Unit 3: Asexual Eukaryotic Reproduction and checkpoints Flashcards
What is the first stage of eukaryotic reproduction?
Interphase
What are the three phases within interphase?
G1, S, G2
What happens during prophase?
- Replicated chromosomes condense
- Chromosomes appear as two sister chromatids held together at their centromeres.
- Centrosomes, duplicated in interphase, begin to move to opposite ends of the cell to form the mitotic spindle.
-Nuclear envelope breaks down
- Microtubles start forming connections to chromosomes through kinetochores (protein complexes built at centromeres)
What are the steps of mitosis in order?
Prophase, metaphase, anaphase, telophase
In prophase _____ duplicated in interphase, begin to move to opposite ends of the cell to form the _____ _____.
centrosomes, mitotic spindle
In prophase chromosomes appear as two sister chromatids held together at their _____.
centromere
In mitosis what happens in metaphase?
- All chromosomes are aligned at equator of the cell, called the metaphase plate.
- Chromosomes are attached to opposite poles and are under tension.
- One sister chromatid is attached
to one centrosome, the other
sister is attached to the other
centrosome.
What are homologous chromosomes?
A pair of chromosomes where one comes from the mom and one comes from the dad.
In mitosis what happens during anaphase?
- Proteins holding centromeres of sister chromatids are degraded allowing sisters to separate
- The mitotic spindle generates a force that pulls sister chromatids toward opposite ends of the cell
- The entire spindle elongates
- Microtubules attached to sister
chromatids shorten
In mitosis what happens during telophase?
- Chromosomes are clustered at opposite poles and decondense
- Nuclear envelopes re-form around chromosomes
- Cleavage furrow starts to form
What happens during cytokinesis?
Cleavage furrow constricts until cell membrane meets in the middle and completely separates the cytoplasm into 2 cells.
What is the second portion of the mitotic phase called?
cytokinesis
What portion of the mitotic phase results in the physical separation of the cytoplasmic components into the two new daughter cells?
cytokinesis
What is the first portion of the mitotic phase called?
karyokinesis (mitosis)
Does cytokinesis always take place?
no
Cell cycle can be put on hold at specific points called ________.
checkpoints
________ are made up of several different proteins that communicate with each other and to the rest of the cell
checkpoints
_________ are proteins that are telling the cell to move on to the next phase (the gas)
Proto-oncogenes
______ _______ are proteins that are telling the cell to slow down or wait (the brakes).
tumor supressors
True or False: Each checkpoint contains proto-oncogenes and tumor suppressors.
true
When_______, proto-oncogenes become oncogenes and push the cell forward too quickly
upregulated
When _________, tumor suppressors fail to slow the cell cycle
downregulated
