Chromosomes
Please immediately take out: 1. Chromosome/meiosis Notes 2. Mitosis/cell division Notes 3. HW (SG#4-7) 4. Blank Piece of paper(lined or unlined)
How much DNA do you have? Human DNA contains 3 billion base pairs The DNA inside one of your cells is 6 feet long
How does it all fit then? DNA is wrapped up very tightly into structures we call chromosomes
How does DNA get wrapped into chromosomes? Chromosomes are made of chromatin. DNA + histone proteins = Chromosome
Basic Structure(READ ONLY) Chromosomes are only visible when a cell is going to divide, so we usually see them in their double-stranded form The halves of a double-stranded chromosome (chromatids) are identical to each other because the DNA in the original chromosome replicated prior to cell division
How many chromosomes do humans have? In every non-sex cell (diploid cell) in your body you have 46 chromosomes (diploid #)----23 from mom and 23 from dad 23 chromosomes + 23 chromosomes = 46 chromosomes from mom from dad
Skin Cell
Types of Chromosomes Heart Cell Skin Cell Humans have 2 sex chromosomes in every non-sex cell of their body (DNA that determines if a person will be male or female) X X = female X Y = male Autosomes -- all of the other chromosomes Humans have 44 autosomes in every non-sex cell of their body 44 autosomes + 2 sex chromosomes 46 chromosomes Total Heart Cell Skin Cell
Diploid or haploid Haploid = Half= 42 Diploid = Double=84
Autosomes Sex Chromosomes
Sex Cells aka Gametes Female sex cell (gamete) = egg Male sex cell (gamete) = sperm Every sex cell (gamete) contains only 23 chromosomes (22 autosomes and 1 sex chromosome) _________ 23 23
Skin Cell
Other Organisms Different species contain different #s of chromosomes Organism # in non-sex cell (diploid) #in sex cell (haploid) Lion ___ 19 Gold fish 94 ___ Chicken 78 Cow 30 Ants 2 Chimp 48 Adders tongue 1000 38 47 39 60 1 24 2000
Sperm (_______) haploid Egg (_______) haploid Mom Dad Zygote (_______) Diploid)
A Kangaroo has 12 chromosomes in every diploid cell of its body A Kangaroo has 12 chromosomes in every diploid cell of its body. Draw a picture of what the sperm and egg would look like. Draw a picture of the zygote
Sperm (Haploid) Egg (Haploid) Zygote (Diploid)
A Fruit Fly has 8 chromosomes in every diploid cell of its body A Fruit Fly has 8 chromosomes in every diploid cell of its body. Draw a picture of what the sperm and egg would look like. Draw a picture of the zygote
Homologous Chromosomes Homologous chromosomes have DNA that codes for the same genes. Has same genes in same locations, but different versions of the genes. MOM DAD
Duplicated Unduplicated Homologous Chromosomes Mom Dad
Draw and explain the following chromosome, homologous chromosome and tetrad(pg. 162) Hair color Hair color Ear lobe shape Ear lobe shape
Sexual Reproduction How am I here? When 1 sperm fertilizes 1 egg it produces a cell called a zygote with 46 chromosomes Sexual Reproduction
Chromosomes replicate Meiosis- formation of haploid gametes (summarized version) Chromosomes replicate 1st cell division 2nd cell division
Males- 4 (haploid) sperm cells are produced. 4 (Humans 46) 2 (Humans 23)
One egg and 3 polar bodies Female One egg and 3 polar bodies
Crossing over/Meiosis Video https://www.youtube.com/watch?v=pdJUvagZjYA https://www.youtube.com/watch?v=4YfDq8rPDdM
Crossing over When homologous chromosomes form tetrads in meiosis I, they exchange portions of their chromatids in a process called crossing over. Crossing-over produces new combinations of alleles/increased genetic variety Crossing-over occurs during meiosis. (1) Homologous chromosomes form a tetrad. (2) Chromatids cross over one another. (3) The crossed sections of the chromatids are exchanged.
Crossing over animation http://local.brookings.k12.sd.us/biology/images/crossingover_movie.gif
13.3 Meiosis! M G2 S G1
13.3 Meiosis! M G1 G2 S Homologous Chromosomes Synapsis Crossing Over Tetrad
13.3 Meiosis! M G2 S G1
13.3 Meiosis! MI G2 S G1
13.3 Meiosis! MI G2 S G1 Diploid Or Haploid?
13.3 Meiosis! MII G2 S G1
THE “ART” YOU ARE ABOUT TO VIEW SHOULD NOT EVEN BE CALLED “ART” AND IS OF SUCH POOR QUALITY AND A LOW TECH NATURE IT SHOULD ONLY BE VIEWED BY A MATURE AUDIENCE….ONCE (ok so a little hyperbole-but it will help with your video)
Independent Assortment video https://www. youtube. com/watch
Why do females only produce one egg during meiosis? It needs to have all of the nutrients to support life and must have enough energy to travel to the uterus. Do females perform meiosis throughout their lifetime? No, they are born with all of the eggs they will ever have!
Meiosis- Division of sex cells What is meiosis? Formation of gametes. What are gametes? sperm and egg.
Are gametes haploid or diploid? Haploid (Half the # chromosomes as a body cell). Humans have 23 chromosomes in their gametes How many alleles for each gene do gametes have? Gametes have one allele for each gene.
How many cells are produced from one meiosis division? 4 sperm and one egg
http://www.youtube.com/watch?v=D1_-mQS_FZ0 http://www.youtube.com/watch?v=uh7c8YbYGqo http://www.youtube.com/watch?v=iCL6d0OwKt8&feature=related
Mitosis VS MEIOSIS Mitosis Body cells 2 Diploid 4. 46 Meiosis Sex Cells 4 Haploid 4. 23 1. What kind of cells are produced? 2. How many cells are produced? 3.Are they haploid or diploid? 4. Number of chromosomes in humans?
Gamete Formation In male animals, meiosis results in four equal-sized gametes called sperm. Meiosis produces four genetically different haploid cells. In males, meiosis results in four equal-sized gametes called sperm.
Gamete Formation In many female animals, only one egg results from meiosis. The other three cells, called polar bodies, are usually not involved in reproduction. Meiosis produces four genetically different haploid cells. In females, only one large egg cell results from meiosis. The other three cells, called polar bodies, usually are not involved in reproduction.