5 Written questions
5 Matching questions
- G2 phase
- Meiosis II
- Eukaryotic Chromosomes
- a Enzymes allow for crossing over. There is a recombination nodule. Enzymes identify areas of homology and allow for exchange.
- b Most eukaryotic species are diploid
Have two sets of chromosomes
Members of a pair of chromosomes are called homologues
The two homologues form a homologous pair
- c 1)Spindle fibers interact with the sister chromatids
2) Kinetochore microtubules grow from the two poles
If they make contact with a kinetochore, the sister chromatid is "captured"
If not, the microtubule depolymerizes and retracts to the centrosome
3)The two kinetochores on a pair of sister chromatids are attached to kinetochore MTs on opposite poles
Functioning of spindle apparatus is complete in prometaphase
Clasping the kinetochore proteins on either side of the sister chromatids is the most important part.
Sister chromatids must be connected to both poles
- d the cell accumulates the materials that are necessary for nuclear and cell division
- e For a diploid organism with 6 chromosomes, mitosis begins with 12 chromatids joined as 6 pairs of suster chromatids
Meiosis 2 begins w/ 6 chromatids joined as 3 pairs of sister chromatids
THERE IS NO S PHASE
Already in the form of sister chromatids
PROMETAPHSE- each pair of S chromatid is connected to either pole.
Then we have metaphase - a single row of very differenlt looking s. chromatids.
Anaphase - each pair of s. chromatids becomes a chromosome
Telophase 2, cytokensis
Results in 4 cells as 2 rounds of meiodid
In the book it says 4 daughter cells, but cells from meiosis are NOT DAUGHTER CELLS BECAUSE THEY ARE NOT GENETICALLY IDENTICAL. They are gametes.
5 Multiple choice questions
- One purpose of cell division is asexual reproduction
A second important reason for cell division is multicellularity
Plants, animals and certain fungi are derived from a single cell that has undergone repeated cell divisions
Humans start out as a single fertilized egg
End up as an adult with several trillion cells
- compaction of chromosome, homologous partner seek for one another (this occurs towards the end of leptotene). The first major change is compaction.
- where chromosomes are replicated
The two copies of a replicated chromosome are termed chromatids
They are joined at the centromere to form a pair of sister chromatids
- Size, position of centromere, and banding patterns
They are not identical to each other
Although we have the same genes, we have different alleles.
5 True/False questions
Aster microtubulues → propagate towards palama membrane, hold the 2 centrosomes in position
interphase nucleus → In actively dividing cells, G1, S and G2 are collectively known as interphase
A cell may remain for long periods of time in the G0 phase
A cell in this phase has
Either postponed making a
decision to divide
Or made the decision to never
Terminally differentiated cells
(e.g. nerve cells)
DIAKINESIS → all of the synaptonemal complexes dissolve and the sister chromatids are separated. From now on, these 2 pairs are always going to move in pairs. The last part of chromosomal changes occurs here in diakinesis. This sister chromatids do not look like the original sister chromatids. This is why we have variation
Relationship between genetic trait and inheritance of a sex chromosome → X linked influence of characters and genes
Embryogenesis and changes over time
Lamarck - theory of acquired inheritance
If you don't use something it is vestigial
Morgan thought if he would but the flies in a dark room, their eyes will atrophy.
This was not true
He exposed them to radiation
1 male white eyed fly was found
This is an example of discovery based research
Now he must conduct hypothesis based research
The white eyed fly was mated with true breeding red eyed females
All of the f1 were red eyed
F1 mated - you will not get a white eyed female
4.4 red : 1 white
Gene has effect one some of the population but not all semi lethal gene
White eyed condition is known as semi lethality
There is an influence pattern and he thoughtit was on the x chromosome
He took a white eyed male and crossed with with a female
telophase and cytokinesis → Chromosomes reach their respective poles and decondense
Nuclear membrane reforms to form two separate nuclei
In most cases, mitosis is quickly followed by cytokinesis
Mitosis and cytokinesis ultimately produce two daughter cells having the same number of chromosomes as the mother cell
The two daughter cells are genetically identical to each other
Barring rare mutations
Reverse prophase = telophase
Reformation of the nucleolous and nuclear membrane
No polar microtubulues or spindle apparatus, there are 2 nuclei
- Actin below the plasma membrane. They will start overlapping and will form a cleavage furrow which is going to move into the cell and pinch it off.
Plant cells have a cell wall so there is no "pinching." the cell wall material will be deposited as a cell plate into the middle of the cell which will extend out and touch the plasma membrane, initiating middle lamina deposition (negatively charged pectins)
Results in 2 daughter cells that are identical in genetic material