chapter 13 - meiosis and sexual life cycles

Download Chapter 13 - Meiosis and Sexual Life Cycles

Post on 25-Feb-2016

40 views

Category:

Documents

1 download

Embed Size (px)

DESCRIPTION

Chapter 13 - Meiosis and Sexual Life Cycles . Review: Describe the functions of mitosis. High frequency quiz mistakes:. 1. Incorrect number of chromosomes used in depiction of mitotic cell division. Question stated that the cell was diploid and the haploid number (n) was 2. . Diploid (2n). - PowerPoint PPT Presentation

TRANSCRIPT

  • Chapter 13 - Meiosis and Sexual Life Cycles High frequency quiz mistakes:Review: Describe the functions of mitosis.1. Incorrect number of chromosomes used in depiction of mitotic cell division. Question stated that the cell was diploid and the haploid number (n) was 2. Diploid (2n)Haploid number (n)(number of chromosomes in a set)2 sets2X= 4 chromosomes in the cell

  • Chapter 13 - Meiosis and Sexual Life Cycles High frequency quiz mistakes:Review: Describe the functions of mitosis.PracticeA. How many chromosomes in a triploid cell with a haploid number of 7?B. A diploid cell has 24 chromosomes. What is the value of n?C. A 4n cell has 40 chromosomes. What is the ploidy of this cell and how many chromosomes would you expect to find in its gametes?2112Tetraploid, 20

  • Chapter 13 - Meiosis and Sexual Life Cycles High frequency quiz mistakes:Review: Describe the functions of mitosis.PracticeD. Draw a triploid nucleus of a cell with n = 2.

  • Chapter 13 - Meiosis and Sexual Life Cycles High frequency quiz mistakes:Review: Describe the functions of mitosis.2. What are the two possible chromosome combinations found in human male sperm?Ans: One of each homologous pair 1 through 22 and X 1 through 22 and Y- Are the gametes haploid or diploid?

  • Chapter 13 - Meiosis and Sexual Life Cycles Review: Describe the functions of mitosis.This brings us to our next adventurehow are the gametes made?Meiotic Cell Division (the other cell division)

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesA. Asexual ReproductionB. Sexual ReproductionAIM: Compare asexual to sexual reproductionReproduction

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesA. Asexual Reproduction1. One parent3. Single-cell organisms (certain protists [ex. amoeba] and fungi [ex. yeast] and all prokaryotes [bacteria])2. Genetically identical offspring (called clones) if we ignore mutations, which they rely on to evolve. AIM: Compare asexual to sexual reproductionA. Prokaryotic cell cycle (binary fission) B. eukaryotic cell cycle (mitosis) 4. Plants (vegetative propagation) and animalsMade possible by begin able to have numerous offspring very quickly as positive mutations are rare, but if you have millions of offspring in a few days one likely has such a mutation.What is a positive mutation in general?One that give the organism (vehicle) a better ability to survive and reproduce in current environment.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesB. Sexual Reproduction- Two parents- Highly variable offspring due to mixing of DNA of two parents- Gametes produced (fertilization)- Most eukaryotesAIM: Compare asexual to sexual reproductionTend to have fewer offspring over longer periods of time making mutations not a reliable means of generating diversitybetter to shuffle the DNA between two organisms.

  • Fig. 8.13Chapter 13 - Meiosis and Sexual Life Cycles Somatic cellsGametesNEW AIM: Describe how gametes are formed.

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell division3. Called reduction division1. Formation of gametes in animals2. Formation of spores in plants and fungi- The number of chromosomes is cut in half (typically from diploid [2n] to haploid [n])- Therefore essential for sexual reproduction

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Compare gametes to somatic cells in terms of chromosome number.(Soma- means body; somatic cell = body cell)Gametes are haploid (have one set of 23 chromosomes in humans), while somatic cells are diploid (have two sets or 46 chromosomes in humans)

  • Fig. 8.13Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Somatic cellsGametes

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Review the DNA/chromosomes in a human nucleus

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. This image shows the 46 chromosomes from the nucleus of a single human male cell.This display of chromosomes is called a Karyotype.You can see that each chromosome has a very similar (homologous) matching pair with the exception of the sex chromosomes (X and Y). Females would have a homologous pair of Xs. Males have an X and a Y (not homologous).

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. These are homologous (similar) chromosomesIf the gene for hemoglobin were on one of these (green bar), then it is on the other as well in the same location (locus).Therefore we have how many of each gene?Ans: at least two of every gene, except for the genes on the X and Y chromosomes in males since these chromosomes are not homologous.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. Every nucleus has 22 pairs of autosomes (chromsomes 1 through 22)

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. and one pair of sex chromosomes

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. *One of each pair comes from the mother, and the other comes from the father.What chromosomes would have been found in the sperm that fertilized the ovum that was to be this person?

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. *Therefore, this is the DNA that would have been packaged in the nucleus of the (sperm or egg?)fathers sperm that penetrated and fertilized the ovum to form a zygote because only males have Y chromosomes.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. *And this is the DNA that would have been packaged in the nucleus of the mothers ovum (has an X).This could also be in a sperm, but the previous slide could not be in an ovum. Explain.Ans: Males are XY. Therefore sperm can have an X or Y (they determine sex. Females are XX and therefore the ovum can only have an X.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. - One of each of chromosomes 1 through 22 and a sex chromosome as shown to the right is considered to be one complete set or n. The word for this is haploid.hap- = one-ploid = set

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. If I said that human cells are 2n that means each cell has how many sets?2

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.Humans have 23 pairs of chromosomes for a total of 46. If I said that human cells are 2n that means each cell has how many sets?2The word for this is diploid.di- = 2-ploid = setsHumans are diploid organisms. What are our gametes, ha- or diploid?Ans: haploid. When they fuse during fertilization the resulting zygote is diploid.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.What is n?n is a complete set of chromosomes (1 of each chromosome)n is called the haploid numberor number of chromosomes in a complete set.

  • Chapter 12/13 - Cell Cycle, Meiosis, and Sexual cyclesAIM: Describe the eukaryotic cell cycle.What is the value of n in humans?23, because we have 23 chromosomes in one set

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.How and where are the gametes formed in humans?Gametogenesis - formation of gametes (two types)1. spermatogenesisFormation of sperm, occurs in testes (male gonads)2. Oogenesis- Formation of ovum, occurs in ovaries (female gonads)This is all meiosis (gametogenesis, spermatogenesis, Oogenesis)

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.The variety of sexual life cycles

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell divisionThis figure shows a simple diploid cell with one homologous chromosome pair (n=1).What will happen first?Red one is maternal (coming from mother) and blue one is paternal (coming from father).Ploidy? n?

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell divisionDNA will be replicated.Then what?

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell divisionHomologous pairs will be pulled apart.And lastly?

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell divisionSister chromatids will be pulled apart.Each resulting cell is haploid with one of each homologous pair!If you want to add a second, third or even 23 pairs, they all behave the same way.

  • Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.Meiotic cell division Overview

  • (Gamete/spore formation)Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are formed.MEIOSIS (meiotic cell division)

  • (Gamete/spore formation)Chapter 13 - Meiosis and Sexual Life Cycles AIM: Describe how gametes are for

Recommended

View more >