Chapter 8 Flashcards
What are blastema cells?
Cells used in regeneration that can divide up to 50 times faster than usual
What do all prokaryotic cells use for division?
Binary fission
What is the central region where all the DNA is compacted in a cell during the cell cycle?
Nucleoid
What is the origin of replication?
A specific region where replication of the bacterial chromosome commences
Middle of the cell where enzymes for DNA are located
What is the mechanism that propels the two replicated chromosomes to their ends?
Unknown
How do dinoflagellates divide differently using mitosis?
The nuclear envelope remains intact during mitosis and the chromosomes bind to the inner membrane
When nucleus divides the chromosomes are segregated
How do eukaryotes store chromosomes? (Strand wise)
In double strands holding one as the copier (diploid)
Some microorganisms hold them in single strands (haploid)
What is the ploidy of a cell or species?
The number of chromosome sets in it
Ex: haploid 1
Diploid 2
Triploid 3
How are sister chromatically held together?
They are held together by proteins called cohesins that encircle the sister chromatids along their length
What is chromosome segregation?
The equal distribution of daughter chromosomes into each of the two daughter cells that result from cell division?
After a chromosome copies and is connected as a sister Chromatid by its centromere what is it called?
A chromosome still
ONE CHROMOSOME
What is a clone?
Genetically identical cell that is created from mitosis
What is G1 phase, S phase, and G2 phase?
G1- cell fairies out its function, some cases it grows
S- DNA replication and chromosome duplication occurs
G2- brief goat in cell cycle where cell growth continues and prepares for mitosis
What is the only phase of the cell cycle that varies in length?
G1 phase
What is the G0 phase?
A phase which stops cell division of a cell is not destined to divide immediately
What occurs doing prophase?
Chromosomes begin to condense into rodlike structures
Nucleolus disappears
Mitotic spindle begins to form as centrosomes migrate to opposite ends
What occurs during prometaphase?
Bundles of microtubules grow from centrosomes
A complex of several proteins called a kinetochore forms on each chromatid at the centromere (the kinetochore microtubules bind to these)
What do microtubules that do not connect to kinetochores do?
Overlap those from opposing spindle poles
What occurs during metaphase?
Spindle reaches its final form
Spindle microtubules move the chromosomes into alignment at spindle midpoint
Chromosomes complete condensation
What is a Karyotype?
The collection of metaphase chromosomes arranged according to size and shape
What occurs during anaphase?
Sister chromatically separate and move to opposite spindle poles
Kinetochore forst to move towards opposite poles
Chromosome segregation is complete once daughter chromosomes have reached the two poles
What occurs during telophase?
Spindle disassembles
Chromosomes at each end decondense and return to extended state
Nucleolus re appears
New nuclear envelope forms
How does cytokinesis unfold in animals, Protists and many fungi?
A cleavage furrow slowly forms and gradually deepens until it cuts the cytoplasm into two
How does cytokinesis unfold in plants?
A new cell wall called the cell plate forms and grows laterally till it divides the cytoplasm
What is a microtubules organizing centre?
The centrosomes that anchors the microtubules cytoskeleton during interphase
What does the centrosomes contain? What do these do
A pair of centrioles which generate the microtubules needed for flagella and cilia
When DNA replicate in S phase, what else replicates?
The centrioles within the centrosome also duplicate
What are asters?
They are the centrosomes at the spindle tips which form the the poles of the spindle
Are centrosomes present in angiosperms or gymnosperms?
No
What two groups are microtubules split into to?
Kinetochore microtubules- connect to chromosome and spindle poles
Nonkinetochore- extend to spindle poles without touching chromosome
How do chromosomes get to spindle midpoints
Unknown but some say they walk themselves using motor proteins
