Lab 2 Flashcards
Define resolution:
the ability to distinguish objects that are close together.
What is contrast?
determines resolution by providing different optical intensities of the sample relative to its background.
Define refraction:
When light bends as it passes through glass.
Define interphase:
the portion of the cell cycle that occurs between division events.
What are the 4 stages of mitosis?
- prophase
- metaphase
- anaphase
- telophase
What happens during prophase?
The nuclear membrane dissolves and the DNA condenses from loose coils into tight coils with identical chromatids joined at the centromere.
What is a chromatid?
One of the two identical copies of DNA making up a duplicated chromosome.
What happens during metaphase?
The chromosomes attach at their centromeres to the microtubules of the mitotic spindle and are positioned mid-planar within the cell.
What is the spindle?
A network of protein filaments that are attached at opposite poles of the cell, which moves and positions chromatids.
What is the centromere?
The region of DNA that occurs typically near the middle of a chromosome where the two identical sister chromatids come closest in contact.
What happens during anaphase?
The sister chromatids are separated and moved to the opposite poles of the cell.
What happens during telophase?
The nuclear envelope reforms, the chromatin reappears in the nucleoli as the DNA uncoils and is compacted with histones and other proteins.
What happens after telophase?
cytokinesis
