Topic1:6 - Cell Division - Mitosis & Binary Fission Flashcards
What are the products of DNA replication
DNA replication produces two identical copies of each DNA molecule.
What are the products of Cell Division (mitosis and binary fission)
2 genetically identical daughter cells
each daughter cell recieves one copy of each DNA molecule and are genetically identical to the parent cell.
What is the purpose and importance of Cell division
Cell division is required for growth and reproduction in living things
In multicellular organisms: cell division increases the number of cells in the body (growth) or replaces older or damaged cells.
In unicellular organisms: cell division results in the formation of a new individual
What process of cell division do unicellular eukaryotes undertake?
mitosis, followed by binary fission. This produces two new individuals
what process of cell division do unicellular prokaryotes undergo
binary fission, produces two new individuals
What process of cell division do multicellular eukaryotic cells undergo
mitosis, then cytokinesis or meiosis
explain the structure and function of eukaryotic chromatin and then chromosomes (4 points)
Each DNA molecule is wrapped around histone proteins to form chromatin.
during cell division, chromatin condenses into smaller linear bodies called chromosomes.
Chromosomes occur in homologous pairs, in which one member of each pair has come from a different parent (maternal or paternal)
Homologous chromosomes carry genes for the same traits and are the same size
which cells undergo meiotic divison? briefly describe.
germ line cells do (they are somatic and diploid). The produce gametes (sperm or ova) which contain half the number of chromosomes (haploid)
State the process of cell division do somatic/non-germline cells undergo?
mitosis (division of the nucleus)
cytokinesis (division of the cytoplasm)
briefly describe the phase before mitosis
Prior to cell division DNA is replicated in the stage called interphase.
Cells spend most of their time in interphase
During interphase, ATP accumulates, organelles are made, DNA replicates
State the four stages of mitosis
*Prophase
*Metaphase
*Anaphase
*Telophase
state the stage after mitosis
cytokinesis
what are sister chromatids made of? what do they consitute to? what is a feature of sister chromatids that allows for cell division to occur.
The two identical copies of DNA produced from DNA replication are called sister chromatids.
*Two sister chromatids constitute one chromosome and are attached at the centromere.
*The centromere is a site for attachment of microtubules forming the spindle.
describe the structure and fuction of the spindle fibre
-The spindle forms during cell division from the cytoskeleton.
-One spindle fibre attaches to each chromosome.
-Spindle fibres align chromosomes in metaphase and pull apart sister chromatids in anaphase.
Explain the process of prophase (4 points)
-Chromosomes become visible because they have shortened and condensed. Each chromosome consists of two sister chromatids.
-Centrioles separate and move to opposite poles of the cell (in animal cells).
-Spindle fibres form and attach to each chromosome at the centromere.
-Nuclear membrane and nucleolus disappear.
explain the process of Metaphase
-Spindle fibres pull chromosomes to align in the centre of the cell along the equator/metaphase plate.
-Each sister chromatid faces the opposite pole of the cell.
-Each chromosome is attached to one spindle fibre.
explain the process of anaphase
Spindle fibres shorten and sister chromatids are pulled apart to opposite ends/poles of the cell.
explain the process of telophase (4 points)
-When the sister chromatids arrive at the pole they are called chromosomes.
-Each chromosome only contains one DNA molecule.
-New nuclear membranes form around each set of chromosomes.
-The nucleolus reappears.
explain the process of cytokinesis in animal cells
-Cytokinesis is division of the cytoplasm so that each new nucleus is surrounded by cytoplasm.
-In animal cells, a new cell membrane forms around each new daughter cell, so each cell contains a nucleus and cytoplasm.
explain the process of cytokinesis in plant cells
-Cytokinesis is division of the cytoplasm so that each new nucleus is surrounded by cytoplasm.
-In plant cells, both a new cell membrane and a cell wall must be formed around each daughter cell.
what is a main trigger of prokaryotic (bacterial) cells dividing?
the size of the cell, when it gets too large, it splits
The process of binary fission typically takes how much time?
20 minutes, which results in the exponential growth of a bacterial population
describe a similarity of binary fission and mitosis
The daughter cells formed by binary fission and Mitosis have the same number of chromosomes and type of chromosome(s) as the parent cell.
Unless spontaneous, induced mutations occur, the genomes of the daughter cells are identical to the genome of the parent cell.
describe the arrangement of the chromosomes in prokaryotic cells after binary fission
In prokaryotic cells, after binary fission, both daughter cells contain a single, circular chromosome and are genetically identical (clones).
