D2.1 Cell and nuclear division Flashcards
What is cytokinesis?
division of the cytoplasm of a cell to form two daughter cells
What is contractile ring in cytokinesis?
ring that surrounds the cell and start to get smaller (cleavage furrow) to separate the cell into two
How cytokinesis occurs in plants?
vesicles centre in the middle and form new membranes by building a membrane wall and then each cell forms cell wall
What is oogenesis?
egg production
What contractile ring made of?
actin and myosin
When unequal division is possible (what the new cell must have for it to be a division)?
when the new cell has nucleus and mitochondrion
What’s the example of unequal cytokinesis?
Budding yeast
What’s the product of mitosis?
two genetically identical daughter cells
What does diploid mean?
means that they have two sets of chromosomes
What’s the product of meiosis?
it produces four genetically unique daughter cells
What does haploid mean?
half the complete set of chromosomes
What are chromosomes?
structures that have two identical chromatids held by centromere (cohesin loop)
What happens to the chromatin before cell division?
chromatin coils and condenses to form chromosomes
What are sister chromatids?
two identical chromatids, where one results from replication
How many DNA molecules humans have and how many chromosomes they can form?
46 and 46
In what form is DNA present in the nucleus?
chromatin (just string of DNA loosely packed around histones)
Why DNA is supercoiled into chromosomes?
so it will be easier to move during mitosis and meiosis
What’s the function of spindle microtubule?
To pull the chromatids to the edge of the cell
What is cytoskeleton?
it is a network of working together protein filaments that are present in cytoplasm for structure and support
Which protein filaments made up cytoskeleton?
microtubules, actin filaments, intermediate filaments
What is a spindle?
it is a structure formed from microtubules that pulls the chromatids to the opposite ends of a cel
Where does the spindle link to the chromatid?
kinetochore on a centromere
What are microtubule motors?
proteins that bind to microtubules and hydrolyse ATP (produce ADP, creates energy), they provide energy for microtubules to shorten and separate the chromosomes
