unit 2 test- mitosis Flashcards
Why do cells have to divide?
1) Has more trouble moving necessary items across the cell membrane
2) Cell gets too big, places too much on the DNA (DNA overload)
What is DNA overload?
When a cell becomes too large and places many demands on the cell’s DNA
In a living cell, what part of the cell represents surface area and which part of the cell represents volume?
Surface area: total area of the cell membrane
Volume: cytoplasm
Cell division occurs in two main stages. What are they?
Mitosis and cytokinesis
What is the cell cycle?
The series of events that takes place in a cell as the cell grows and divides
What are the 4 stages of the cell cycle?
G1, S, G2, and M
What is G1 phase?
cell growth, synthesizes new proteins and organelles
What is S phase?
DNA replication, DNA is synthesized as chromosomes are replicated
What is G2 phase?
prepping for cell division, shortest phase
What is M phase?
mitosis, splitting a cell into two daughter cells
What is G0 phase?
The phase when a cell is not in the replicative cell cycle
What are 3 cells that can go into G0 phase indefinitely?
Heart cells, nerve cells, red blood cells
Cells spend most of their lifetime in what stage?
Interphase
What phases of the cell cycle does interphase include?
G1, S, and G2
What are the 4 stages of mitosis in order?
PMAT, prophase, metaphase, anaphase, telophase
What happens during prophase?
Chromosomes become visible as tightly coiled threadlike structures
What happens during metaphase?
Nucleus dissolves, chromosomes condense and move towards the center of the cell
What happens during anaphase?
The sister chromatids separate from each other and are pulled towards opposite ends of the cell
What happens during telophase?
Chromosomes spread out into a tangle of chromatin and mitosis is complete
How are chromatin and chromosomes different in structure?
Chromatin: spread out and messy
Chromosomes: bundled in an X shape
How are chromatin and chromosomes different in appearance?
Chromatin: Long, thin, loosely coiled
Chromosomes: supercoiled, compact
How are chromatin and chromosomes different in organisation?
Chromatin: not organised, spread throughout nucleus, easier for replication and transcription
Chromosomes: organised, necessary for replication
How are chromatin and chromosomes different in presence in a cell?
Chromatin: found throughout interphase
Chromosomes: seen only during cell division
How are chromatin and chromosomes different in visualisation on a microscope?
Chromatin: beads on a string when stained and under a powerful electron microscope
Chromosomes: can be seen with a powerful light microscope
What does an unduplicated chromosome look like?
< or >
What is the name of the proteins that regulate the cell cycle?
Cyclins
Define cancer?
Disease of the cell cycle, cells divide uncontrollably and do not die, they are immortal
What are tumors?
Tumors are clumps of cancer cells
What causes cancer?
Genetics, exposure to chemical or other genetic factors, viruses and/or lifestyle (not exercising, sleeping badly, eating badly, etc)
What are the 3 most common ways to treat cancer?
Surgery, chemotherapy, radiation
Where is the centromere in a chromosome?
In the middle of the X shape
Where are the sister chromatids?
> < those guys are the sister chromatids before they connect and make a chromosome
Where are the telomeres?
At the ends of each leg (feet of the chromosome)
How is 6 feet of DNA into the nucleus of a cell?
DNA wraps around proteins called histones. DNA in groups of 8 histones are called nucleosomes and the DNA further wraps around them. This is called chromatin, chromatin is loosely coiled. When a cell is starting mitosis, chromatin becomes chromosomes which are supercoiled.
How many chromosomes are in the human body?
46
How many chromosomes are in a human sex cell (egg/sperm)?
23
What is angiogenesis?
New blood growth
What is a benign tumor?
A tumor that stays in one spot
What is a malignant tumor?
It has metastasised (left tumor site and spread)
What is apoptosis?
Programmed cell death, normal cells will die, cancer cells will not die.
What is DNA in a group of 8 histones called?
Nucleosomes
