Presentation on theme: "Happy Friday! Please do the following: pick up the handouts get a chrome-book and get out your Oreo Mitosis lab – you have 15 minutes to submit your video."— Presentation transcript:
Happy Friday! Please do the following: pick up the handouts get a chrome-book and get out your Oreo Mitosis lab – you have 15 minutes to submit your video link https://www.youtube.com/watch?v=gwcwSZIfKlM
You started as a cell smaller than a period at the end of a sentence…
1 set of chromosomes came from your mother (n) 1 set of chromosomes came from your father (n) Chromosomes are found in homologous pairs (two of each chromosome – 2n)
Typical Human Family Tree
Creating Haploid Cells 12
Meiosis is: – Cell division that halves the # of chromosomes – The process that germ cells go through to produce gametes (sperm & egg) – Fundamental basis of sexual reproduction Diploid (2n) Haploid (n) The zygote is a unique genetic mixture of both parents.
from momfrom dadchild meiosis reduces genetic content too much! The right number!
20 chromosomes (diploid) chromosomes A cell containing 20 chromosomes (diploid) at the beginning of meiosis would, at its completion, produce cells containing how many chromosomes? chromosomes (haploid or 1n)
daughter cells contain half the number of chromosomes as the parent cell produces gametes (sperm & egg) occurs in the testes in male occurs in the ovaries in females
A pair of the same chromosomes, one from mom and one from dad, get blended together to form a single chromosome that is a mixture of both parents DNA.
Homologous chromosomes in a tetrad cross over each other Pieces of chromosomes or genes are exchanged Produces Genetic recombination in the offspring
Yes! It is called nondisjunction. – Chromosomes don’t separate properly and some gametes end up with too many or not enough chromosomes.
makes genetically unique cells makes genetically identical cells allows asexual reproduction allows sexual reproduction new cells have full set of chromosomes (diploid) new cells have half set of chromosomes (haploid) number of divisions – 1 number of divisions – 2 makes 4 daughter cells makes 2 daughter cells occurs in somatic cells occurs in germ cells