Unit 2 lecture 5 10/3/22 Flashcards
The continuity of life is based on the reproduction of cells, or ______
Cell division
Cell division is an integral part of the _____, the life of a cell from formation to its own division
Cell cycle
DNA is passed from one generation of cells to the next with remarkable ____
fidelity
All the DNA in a cell constitutes the cell’s ____
Genome
DNA molecules in a cell are packaged into
chromosomes
Eukaryotic chromosomes consist of ______a complex of DNA and protein
Chromatin
_____(nonreproductive cells) have two sets of chromosomes
Somatic cells
______(reproductive cells: sperm and eggs) have one set of chromosomes
Gametes
Each duplicated chromosome has two _______joined identical copies of the original chromosome
sister chromatids
The ______is where the two chromatids are most closely attached
centromere
Eukaryotic cell division consists of three major phases:
1.______
2.______
3.______
1.Interphase: when growth and DNA replication occur
2.Mitosis: the division of the genetic material in the nucleus
3.Cytokinesis: the division of the cytoplasm
Gametes are produced by a variation of cell division called ______
meiosis
Meiosis yields ______daughter cells that have only one set of chromosomes, half as many as the parent cell
nonidentical
Interphase (about 90% of the cell cycle) can be divided into subphases
1.
2.
3.
1.G1 phase (“first gap”)
2.S phase (“synthesis”)
3.G2 phase (“second gap”)
During G1 the cell grows in size and synthesis of 1._____ and 2.____necessary for DNA replication occurs
1.mRNA
2.proteins
During S phase, ____ replication occurs
DNA
_______ is period of rapid growth in final preparation for mitosis and cell division and ends with the onset of prophase in mitosis; not all cells need it
G2 phase
Mitosis relates specifically to the division of the _____
nucleus
Includes five distinct stages:
1.
2.
3.
4.
5.
1.Prophase
2.Prometaphase
3.Metaphase
4.Anaphase
5.Telophase
_____overlaps the latter stages of mitosis
Cytokinesis
The ________ is a structure made of microtubules and associated proteins and It controls chromosome movement during mitosis
mitotic spindle
The mitotic spindle includes the 1.________the 2._______and the 3._____
1.centrosomes
2.spindle microtubles
3.asters
In animal cells, assembly of spindle microtubules begins in the _______the microtubule organizing center
centrosomes
The centrosome replicates during _______forming two centrosomes that migrate to opposite ends of the cell during prophase and prometaphase
interphase
An _____(radial array of short microtubules) extends from each centrosome
aster
During ______, the chromatin condense and become visible, nucleoli disappear, and the mitotic spindle begins to form
Prophase
During _____,some spindle microtubules attach to the kinetochores of chromosomes and begin to move the chromosomes
prometaphase
Formed in prometaphase, _______are protein complexes that assemble on sections of DNA at centromeres
kinetochores
At metaphase the centromeres of all the chromosomes are at the ________ an imaginary structure at the midway point between the spindle’s two poles
metaphase plate
In ______sister chromatids separate and move along the kinetochore microtubules toward opposite ends of the cell
anaphase
During ______, the nuclear envelopes begin to reform, mitotic spindles begin to dissolve, and cell begins cytokinesis
telophase
________is where daughter cells actually split, and begins during anaphase or telophase and the spindle eventually disassembles
Cytokinesis
In animal cells, cytokinesis occurs by a process known as cleavage forming a ________ and In plant cells, a cell plate forms during cytokinesis
cleavage furrow
Prokaryotes (bacteria and archaea) reproduce by a type of cell division called _______
binary fission
The cell cycle is driven by specific _________ present in the cytoplasm
signaling molecules
For many cells, the ______ seems to be the most important If a cell receives a go-ahead signal at the G1 checkpoint, it will usually complete the S, G2, and M phases and divide
G1 checkpoint
If the cell does not receive the go-ahead signal, it will exit the cycle, switching into a nondividing state called the ______
G0 phase
The cell cycle is regulated by a set of regulatory proteins and protein complexes including 1.____and proteins called 2._____
1.kinases
2.cyclins
An example of an internal signal occurs at the M phase checkpoint Attachment of all of the kinetochores activates a regulatory complex, which then activates the enzyme _______
separase
______ allows sister chromatids to separate, triggering the onset of anaphase
Separase
Some external signals are ______ proteins released by certain cells that stimulate other cells to divide
growth factors
Another example of external signals is ________ in which crowded cells stop dividing
density-dependent inhibition
Most animal cells also exhibit ________ in which they must be attached to a substratum in order to divide
anchorage dependence
