chapter 11 launchpad

in this partial image of anaphase I of meiosis, most of a chromosome is shaded dark, whereas a portion of what is in the circle is shaded light. which of the statements best explains the meaning of this shading? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q3-1.png

the light part came from the homolog of crossing over

predict what happens when both centrosomes of a cell are removed during the prophase stage of mitosis

the mitotic spindle does not form and mitosis does not continue

Why are the X and Y chromosomes not considered homologous?

they do not carry the same set of genes

what is the function of histone proteins?

to package DNA in eukaryotic chromosomes

true or false : Trisomy 21 (down syndrome) is one of only a few examples of an autosomal trisomy in which the fetus develops to term and is born alive

true

true or false : nondisjunction can occur in both mitosis and meiosis

true

Reproduction by mitotic cell division results in what?

two daughter cells that are genetically identical

consider the sages of mitosis, depicted in the image. in what order do the stages of mitosis occur? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/morris3e/morris3e_fig_11_05_1_copyright.png

V > II > IV > I > III

Under experimental conditions, we can delete the gene for the motor protein involved in contraction of the contractile ring during animal cell cytokinesis. Which of the following results might you predict?

additional rounds of the cell cycle continue producing a multinucleate cell

a couple has a baby that only has one X chromosome and no Y chromosome. this could have occurred because : -there was nondisjunction of the sister chromatids in meiosis II in the mother. meiosis in the father was normal -there was nondisjunction of the paired X and Y chromosomes in meiosis I in the father. meiosis in the mother was normal -there was nondisjunction of sister chromatids in meiosis II of the father. meiosis in the mother was normal -there was nondisjunction of homologous chromosomes in meiosis I in the mother. meiosis in the father was normal -all of the above

all of the above

which cellular conditions promote progression of the cell cycle? -the activation of CDKs -binding of cyclins to CDKs -the accumulation of cyclins -the expression and synthesis of cyclin proteins -all of the above

all of the above

the microtubules that form the mitotic spindle extend out from the centersome. where would you expect to find the plus end of a spindle microtubule?

away from the centrosome and towards the kinetochore

the process of cell division in a prokaryotic cell is called :

binary fission

in the figure, which box contains only single gene copies from one of the parents? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q5-1.jpg

box A

in the figure, which box encloses gene variants (alleles) of the same genes from both parents? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q5-1.jpg

box B

in the figure, which box encloses two copies of the same gene variants (alleles) from only one of the parents? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q5-1.jpg

box C

in the figure, which box contains some gene variants (alleles) from one parent and some from the other, but not variant alleles from the same gene? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q5-1.jpg

box D

which of the following is a characteristic of meiotic cell division? -meitoic cell division ultimately results in the formation of two cells -cell division results in the production of gametes -the cells produced by meiosis are genetically identical -meiotic cell division requires two rounds of DNA replication

cell division results in the production of gametes

in the image, let the light shade indicate maternally derived chromosomal material and the dark shade indicate paternally derived material. which circle is likely to contain both paternal and maternal gene variants (alleles)? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_meiotic_cell_division/q4-1.jpg

circle B

non-sister chromatids are :

copies of homologs but not fully identical chromosomes

what are the functions of cyclins?

cyclins activate kinases that regulate passage of cell cycle checkpoints

Muscle cells in the mammalian heart are multinucleate, meaning that multiple nuclei are present in the cytoplasm of a large cell. Predict what is different about the cell cycle in a muscle cell.

cytokinesis does not occur

predict what would happen if crossing over between homologous chromosomes occurred as part of mitosis

daughter cells would not be genetically identical

if you analyze the sequence of the two copies of any of the chromosomes shown in the karyotype, there would be slight sequence differences. what could account for the small differences between a few of the homologous chromosomes?

each homologous chromosome in a pair is from a different parent

which is true? -errors in chromosomes segregation can occur in either the first or second meiotic division -down syndrome is the one inherited disorder that results from an extra copy of an entire chromosome -down syndrome is caused by errors in fertilization -nondisjunction can only produce gametes with extra chromosomes, not missing chromosomes

errors in chromosomes segregation can occur in either the first or second meiotic division

what is nondisjunction?

failure of chromosomal separation

true or false : all cancers are caused by viruses

false

true or false : nondisjunction can only occur in the sex chromosomes and not autosomes

false

prophase of meiosis I has some important differences from prophase of mitosis. these differences include : __________ pair, and _______ occurs

homologous chromosomes ; crossing over

in normal meiosis, when do homologous chromosomes separate from each other

in the first meiotic division

which statement regarding the S cyclin-CDK complex is true? -it is responsible for the degradation of nuclear membranes -it regulates the expression of histone proteins -it is responsible for the phosphorylation of nuclear proteins -it ensures that DNA is not replicated multiple times -it is regulated solely by the action of p53

it ensures that DNA is not replicated multiple times

what properties are associated with a malignant cancer?

it invades surrounding tissues, it is metastatic, it is fast growing

Why would a compound that interferes with bacterial cell wall synthesis be useful for treating a bacterial infection?

it would limit growth of the bacterial population through cell division

which stages of mitosis are correctly matched with the events that occur in the stage? select all that apply -metaphase ; chromosomes line up in the middle of the cell -prometaphase ; nuclear envelope reforms -cytokinesis ; a contractile ring of actin filaments forms at the cell equator -telophase ; nuclear envelope breaks down -anaphase ; chromosomes start to condense

metaphase & cytokinesis

which cytoskeleton component plays a major role during cytokinesis?

microfilaments

the assembly of what cytoskeletal structures are initiated by the M cyclin-CDK complex?

microtubules

which cytoskeleton component plays a major role in the formation of the mitotic spindle?

microtubules

the process of cytokinesis involves components of the cytoskeleton. it is most similar to what other cytoskeletal function?

muscle contraction

the contractile ring that leads to cytokinesis in animal cells has been shown to be made primarily of actin filaments (microfilaments). which motor protein would you predict is involved in contraction of the ring?

myosin

would genetic recombination result if crossing over occurred between sister chromatids?

no, because sister chromatids are genetically identical or nearly identical

during meiosis crossing over takes place between :

non-sister chromatids

in which type of nondisjunction could the two copies of a chromosome in a gamete be heterozygous?

nondisjunction in the first meiotic division

during prometaphase, the microtubules of the mitotic spindle attach only to the kinetochore of a single sister chromatid and not to the other for the maternal copy of chromosome 21. what will happen to the copy number of chromosome 21 in the resulting daughter cells?

one of the daughter cells has trisomy (three copies) of chromosome 21 and the other daughter cell is missing one of the two copies of chromosome 21

what type of gene is c-src (cellualr-src)?

pro-oncogene

several years ago, a man noticed a small mole on his wrist. years later, the mole grew in size and the man was diagnosed as having metastatic melanoma. this was likely the result of :

several mutations affecting pro-oncogenes and/or tumor suppressor genes

which statement represents a misconception about sister chromatids? -sister chromatids are attached to each other at their centromere -sister chromatids are formed when the prokaryotic circular chromosomes attaches at the plasma membrane -sister chromatids are formed in the S phase of the cell cycle when the chromosomes undergoes replication -sister chromatids are identical or nearly identical DNA sequences -sister chromatids are also called homologous chromosomes

sister chromatids are formed when the prokaryotic circular chromosome attaches at the plasma membrane

How must spindle microtubules attach to chromosomes during prometaphase of meiosis I?

spindle microtubules from one pole must attach to both kinetochores in a pair of sister chromatids

what would happen to the daughter cells if the G2 phase of the parent cell is shortened?

the cells would be smaller than normal

what would happen if a pair of sister chromatids only connected to the mitotic spindle at one of their kinetochores?

-the sister chromatids would not separate -the chromosomes would not line up properly at metaphase -one of the daughter cells would have an extra copy of that chromosome

in the figure, which lettered item is a centromere? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_mitotic_cell_division/q1-1.jpg

D

which statement is true regarding binary fission? -DNA replication of the circular bacterial chromosome during binary fission is a bidirectional process, starting at one point but progressing in opposite directions -in binary fission, cell division is typically asymmetrical, with one daughter cell appearing much smaller than the other -tubulin, rather than FtsZ, is responsible for cell division during binary fission -proteins only anchor the original circular genome to the plasma membrane; the copy produced by DNA replication is free-floating

DNA replication of the circular bacterial chromosome during binary fission is a bidirectional process, starting at one point but progressing in opposite directions

in the figure, which lettered item is a chromatid? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_mitotic_cell_division/q1-1.jpg

E

a cell undergoing mitosis is shown. which roman numeral correctly identifies the sister chromatids? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/morris3e/morris3e_vsmapcellcommunities_ch11_01_copyright.png

IV

at which stage of the cell cycle would you see sister chromatids with a microscope?

M

at the end of M phase for a single cell, how many daughter cell(s) are present?

2

if nondisjunction occurs in the first meiotic division, how many of the four possible gametes produced from meiosis will have the wrong number of chromosomes?

4

in the figure, which lettered item is a centrosome? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_mitotic_cell_division/q1-1.jpg

A

in the figure, which lettered item is a chromosome? https://www.macmillanhighered.com/brainhoney/Resource/10962050,8,0,6B/Assets/resources/11_mitotic_cell_division/q1-1.jpg

C