Cell Growth and Division Flashcards
2 reasons why cells can’t grow more and more?
- volume of cell grows (l x h x w) and surface area only grows l x h, making it difficult over time for the membrane to assist in caring for the volume of the cell. 2. there would have to be a movement of more material across the membrane for bigger organelles, causing traffic jams.
cell division?
momma cell divides into 2 daughter cells
what must happen first in order for cell division to occur?
DNA must be replicated
asexual reproduction?
producing genetically identical offspring from only 1 parent cell
can asexual reproduction occur in multicellular organisms?
yes. even some plants are asexual reproducers (shoots on the tip of a plant)….binary fission, budding
sexual reproduction?
2 separate parent cells create offspring with genetic information from each parent
Can some single celled organisms reproduce using sexual reproduction?
yes.
advantages of sexual reproduction?
genetic diversity
advantages of asexual reproduction?
quick and easy
disadvantages of sexual reproduction?
need to find a mate
what plant reproduces both sexually and asexually?
strawberry. the strawberry fruit grows from sexual reproduction from seeds and pollen but the green leafy runners that grow off of the berry are a product of asexual.
chromosomes? main function?
genetic information (DNA) bundled into packages. main role - to package all the information nicely so that it can remain organized during replication and so that it can hold a lot of information efficiently
chromatin?
DNA tightly bound to and coiled around histones (protein)
nucleosomes?
chromatin bound so tightly that it forms these beadlike structures that are thick and fibrous.
what is the “x” like chromosome shape in textbooks of DNA replication suppose to represent?
duplicated chromosomes with supercoiled nucleosomes.
what 3 things happen in a What cell cycle?
- cell grows, 2. cell prepares for division, 3. cell divides,
the eukaryote cell has 4 stages. what are they?
G1, S1, G2, and M
interphase includes which 3 stages?
G1, S1 and G2
What happens in G1? S1? G2?
G1 - cell growth, S1 - DNA replication, and G2 - where DNA and organelle reproduction are completed
Is mitosis part of interphase?
no. Its part of the M phase - the phase where the cell actually divides (but the DNA and organelles have already been replicated). M phase - mitosis and cytokinesis.
Which is the longest: G1, S1 or G2? Why?
S because this where DNA gets replicated and thats filled with detailed info
Which takes longer; mitosis or interphase?
interphase….requires more time to replicate than to separate.
centromere?
centromere- the center where 2 chromatids meet (sister chromatids). spindle fibers - the special skeletal fibers that help the cells divide.
centrosome?
centrosome - an area just outside the nuclear envelope ( but in the nucleus) where the spindles and centrioles are at.
centrioles?
centrioles - tiny paired structures in the centrosome that connect the spindles.
spindle fibers?
spindle fibers - the special skeletal fibers that help the cells divide.
prophase? what happens?
genetic material inside the nuclear envelope condense, the sister chromatids become visible, spindle fibers form, the centrioles start moving to the poles
metaphase?
nuclear envelope is gone, chromatids (centromeres) line up (no separation of sister chromatids yet), centrioles reach the poles, spindle fibers attach the chromatids to the centrioles.
anaphase?
sister chromatids detach!
telophase?
2 new nuclear envelopes form around the condensed , separated chromatin. spindle fibers shrink. there’s a dent in the cell’s membrane.
cytokinesis?
division of the cytoplasm to form to separate cells.
