Forensic biology - cell cycle

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  • Created by: aarafa11
  • Created on: 01-06-20 00:25
purpose of mitosis
cells divide to form identical copies to allow growth and repair of damage
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What are the stages of cell division of mitosis
Interphase; Prophase; Prometaphase; Metaphase; Anaphase; Telophase; Interphase
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What is part of interphase (mitosis)
G1- growth & metabolism (10h); S- DNA synthesis & chromosome duplication (9h); G2- preperation for mitosis (4h)
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What happens in interphase (mitosis)
DNA is replicated, the cell builds up energy reserves and replicates organelles
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What happens in prophase (mitosis)
Chromosomes condense & become visible; Each chromosome consists of a pair of chromatids; centrioles begin to migrate to opposite ends of cell; Spindle fibres start to form
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What happens in prometaphase (mitosis)
Nuclear envelope breaks down; The centromeres (area where the two chromatids join) align with the spindle fibres; Centrioles migrated to either end (poles) of cell
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What happens in metaphase (mitosis)
Chromatids align along the metaphase plate in the centre of the cell.
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What happens in anaphase (mitosis)
The two chromatids separate; The spindle fibres pull the separated chromosomes to opposite ends (poles) of the cell
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What happens in telophase (mitosis)
Nuclear envelope begins to reform; The chromosomes become diffuse; Nucleolus reforms; The cell is nipped in two along the cleavage furrow
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What happens in cytokinesis (mitosis)
division of the cytoplasm
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How do plants cells form a new cell wall
vesicles from the golgi complex align along the cell plate & fuse; Vesicle membranes forms the new plasma membrane & the vesicle contents form the new cell wall
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What occurs in meiosis
homologous pair of chromosomes replicates; sister chromatids from the replicated homologous pair remain associated, forms a Tetrad; chromatids from each pair goes into a separate cell; requires to split the chromatids & produce haploid cell
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What happens in interphase I (meiosis)
DNA is replicated, the cell builds up energy reserves and replicates organelles
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What happens in prophase I (meiosis)
homologous pair of chromosomes associate with each other; The four chromatids of the pair are called a Tetrad
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What happens in metaphase I (meiosis)
The chromatids arrange on the metaphase plate still in their homologous pairs (tetrads)
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What happens in anaphase I (meiosis)
The spindle fibres separate the tetrad, pulling the sister chromatids to opposite sides of the cell; The sister chromatids remain attached at their centromeres!
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What happens in telophase I (meiosis)
Each pole of the cell has a haploid chromosome set; Note: each chromosome still has 2 sister chromatids!
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The 2nd division of meiosis
At the end of the first division, there are two daughter cells The daughter cells are in Interphase for a brief period before the second meiotic division begins; This proceeds through prophase, metaphase
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What happens in metaphase II (meiosis) - 2nd division
Chromatids align along the metaphase plate in the centre of the cell
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What happens in anaphase II (meiosis) - 2nd division
The two chromatids separate; The spindle fibres pull the separated chromatids to opposite poles of the cell
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What happens in telophase II (meiosis) - 2nd division
daughter cells separate from each other along the cleavage furrows & each have half the number of chromosomes present in the original parent cell; all genes of the organism’s genome are present in daughter
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What are the type of genetic variation - genetic mixing
independent assortment; crossing over; chromosome mutation
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What is the name of the location in which crossing over occurs
chromosome segments between chromosomes is called the chiasma
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Which part of meiosis does crossing over occur
during prophase I of meiosis
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An example of why chromosome duplication can be beneficial
duplication of the gene that codes for a protein metallothionein which detoxifies many heavy metals by binding to them; – twice the genes, twice the protein
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What is the result of non-disfunction
One gamete completely lacks this chromosome; The other has both homologous chromosomes
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What is the result of non-disfunction at fertilisation
the gamete with both chromosomes results in a zygote with 3 copies of the chromosomes - Trisomy; the gamete without the chromosome results in a zygote with one copy - Monosomy
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Types of diseases that a person would get when they have trisomy
patau syndrome & edwards syndrome
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Types of diseases that a person would get when they have monosomy
Turners syndrome
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What is the problem with polyploid
can reduce fertility or render plant infertile
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Other cards in this set

Card 2

Front

What are the stages of cell division of mitosis

Back

Interphase; Prophase; Prometaphase; Metaphase; Anaphase; Telophase; Interphase

Card 3

Front

What is part of interphase (mitosis)

Back

Preview of the front of card 3

Card 4

Front

What happens in interphase (mitosis)

Back

Preview of the front of card 4

Card 5

Front

What happens in prophase (mitosis)

Back

Preview of the front of card 5
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