DNA and RNA Flashcards
Shape of DNA
Double helix
Purpose of RNA
Used as a messenger to communicate with the rest of the cell while the DNA stays in the nucleus
Used in protein synthesis
Components of the nucleotides that make up DNA and RNA
Nitrogen base
Pentose (five-carbon) sugar
Phosphate group
(Pentose and phosphate make up the sugar phosphate backbone)
Pentose sugar found in DNA
Deoxyribose
Pentose sugar found in RNA
Ribose
Nitrogen bases found in DNA
Adenine
Guanine
Cytosine
Thymine
Nitrogen bases found in RNA
Adenine
Guanine
Cytosine
Uracil
Nitrogen bases which are purines
Adenine
Guanine
Nitrogen bases which are pyrimidines
Thiamine/uracil
Cytosine
DNA bases which pair together
Adenine and thiamine
Guanine and cytosine
RNA bases which pair together
Adenine and uracil
Guanine and thiamine
Term for a set of three adjacent nucleotides
Codon
Number of amino acids
20
Number of possible codon combinations in the human genome
64
Segment of DNA or RNA which codes for a protein
Exon
Segment of DNA or RNA which does not code for a protein, and which is eliminated by splicing before translation
Intron
Production of new DNA from template DNA
Replication
Process by which RNA is synthesised by DNA
Transcription
Part of the cell where transcription takes place
Nucleus
Unprepared RNA which contains the introns which do not code for polypeptides
Heterogenous nuclear RNA
Process by which heterogenous nuclear RNA has introns removed
Splicing
Enzymes which transcribe RNA from DNA
RNA polymerases
Three main types of RNA
Messenger RNA
Transfer RNA
Ribosomal RNA
RNA which carries information from DNA out to ribosomes
Messenger RNA
Process by which RNA synthesises proteins
Translation
RNA which brings amino acids to the ribosome during translation
Transfer RNA
RNA which make up ribosomes and provide a place for mRNA and tRNA to attach to during translation
Ribosomal RNA
Area of the cell where translation occurs
Cytoplasm
Structure which ribosomes attach to for translation
Endoplasmic reticulum
Type of endoplasmic reticulum formed by the attachment of ribosomes
Rough ER
Process by which transfer RNA is attached to amino acids according to its codon sequence in order to bring them to the ribosomes
Amino acid activation
Enzyme which catalyses amino acid activation in order to add the amino acids to RNA molecules to form tRNA
Aminoacyl-tRNA synthetase
Electrolyte required for amino acid activation
Mg2+
Three phases of translation
Initiation
Elongation
Termination
Steps in the initiation phase of translation
Ribosome assembles around the correct area of mRNA where it finds a start codon
First tRNA molecule attaches to the start codon of the mRNA
Steps in the elongation phase of translation
Other tRNAs with matching anticodons attach to the appropriate codons of the mRNA
First tRNA molecule drops off its amino acid which is attached to the second amino acid, and picks up another amino acid to reattach
The amino acids join in a long chain with peptide bonds to make a polypeptide
Steps in the termination phase of translation
A stop codon on the mRNA is reached
The ribosome releases the completed polypeptide
The ribosome moves on to the next mRNA to be translated
Equivalent of codons found on tRNA
Anti-codons
Most common start codon found on mRNA
AUG
Most common stop codons found on mRNA
UAA
UGA
UAG
Changes that occur in a protein molecule after translation but before it becomes functionally active
Modification
Parts of the cell where protein modification takes place
Endoplasmic reticulum
Golgi bodies
Protein modification process where a phosphorus/oxygen group is added to a protein to activate or inactivate it
Phosphorylation
Protein modification process where carbohydrate molecules are added
Glycosylation
Part of the cell aberrantly folded proteins are taken to during modification in order to be destroyed
Lysosomes
Protein which attaches to unwanted cellular proteins to label them for degradation
Ubiquitin
Function of proteasomes within a cell
To degrade cellular material
Region of DNA which initiates RNA transcription
Promoter region
Mnemonic for purines and pyrimidines
Purines - Pure as gold (adenine, guanine)
Pyrimidines - pyramids CUT (cytosine, uracil, thiamine)
An individuals collection of genes
Genotype
An individual’s collection of chromosomes
Karyotype
A set of polymorphisms which tend to be inherited together
Haplotype
Number of DNA codons which are stop codons and do not code for an amino acid
3
Number of DNA codons which code for amino acids
61
Most common stop codons found on DNA
TAA
TAG
TGA
Most common start codon found on DNA
ATG
Measure of the distance between loci
Recombination fraction
Minimum and maximum values for the recombination fraction of two loci
0-50%
Percentage of the human genome which codes for proteins
2%
Process that allows a single gene to code for multiple proteins
Alternative splicing
Amino acid which is coded for by the start codon
Methionine
Components of nucleosides
Nitrogenous base
Pentose sugar
Difference between nucleotides and nucleosides
Nucleotides are phosphorylated nucleosides
Structure in the cell where proteins are stored temporarily after synthesis
Golgi complex
Structure in the cell responsible for energy production
Mitochondria
Structure in the cell which is the site of protein synthesis and contains rough ER
Nissl substance
Structure of the cell which is used for structural support and transportation
Microfilaments and microtubules
Most common post-translational protein modification
Phosphorylation
Organelles which are involved in the degradation of lipids
Endosomes
Step that occurs after RNA is transcribed in order for it to be processed for translation
Introns are removed through splicing
Collection of expressed mRNA
Transcriptome