mitosis

Question 1

what is mitosis and its function?

Answer 1

eukaryotes depend on mitosis, development from a fertilized cell, growth, repair

Question 2

what is the product of mitosis?

Answer 2

results in duaghter cells that are identical with genetic information as parents DNA, 2 diploid

Question 3

what is a genome?

Answer 3

all the DNA in a cell

Question 4

what are chromosomes?

Answer 4

a single DNA molecule common in prokaryotes or many DNA molecules which are common in eukaryotes

Question 5

what is chromatin?

Answer 5

a complex of DNA and histones that condense during cell division

Question 6

what are somatic cells?

Answer 6

non reproductive cells that have two sets of chromosomes, diploid

Question 7

what are gametes?

Answer 7

reproductive cells that have as many chromosomes as somatic cells haploid

Question 8

how many chromosomes are in drosophila and humans?

Answer 8

Drosophila has 8 and humans have 46

Question 9

what is a karyotype?

Answer 9

an image that reveals an orderly arrangement of chromosomes

Question 10

what are homologous chromosomes?

Answer 10

matching pairs of chromosomes one from each parent, that can possess different versions of the same genes

Question 11

what is the total condensation of chromosomes?

Answer 11

10000 chromosomes

Question 12

what are sister chromatids?

Answer 12

each duplicated chromosome has two sister chromatids which are joined copies of the original chromosome. they are attached along their lengths by cohesions

Question 13

what is a centromere?

Answer 13

a narrow waist of the duplicated chromosome, where the two chromatids are most closely attached

Question 14

what is the kinetochore?

Answer 14

its the centromere + protein attachment

Question 15

how do chromatids separate?

Answer 15

separase separates chromatids by hydrolyzing cohesin

Question 15

what does the mitotic phase consist of?

Answer 15

mitosis and cytokinesis

Question 16

what are the three phases of interphase?

Answer 16

G1 phase, S phase, and G2 phase

Question 17

how many nucleosomes are present?

Answer 17

6x, and nucleosomes around a 30nm fiber are 1000x

Question 18

what is the microtubule organizing center?

Answer 18

structure with microtubules emerge, it organizes cilia and flagella, and organizes mitotic and meiotic spindles

Question 18

what is mitotic spindle?

Answer 18

a structure made of microtubules that control chromosome movement during mitosis

Question 18

what is a centrosome?

Answer 18

assembly of spindle microtubles begins in the centrosome in animal cells and during interphase forming two centrioles that migrate to the opposite end of the cell

Question 19

what is considered a centriole?

Answer 19

9 triplets of microtubules

Question 20

what are kineotochore fibers?

Answer 20

during prometaphase some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes

Question 21

what are non-kinetochore microtubules?

Answer 21

not connected to centromeres

Question 22

what happens in metaphase?

Answer 22

the chromosomes line up at the metaphase plate, a plane midway between the spindles two poles

Question 23

what happens during anaphase?

Answer 23

the cohesins are cleaved by an enzyme called separase, sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell, microtubules shorten by depolymerizing at their kinetochore ends

Question 24

what happens in telophase?

Answer 24

genetically identical daughter nuclei form at opposite ends of the cell

Question 24

what do non-kinetochore microtubules do?

Answer 24

non-kinetochore microtubules from opposite poles overlap and push against each other elongating the cell

Question 25

what happens in cytokinesis?

Answer 25

begins during anaphase or telophase and the spindle eventually disassembles

Question 25

what is the eukaryotic cell cycle regulated by?

Answer 25

the molecular control system

Question 26

what is the molecular control system?

Answer 26

bacteria= 20 min drosophila= 8 min mouse= 3 hours mammalian= 24 hours frog= 30 min

Question 27

what do not divide after maturity, how are liver cells different?

Answer 27

heart, rbc, and nerve cells, liver cells retain ability to divide

Question 28

what does kinases do?

Answer 28

phosphorylates proteins

Question 29

what is the cell cycle control?

Answer 29

the sequential events of the cell cycle are directed by a distinct cell cycle control system which is like a clock

Question 30

what is the maturation promotion factor?

Answer 30

a cyclin complex that triggers cells passage past the G2 checkpoint into M phase, phosphorylates proteins, promotes spindle formation, promotes condensation of chromosomes, contributes to degradation of nuclear envelop, ER and Golgi

Question 31

what is the G1 checkpoint?

Answer 31

checks cell size, growth factors, proteins, organelles and mRNAs

Question 32

what is G2 growth?

Answer 32

chromosome duplication and DNA is not damaged before entering cell division

Question 33

what is the M division?

Answer 33

ensures attachment of each kinetochore to a spindle fiber before entering irreversible anaphase, this ensures daughter cells have the correct number of chromosomes

Question 33

what are external factors?

Answer 33

specific growth factors

Question 34

what is necrosis?

Answer 34

low oxygen, toxins, ATP depletion, random fragmentation, ingested by phagocytes, inflammation

Question 34

what happens in density dependent inhibition?

Answer 34

crowded cells will stop dividing by cell- cell contact, cancer cells lose this

Question 34

what are growth factors?

Answer 34

released by certain cells and stimulate other cells to divide

Question 35

what is apoptosis?

Answer 35

natural cell death, chromatin condensation, membrane blebbing, ingested by neighboring cells, no inflammation, vitamin D dependent

Question 36

what happens at G1 checkpoint what does it do?

Answer 36

makes proteins and organelles needed for DNA synthesis, check for nutrients, longest most important, decides whether or not to divide,

Question 37

what is the G2 checkpoint?

Answer 37

checks for DNA damage, DNA replication, cell proteins and organelles, cell stress, prevents cells from entering mitosis if DNA is damaged, pause repair preventing proliferation of cells