Bio 10 Flashcards
cell division
after growth a cell divides into 2 daughter cells
DNA overload
when the molecules needed are too much for the amount of DNA there is too code for them
Why don’t cells just keep growing?
- DNA overload
- Material Transport
What problems to material transport does a large cell pose?
A too large cell has too much space to be efficient. Any molecules take a while to move from point a to point b
how is the SA/V ratio effected by size of cell
The larger the cell, the smaller the ratio
What are the main 4 phases of the cell cycle
G1- cell growth
S- replicate chromosomes
G2- preparefor mitosis
M- cell devision
What are the three types of of cell division and what kinds of cells use them?
- Procaryotic- Binary fission
- Eucaryotic- asexual reproduction-cell cycle
- Formation of Gametes- CHAPTER 11!!
True or False: DNA must be passed on during cell division
TRUE!!
Binary Fission
Cell division of prokaryotic cells
- Stage 1- DNA is copied
- Stage 2- Cell divides
Genes
segments of DNA coding for a specific thing
DNA
deoxyribonucleicacid
- nucleic acid containing thousands of genes
Chromosome
Structures of tightly wound DNA and histone proteins
CAN BE ONE OR TWO
Chromatids
One of the pair of strands making up a x chromosomes
two are called sister chromatids
Centromere
the point in the middle of a chromosome where the sister chromatids meet together
Interphase
G1, S, G2, where the cell grows and prepares for division
mitosis
the first phase of the M phase where the nucleus divides
When can you see chromosones
During cell divisions the chromosones condense and become visible
What are the 4 phases of mitosis
prohpase (longest)
metaphase
anaphase
telophase
How long does mitosis take?
between a few minutes and a few days
Prophase
The first phase of mitosis taking 50-60 % of time
- chromosomes condense
- centrioles move apart off of centrosome
- nuclear envelope dissolves
How are spindles formed and what happens to them after they are formed?
The spindles are structures made up of both centrioles and microtubules:
as the centrioles move off of the centrosome in the Prophase, the spindles are formed
After the chromosomes have been split the spindles dissolve into the cell.
centrosome
an area in the cell where centrioles usually rest
metaphase
2nd phase
Chromosomes line up in the middle of the cell at the equator/metaphase plate because spindles play “tug of war” with each sister chromatid
equator vs. metaphase plate
TRICK QUESTION!!
they are the same thing, they are the theoretical line where chromosomes line up during the metaphase
Anaphase
3rd phase
The chromosomes split at the centromeres because the spindles holding onto each of them shrink to be shorter
Telophase
4th phase
Sister chromosomes disperse into a tangle of DNA on their sides and new nuclear envelope forms
cytokinesis
Division of cytoplasm
- cell membrane pinches in
How do animal and plant cells differ in the way they split
animal cell membranes pinch together
plant cells build a sort of NEW membrane
(because plant cells are rectangular)
G1 phase
The cells FIRST stage, growth stage where cell synthesis’s proteins and organells and nearly doubles in size
G0 phase
A state a cell goes into WHEN THEY CAN’T DIVIDE
- continuous growth, or at least no loss in size
S phase
2nd phase in cell cycle, (Synthesis Stage)
DNA IS SYNTHEZISED OR COPIED
G2 phase
3rd phase (2nd growth phase)
Coiling of genetic material
Replication of Centrioles
Microtubules arranged
FINAL CHECK
(nucleus is prepared)
When cells come in contact with other cells, do they grow?
NO! cells will usually grow more to fill spaces (heal cuts)
If cells dont have growth restrictions- CANCER
Cancer
A body’s cells’ loss of ability to control growth
What are some causes of cancer?
Deletion- deleting a gene
Dupliaction- multiple of the same gene
Inversion- reversing orientation or order of genes
Translocation- moving part of one gene onto another
Regulators of the cell cycle
Different internal or external regulators that makes sure a cell is ready and has the space to split
What are the 3 checkpoints of the cell cycle
G1 checkpoint
G2 checkpoint
Mitosis checkpoint
G1 checkpoint
Decides if cell can divide- if cell is big enough/has enough room
- IF NOT- cell grows more
- IF STILL NOT- cell remains in G0 phase
G2 checkpoint
Decides if cell can still divide- checks if DNA is properly replicated
- IF NOT - more time to fix
- IF STILL NOT- cell death
Mitosis checkpoint
Triggers the cell to stop mitosis and move onto cytokinesis
- CHECKS IF CHROMOSOMES ARE ATTACHED TO SPINDLES
Regulator EX.
Cyclin, a protein that makes sure there is space for cell division and helps to control timing of cell division
Internal Regulators
Proteins that respond to internal cell events
- such as those found at the checkpoints
- cause cells to stop or proceed
External Regulators
Proteins responding to external events (growth factors)
- such as checking if there is space
- cause cells to speed up or slow down
