By102 Zach Nolen LAB 4 HUMAN TRAITS AND
By-102 Zach Nolen LAB 4 HUMAN TRAITS AND MITOSIS
Chromosomes Chromosome – DNA strands that are located with the nucleus of the cell. � Centromere – The connecting point on the chromosome. Spindle fibers will connect here during mitosis. �
Homologous vs. Heterozygous � Homologous simply means that a pair of chromosome are the same. � Heterozygous means that the a pair of chromosomes are different.
Haploid vs. Diploid � Haploid (n) � Diploid (2 n) � Cells have only 1 copy of � Cell has 2 copies of DNA � Only sex cells (sperm and egg) are haploid. (1 from mom, 1 from dad) � All cells in the body are diploid EXCEPT sex cells
Interphase � Interphase, which is not part of mitosis, is also called the growth or resting stage in the cell cycle.
Mitosis � Mitosis is the process of cell division. In this process, 1 diploid cell will divide into 2 daughter cells which are also diploid. � There are 4 phases of mitosis: �Prophase �Metaphase �Anaphase �Telophase and Cytokinesis
Prophase � Chromatin condenses into chromosomes. � Spindles begin to form at poles � Nuclear envelope breaks down.
Metaphase � Chromosomes line up in middle of cell (metaphase plate). � Spindle fibers attach to chromosomes.
Anaphase � Centromeres break down. � Chromosomes are pulled toward poles by spindle fibers
Telophase and Cytokinesis � Chromosomes arrive at poles. � Spindles dissolve � Nuclear envelope forms. � Cytokinesis – division of the cytoplasm
Meiosis � Meiosis is similar to Mitosis, but there a few differences. � Start with 1 Diploid cell and end with 4 haploid cells.
HUMAN TRAITS
What are human traits? � Human traits are carried on genes on chromosomes. � Humans have become quite diverse due to many generations of genetic recombination.
Dominant vs. Recessive Traits � Dominant � Recessive � Is expressed if present � Is only expressed if � Dominant=/=Prevalent dominant form of gene not present.
Genotype vs. Phenotype � Genotype � The genetic makeup of an individual � Phenotype � What an individual looks like
Punnett Squares � Allow us to determine potential genotype and phenotype of offspring. � Example: �What would be the genotypic and phenotypic ratios of the offspring of a couple where one is Heterozygous and the other is Homozygous recessive?
CLASS HUMAN TRAITS
Bent Pinky Dominant Recessive
PTC Tasting Dominant Recessive
Eye Color Dominant Recessive
Mid-Digital Hair No hair present Dominant Recessive
Tongue Rolling Dominant Recessive
Widow’s Peak Dominant Recessive
Thumb Crossing Left over Right over left Dominant Recessive
Ear Lobes Dominant Recessive
Hitchhiker’s Thumb Dominant Recessive
Mitosis Drawings � You should draw ALL stages of mitosis. � In your drawings, use cells that have 3 chromosomes. � Label all relevant parts in each stage
Review Questions What are the stages of mitosis? 2. What is the difference between a genotype and a phenotype? 3. Which cells in the body are haploid? 4. What is the difference between mitosis and meiosis? 1.
Before You Leave Lab � Look through the microscopes to observe mitosis. �Do not mess with the adjustment knobs! Only use the stage knob. �You must identify 2 stages of mitosis using the microscope and have me check before you can leave, but you must draw all 6 stages.
Before Next Lab � Complete all sections in lab notebook to be turned in. � Complete Mitosis Handout � Study for Test � Prepare Study guide (Bonus)
- Slides: 30