DNA and cells - MITOSIS Flashcards
What is mitosis?
A type of cell division
Name 3 uses of mitosis
Growth, repair and asexual reproduction
How many daughter cells does mitosis create?
2
How many division rounds does mitosis undergo?
1
Describe the daughter cells compared to the parent cells
Gentically identical, 46 chromosomes
What is the cell cycle?
The sequence of events which occurs in a cell between its formation and the time when it divides to form daughter cells
What happens during interphase?
- Phase G1: protein synthesis; cell grows, hence volume of cytoplasm increases; more organelles produced
- Phase S: DNA replicates
- Phase G2: proteins needed for cell division are synthesised
What happens during prophase?
- DNA coils and condenses
- Sister chromatids are held together at the centromere
- Centrioles move to opposite poles of the cell
- Microtubules assemble around each centriole
- Nucleolus disappears
What happens during metaphase?
- Microtubules extend between the centrioles, forming the fibres of the nuclear spindle
- Spindle fibres attach to the centromeres of the chromosomes
What is the role of spindle fibres?
- Made of protein
- Centrioles make the spindle
- Attaches to chromosomes at centromere
What happens during anaphase?
- Centromeres divide
- Spindle fibres contract and pull the sister chromatids to opposite poles of the cell
What happens during telophase?
- Nuclear membrane forms around each group of chromosomes
- Chromosomes unwind into chromatin
- Nucleoli form in each nucleus
- Spindle fibres disappear
What happens during cytokinesis?
- Cytoplasm divides to fully form 2 new cells
- Daughter cells are genetically identical to parent cells
What are the two joined copies of a chromosome properly called?
Chromatids
What is the point where the two chromosome copies are joined called?
Centromere
What stage of the cell cycle involves the division of the cytoplasm?
Cytokinesis
What stage of the cell cycle involves DNA replication?
S
Which organisms carry out mitosis?
All living things
What stage of the cell cycle involves the separation of the chromatids?
Anaphase
A cell divides every one minute - At this rate of division it can fill a 100ml beaker in one hour. How much time does it take to fill a 50ml beaker? (PPQ)
59 minutes
When does the nuclear envelope break down?
Prophase
The chemotherapy drug cytarabine is an anti-metabolite similar to the nucleotide cytosine. The drug kills cancer cells by stopping them making and repairing DNA. At which stage in the cell cycle will cytarabine be incorporated into DNA? (PPQ)
S
Where in the body do you think mitosis frequently needs cells replacing?
- Skin
- Lining of the gut
- Red blood cells
Give one advantage of mitosis in asexual reproduction
As the genetic make up of the parent has enabled it to survive and reproduce, if the offspring have the same genetic material, they are also likely to survive and reproduce
