Lecture 30 Flashcards
(28 cards)
Different moments of a cell cycle do what
carry out functions determined by the genes specified as part of its differentiation (normal work)
or replicating its genome and dividing (division)
Why can’t cells do normal work and divide at the same time?
bc mechanisms for DNA replication and gene expression get int the way of each other and too many problems would happen if we did them at the same time
How do single-cell organisms reproduce
division (binary fission)
example of a single-cell organism that divides as reproduction
amoeba
how do single-celled organisms grow
through obtaining nutrients (food, carbon) which increases the cell size
con of single-cell organism growth
limits how large the cell can because if too big the intracellular functions have problems (things too far apart)
binary fission allows
shift from normal behaviors of eating and metabolism to cell division (binary fission)
Multi-cell organism must
replenish cells
3 main reasons why our cells divide
- growth of our body
- replacement of lost or damaged cells.
- pass genetic material onto offspring
how long is the cell cycle 4 main phases
~24 hrs
Four main phases of cell cycle
GSGM
Get stoaked go mainy
Gap1
Synthesis
Gap 2
Mitosis
Gap1
11 hrs
Cell carries out its normal differentiated functions
Synthesis
8hrs
DNA synthesis- replication of the genome
Gap2
4 hrs
Rapid protein production preparing for mitosis
Mitosis
1hr
division of genomes into 2 daughter cells
The human genome during mitosis has
pairs of chromosomes (one from mom and dad), and within each pair the chromosomes are replicated (sister chromatids)
5 stages of mitosis
PPMAT
Please pick my apple tree
prophase
prometaphase
metaphase
anaphase
telophase (& cytokinesis)
what are centrosomes
protein structures that serve as microtubule-organizing centers (MTOCs)
Centrosomes are what during S phase
Replicated, spread to 2 sides of the cell, and long microtubule proteins extend between the forming spindle fibers
What are kinetochores
protein surrounding centromeres of sister chromatids, they act as attachments to spindle fibers
as microtubules of the spindle grow, they cause the chromosomes to line up along the midpoint of the cell
What happens in metaphase
when the chromosomes are all lined up at metaphase plate
What happens in anaphase
spindle pulls apart sister chromatid pairs
what happens in telophase
nuclear envelope reforms, chromosomes decondense
what happens in cytokinesis
cytoplasm is divided forming two daughter cells