Chapter 5 - New Cells Flashcards
Define DNA.
Deoxyribose nucleic acid.
What’s the difference between Mitosis and Meiosis?
Mitosis is the cell division which cells are produced for growth, maintenance and repair.
Meiosis is the process by which cells are produced for sexual reproduction.
What are the functions of DNA in mitosis?
Determines:
•The types of protein that the cell can make.
•The structure of the cell.
•The structure of the whole body.
•The way each cell functions.
•The enzymes that will be made.
•The chemical reactions that go on inside and outside the body cells.
Mitosis; What happens at Interphase?
DNA molecules duplicate.
Mitosis. What happens at Prophase?
- Pairs of centrioles become visible and move to opposite ends of the cell
- Chromatin coils to become chromosomes.
- Nucleolus and nucleus break down
- Spindle fibers grow from centrioles
- Centrioles move to opposite poles of the cell.
Mitosis. What happens at Metaphase?
- Chromosomes lie along the middle of the cell.
* Some spindle fibers attach to centromeres
Mitosis. What happens at Anaphase?
- Centromeres divide in two.
- Spindle fibers pull new chromosomes to opposite poles of the cell.
- Each pole (future daughter cell) possess an identical set of genes.
Mitosis. What happens at Telophase?
- Chromosomes gather at each pole of cell.
- Chromatin uncoils.
- New nuclear membrane appears at each pole.
- New Nucleolus appears in each nucleus.
- Mitotic spindle disappears.
Where does Meiosis take place?
In the Sex Organs of sexually reproducing organisms- those that produce gametes.
What are the two types of Gametogenesis?
Spermatogenesis
Oogenesis
Why is Meiosis sometimes referred to as the Reduction Division?
Because the number of chromosomes in the daughter cells is reduced to half the usual chromosome number.
Why’s Meiosis different from Mitosis?
Chromosomes pair off during the prophase stage. The members of each pair of chromosomes are identical in size and shape = Homologous Chromosomes.
The 1st Meiotic Division. What happens at Prophase 1?
•Homologous chromosomes become paired and Crossing Over occurs.
The 1st Meiotic Division. What happens at Metaphase 1?
- Homologous pairs become align at the center of the cell.
* independent assortment.
The 1st Meiotic Division. What happens at Anaphase 1?
The homologous chromosomes separate.
At the end of the first Meiotic division, how many number of chromosome is at each pole of the cell?
Half the number; 23 chromosomes
What happens during Telophase?
During Telophase, the cytoplasm may divide into 2 parts.
The second Meiotic Division
A new spindle forms at each end of the original spindle and usually at right angles to the original.
The second Meiotic Division
When the homologous chromosomes are paired the chromatids may break and exchange segments.
Creates new combinations of genes so that the chromosomes passed on to the offspring are not the same as those inherited from the parents.
What’s Cytokinesis?
Cytokinesis is the division of the cytoplasm and it takes place while telophase is occurring.
What’s the difference between a Chromatid and Chromosomes?
Chromatids are two identical strands of DNA that make up a chromosome, whereas a chromosome is a structure in the cell nucleus that is simply two chromatids.
