Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
24 Cards in this Set
- Front
- Back
What are Somatic Cells? |
All Diploid cells in the body besides Gametes and their precursors.
Contains 46 Chromosomes |
|
What are Diploid cells? |
* Cells that contain 2 sets of Chromosomes. * Called 2N (N = 1 set of Chromosomes) |
|
What are Haploid cells? |
* Cells with one set of Chromosomes * Sperm & Egg * Called N |
|
How do Somatic cells divide? |
By Mitosis
* One 2N cell --Mitosis--> two identical 2N cells. |
|
How are Haploid (sex cells) formed? |
By Meiosis or Reductional Division.
* One N cell ---Meiosis--> 4 (non identical) Haploid Cells |
|
What two Chromosomes determine the sex of a female or male embryo? |
XX = Female XY = Male |
|
On what Chromosome do you see the defect for Down Syndrome? |
Chromosome 21 |
|
What is Asexual Reproduction? |
Reproduction by cloning yourself, making an exact copy. Down side: no new chromosomal information. |
|
What is a Genome? |
All of the genetic information that is stored in the DNA of of a cell. |
|
Why is Meiosis called Reductional division? |
Because the sets of Chromosomes go from Diploid (2N) to Haploid (N). |
|
Describe Meiosis I - Prophase I. (7) |
* Centrosomes migrate * Chromatin condenses * Nucleolus disappears * Nuclear envelope disappears * Spindle forms * Spindle attaches to Chromosomes * SYNAPSIS occurs |
|
What makes Meiosis different from Mitosis? |
Synapsis |
|
What is Synapsis? |
When Chromosomes in Prophase I "feel out" their partner and join at the Kinetochore and become Tetrads or Homologous Chromosomes. |
|
Describe Meiosis I - Metaphase I. |
The Tetrads align along the Metaphase plate |
|
Describe Meiosis I - Anaphase I. |
The Tetrads are pulled apart randomly |
|
Describe Meiosis I - Telophase I/Cytokinesis (4) |
* The Tetrads reach the poles * Pinch in and create Cleavage Furrow * Chromosomes decondense * Nuclear envelope re-forms |
|
Describe Meiosis II - Prophase II. (2) |
* Centrosomes replicate * Spindle forms |
|
Describe Meiosis II - Metaphase II. |
The Chromosomes line up along the Metaphase plate. |
|
Describe Meiosis II - Anaphase II. |
The Sister Chromatids pull apart |
|
Describe Meiosis II - Telophase II / Cytokinesis. (3) |
* Nuclei form * Chromosomes decondense * Four distinct Haploid daughter cells |
|
What is "crossing over" in Synapsis? |
When pieces of the Sister Chromatids break off and attach themselves to the same spot in the other Chromatid in the pair. This is why kids might have Dad's big feet and hair color, but Mom's eye color. |
|
What is Spermatogenesis? |
The creation of Sperm. 2N splits to N & N which split into 2 smaller sets of n & n which form four sperm. |
|
What is Oogensis? |
Creation of eggs. At birth, all eggs are at Prophase I Synapsis. At puberty 1 egg/month matures and completes Meiosis I when it is released. If fertilized, it completes Meiosis II. 2N splits to N + polar body, N splits again to N + polar body. |
|
What is Independent Assortment? |
Two equally probable arrangements of Chromosomes at Meiosis I. |