Nucleic Acids - The Molecular Basis Of Inheritance Flashcards
Three components of a nucleotide?
Deoxyribose
Phosphate group
Nitogenous base
Explain how the structure of DNA underpins replication
The combination of nitrogenous bases write the recipe for synthesis of molecules.
The process of replication including the role of enzymes
Multiple areas of replication along the double helix molecule at once, can split divide grow and move on. DNA polymerase is the enzyme that reads and creates a copy of the DNA, can only extend 5 to 3 end. Means one strand that is being copied is made in segments or fragments.
What are the 3 fundamental differences between RNA and DNA
- The 5 carbon sugar in RNA is ribose (with Oxygen) instead of deoxyribose(without oxygen).
- Uracil in place of thymine.
- single stranded molecule however can form double stranded regions.
What is the central Dogma
Th full recess from transcription of a gene on a double helix strand of DNA through to the translation of RNA into a new protein by a ribosome.
Transcription brief definition
DNA template strand replicated into a RNA replicate to be passed onto a ribosome.
Translation brief definition
Ribosome RNA reading the combination of nitrogenous bases on an mRNA to produce a protein from amino acid combinations specified by the mRNA and ultimately the DNA template strand.
DNA consist of three components
- Pentose (5 carbon sugar) - deoxyribose
- phosphate group
- nitrogenous base purine(adenine and guanine) pyramidine (thymine,cytosine).
Difference between deoxyribose and ribose
Deoxyribose lacks an oxygen atom attached to the 2 Carbon.
Purine structure in DNA
Double ringed.
Pyrimidine structure.
Single ring
Semi conservative replication
One of the 2 strands of dna is used as a template for synthesis of new dna strand. The nature of the new dna strand is determined by the order of the base pairs in the template strand.
RNA
Ribonucleic acid
RNA consists of 3 components?
- The 5 carbon auger Ribose
- Nitrogenous bases: adenine, uracil, guanine and cytosine
- Phosphate group.
Three types of RNA involved in protein synthesis
Ribosomal RNA
Transfer RNA
Messenger RNA
rRNA
Ribosomal RNA
80% of all RNA, most of a ribosome is rRNA.
tRNA
Transfer RNA
Carries amino acids to ribosomes for protein synthesis.
mRNA
Messenger RNA
Template for protein synthesis, Carries the information from dna to rRNA.
DNA polymerase
The enzyme that synthesises the new DNA strand.
dNTPs
Deoxyribonucleotide triphosphates
Used as the source of nucleotides in DNA synthesis. The dNTP loses 2 phosphate groups when attached to the newly forming DNA strand, the dNTP is chosen from the opposing base on the template strand.
Histones
Protein that packs the DNA so that it fits neatly arranged in the nucleus
Each of the 20 amino acids has a corresponding……
tRNA
Translation
Process of RNA translating information from mRNA into the synthesis of a protein.
RNA synthesis occurs in what direction?
5’ to 3’ direction
RNA polymerase catalyses the formation of what bond?
Phosphodiester
Operon
A cluster of genes copied by a single RNA
A ribosome attaches to what end of mRNA
5’ end
Initiation codon of mRNA?
AUG
The 2 sites tRNA have are
mRNA recognition site and an amino acid attachment site.
Stop codons
UAA, UAG, UGA.
The cell cycle phases
G1
Cell growth and nutrient accumulation. A commitment to decide or not divide is made.
The cell cycle phases
G0
Is a phase which the cells can be arrested in indefinitely. Like G1 but with nil net growth.
The cell cycle phases
Synthesis or S phase
DNA synthesis occurs and chromosomes are replicated.
The cell cycle phases
G2
The cell grows more, synthesising proteins necessary for mitosis.
The cell cycle phases M phase (mitosis)
duplicated genetic material is divided in 2 and the cell is prepared for cytokinesis.
The four phases of mitosis in order:
- Prophase
- metaphase
- anaphase
- telophase
The phases of mitosis
Prophase
Chromosomes condense, microtubules reach from centrosomes into the centre of the cell.
The phases of mitosis
Metaphase
Nuclear membrane degrades. Chromosomes align in the middle of the cell.
The phases of mitosis
Anaphase
Chromatids seperate and form at opposing poles of the cell. The chromatids are now fully fledged chromosomes.
The phases of mitosis
Cytokinesis
A contractile ring or cell plate forms and the cytoplasm divides.
How many sets of divisions (prophase, metaphase, anaphase and telophase) occur in meiosis?
2
Genetic diversity is generated in meiosis in two ways
- Chromosomes of an homologous pair assort independently of other pairs.
- Crossover occurs and genetic recombination occurs and results in the swapping of DNA segments between homologous chromosomes.
Adenine always pairs with a
Thyomine
Guanine always pairs with a
cytosine
DNA B helicase
Unwinds double helix of DNA
DNA Ligase
Welds together Okazaki fragments and broken links
Write DNA molecules written in the
5 prime to 3 prime end
