Module+6+Review

__**Chapter 9:**__ //**Somatic cells:** Are body cells, they contain a full set of chromosomes.// //**Germ cells:**// //A sexual reproductive cells that develop into sperm or eggs.//
 * 1) **Distinguish between somatic cells and germ cells.**

> Interphase has 3 parts that get the cell ready for Mitotic phase. **When is the DNA replicated?** DNA is replicated during the “S” stage. 'S' stands for synthesis. Mitotic Phase, which comes after interphase.
 * 1) **Define the terms chromatin, chromosome, sister chromatids and centromere.**
 * **Sister chromatids**: Two identical copies of a chromatin that is connected by a centromere.
 * **Chromatid**: One of the two identical copies of DNA that make up a duplicated chromosome.
 * **Centromere**: A region of DNA typically found in the middle where two identical sister chromatids come closest in contact.
 * **Chromosome:** A complete molecule of DNA & its attached proteins.
 * 1) **Describe the cell cycle. Name the stages and describe the key events that occur in each stage. What happens in interphase?**
 * G1: 1st Growth phase, cell is carrying out normal functions.
 * S: DNA replication (synthesis) Makes sister chromtins.
 * G2: 2nd Growth phase, prepares for mitosis.
 * When does mitosis take place?**
 * How much of the cell cycle is devoted to mitosis?** ¼ or less.

Use this space to draw out the phases of mitosis and DESCRIBE in words what is going on, using as many vocabulary words as possible. Try to avoid using "plain English” and try and stick to the biological vocabulary you have learned as much as possible.
 * 1) **Explain briefly the significance of mitosis in the life of a cell. List its four main stages and describe in detail the key events and structures involved in each stage.**


 * 5. Briefly compare the process of cytokinesis (cytoplasmic division) in plant and animal cells.**
 * In animal cells it is called cleavage furrow. It is like a little draw string pulls tight dividing the cell into two parts.
 * In plant cells they form a cell plate. As it forms it divides the cell into two like a wall would.

__**Chapter 10:**__ > //**Asexual**////: Involves a formation on a new cell where all genetic information comes from ONE parent. Clones itself.// > //**Sexual**////: The more fun kind. Involves the formation of a new cell when the genetic information from TWO parent cells “get together” during sexual reproduction. The new cell results after fertilization takes place. This allows for unlimited variety, no two people will ever have the same genetic make-up, except for twins.// > **Gene**: Small sections of DNA that contain the units of genetic information related to specific traits. > **Alleles**: Alternate forms of genes. > > **Homologous chromosomes** are chromosomes that have the same gene sequence. > > > This happens in prophase 1. Cross over occurs when homologous chromosomes find each other and make sister chromatids. This creates 4 tetrads (two homologous chromosomes made up of 2 sister chromatids). They all get real cozy and swap some genes... This creates genetic variation because none of them are identical anymore. > **Random fertilization** is when 2 random haploids get together creating a unique sequence of genes. > **Independent assortment:** random assortment of chromosomes during the production of gametes. > **Cross over:** the swapping of genetic info between sister chromatids. > All of these contribute to genetic diversity because it creates a cascade of unique changes to the individual who will be conceived. It really is truly amazing how many variations can take place throughout these processes. >
 * 1) **Distinguish between asexual and sexual reproduction. Explain the major biological advantages of sexual reproduction.**
 * 1) **Distinguish between the terms gene and allele.**
 * 1) **Describe homologous chromosomes. Where do they come from?**
 * 1) **State the diploid number and haploid number for humans.** N=23 (our reproductive cells carry this number) 2n=46 (non reproductive cells carry this number)
 * 2) **Describe the key events and stages of Meiosis I and Meiosis II. Please use your biological vocabulary!**
 * 1) **Explain what is meant by “crossing over” and when does it occur during the process of Meiosis.**
 * 1) **Explain how random fertilization, independent assortment, and crossing over contribute to genetic diversity.**
 * 1) ** Compare and contrast the overall process of mitosis and meiosis in terms of the type of cells each occurs in, the number of chromosomes present at the beginning and end of each process, the number of daughter cells produced, and are the daughters identical to each other or not. **

__**Chapter 11:**__ > The monk Mendel died in obscurity. His notes were found later and they realized he was onto something with his research into his Pea plants. He became the father of genetics and he never even knew it... His research was the study of inheritance patterns. > Gene is small section of DNA that contain the units of genetic information related to specific traits.
 * 1) Briefly discuss the significance of Mendel’s work to the field of genetics.
 * 1) ** Define the term gene. **

> **What is a true breeding organism?** > A true breeding organism means that two organisms with a particular, inheritable phenotype produce only offspring with that (same) phenotype > **P generation**: Parent generation. > **F1**: Children of parent generation. > **F2**: Grandchildren of 'P' generation. > **Genotype**: The actual genetic make-up. > **Phenotype**: The observable traits or outward physical appearance of an organism. > **Dominant genotype:** (let’s say for pea plants PP, Pp) The gene that will be expressed as the phenotype. > **Recessive genotype:** (let’s say for pea plants pp: The gene that will not be expressed but can be passed onto children. > **Heterozygous**: When genes from each parent are different from each other. (Non-identical alleles.) > **Homozygous**: When genes from each parent are the same. (they inherit identical alleles.) //Do all the combinations you can think of with a monohybrid cross to the F2 generation to make sure you see all the patterns.//  Parent creates F1 generation.  F1 generation creates F2
 * 1) ** Define and distinguish between these groups of terms: “true-breeding” organisms and hybrids; P, F1, and F2 generations; genotype and phenotype; dominant and recessive; heterozygous and homozygous. **
 * 1) **Predict the phenotypic and genotypic outcome of a simple monohybrid cross.**

> > Theory of Segregation states that diploid cells have “pairs” of genes for given traits that are located on homologous chromosomes and they separate from each other during Meiosis and end up on different gametes. > Independent assortment states that each allele for a specific trait separate independently from each other. > **Incomplete dominance:** When the appearance is a 'blending' of dominant and recessive traits. **Codominance:** When the appearance of 2 dominant traits for a given allele can both be expressed in heterozygous chromosomes. (blood typing)
 * 1) **Describe the process of running a “testcross” to determine an unknown genotype. Used to determine if an individual exhibiting a [[file:///wiki/Dominant_trait|dominant trait]] is [[file:///wiki/Homozygous|homozygous]] or [[file:///wiki/Heterozygous|heterozygous]] for that trait. Simplier, test crosses determine the genotype of an individual with a dominant phenotype.**
 * 1) **Explain Mendel’s theories of “segregation” and “independent assortment”.**
 * 1) **Explain the concepts of incomplete dominance and codominance as they relate to gene expression. Cite the examples from your text of each of these phenomena.**

** Epistasis: ** the phenomenon where the effects of one gene are modified by one or several other genes, which are sometimes called ** modifier genes **. The gene whose is expressed is called ** epistatic **, while the phenotype altered or suppressed is called ** hypostatic **.

**Pleiotropy** : occurs when one influences multiple. Consequently, a in a pleiotropic gene may have an effect on some or all traits simultaneously.

__**Chapter 12:**__ > **Autosomes** are chromosomes that are the same in both sexes. Generally provide info for making eyes, ears, hair, etc. > **Sex chromosomes** are those that differ between male and females and determine a person's gender. XX and XY. > Karyotyping is a visual mapping of chromosomes under a microscope during late prophase and early metaphase. **Duplication**: when cross over occurs a fragment attaches without the complimentary strand leaving. Creates duplicate instructions. **Inversion**: during cross over a fragment attaches in reverse order. **Translocation**: during cross over this occurs between non-homologous chromosomes. **Deletion**: during cross over a fragment fails to attach and is lost. These have a nondisjunction effect (a chromosomal defect where they do not split properly) and it usually causes spontaneous abortions, more kindly known as miscarriages.
 * 1) **Distinguish between autosomes and sex chromosomes. State the sex chromosome difference for human males and females.**
 * 1) **Describe the process of karyotyping.**
 * 1) **Describe the changes in chromosome structure that result due to duplication, inversion, translocation, deletion, and non-disjunction “errors” that occur in meiosis.**