22/10/2015meiosis l.o: to understand meiosis and how the sex cells determine gender
TRANSCRIPT
Can you identify what this Can you identify what this picture is showing?picture is showing?
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Meiosis – another type of cell division!
http://www.youtube.com/watch?v=D1_-mQS_FZ0
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20/04/23 What is meiosis?What is meiosis?
Meiosis begins with a single cell. (23 chromosome pairs)
First the cell makes a copy of each chromosome. (92 chromosomes in total)
During the first division the pairs a split up.(l46 chromosomes in each)
original cell
firstdivision
seconddivision
4 new cells
Now the chromosome copies split from the original.The new cells contain half the genetic information and unpaired chromosomes(23 chromosomes in each)
Look at the meiosis microscope slide. Draw and explain what you can see.
Why can’t we look at a normal body cell to see meiosis
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20/04/23 What type of cells are formed by What type of cells are formed by meiosis?meiosis?
In animals, meiosis produces ova in females and sperm cells in males.
In plants, the gametes produced by meiosis are pollen grains and ovules.
Sexual ReproductionSexual Reproduction
The human egg and sperm cell
(“GAMETES”) contain 23
chromosomes each and are created by
meiosis.
When fertilisation happens the gametes fuse together to
make a single cell called a ZYGOTE. The zygote has 46 chromosomes (23 pairs) and continues to grow through
mitosis.
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Mitosis vs. MeiosisMitosis vs. MeiosisMitosis:
1. Used for growth and repair of cells
2. Used in asexual reproduction
3. Cells with identical number of chromosomes and genetic information are produced
Meiosis:
1. Used to produce gametes for sexual reproduction
2. Each daughter cell has half the number of chromosomes of the parent
Tick or cross to indicate whether the Tick or cross to indicate whether the feature applies to meiosis, mitosis or feature applies to meiosis, mitosis or
bothbothFeature Mitosis Meiosis
Occurs in growth and repair
Movement of chromosomes occurs
Daughter cells are identical to the parent cell
Chromosome number is halved
Produces haploid cells from diploid cells
Daughter cells can be different from each other