Biology - Mitosis/Meiosis/Cancer Flashcards
Defining Mitosis Meiosis and Cancer
1
Q
Is a big cell always better?
A
- If a cells size is doubled then it would require 8x more nutrients and have 8x more waste to excrete
- Surface area increases by 4x
- Plasma membrane would not have enough surface area to allow oxygen, nutrients, and wastes to diffuse
- Cells would either die from their own waste or starve to death
2
Q
Cell size:
A
- Limited in size
- Female egg is the largest cell in the human body (can be seen without a microscope)
3
Q
Structure of eukaryote chromosomes
A
During most of cells life cycle, the chromosomes exist as CHROMATIN (strands of DNA wrapped around protein)
4
Q
Chromosomes
A
When cell enters mitosis, chromatin coils up into the form of chromosomes
5
Q
Chromosomes structure
A
- Consists of DNA wrapped
around proteins (Histones) - DNA & histone molecules form bead like structures called NUCLEOSOMES
- Nucleosomes fold DNA and become tightly packed to form chromosomes during mitosis
6
Q
Two Copies
A
- Due to DNA replication in the S phase, each chromosomes has an identical copy
7
Q
The Cell Cycle
A
- Cells go through to two general periods
- Interphase is the growth period (growing)
- Mitosis is the period of division (÷ of nucleus)
- Most of the cells life is spent carrying out the activities of interphase.
8
Q
What is cytokinesis ?
A
When the chromosome membrane splits
9
Q
What are the roles of cell division ÷
A
- Un unicellular organisms
+ Method of Reproduction - Multi cellular organisms
+ Growth
+ Maintenance
+ Replacement
10
Q
What are spindles and what stage of the cell cycle are they found?
A
- Found in the Metaphase stage
- Football shaped structure consisting of thin fibers made of micro-tubes
- Separates sister chromatids
11
Q
What is a chromatid
A
- Esch sister chromatic is attached to its own spindle fiber
- Ensures that each new cell will get an identical and complete set of chromosomes
12
Q
What is Cytokinesis and what cells is it found in?
A
- Found in animal cells
- Toward the end of telophase the plasma membrane pinches in along the equator to creat two separate cell identical to the original
13
Q
What happens to plant cells?
A
- PLasma membrane doesn’t pinch in. Instead, a cell plate is formed and is place across the cells equator. (Picture a line down the center of the cell)
14
Q
What is contacts inhibition?>
A
- Cell to cell communication
- Cells communicate w/ each other by producing band secreting chemical signals
- When changes occur in the genetic control of these chemicals - cancer can result.
15
Q
What is the structure and function of DNA?
A
- DNA is made up of nucleotides
- Each. Nucleotide contains:
+ Deoxyribose (sugar)
+ a phosphate group
+ a nitrogen base
