Chapter 3 Part B Flashcards
What is a nucleotide
A nucleotide is the monomer used to form nucleic acids made up of a pentose monosaccharide the phosphate group and a nitrogeneous base
What is a DNA nucleotide
In a DNA nucleotide the pentose sugar is deoxyribose and the bases can be either cytosine adenine thymine or guanine
What is an RNA nucleotide
The pentose sugar in RNA is ribose and the bases can be cytosine adenine guanine or uracil which replaces thymine
What is a polynucleotide
many nucleotides linked together by phosphodiester bonds the phosphate group on the 5th carbon of the sugar makes a covalent bond with a hydroxyl group on the third carbon of another nucleoside in a condensation reaction which can be broken down by hydrolysis
What is the double helix structure
two DNA polynucleotide strands can join together by hydrogen bonding between bases through complqmentary base-pairing which is specific hydrogen bonding between nucleic acid bases adenine binds to thymine and cytosine binds to guanine
What are the base pairing rules
Pyramidines means always bond with purines
Thymine and cytosine are pyrimidines
Adenine and guanine are purines
Adenine forms two bonds with thymine
Cytisine from 3 bonds with guanine
How can you purify DNA
Grind the sample to break down cell walls
Mix sample with detergent to break down cell membrane
Add salt to break hydrogen bonds between DNA and water
Add protease enzyme to break down proteins
Adilet of alcohol causing DNA to precipitate out
Remove DNA strands using glass rod
Explain semiconservative DNA replication
DNA helicase breaks the hydrogen bonds between the two DNA strands causing the helix to unzip
each original strand acts as template for a New strand and free-floating DNA nucleotides join exposed bases by complementary base pairing
DNA polymerase joins together nucleotides of the new strands and hydrogen bonds form between
Each new DNA molecule has one original strand and one New strand
What is the genetic code
The genetic code is a sequence of three bases known as a triplet code which code for specific amino acids
it is not overlapping each triplet is separate from the one after it
it is degenerate so there are more possible combination of triplets than amino acids so some a coded for by more than one triplet
It is universal it code to the same amino acids in all living things
What is transcription
DNA helicase attaches at the beginning of a gene breaking hydrogen bonds and unwinding the strand
one of the strands is used as a template and free RNA nucleotides will base pair with complementary base pairing except T is replaced with U
RNA polymerase forms for phosphodiester bonds between the RNA nucleotides
The mrna then detaches and moves out of the nucleus through a nuclear pore and attaches to a ribosome in the cytoplasm
What is translation
Mrna attaches itself to a ribosome
A trna molecule with an anticodon complementary to start codon bines to the mrna carrying the amino acid
A second trna molecule with an anticodon complementary to the next codon attaches also carrying an amino acid
Ribosomal RNA catalyzes the formation of a peptide bond between the amino acids
The ribosome is along the mrna releasing the first trna and the process repeats until it meets a stop codon
What is ATP
ATP compromises of a nitrogenous base a pentose sugar and three phosphate groups it is used for energy transfer in all living things
What is ADP
ADP is a nucleotide compromised of a nitrogenous base pentose sugar and two phosphate groups
Write down the equation of ATP to ADP
ATP is hydrolyzed and releases energy to form phosphate and ADP ADP + phosphate takes place in a condensation reaction using energy to make ATP
