Reading...
Play button
Play button
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;
38 Cards in this Set
- Front
- Back
|
Structure of a chromosome
|
Rod-shaped structure that contains supercoiled DNA (double helix)
|
|
|
Before the cell splits:
|
DNA is copied and the rod-like structures become 'X'-shaped
|
|
|
Sister Chromatids
|
The two parts of the 'X'-shaped chromosomes- identical
|
|
|
In somatic (body) cells, chromosomes occur in [...]? Where does each come from?
|
[pairs]
One pair from mom, one from dad Think <DIPLOID> |
|
|
These pairs are HOMOLOGOUS, meaning:
|
They have similar but not identical genes
|
|
|
In sex cells, chromosomes occur [...].
|
Individually
|
|
|
<HAPLOID>
The information comes as [...] from... |
The information comes as a half set of info from EITHER mom OR dad- but not both
|
|
|
Why is it important that information for Haploids comes this way?
|
Fertilization joins haploid cells together to create the first unique haploid cell
|
|
|
Species have a [...] number of chromosomes in the somatic cells.
|
[Specific]
|
|
|
What is the relationship between the number of chromosomes and complexity?
|
No relation. Number of chromosomes is NOT an indication of complexity.
|
|
|
Autosomes:
|
Chromosomes that do not contain genes relating to gender.
|
|
|
Sex Chromosomes
|
Last pair determines gender.
These contain genes other than gender, however. |
|
|
XX
|
Female
|
|
|
XY
|
Male
|
|
|
Gametes:
|
Sex cells- Egg + Sperm
|
|
|
Characteristics of sex cells
|
Sex cells are:
Haploid and unique (unique combinations of genes) |
|
|
Gametes are formed through the process of..
|
Meiosis
|
|
|
What is the location of Meiosis?
|
Reproductive organs: Ovaries and Testes
|
|
|
What is the function of Meiosis?
|
Meiosis is a series of two nuclear cell divisions that results in unique haploid cells.
|
|
|
Name the four phases of Meiosis 1.
|
Prophase
Anaphase Metaphase Telophase (Cytokinesis) |
|
|
Name the four phases of Meiosis 2.
|
Prophase 2
Anaphase 2 Metaphase 2 Telophase 2 (cytokinesis) |
|
|
What are the differences between Meiosis 1 and 2?
|
The stage of "Crossing-Over" and Independent Assortment.
|
|
|
"Crossing Over" occurs during which phase?
|
Prophase 1
|
|
|
What happens during "Crossing Over"?
|
Homologous chromosomes swap portions of chromatids creating four unique sets of genes on the chromatids.
|
|
|
What is the significance of "Crossing Over"?
|
The four unique sets of genes on the chromatids guarantess genetic diversity.
|
|
|
When does independent assortment occur?
|
During Anaphase 1 and 2.
|
|
|
What happens during independent assortment?
|
The chromatids segregate any influence by chromosome pairs.
|
|
|
What is the significance of independent assortment?
|
Guarantees genetic diversity.
|
|
|
Why is genetic diversity so important?
|
Genetic diversity is important because a whole species could die out, all of them being susceptible to a disease/weakness without "crossing over".
|
|
|
Oogenesis:
|
Formation of eggs (ootids) in the ovaries.
|
|
|
What does oogenesis result in?
|
One viable egg, three polar bodies.
|
|
|
What happens to the three polar bodies? Why?
|
The egg is much larger- the three polar bodies are tiny, and dissolve.
|
|
|
Oocites:
|
Egg follicles
|
|
|
What happens to the oocites when mature?
|
At puberty, the oocites will be released once a month for approximately forty years until menopause.
|
|
|
Spermatogenesis:
|
The formation of sperm cells (spermatids) in the testes.
|
|
|
Spermatogenesis results in:
|
Spermatogenesis results in four viable sperm cells
|
|
|
This process begins at [...] and continues until the age of [...].
|
[puberty]/[70]
|
|
|
This means that approximately how many sperm cells are made per day?
|
Thousands
|
