DNA 1
The three parts of a nucleotide are
Base, phosphate group, sugar
What are the 5' to 3' ends?
The direction that DNA is synthesized
What is helicase?
An enzyme that unwinds DNA by breaking hydrogen bonds between base pairs.
Explain the role of RNA polymerase
What is entropy?
Randomness or disorder in a system
A and G are ________; C and T are ___________
purines; pyrimidines
What are Okazaki fragments?
The fragments that are formed by the lagging strand
What is DNA ligase?
An enzyme that seals DNA once primers are removed from the strands.
Explain the role of a promoter
The DNA sequence that signals the start of transcription
How does ATP power cellular work?
By providing energy to the cell to perform the cells functions
Strand that runs 5' to 3' towards the fork and is made continuously
What is the origin of replication?
Specific location where DNA replication begins
Where does transcription occur? Where does translation occur?
Nucleus; ribosome
Explain the role of an operator
A DNA sequence that can stop DNA transcription if a repressor is bound to it
How do enzymes control the rate of chemical reactions?
They reduce the activation energy (energy required for the reaction to take place), speeding up the rate of the reaction
What is a lagging strand?
Strand that runs 5' to 3' away from the fork and is made into small fragments
What is RNA primer?
Steps of transcription...
Initiation: RNA polymerase binds to promoter and separates strands
Elongation: polymerase builds RNA out of complementary base pairs, replacing thymine (T) with uracil (U)
Termination: Terminator sequence signals transcription is complete, RNA is released
Explain the role of a repressor
A protein that can bind to an operator to stop transcription
Explain the induced fit model of enzyme action
When an enzyme binds to a substrate, the enzymes shape changes slightly, creating an even tighter fit
Explain the mechanism for DNA replication
1. Double helix DNA is "unzipped" and hydrogen bonds are broken by the enzyme, helicase.
2. The new strands are used as templates for synthesis of a new complementary strand in the 5' to 3' direction
What is DNA Polymerase?
An enzyme that makes DNA by adding nucleotides one by one to the DNA chain that are complementary to the template
Steps of translation:
Initiation: Ribsome assembles around the mRNA to be translated and the tRNA that contains the amino acid methionine that corresponds to the start codon (AUG)
Elongation: mRNA is read one codon at a time, and the amino acid matching each codon is added to a growing protein chain
Termination: When a stop codon is read by the ribosome, it triggers a response releasing the tRNA and the new polypeptide chain
Explain the role of a STOP codon
A sequence of RNA that codes for the end of translation for a specific protein
How do allosteric enzymes and cooperativity work to regulate metabolic pathways?
Allosteric enzymes can either increase or decrease to the function of active sites, while cooperativity involves the substrate acting as an allosteric activator, meaning when one active site is activated, the function of other sites increases