Chapter 10.1: (Meiosis and) Sexual Reproduction - PPT notes - 2012
Remember there are 2 types of eukaryotic cell division – mitosis and meiosis
 mitosis is used for _________________________________________________________________
 meiosis is used for _________________________________________________________________
MEIOSIS – process that __________________________________________________________________
_____________________________________________________________________________________ meiosis, like mitosis, must be followed by ________________________________ in order for the process of cell division to be complete
MEIOSIS
 follows _____________________________ a period of cell growth, preparation for division and DNA replication
 produces ______________________________________ that are genetically different from each other and will be used in sexual reproduction
 does not follow a “cell cycle” as mitosis does
 involves the pairing and separation of ___________________________________________
 involves _____________________________ and _________________________________
 involves _____ nuclear divisions….Meiosis 1 and Meiosis II
 begins with 1 diploid cell and produces “____” haploid cells
HOMOLOGOUS CHROMOSOMES (or HOMOLOGUES)
 are PAIRS OF CHROMOSOMES found in organisms that reproduce sexually
 are PAIRS OF CHROMOSOMES THAT ARE ALIKE in….
1.
____________________ 2. ____________________ 3. __________________________________________
What is a gene? __________________________________________________________________________________
Where do PAIRs of chromosomes come from? __________________________________________________
PLOIDY - refers to the number of complete sets of chromosomes in a cell
DIPLOID CELLS
 contain ______ CHROMOSOMES of each homologous pair
 contain homologous pairs
 somatic (body) cells are diploid
 represented ____ (n=number of chromosome pairs)
HAPLOID CELLS
 contain ____ CHROMOSOME of each homologous pair
 contain NO homologous pairs
 sex cells/gametes/germ cells are haploid
 represented ____ (n=number of chromosome pairs)
FERTILIZATION … ________________ + _________________ = _________________
Let’s Practice – DIPLOID and HAPLOID
How many chromosomes do humans have in…
somatic/body cells? _____ diploid cells? ______ sex cells? _____ haploid cells?_____
How many chromosome pairs do humans have in…
somatic/body cells? ____ diploid cells? ______ sex cells? _____ haploid cells? _____

MEIOSIS I and MEIOSIS II
MEIOSIS I - first nuclear division
 involves the pairing and division of homologous chromosomes + produces ______ haploid cells

4 stages (followed by cytokinesis) - _________________________________________________
MEIOSIS II –second nuclear division
 involves the division of the double-stranded chromosomes + produces ______ haploid cells

4 stages (followed by cytokinesis) - _________________________________________________
MEIOSIS I - the first nuclear division
PROPHASE I
 ________________________________________________________________________________

________________________________________________________________________________
 synapsis ______________________________________________________________________
 crossing over _________________________________________________________________
METAPHASE I

________________________________________________________________________________
ANAPHASE I

________________________________________________________________________________
TELOPHASE I

________________________________________________________________________________

________________________________________________________________________________
CYTOKINESIS

________________________________________________________________________________
MEIOSIS II - the second nuclear division (occurs simultaneously in 2 cells)
PROPHASE II
 ________________________________________________________________________________

________________________________________________________________________________
METAPHASE II

________________________________________________________________________________
ANAPHASE II

________________________________________________________________________________
TELOPHASE II

________________________________________________________________________________

________________________________________________________________________________
CYTOKINESIS
 ________________________________________________________________________________

MEIOSIS DIFFERS IN MALES and FEMALES
MEIOSIS in males is called _________________________________

MALE gametes are called ___________________________________
 are formed in the ______________________
 produce _____ haploid cells from 1 diploid cell
MEIOSIS in females is called ____________________________

FEMALE gametes are called ____________________________
 are formed in the ____________________
 produce ____ haploid cells and 3 _______________________ from 1 diploid cell
Are there other differences in the process of meiosis in males and females? Why?
ASEXUAL and SEXUAL REPRODUCTION
Asexual Reproduction Sexual Reproduction

In SEXUAL REPRODUCTION 2 haploid gametes (produced by meiosis) fuse in a process called FERTILIZATION and form a diploid cell called a ZYGOTE
GENETIC RECOMBINATION
OCCURS DURING CROSSING OVER IN __________________________ OF MEIOSIS
 allows for variety among organisms
*THE MORE VARIETY WITHIN A SPECIES THE MORE LIKELY THAT SPECIES WILL SURVIVE*