GENETICS VOCABULARY
SBI 3C: NOVEMBER 2012
IMPORTANT TERMS:

Genetics:
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Mitosis

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Cell division process that involves two divisions with only one
duplication of chromosomes
Parent cell


Division of nucleus into two genetically identical nuclei
Meiosis

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The study of the relationship between genes and heredity
Cell that divides by mitosis into two genetically identical cells
Daughter cells

Genetically identical cells produced from parent cell
IMPORTANT TERMS:

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Chromatin
 Thread-like structure of DNA and proteins in nucleus
Chromatid
 Each of the two identical chromosome strands in a replicated
chromosome attached by their shared centromere
Chromosome
 Carries genes, formed when chromatin condenses
Chromatid
(when together
and chromosome
when separated)
IMPORTANT TERMS:

Gene


Allele
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General body cells, have the diploid number of chromosomes
Sex cells

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(n) number of chromosomes in a cell that contains a single set of chromosomes,
present in gametes
Somatic cells

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(2n) number of chromosomes in a body cell of an organism, having two
chromosomes of each type per cell
Haploid

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One form of a gene for specific trait (ex. If gene was eye colour, allele would be
blue/brown/green)
Diploid


Segment of DNA that carries the code for a specific protein
Haploid reproductive cells, sperm and egg, whose union is necessary in sexual
reproduction to initiate the development of a new individual (also called gametes)
Gametes

Egg and sperm cells that unite during sexual reproduction
CELL CYCLE AND MITOSIS
SBI 3C: NOVEMBER 2012
THE CELL CYCLE:
Interphase:
 in between stages of dividing
 G1—beginning cell growth
 S—DNA duplicates (makes a copy)
 DNA is in the form of chromatin
 G2—cell undergoes it’s function
Purpose:
 to replace dead or dying cells
 to allow an organism to grow and
develop
Mitosis animation:
http://www.youtube.com/watch?v=AhgRhXl
7w_g
interphase
MITOSIS:
What is it?

DNA copies (chromosomes) are separated & sorted into two
sides of the cell

the cell then splits in two and part of each parent is carried to
the two new cells.

each ‘daughter’ cell is identical to the parent cell

results in cells such as internal organs, skin, bones, blood, etc.
PHASES OF MITOSIS:

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Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
IPMATC
Interphase occurs just before Mitosis begins:
DNA is replicated
along with
organelles and
other cellular
components and
the cell prepares
for division.
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm
Mitosis Interphase
Animal cell
Plant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
STEP 1:Prophase (preparation phase)
•
•
•
the DNA recoils, and the chromosomes condense
the nuclear membrane disappears
mitotic spindles begin to form
Nuclear membrane
Mitosis Prophase
Animal cell
Plant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
STEP 2: Metaphase (organizational phase)


spindle fibres attach to the chromosomes at the
centromere
chromosomes line up the middle of the cell
Mitosis Metaphase
Animal cell
Plant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
STEP 3: Anaphase (separation phase)

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the chromosomes split at the centromere
the ‘sister’ chromatids are pulled by the spindle fibers
to opposite poles of the cell.
Mitosis Anaphase
Animal Cell
Plant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
STEP 4:Telophase


the chromosomes, the cytoplasm and organelles divide into 2
portions.
this diagram shows the end of telophase
Mitosis Telophase
Animal cell
Plant cell
Photographs from: http://www.bioweb.uncc.edu/biol1110/Stages.htm
After Mitosis: Cytokinesis
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the actual splitting of
the cytoplasm into two
separate cells is called
cytokinesis
occurs differently in
both plant and animal
cells
Animal cells: cleavage
furrow pinches cell
Plant cells: cell plate
forms in between
Beginning of cytokinesis in a plant:
Beginning of cytokinesis in an animal:
http://www.bioweb.uncc.edu/1110Lab/notes/notes1/lab6.htm
Mitosis
 Mitosis
animations:

http://www.youtube.com/watch?v=2WwIKdyBN_s&feature=related

http://www.youtube.com/watch?v=VlN7K1-9QB0