CC - Nucleic Acids Flashcards
What are the 3 types of mutation in substitution?
Missense - Change in aa
Silent - doesn’t change aa
Nonsense- Changes aa to a ‘stop’.
What are the 3 subsectional phases of translation?
Initiation - START codon
Elongation - ribosomal enzyme
Termination - STOP codon
Where is the anticodon and where is the codon located?
Anticodon - tRNA
Codon - mRNA
Which is the continuos strand in DNA replication?
In the strand which has the DNA polymerase enzyme working towards the old double helix.
What type of mutation can deletion cause?
Frameshift
List 5 roles of ATP
AT
Metabolic processes
Movement
Nerve transmission
Secretion
Where is the energy stored in lipid and carbohydrate molecules?
In the bonds and can be released by breaking them.
Who proposed the molecular structure of DNA in 1953?
Watson and Crick
What type of nucleotides are DNA and RNA
Polynucleotides
Formed by the condensation reactions of phosphodiester bonds between the phosphate groups.
How many amino acids are there?
20
Who carried out the DNA replication experiment
Meselson–Stahl
Why is the genetic code described as being universal?
Because all genetic code in DNA is made up of the same 4 nucleotides, no matter what type of organism it is.
What is the addiction of a phosphate to ADP called?
Phosphorylation
What is the structure formed at the bottom of the DNA polymer called in step 1 of the DNA replication process
Replication fork
What is the structure for rRNA
Long large complex molecule made up of double and single helixes However is still single stranded, just becomes double because it folds back on itself
When translating an amino acid sequence what code do you use?
mRNA code
How does RNA work differently in eukaryotic and prokaryotic cells?
Eukaryotic = Requires processing before translation due to the inclusion of introns.
Prokaryotic = Translated directly into proteins.
What is there on either end of the activated tRNA molecule?
one end - amino acid
other end - anticodon
What happens to ATP if it is hydrolysed
Becomes ADP by undergoing an exergonic reaction in which for every mole of ATP hydrolysed 30.6kJ of energy is released. Single step reaction that releases energy immediately.
What is the structure of tRNA
Clover leaf shape w/ aa attachment site on end containing CCA bases.
Opposite end = series of 3 bases = anticodon
Small single stranded
What enzyme carries out mRNA processing and using what process?
Splicing by the splicesosome enzyme
Define polysomes
Many ribosomes read the same pieces of RNA at the same time.
What does DNA contain
All the genetic information that determines how life grows, develops and functions
What are the 2 types of nitrogenous bases?
Pyrimidines (single ring) = Cytosine + thymine
Purines (double ring) = Adenine + Guanine
What’s the one gene polypeptide hypothesis?
1 gene codes for one polypeptide chain. This theory has evolved as genes were linked to a larger range of proteins.
Explain how the DNA polymerase enzyme works
Only works in 1 direction so has to travel up 1 strand + down the other due to DNA strands being anti parallel to 1 another
Wheres does translation take place?
Ribosomes
What are the 3 main types of mutation
Deletion
Insertion
Substitution
What can post translation modification include?
Addition of lipids, carbs, phosphate groups or other proteins.
What is a codon?
3 nucleotides that code for a specific amino acid
What phase of the cell cycle is protein synthesis?
Interphase
Why type of mutation doesn’t result in an abnormal amino acid sequence
silent
What is the function of the RNA?
Combines w/ ribosomes to form proteins. Allows the transfer of info to ribosomes for protein synthesis as mRNA and tRNA.
What are the two subsections of eukaryotic genes?
Introns - non-coding part/ interruption to gene
Exons - coding sections
Why might the DNA in a virus be different to that in other organisms?
Because it might be single stranded.
What is the structure of the mRNA
Long single stranded molecule into a helix
Give 2 examples of cellular processes in which ATP would be converted to ADP
Active transport Nerve impulses
List 3 variables that would need controlling in the centrifugation process in DNA replication experiment
Duration of spinning
Speed of spinning
Concentration of caesium chloride
What is the function of tRNA
Brings aa to ribosomes for protein synthesis
What is the function of rRNA
To make ribosomes
Define a gene
Length of DNA that codes for a polypeptide.
What is the maximum number of different DNA triplets that can be made using 4 bases?
64
What is sickle cell anaemia?
The result of a mutation in the gene coding for part of the haemoglobin molecule. The sickled cells tend to get stuck in blood vessels, causing pain and ⬆️ risk of stroke.
What is another way to say DNA replication
Semi conservative replication
Explain the process of Activation and translation in protein synthesis
Activated tRNA molecule within the ribosome attaches to the 1st codon on the mRNA strand at P site by H bonds.
2nd activated tRNA (w/ anticodon complementary to codon) attaches to the A site by H bonds.
Ribosomal enzyme catalyses peptide bond to form between the 2 amino acids using energy from ATP.
1st tRNA molecule separates itself from the amino acid + leaves ribosomes, leaving p site vacant.
Ribosome then moves along mRNA to next codon.
Another tRNA molecule brings next amino acid into place + peptide bond forms between 2nd + 3rd amino acids = polypeptide chain.
Cycle of chain elongation continues until a STOP codon is reached in which polypeptide chain is complete.
What does ADP stand for
Adenosine diphosphate
What is the function of DNA
Replication in dividing cells
Carries genetic info coding for protein synthesis
What is the relationship between introns and genetic variation?
Introns contains repeated blocks of nucleotides. The number of times these are repeated produces genetic variation we see in fingerprints.
Define the universal energy currency of ATP
Used by all living organisms to carry energy from energy releasing reactions to energy consuming reactions for all biochemical reactions in the cell.
What is DNA made up of
Deoxyribose sugar
P group
Nitrogenous base
Briefly describe the process of DNA to protein
Transcription Translation Folding into protein
What are the 3 types of RNA
mRNA - messenger tRNA - transfer rRNA - ribosomal
What’s the difference in the way energy is released between ATP and glucose molecules?
ATP - Energy is released in small amounts where and when needed. Glucose - Releases energy in large amounts all at once.
What is the DNA replication process
Copying of DNA before cell division occurs in mitosis or meiosis
What are the differences between a DNA nucleotide and an RNA nucleotide
DNA: A+T and C+G nitrogenous bases Deoxyribose sugar RNA: A+U and C+G nitrogenous bases Ribose sugar
What is transcription?
Mechanism by which the base sequence of a gene on a DNA strand is converted into the complementary base sequence of mRNA.
Where does transcription take place?
Nucleus
What type of phosphate is ATP?
Inorganic
What 2 chemical components make up a ribosome?
RNA Ribosomal proteins
Explain post-translational modification
Occasionally the primary structure of a polypeptide is functional but usually the polypeptide is folded into secondary, tertiary or quaternary structures in the Golgi body and may be chemically modified too.
Describe the processes of the DNA replication
- Gene unwinds + unzips due to H bonds between complimentary bas pairs being broken by DNA helicase enzyme. = Exposes bases = template strand created. 2. Free DNA nucleotides bind to template strands in nucleoplasm to form hydrogen bonds w/ compl. Base pairs. 3. DNA polymerase enzyme joins bases above and below each other so that double helix can form 4. New DNA molecule is made identical to initial one
Which type of mutations are responsible for new variations of a trait?
Deletion, insertion and misense
What is added to ADP to make ATP?
Another phosphate group - phosphorylation.
What are the 5 key features of the genetic code?
Triplet codes Non-overlapping Degenerate (most amino acids have more than one code) Universal (All life on earth has the same DNA code for amino acids) Determines the amino acid sequence (DNA codes for RNA, which codes for proteins, these then form and regulate other processes)
Which is the series of short strands
In the strand which has the DNA polymerase enzyme working away from the old double helix.
Why is complimentary base pairing significant in the conservation of the base sequence of DNA
Very important DNA replication is semi-conservative so the compl. base pairings allows the 2 DNA molecules to be identical to each other due to having the same base sequence. New strands formed are therefore complimentary to their template strand but also identical to the original template,
Describe the process of transcription
Gene unwinds + unzips due to H bonds between complimentary bas pairs being broken by DNA helicase enzyme. = Exposes bases = template strand created. Freely activated RNA nucleotides bind w/ H bonds to complementary bases on template strand. These are joined together at their sugar phosphate backbone by the RNA polymerase enzyme. mRNA produced is complimentary to nucleotide base sequences on template strand of DNA so is a copy of the coding strand. A stop-transcribing sequence is where the RNA polymerase leaves the DNA. mRna is released from DNA + passes out of nucleus via nuclear pore into cyt. where it attaches to a ribosome.
Yes or no to cell wall, enzyme molecules and capsid present in bacterium and HIV
Cell wall = B - Yes / HIV - NO Enzyme molecules = B + HIV - Yes Capsid = B - NO / HIV - Yes
What is meant by the term semiconservative replication?
Each strand of DNA is used as a template to make a new DNA strand. New DNA is made from 1 old strand linked to a new strand.
