Cell Biology VII

Question 1

Is the nucleolus membrane-bound?

Answer 1

No

Question 2

Now many nucleoli are present in a typical cell?

Answer 2

1-2

Question 3

What are the three components of the nucleolus?

Answer 3

1) Nucleolar-organizer DNA
2) Pars fibrosa
3) Pars granulosa

Question 4

What is the function of nucleolar-organizer DNA?

Answer 4

Contains base sequence that codes for transcription of rRNA

Question 5

What is the function of the pars fibrosa?

Answer 5

Newly transcribed rRNA just beginning to become complexed with proteins

Question 6

What is the function of the pars granulosa?

Answer 6

Maturing subunits of ribosomes

Question 7

What is nucleostemin?

Answer 7

p53 binding protein found in undifferentiated cells

Question 8

What happens to the levels of nucleostemin as the cell becomes more differentiated?

Answer 8

Decreases

Question 9

During what phase of the cell cycle does replication of centrioles begin?

Answer 9

G1

Question 10

During what phase of the cell cycle is centriole replication complete?

Answer 10

G2

Question 11

What events take place during prophase?

Answer 11

1) Chromatids are condensed
2) Tetrads form
3) Centromere forms
4) Kinteochore forms
5) Cytoplasmic microtubules are disassembled and reorganized into mitotic spindle
6) Centriolar pairs migrate to opposite ends

Question 12

During what phase of the cell cycle are chromatids condensed?

Answer 12

Prophase

Question 13

During what phase of the cell cycle do tetrads form?

Answer 13

Prophase

Question 14

During what phase of the cell cycle does the centromere form?

Answer 14

Prophase

Question 15

During what phase of the cell cycle does the kinetochore form?

Answer 15

Prophase

Question 16

During what phase of the cell cycle do microtubules disassemble and reorganize into mitotic spindle?

Answer 16

Prophase

Question 17

During what phase of the cell cycle do centriolar pairs migrate to opposite ends of the cell?

Answer 17

Prophase

Question 18

What is the starting point for prometaphase?

Answer 18

Disappearance of nuclear envelope

Question 19

What events take place during prometaphase?

Answer 19

1) Nuclear envelope dissolves
2) Attachment of microtubules to kinetochores
3) Chromatids organize at equator of cell
4) Nucleoli disappear

Question 20

During what phase of the cell cycle are microtubules attaching to the kinetochore?

Answer 20

Prometaphase

Question 21

During what phase of the cell cycle are chromatids organizing at the equator of the cell?

Answer 21

Prometaphase

Question 22

During what phase of the cell cycle does the nucleolus disappear?

Answer 22

Prometaphase

Question 23

What drug will arrest development at metaphase?

Answer 23

Colchicine

Question 24

At what phase of the cell cycle does colchicine cause arrested development?

Answer 24

Metaphase

Question 25

What events take place during anaphase?

Answer 25

Chromatids separate and are referred to as chromosomes

Question 26

Telomerase is found in what cell types?

Answer 26

Germinal cells and stem cells

Question 27

What happens when phosphatidylserine is translocated to the extracellular lipid monolayer?

Answer 27

Cell is marked for death

Question 28

What are the characteristics of extrinsic pathway for caspase activation?

Answer 28

1) Fas ligand and Fas receptor (death receptor)
2) Adaptor protein
3) Inactive caspase 8 —-> active caspase 8

Question 29

What are the characteristics of intrinsic pathway for caspase activation?

Answer 29

1) Cell injury causes release of cytochrome c
2) Cytochrome c adaptor protein (Apaf-1) complex forms
3) Inactive caspase 9 —-> activated caspase 9

Question 30

What effect does estrogen have on osteoblasts?

Answer 30

Anti-apoptotic

Question 31

What is the normal role of Bad?

Answer 31

Pro-apoptotic

Question 32

When phosphorylated, is Bad active or inactive?

Answer 32

Inactive

Question 33

What happens to Bad levels when estrogen is depleted?

Answer 33

Bad is inactivated