poles
t2- uncle form and chromosomes decondense and cytokinesis cytokinesis occurs and there are now four genetically different cells

Question 15

three unique events in meiosis

Answer 15

1. synapsis (crossing over) ( formation of synapse complex holds them
2. homolog pair at metaphase plate in metaphase one 00 00. and INDEPENDENT ASSORTMENT
3. seperation of homologs in anaphase one duplicated chromosomes move to each pole and sister chromatids stay together until they are separated in meiosis 2

Question 16

chiasma

Answer 16

site of crossing over

Question 17

genetic variation

Answer 17

independent assortment- random orientation of paris of homologs at m1 plate and maternal and paternal chromosomes have 50/50 chance of being either way all of them are independent to eathother so gametes have a random mix of paternal and maternal chromosomes
crossing over- chromosomes mixture of maternal and paternal chromosomes - usually 3 crossover events occur so then the chromosomes in gametes carries genes from both mom and dad this creates a new combination of alleles and the sister chromatids are no longer identical
random fertilization- 8.4 million possible combinations of gametes for both male and female– changes up alleles

Question 18

mendels experiment

Answer 18

parents pass on heritable units called characters that vary amongst organisms he bread garden peas to observe and track distinct characters he bread two organisms with the same alleles

Question 19

four concepts that make up menders 3:1 inheritance of F2 gen

Answer 19

1. versions of genes account for variations in inherited characteristics – certain genes exist in multiple versions called alleles
2. for each character organisms inherit 2- one from mom one from dad- if two alleles differ they are hybrids
3. tow alleles differ the dominant allele determines the appearance and the recessive is not shown
4. law of segregation of alleles - two alleles of a gene segregate from each other during gamete formation

Question 20

test cross

Answer 20

breeding unkown organisms with recessive homozygote to reveal the genotype

Question 21

probability

Answer 21

law of segregation and independent assortment have the same rules as probability– 0 to1 1 it will happen 0 it won’t happen- the outcome of the event is unaffected by the previous event
FOR FINAL GO OVER COMPLEX GENETIC PROBLEMS AND PROBABILITY ITS TO HARD TO PUT ON A FLASHCARD

Question 22

complete dominance

Answer 22

recessive gene completely masked

Question 23

incomplete dominance

Answer 23

neither allele completely dominant so it is blend the phenotype between parents/ heterozygous individuals have a blend

Question 24

codominance

Answer 24

two alleles effect phenotype in separate ways ex; blood type– ab has allele a and b BOTH TRAITS ARE SHOWN

Question 25

tay sachs disease

Answer 25

cannot metabolize lipids because enzyme is defective and this is in the brain if you have recessive allele you have the disease and it is considered codominant because heterozygous individuals can make both enzymes – heterozygous produce enough normal enzyme so the symptoms are not shown –half normal enzyme, half recessive therefore its codominant

Question 26

pleitropy

Answer 26

single allele has multiple effects on phenotype in humans this is sickle cell anemia and cystic fibrosis

Question 27

epistasis

Answer 27

phenotypic gene at one locus alters gene at a second locus – labs - hair colour black is dominant and brown is recess if second gene if pigment is in hair e pigment dog can be black or brown depending on the alleles
ee dog will not produce pigment regardless of the colour

so if pigment is produced EE or Ee the dog is going to be colour black or brown but if the dog has the phenotype for hair BB so it will be black and it does not produce pigment ee it will be yellow even though it doesn’t have the recessive allele
** gene pigment for deposition E or e is epistatic to the gene that codes for the black or brown pigment

Question 28

polygenic inheritance

Answer 28

effect of two or more genes (opposite of pleiotropy) – skin pigment is controlled by three different genes

Question 29

phenotype and environment

Answer 29

phenotype reflects overall genotype and unique environmental history

Question 30

pedigree analysos

Answer 30

DO WORKSHEET ON FOR FINAL

Question 31

recessively inherited diseases

Answer 31

it could code for a protein that is defective or no protein at all. the disease only shows up in recessive individuals , heterozygous individuals are okay because the dominant trait makes them healthy but the still carry the disease

• cystic fibrosis- normal allele codes for membrane protein that transports chloride ions the recessive allele is defective so there is a high cellular concentration of chloride ions which creates thick mucus in the pancreas LUNGS and digestive track
• sickle cell- substitution of amino acid in hemoglobin the homozygous recessive creates abnormal hemoglobin and it deforms red blood cells and transports low levels of oxygen because they can’t function properly and can clog blood vessels. heterozygous individuals produces both types of hemoglobin (CODOMINANCE) and in africa 1 in 10 people carry the trait because heterozygous individuals are immune to malaria because it lowers the parasite density and reduces the symptoms. in malaria environment like the lowlands of rest africa carriers of the trait have an advantage

Question 32

chromosome theory of inheritance

Answer 32

walter sutton and Theodor borer said that mendelian genes are on specific loci on a chromosomes and when the pairs segregate and undergo independent assortment the two different traits on different chromosomes can be carried – the behaviour of the chromosomes account for segregation

Question 33

morgan

Answer 33

proved chromosomes are the location of menders heritable factors with his fruit fly experiment drosophila in 1907 he looked at the flies because they breaded fast and they had four distinguishable chromosomes
he mated a male with a mutation of white eyes and a female with the wild type red eyes, the result was 3;1 ratio of red and white eyes (1 being white) and it only showed up in males - the second generation had all females with wild type eyes and half males with mutant and the other half with wild type this must mean that the eye colour is linked to sex. the gene involved with white eyes located on sex chromosome x and no corresponding allele on the y chromosome
(male xy) either white or red no dominant allele(female xx)only half females could have white eyes if she had recessive genes

Question 34

sex linked genes

Answer 34

male xy female xx y small only some regions are homologous with x and this allows them to separate in meiosis all female gametes are only x so the sperm determines sex by either giving it x or y the genes on x or y are sex linked genes

Question 35

inheritance of x linked genes

Answer 35

fathers pass x to daughters, sons only get x genes from mom if x is recessive males display no matter what, but since females have xx they must be homozygous recessive to display the recessive traits this is why more males inherit more x linked recessive disorders like colour blindness– if a daughter is colourblind the father must be colour blind and the mother must have been a carrier atlas

Question 36

x inactivation in females

Answer 36

since there are two xs in females one chromosome in each cell is inactivated so the cells in male or female only have one dose of the x linked genes
barbody- inactive x chromosome it condenses and lies along the inside of the nuclear envelop- genes are not expressed
mary lyon- selection of which x will form barbody will occur randomly and independently from each embryonic cell present at the time of inactivation– females have two different types of cells x from mom and x from dad
- inactivated x has DNA modification and histone proteins on x chromosome regions have several genes involved in the inactivation process 2 regions on the x chromosome associate the X INACTIVE SPECIFIC TRANSCRIPT and becomes active on one

Question 37

linked genes are inherited together

Answer 37

genes near each other are inherited together and they are called linked genes
fruit fly– colour and wing size have two different phenotypes the results varied and there was a much higher portion of parental types and the reason was because these two traits were inherited together.
genetic recombination-chances genes aren’t always linked- depending where crossing over can occur although unlikely is the production of offspring with combination of traits that differ from parental type

Question 38

new combinations of alleles

Answer 38

results from evolution and natural selection– variation results from crossing over and independent assortment – recombinant chromosomes have alleles that are different in combination as gametes, there are multiple possibilities of the distribution of the gametes and there is also random fertilization increasing the variant allele combinations this variation is the raw material for natural selection

Question 39

abnormal number of chromosomes

Answer 39

-nondisjunction-homologs do not separate in m1 or sister chromatids do not separate in m2 the zygote has abnormal number of chromosomes and this is called aneuploidy
-monosomic- one less
-trisomic 2n+1 ( one more)
downsyndrome- trisomy** on the 21st chromosome nondisjcution can occur in mitosis errr in the embryo is passed on
polyploidy- make more than 2 sets in somatic cells - produced by fertilization and nondisjunction of all chromosomes – this is common in plants

Question 40

alteration of chromosome structure

Answer 40

deletion- removal of chromosome segments resulting in missing genes
duplication- deleted fragment becomes attached to a sister chromatid and the segment is repeated
inversion- deleted ferment of chromosome reattaches backwards
translocation-deleted fragment joins a non homologous chromosome
* deletion and duplication are very likely in meiosis due to crossing over- non sister chromatids sometimes share unequal amounts of dna
missing genes are lethal- extra genes are harmful if they alter the phenotype they can be really bad

Question 41

aneuploidy of sex chromosomes

Answer 41

klinefelter syndrome males xxy- effects males sex organs and characteristics – small testes- sterile- some breast tissue- subnormal intelligence- female characteristics common
xyy- men basically normal
xxx– females slightly taller risk for learning disabilities
xo- female- called turner syndrome females are sterile sexual organs do not mature and they have normal intelligence

Question 42

structurally altered chromosome conditions

Answer 42

deletion- cru du chat - cry of the cat-cry sounds like cat- person intellectually disabled with a small head and unusual features
translocation- chromic myelogenous leukemia0 recipricol translocation of mitosis of white blood cells - large portion of chrome 22 switched with small portion of chrome 9 called the philadelphia chromosome – 22 is shorter and it activates and onco gene causing cancer