B7 Nucleic Acids and B8 Protein synthesis Flashcards
What are the three things a nucleotide is made from?
Bases , deoxyribose sugar and a phosphate
Is a nucleotide a polymer or monomer?
monomer
How are the three components of nucleotides formed?
Via condensation reactions (2)
What are the two purines?
Adenine and Guanine
What are the two Pyrimidines
Thymine and Cytosine
What is the rule with both purines and pyrimidines?
There will be equal amounts of Thymine and Adenine and equal amount of cytosinea and guanine
What do we call 3 bases
Codon
What is a particular range of proteins that a cell makes called?
Proteome
What are the characteristics of RNA?
- Single stranded
- Contains Uracil instead of Thymine
- It doesn’t have any complimentary bases
- No hydrogen bonds
- Sugar deoxyribose isn’t present instead there is ribose sugar
What are the characteristics of mRNA?
- Single stranded polynucleotide chain
- Shorter than DNA
- Sequences of bases are complimentary to the sequence of bases it is copying
- No hydrogen bonding
-Several 100s-1000s nucleotides in a chain - Ribose sugar
What are the characteristics of tRNA?
- Single stranded
- Contains Adenine and Guanine
- Contains Cytosine and Uracil
- Hydrogen bonds are present in parts of molecule
- This creates a clover-like shape
- About 75 nucleotides in a chain
What type of sugar does mRNA have?
Ribose sugar
What type of sugar does tRNA have?
Ribose sugar
What type of sugar does DNA contain?
Deoxyribose sugar
What bases does mRNA contain?
Purine bases: Adenine or guanine
Pyrimidine bases: Cytosine and Uracil
What bases does DNA contain?
Purine bases: Adenine Guanine
Pyrimidine bases: Cytosine and Thymine
What bases does tRNA contain?
Purine bases: Adenine and Guanine
Pyrimidine bases: Cytosine and Uracil
What are the characteristics of DNA?
- Contains deoxyribose sugar
-Contains Adenine, guanine, cytosine and Thymine - Has 2 polynucleotide strands (double-stranded)
- Hydrogen bonding present
- ## Many millions of nucleotides in a chain
What is the Chargaff’s rule?
That there will be equal amounts of adenine and thymine and also equal amounts of Guanine and Cytosine.
What are ribosomes made of?
Protein and rRNA
Describe Chloroplast DNA.
- Less genes
- Circular not linear
- Shorter than DNA in nucleus
What does ATP stand for?
Adenosine TriPhosphate
What is the structure of ATP like?
- Similar to RNA
- It is made of a molecule of ribose and adenine (adenosine) and three phosphate groups
How to you turn ATP to ADP?
Hydrolyse the covalent bonds between phosphate groups using an ATP hydrolase enzyme and energy is released. We are then left with 2 phosphate groups (ADP) and an inorganic phosphate
How do you turn ADP back into ATP?
Via a condensation reaction using the ATP synthase enzyme
What is the DNA in chromosomes held in place by and wrapped around in eukaryotic cells?
Histones (proteins)
What is DNA and histones together called?
Chromatin Fibres
What is a Karyotype?
All 46 chromosomes in each cell
What is homologous pairing?
- When mother and father chromosomes join and they “carry the same genes in the same positions. They are also the same shape”
What does loci (locus) mean?
Location of a gene
Why is DNA long?
To store more information
Why is DNA double stranded?
Allows for a template during transcription or replication
Why is DNA a double helix?
Coiled which makes it more compact
What is a gene?
A section of DNA that codes for a protein
What are the two processes in proteins synthesis?
Transcription and translation
Describe the process of transcription.
- Hydrogen bonds are broken by an enzyme called helicase
- One strand of the DNA acts as a template
- Free RNA nucleotides align by complimentary base pairing (Uracil is used instead of Thymine)
- RNA polymerase joins nucleotides up forming phosphodiester bonds - This forms pre-mRNA
- The introns are removed from the Pre-mRNA by a process called splicing and mRNA is formed which then travels out of the nucleus via its pores
What do extrons do?
Code for amino acids
Where does transcription occur?
Nucleus
Where does translation occur?
Ribosome
What are the two parts of a ribosome called?
Small sub-unit and and large sub-unit
Describe the process of translation.
-mRNA associates to the ribosome
- The ribosome finds the start codon (AUG)
- TRNA brings a specific amino acid
- Anticodon on tRNA is complimentary to the codon on mRNA
- Ribosome moves mRNA to the next codon
This process repeats and amino acids are joined via condensation reaction with a peptide bond
What are the two parts on tRNA called
Amino acid attachment site and anticodons
DNA is universal, what is the definition of universal?
3 bases code for the same amino acid in all organisms
DNA is degenerate, what is the definition of degenerate?
More than one codon codes for the same amino acid
DNA is non-overlapping, what is the definition of non-overlapping?
Each base is only part of one codon
What are the functions of tRNA?
- Allows mRNA to associate itself
- Allows tRNA with codons to bind with mRNA
-Catalyses formation of peptide bonds between amino acids
Does prokaryotic DNA contain introns?
No
What are introns?
Non-coding DNA inside genes
What are non-coding repeats?
multiple repeats of base sequences that is outside of gene
What is the genetic code?
The sequence of codons in mRNA which code for a specific amino acid
What is the definition of a genome?
Complete set of genes in the cell
What is the definition of proteome?
The full range of proteins that the cell is able to produce
