Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
23 Cards in this Set
- Front
- Back
|
What are the main functions of cell division?
|
Creation of new cells from old cells. Creates reproductive cells by meiosis and somatic cells by mitosis
|
|
|
List the phases of the cell cycle in their correct sequence.
|
G1,S,G2,M
|
|
|
State the meaning of terms "S" and "G" in the phases of interphase.
|
G- growth
S - synthesis |
|
|
For an animal cell in metaphase of mitosis, list the structures that are present.
|
Chromosomes, centromeres, kinetichore, spindle fibers, kinetichore microtubules, centrosome (2 centrioles) or microtubule organizing center
|
|
|
Describe the events that occur from G1 interphase to prophase of mitosis in the nucleus and in the cytoplasm
|
G1 - growth
S - synthesis of chromosomes G2 - growth prophase - mitotic spindle forms, chromosomes condense |
|
|
During prometaphase, briefly describe the changes which involve microtubules. Identify the two types of
microtubules and discuss their functions. List the other structures that are present. |
nuclear envelope breaks down, spindle fibers contact chromosomes at kinetichore.
kinetichore microtubules assist movement of xsomes nonkinetichore xsomes help elongate the cell in anaphase and facilitate activity of cell components in cage like network |
|
|
Disjunctional segregation at anaphase depends upon structural components in the cell. List them.
|
binding proteins between sister xmatids breakdown, centromeres segragate, kinetochore fibers shorten and motor proteins pull xsomes along kinetochores to opposite sides
|
|
|
Describe mitotic anaphase. State the mechanism that moves the once-joined sister chromatids (now each considered chromosomes) to opposite poles. Your answer should refer to structural proteins (how they function) and to enzyme activities and motor molecules.
|
binding proteins between sister xmatids breakdown, centromeres segragate, kinetochore fibers shorten and motor proteins pull xsomes to opposite sides
tubulin subunits in kinetichore microtubules depolimerize, motor proteins (dynein) attach and detach resulting in xsome movement |
|
|
Distinguish between the terms "centrosomes" and "centromeres" and “centrioles”..
|
centrosome- composed of two centrioles. exists in animals
centrioles - two in centrosome, composed of 9 triplets of microtubules centromere - in middle of xsome, links two chromatids |
|
|
Distinguish between cleavage furrow formation and cell plate formation.
|
animals - cleavage furrow, ring of actin filaments and myosin
plants - cell plate, vesicles transferring cell wall and plasman membrane |
|
|
What is "MPF"?
|
Mitosis promotic factor composed of cyclin and cyclin dependent kinase (Cdk). Phosphorilates proteins that initiate mitosis. activated by dephosphorilation of Cdk
|
|
|
Identify the components of MPF. Which component present in MPF varies in concentration in a cell?
|
Cyclin and Cyclin dependent kinase (Cdk). Cyclin oscillates in concentration, Cdk is recycled.
|
|
|
List the enzymes that are involved in regulating the completion of mitosis.
|
Cdk, phosphatase, protease
|
|
|
Chemical signals regulate progress through a cell division cycle. Show using labelled diagrams, evidence
from cell fusion experiments that such signals exist. |
Fig 11.13. Cell fusions of S and M cells with G1 or G2 cells induce S and M. M phase cytoplasm injected into G2 cell induced mitosis.
|
|
|
List 3 advantages to cells of using checkpoints.
|
DNA replication and mitosis take place during favorable conditions
regulate correct sequence of events and enforce synchrony of different processes prevents replicated of damaged DNA and errors, prevents cancerous growth |
|
|
Define Go.
|
quiescent cells are in Go and do not pass G1 checkpoint. Do not enter S or M phase.
|
|
|
Distinguish between binary fission and mitosis.
|
binary fission occurs in bacteria, two identical daughter cells. cannot be divided into phases, no nucleus
animals, fungi, and plants undergo mitosis |
|
|
How is cell division in cancerous cells different from that which takes place in normal cells?
|
Cencerous cells lack a checkpoint and have uncontrolled cell division, divide faster, cell cycle not regulated
|
|
|
How do radiation treatments “kill” a tumor?
|
Xrays focus upon the cancer site, react with water in cells and disrupt DNA structure, replication, and division
|
|
|
What are the advantages and disadvantages of radiation therapy?
|
Slowls tumor growth
may damage normal cells |
|
|
How do chemotherapy drugs “kill” a tumor?
|
applied to whole body via injections, kill rapidly dividing cells or causes them to stop in G1.
|
|
|
What are the advantages and disadvantages of chemotherapy?
|
Can kill damage rapidly dividing cells
Whole body exposure new research may allow them to target cancerous cells (liposomal nanomedicines) |
|
|
As discussed in lecture, microtubules depolymerize during anaphase. Describe the experiment that supports
the hypothesis of microtubule depolymerization. |
How do microtubules shorten?
1. Use fluorecense to label xsomes and microtubules 2. at the start of anaphase photobleach section of microtubules Results: photobleached section remains visible but distance b/w bleached section and xsomes shortened. Microtubules shorten at one end, at the kinetichore |
