Cell biology VII Flashcards Preview

Year 1 Cell Biology > Cell biology VII > Flashcards

Flashcards in Cell biology VII Deck (33):
1

Is the nucleolus membrane-bound?

No

2

Now many nucleoli are present in a typical cell?

1-2

3

What are the three components of the nucleolus?

1) Nucleolar-organizer DNA2) Pars fibrosa3) Pars granulosa

4

What is the function of nucleolar-organizer DNA?

Contains base sequence that codes for transcription of rRNA

5

What is the function of the pars fibrosa?

Newly transcribed rRNA just beginning to become complexed with proteins

6

What is the function of the pars granulosa?

Maturing subunits of ribosomes

7

What is nucleostemin?

p53 binding protein found in undifferentiated cells

8

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

Decreases

9

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

G1

10

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

G2

11

What events take place during prophase?

1) Chromatids are condensed2) Tetrads form3) Centromere forms4) Kinteochore forms5) Cytoplasmic microtubules are disassembled and reorganized into mitotic spindle6) Centriolar pairs migrate to opposite ends

12

During what phase of the cell cycle are chromatids condensed?

Prophase

13

During what phase of the cell cycle do tetrads form?

Prophase

14

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

Prophase

15

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

Prophase

16

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

Prophase

17

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

Prophase

18

What is the starting point for prometaphase?

Disappearance of nuclear envelope

19

What events take place during prometaphase?

1) Nuclear envelope dissolves2) Attachment of microtubules to kinetochores3) Chromatids organize at equator of cell4) Nucleoli disappear

20

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

Prometaphase

21

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

Prometaphase

22

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

Prometaphase

23

What drug will arrest development at metaphase?

Colchicine

24

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

Metaphase

25

What events take place during anaphase?

Chromatids separate and are referred to as chromosomes

26

Telomerase is found in what cell types?

Germinal cells and stem cells

27

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

Cell is marked for death

28

What are the characteristics of extrinsic pathway for caspase activation?

1) Fas ligand and Fas receptor (death receptor)2) Adaptor protein3) Inactive caspase 8 ----> active caspase 8

29

What are the characteristics of intrinsic pathway for caspase activation?

1) Cell injury causes release of cytochrome c2) Cytochrome c adaptor protein (Apaf-1) complex forms3) Inactive caspase 9 ----> activated caspase 9

30

What effect does estrogen have on osteoblasts?

Anti-apoptotic

31

What is the normal role of Bad?

Pro-apoptotic

32

When phosphorylated, is Bad active or inactive?

Inactive

33

What happens to Bad levels when estrogen is depleted?

Bad is inactivated