Chapter 3 - E1 Flashcards
Products of Mitosis
Produces 2 identical daughter somatic cells
What is included interphase?
G1, G0, S, and G2
Characteristic of G1?
High levels of gene expression
S (synthesis phase) characteristics
Where DNA replication occurs
G0 characteristics
Where cells express their genetic information and carry out normal function but do not replicate
G2 characteristics
Preparation for cell division
M phase substages
Prophase
Metaphase
Anaphase
Telophase/Cytokinesis
Karyokinesis
Equal partitioning of the chromosomal material into the nuclei of 2 daughter cells
Cytokinesis
Equal partitioning of the cytoplasmic contents into 2 daughter cells
Centromere
Specialized DNA sequence on each chromosome where sister chromatids are joined together
What occurs in Prophase?
Chromosome condensation begins
Centrosomes migrate toward opposite poles
Microtubules extend to form a partial mitotic spindle
What occurs in Prometaphase?
Centrosomes extend microtubules that attach to kinetochores of chromosome centromeres
Chromosomes move toward the middle
What occurs in Metaphase?
Chromosomes are fully condensed and are aligned so that the sister chromatids lie on either side of the metaphase plate
- Kinetochore, nonkinetochore, and astrial tubules are fully extended
What occurs in Anaphase?
Sister chromatid seperation trhgouh the breakdown of cohesin
Daughter chromosomes move toward opposite poles
What occurs in Telophase/Cytokinesis?
Cells are elongated
Cytokinesis diveds the cytoplasm to create 2 new cells
How to spindle fiber microtubules elongate?
Through the addition of tubulin subunits
Where do the - and + ends anchor?
- end anchors at the centrosome
+ end grows away from the centrosome
What is the role of cohesin?
Coats sister chromatics (most concentrated near the centrosomes)
Hold the chromosomes together to reduce the pull of the kinetochore
Definition of disjunction
Seperation of chromosomes
What are the four checkpoints?
G1, S, G2, and Metaphase
Products of Meiosis
4 haploid gametes
Events that occur in Meiosis 1
Homologous chromosomes pair
Crossing over occurs
Segregation of the homologous chromosomes (reduces it to haploid number)
Events that occur in Meiosis 2
Sister chromatids seperate
Produces 4 genetically distinct haploid cells
What is SRY?
Sex determining region of the Y gene in human males
- inhibits femaleness
What is a Barr Body?
Inactivated X chromosome when too many X’s are present
- Random X-inactivation hypothesis
What are kinesin motor proteins?
Use ATP hydrolysis to physically move toward the plus end
What are dynein motor proteins?
Move toward the minus end
Role of separase
Cleave the cohesin complex to promote chromatid seperation
Chiasma
Contact points between homologous chromosomes where recombination has already occurred
What does TDF do?
Stimulates transcription of genes needed for Wolffian duct development into male reproductive tissues
