CH 11 Cell Division Reading Guide Flashcards
What does a daughter cell need from the mother cell in order to be functional and viable?
Full compliment of DNA from both parent cellsParent cell must be large enough to divide and contribute cytoplasmic components like proteins, lipids and macromolecules
Define the cell cycle
Series of steps that make up cell divisionConsists of two main stage s phase and m phase
Define binary fission
Splitting of DNA by asexual reproduction
How is prokaryotic DNA organized in the cell and how is different from eukaryotic DNA in the cell?
Prokaryotic DNA is arranged in a ring within the cellEukaryotic DNA is stored as chromosomes in the nuclear envelop
Describe cell pinching for prokaryotes?
Begins with synthesis of new membrane and wall material at the mid point
Define genome how many genomes are present in each cell go the human body?
Compete set of DNA found inside a cell2 because humans are diploid
Where in the cell is the genome housed in a eukaryotic vs a prokaryotic cell?
Eukaryotic genome is found in the nuclear envelopProkaryotic genome is found as a ring at the edge of the cell membrane
How May eukaryotic cell division and prokaryotic cell division be related?
Dinoflagellates single called eukaryotes keep their nuclear membrane during cell division therefore the nuclear membrane splits similar to binary fission
What occurs during interphase? How long does it last?
Replication of DNA Increase of cell size 10 to 14 hours
What occurs during m phase ?
Mitosis the separation of the chromosomes into two nucleiCytokinesis division of the cell into two separate cells
Explain G1 of interphase
Size and protein content increase Specific regulatory proteins are made and activated Preparation time for S phase
Explain G2 of interphase
Preparation time for M phaseSize and protein content increase in time for cell division
Explain S phase
Replication of the entire DNA content
Explain G0 phase
Exite the cell cycle and perform specialty functionEx metabolism and detoxification in liver cells
How are eukaryotic genomes organized in the cell?
Organized with histomes into chromatids Wichita are looped and packed as chromosomes
What is the average length of a DNA strand in eukaryotic cells?
1 to 2 meters
Define diploid
A cell with two complete sets of chromosomes
How many chromosomes in a human skin cell?
46
Define a karyotype how are they arranged?
Portrait formed by a number of chromosomes arranged by size largest to smallest
Define homologous chromosomes
22 pairs of identical chromosomes
Where do you get your two homologous of chromosomes?
One from the mother and one from the father
Explain prophase
Chromosomes condenseCentrosome radiate microtubules and move to the poles
Explain pro metaphase
Mitotic spindle attaches to chromosomes
Explain metaphase
Chromosomes align in the Center of the cell
Explain anaphase
Centromere splits into sister chromatids separates and travel to opposite poles
Explain telophase
Nuclear envelop reforms and chromosomes condense
How do chromosomes appear during interphase?
Long and scraggly
What is the mitotic spindle made of?
Microtubules
When and where does the centrosome move before mitosis can begin?
During S phaseDefine opposite ends of the cell
During prophase where do the centrosomes migrate two?
Opposite poles of the cellForm mitotic spindle that acts as guide wires for chromosome movement
What is a kinetichore and how does it relate to the centromere?
Protein complexes located on each side of the centromere constriction That attach to the mitotic spindle
Where do chromosomes align during metaphase.
In the Center of the cell
What must happen for a pair of sister chromatids to separate?
When the centromere is cut resulting in two separate chromosomes
During anaphase what motor protein move the chromosomes towards the centrosomes?
Microtubules
Explain telophase
Nuclear envelope reforms and the chromosomes condense this marks the end of mitosis
Which cytoskeletal component creates the contractile ring during cytokinesis?
Actin
How is mitosis different from cytokinesis?
Mitosis doesn’t involve e splitting of the cell only making two nuclear envelops of new daughter chromosomes
What is the basic difference between gametes and somatic cells?
Gametes are haploid that bind together during sexual reproduction.Somatic cells are diploid
What’s the first thing that must occur before me ionic cell division can occur?
DNA replication
What happens in the first meiotic divion?
Separate the homologsInto their X shape
What happens in the second meiotic division?
Separation of the chromatids From X to to II
Differences between mitotic and prophase 1 meiosis?
Chromosomes undergo gene to gene pairing in step 2Each pair of homologous chromosomes forms ambivalent in step 3Chiasmata forms during step 4Nuclear envelops breaks down in step 5
Define chiasmata and why are they important
Crossover, the physical breakage and reunion of non sister chromatidsImportant because it physically links homologues to each other
What lines up on the metaphase plate in meiotic metaphase 1?
The non sister chromatids joined by a chiasma
How do bivalvent orientate themselves on the metaphase 1 plate?
Line up so that two centromeres are across each other on the plate Orientation of the bivalve td is otherwise random
During anaphase 1 what separates and was doesn’t not?
Homologous chromosomes separateSister chromatids do not
Explain prophase 2
The nuclear envelop breakdown and the chromosomes condense
What lines up during metaphase 2?
Chromosomes line up in the Center of the cell
What separates during anaphase 2? What gets cleaved?
The sister chromatids the centrosome gets cut
Explain telophase 2
Chromosomes uncoil and the nuclear envelop reforms
Define equational division
Cell in meiosis 2 have the same number of chromosomes at the start as they do at the end
If strawberries are octopod what ploidy would strawberry eggs and sperm be?
Tetra ploidy? 4 ploidy
Why should cell division be regulated, what types of tissues would have higher rates of cell division, why do unicellular organisms bother regulating cell division?
Unregulated cell division lead to cancerEpithelial cells would have high rate of cell divisionUnicellular organisms should only divide when appropriate nutrients are available
What are some external signals and internal signals that a cell would use to regulate when to divide?
Ex has all the DNA been replicated during S phaseEx is the cell large enough to support divi on into viable daughter cells
Provide some examples of cyclical changes
Chromosomes deco sensing and condensingNuclear envelop breaking and reforming
What is the behaviour of cycling during the cell cycle?
Cyclin levels rise and fall with each turn of the cell cycle.
Explain cyclin dependant kinases of CDKs
Always present within the cell but only become active when bound to the appropriate cyclin. It is CDK activity that prompts different stages of the cell cycle
When do you expect to see maximum and minimum levels of CDK activity?
When the cell is dividing and just finished dividing
Do cyclin levels vary thought the cell cycle?
Yes Levels increase and decrease as the embryo divide during mitosis
Why might a cell need more than a single cyclin CDK complex?
Because certain stages of the cell cycle are activated by different CDK complexes
What might a cell need in place before it can successfully proceed with DNA replication?
Activation of protein complexes involved in DNA replication
What is the function of S cyclin- CDK ?
Prevents the replication complex from reassembling the same place and re replicating the same DNA sequence
What are the functions of M cyclin CDK?
Phosphorylates structural proteins in the nucleus that trigger breakdown of the nuclear envelopPhosphorylates proteins that regulate the formation of Tubulin into microtubules promoting the formation of the mitotic spindle
Where are the three checkpoints found in the cell cycle?
End of G1 detects if DNA is damagedEnd of G2 detects to see is all the DNA is replicatedStart of am phase detects to make sure that all the chromosomes area attached to the spindle
When is p53 activated and what is the consequence of activating p53?
Activated when DNA damaged by radiation is detectedIt activates a protein that inhibites the activity of G1/S cyclin CDK thereby arresting the cell in the G1/S transition
How is asexual and sexual reproduction different?
Asexual reproduction occurs when a single cell splits into 2 daughter cellsSexual reproduction occurs when genetic material is passed down from 2 parents half the genetic material is passed from the female the other half from the male parent
