Lecture 7: Cells And Tissues cont. Flashcards
Meiosis
2 divisions of nucleus and four daughter cells
Mitosis
Forms 2 daughter nuclei with the same genes as the mother nucleus
Chromatids
(Condensed DNA). 2 strands of chromosomes held by a button like body.
Centromere
Button like body that binds together chromatid
Chromatin
Non-dividing cell DNA
Interphase
Cell grows and carries out usual metabolic activities
DNA polymerase
Replicates DNA
Early prophase
Centrosomes move to opposite sides of the cell, mitotic spindles form, nuclear envelope disintegrates, chromatin condenses to chromatid
Late prophase
Nuclear envelope and nuclei disappear and chromosomes become spindle fibers
Mitotic spindles
Attach to center of chromatids (centromere)
Metaphase
Chromosomes cluster and line up at metaphase plate
Metaphase plate
Center of spindle midway between centrioles
Anaphase
Centromeres that held chromatids together split
Cleavage furrow
Contractile ring of micro filaments over midline of spindle, which eventually squeezes cytoplasmic mass in two
Telophase
(Reverse prophase). Envelope forms chromatids un condense and mitotic spindles disappear.
Cytokinesis
Pinching off of cells
Uses of DNA
Replicates itself for cell division
Master blueprint for protein synthesis
Transcription
DNA used as a template to make mRNA
rRNA
Main component of ribosome
tRNA
Carries amino acids
Promoter region
Start point for transcription
Terminator
End point for transcription
Translation
mRNA used as a template for protein synthesis
P site
(Peptidyl binding site) where tRNA binds
Codon
3 nucleotides that form a unit of code in DNA or RNA molecule
Start codon
First codon of mRNA
Stop codon
Signals termination of translation
A site
Aminoacyl binding site
Describe translation
tRNA enters at A site, waits for P site to clear. P site clears and tRNA moves there, donates it’s amino acid to the chain, holds the chain. Another tRNA enters and replaces it, the first lets go and moves on.
