1 / 41

Cell Reproduction & Genetics

Learn about the structure of chromosomes and the process of cell reproduction. Understand the relationship between genes, chromosomes, cells, and organisms. Explore the concepts of genetics, heredity, and DNA.

kempa
Download Presentation

Cell Reproduction & Genetics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cell Reproduction & Genetics Do Now: 1/20 Week 21 Objectives: Describe the structure of chromosomes, including the terms gene, chromatid, and centromere. Describe the relationship between genes, chromosomes, cells, and organisms. TASK: (to be collected!) 1. Draw a line down the center of a sheet of paper. Label one side “Know” and the other “Want to Know.” Write everything you can think of about genetics, heredity, chromosomes, or DNA in the two columns. 5 minutes!

  2. Chromosomes

  3. What’s the big idea? • Most of the time, DNA is uncoiled, so that it can perform its function of providing instructions to the cell. • Only during cell reproduction does DNA get tightly packed into chromosomes

  4. Chromosome Structure DNA strand Gets wrapped around many histone proteins (aka histones) forming a coil. Coils are coiled up even more to form a supercoil, which is then packaged even more to make a chromosome.

  5. Parts of a chromosome The 2 chromatids that make up a chromosome are called sister chromatids, which are extremely similar to each other.

  6. Quick review • DNA is organized into highly coiled structures called chromosomes. • Each chromosome contains thousands of individual genes.

  7. Dogs Have 78 Chromosomes! • Every species of organisms has a characteristic number of chromosomes. 78 Dog Adder’sTongue Fern 1,262 46 48 Humans chimps

  8. Autosomes and Sex Chromosomes • Human and animal chromosomes are categorized as autosomes or sex chromosomes. Sex Chromosomes determine an organisim’s sex. All of the others are called autosomes Typical human male 44 autosomes, 1 X sex chromosome 1 Y sex chromosome Typical human female 44 autosomes, 2 X sex chromosomes

  9. Homologous Chromosomes • Every cell contains two copies of each autosome. To put it another way, autosomes come in pairs. These two chromosomes are called HOMOLOGUS CHROMOSOMES. Genes for eye color are found at The same location on both Chromosomes. The gene for brown Eyes I got from my dad is in exactly The same location on one chromosome As the gene for blue eyes I got from my Mom on the other homologous Chromosome. Specific genes are found in the Same location on each homolugous Chromosome. Consider me for example…

  10. Do Now 1/22 (HW check: 145-147) • Objectives: • Define and distinguish haploid and diploid cells. • Describe how chromosome number changes during sexual reproduction in animals. • Define karyotype, and analyze karyotypes to diagnose genetic disorders. • Task: Please copy the following definitions into the notes outline you just picked up: • Diploid: (2n) having 2 copies of each chromosome type. • Haploid: (n) having 1 copy of each chromosome type. • Karyotype: A picture of a cell’s chromosomes.

  11. Diploid and Haploid Cells • Cells are considered diploid when they have 2 copies of each chromosome. Most of your body’s cells are diploid. • Cells are haploid if they have only one copy of each chromosome pair. This is the case for gametes, like sperm and egg cells, used for reproduction.

  12. Diploid vs. Haploid

  13. Karyotypes • A karyotype is a picture of all the chromosomes in a dividing cell. A karyotype of one of your cells might look something like this:

  14. Normal Karyotype • Humans almost always have 23 pairs of homologous chromosomes. • Is this karyotype of a male or female?

  15. Abnormal Karyotype • Some serious genetic disorders are caused by trisomy – a certain kind of mutation that gives an individual 3 copies of a chromosome. • The karyotype below shows trisomy-21, better known as Down’s Syndrome.

  16. Do Now 1.22 • OBJECTIVES: • Identify, describe and distinguish the 3 types of cell division: mitosis, meiosis, and binary fission. • Describe the cell cycle by identifying the characteristics of cells in G0, G1, S, G2, and M stages. TASK: 1. HW check (8.3, 8.17) 2. Complete the chart “Chromosome Formula…” you have approximately 5 minutes. It will be collected.

  17. Cell Division: 3 types Do Now 1/24: OBJECTIVE: 1. Complete yesterday’s objectives. 2. Describe the three types of cell division: mitosis, meiosis, and binary fission, including the types of cells that do the processes and the types of cells that result. TASK: HW check 2. Arrange the following from SMALLEST to LARGEST: Eukaryotic cell Chromosome Atom Prokaryotic cell Protein Multicellular organism

  18. Cell Division • Cell division, or reproduction comes in many forms, but there are some important similarities common to all. • The DNA of the cell is copied. • The cell divides one or more times, so 2 or more cells exist after 1 cell divides.

  19. Binary Fission • Simplest form of division. • Done by prokaryotes. • Chromosome copied, cell divides. • Results in 2 identical daughter cells.

  20. Mitosis • Mitosis is the type of cell division used by humans and other multicellular organisms to produce new body cells. • In this process, one diploid cell copies all of its chromosomes and then divides once to produce 2 new diploid cells identical to the parent cell. • The process involves several stages we will investigate next week.

  21. Meiosis is a specialized form of cell division used only by organisms that reproduce sexually. • Meiosis produces gametes, which are haploid cells such as sperm and egg cells required for sexual reproduction. • A specialized diploid cell (in the gonads) copies its chromosomes to become (2-chromatid) 2n, then divides twice to produce 4 new haploid gametes. • Fertilization is when two haploid gametes combine to form a new diploid individual.

  22. The Cell Cycle & Mitosis Do Now 1/23: OBJECTIVES: Describe what happens during the four phases of the cell cycle, G1, S, G2, and M. Describe the process of mitosis and identify cells in the stages of interphase, prophase, metaphase, anaphase, and telophase TASK: Decide whether each example given is an example of binary fission, mitosis, or meiosis: A paramecium (unicellular eukaryote) splits into 2 new cells. In the testis of a frog, specialized cells produce sperm. Cells that line the inside of your digestive tract are constantly scraped off and replaced by new cells The anthers of a flower produce thousands of grains of pollen, which may be carried by wind or insects to fertilize other flowers.

  23. QUIZ Wednesday • Topics: • Chromosomes • What are they made of, and what parts do they have • Number and types • Autosomes vs. sex chromosomes • Human 2n=46, and what do the “2,” “n,” and “46” mean • Diploid vs. haploid • Homologous chromosomes • Male XY, female XX • Cell division • Binary fission, mitosis, meiosis • What cells do them, what is the purpose, and what happens to chromosome number.

  24. Diploid vs. Haploid • Most of the cells in your body (and in all mammals) are DIPLOID, meaning they have 2 copies of all of your DNA

  25. Haploid Cells • Some cells (like animal reproductive cells – sperm and eggs) have only 1 copy of each chromosome. They are haploid.

  26. Do Now 2.19 Week 25 • OBJECTIVES: Complete objectives from Thursday, 2/15. • TASK: • 1. Pass up week 24 Do Nows 2. `The wing cells of a fruit fly are diploid and contain 8 chromosomes in the nucleus. How many types of chromosomes are present? What process makes fly gametes, and what number of chromosomes do they contain?

  27. The Cell Cycle • The cell cycle is like a cell’s life cycle.

  28. Do Now 1/28 • OBJECTIVE: Identify and describe the stages of mitosis: prophase, metaphase, anaphase, telephase • TASK: • 1. HW check. • 2. Rats are diploid organisms, like humans and almost all animals. The body cells of a rat have 42 chromosomes. • How many chromosomes are in a rat egg cell? • What is the 2n number of a rat? • What is the n number of a rat? • A rat skin cell is in G2 of the cell cycle. How many chromatids are present?

  29. Mitosis • Mitosis is the process of a cell making two identical “daughter” cells. • It is a form of asexual reproduction.

  30. Foldables • Make cell cycle and mitosis foldable notes! • Follow instructions carefully • Cell cycle steps on top (G1, S, G2, M) • Mitosis steps on bottom (P, M, A, T) • Details / sketches on the inside.

  31. Stages of Mitosis • Prophase: chromosomes become visible • Metaphase: chromosomes line up in middle of cell • Anaphase: chromosomes move apart • Telophase: 2 new nuclei begin forming

More Related