Structure Flashcards
(32 cards)
What is the central dogma of molecular biology?
Explanation of flow of genetic information within a biological system
DNA-RNA-Protein
Describe the tertiary structure of DNA
The structure of nucleucacids baseparing and make a two stranded double Helix. These wind around eachother, coiling into a really condenced structure
What is a chromatin vs chromosome?
Chromatin is a less condensed state than chromosomes
A chromosome is the highest order of DNA organization
What is a nucleosome?
The DNA is packed and wound around proteins called histones, the “beads” containing 8 histones is called nucleosomes
What is supercoiling?
The extreme coiling of a DNA double helix around its own axis
What is cruciform?
Underwound DNA that takes the shape of a “crucifix”
What is a topoisomerase?
Enzym that can underwind or relax DNA
What are the two types of topoisomerase and their function?
Type 1: breaks one of the two strands trmporarily
Type 2: breaks both strands
How does the chromosomes change during the cell cykle?
During interphase (G0,G1,G2) the chromatine is spread in the whole cell without certain organisation In S-Phase DNA replicates In Prophase the chromosomes condences into sister chromatides
What is a genome?
The genetic material of an organism
What is a Gene?
All the DNA that encodes the primary sequence of some final Gene product
What is a regulatory sequence?
Sequence that signals that denotes the beginning or end of gene
What are viral genomes?
Not free living organisms
Infectous parasites
Genome with surrounding protein coat
DNA or RNA
What is the characteristics of prokaryote genome?
Longer than virus
One doublestranded, circular DNA molecule
Plasmids-small circular DNA free in cytosol
What are the characteristics of eukaryotic genome?
Complex organisation
Specific number of chromosomes
Have introns
3% Consists of highly repetitive sequences SSR
Describe the chromosome structure in eukaryotic
Centromeres: in celldivison its the attachment point for proteins linking the chromosome to the mototic spindle
Telomere: end of the chromosome
What is the primary structure of DNA?
Nucleotide sequence
What is the Secundary structure of DNA?
Regular stable structure taken up by the nucleotides in a nucleic acid
What are the characteristics of DNA structure?
Double helix Righthanded Backbones of deixiribose and phosphate groups "Links" of nitrogenous bases Chains are antiparalell Strands are complementary
What are the forces holding the DNA double helix?
Hydrogen bonding between complementary base pairs
Base stacking interactions
What is DNA-denaturation and What causes it?
It is a disruption of hydrogen Bonds and base stacking interactions
Splits the strands into two Single strands
Extreme pH or increased temperatures
What is DNA renaturation?
When a denaturated DNA find their way back to eachother, “zipping” back together
How does the sequence of basepairs affect the stability?
G-C base pairs are more stable due to triple hydrogen Bonds between them
A-T base pairs have two hydrogen Bonds, thus needs less to break them
What is a nucleotide?
Nitrogenous base
Pentose
Phosphate
