Chapter 4,12, and 15 review for exam Flashcards
four types of bases in DNA
Adenine
thymine
guanine
cytosine
four types of bases in RNA
Adenine
Uracil
guanine
cytosine
what does the backbone of DNA and RNA consist of?
phosphate group
nitrogenous base
five carbon sugar
how does DNA become proteins
DNA ——> RNA——> Proteins
transcription turns DNA into RNA
translation turns RNA into proteins
What nitrogenous bases are pyrimidines
cytosine
uracil or thymine
what nitrogenous bases are purines
guanine
adinine
(both guanine and adenine have the word “nine” in the word which links them to purines)
what is the bond that holds two nucleotides together
phosphodiester linkage
Characteristics of polymerization
- requires energy
- non spontaneous reactions
- ATP is an activated nucleotide
What is the difference between DNA and RNA structure?
DNA structure:
- has thymine in it
- double stranded and double helix
- very stable and not as flexible
- carries more information because it is more stable
RNA structure:
- hydroxyl group (making it more reactive)
- has uracil in it
- single stranded
- more bendable and flexible
- can be a ribozyme that can act as a catalyst
What are the complementary base pairs of both DNA and RNA
DNA
- A and T (two hydrogen bonds)
- G and C (Three hydrogen bonds)
RNA
- A and U (two hydrogen bonds)
- G and C (Three hydrogen bonds)
DNA Structure:
primary: sequence of deoxyribonucleotides; bases are A T G and C
secondary: two antiparallel strands twisted into a double helix, stabilized by hydrogen bonding, hydrophobic interactions, and van der waals interactions
tertiary: double helical DNA forms compact structures by wrapping around histone proteins or twisting into supercoils.
DNA Synthesis occurs in which direction
five prime to three prime direction
RNA Structure:
Primary: sequences of ribonucleotides; bases are A U G and C
Secondary: most commonly a single strand that folds back on itself to form a double helical “stem” and unpaired “loop”
Tertiary: Secondary structures fold to form a wide variety of distinctive three dimensional shape
what does semi conservative mean regarding DNA synthesis?
each new double stranded DNA molecule consists of one of the original strands from the parent molecule in order to conserve the original DNA in each copy
What are the enzymes that are involved in DNA Synthesis
- DNA Helicase
- Topoisomerase
- Primare (RNA polymerase)
- DNA polymerase I
- DNA polymerase III
- Ligase
What does Ligase do?
enzyme that puts the two strands of DNA together
- carries out the reaction to form a phosphodiester linkage at the end
what does DNA helicase do?
breaks the bonds between nitrogenous bases and unzips the double helix so the DNA can be replicated
function of topoisomerase
cutting, shuffling, and religating DNa strands
function of primase (RNA polymerase
synthesis of RNA primer
function of DNA polymerase III
responsible for synthesizing new DNA strands during DNA replication
function of DNA polymerase I
to remove RNA primers from the newly synthesized DNa strand during replication and fill in the gaps left behind by the primers with the needed DNA nucleotides in the lagging strand
Is DNA Synthesis exergonic or endergonic
dna synthesis is endergonic
where is DNA found in eukaryotic cells?
in the nucleus
where is dna found in prokaryotic molecules?
in the nucleoid
