DNA Flashcards
Describe the structure of DNA
It’s made up of nucleotides, composed of a sugar molecule phosphate group and nitrogenous base, nucleotides are held together by a weak hydrogen bonds, DNA joints to form a double helix, the order of the nitrogenous bases determines the genetic code, DNA is about 2 to 3 m long, DNA has deoxyribose sugar
Describe the structure of RNA
Composed of a chain of nucleotides, made up of rubber sugar, single-stranded, can fold its self turning the hydrogen bonds between complimentary bases
Name and describe the types of DNA
- nuclear DNA form very long strands which are bound to proteins and histone’s
- mitochondrial DNA located in the mitochondria and form circular molecules which are not bound to proteins there are five molecules of mitochondrial DNA In each mitochondria which contain 37 jeans 24 of these jeans code for making transfer RNA which are used in protein synthesis and the other 13 or instructions for making enzymes for cell respiration
Name and describe the types of RNA
Messenger RNA- made in the nucleus and takes genetic code to the cytoplasm allowing for genetic code to be read by ribosomes
Ribosome RNA: 60% of ribosome or RNA insure correct alignment of mRNA and tRNA ribosome or RNA also have an enzymatic role in the formation of a peptide bond between the amino acids
Transfer RNA- small molecule of RNA containing 70 to 90 nucleotides each tRNA molecule is able to carry a specific amino acid which plays a role in protein synthesis
What is the role of DNA
The genetic coding DNA provides instructions of protein synthesis the sequence of the bases in DNA controls the order of amino acids meaning it affects the type of proteins that can be produced They also determine the structure of the cell and how it functions
Explain the types of jeans and how they interact
Promoter gene: indicates which structural gene will be transcribed for protein synthesis so the RNA polymerase will bind to the gene then transcribe the structure gene if this gene is turned off the structure gene will be turned off meaning the gene is off.
Structural gene: the nucleotide sequence which codes for a specific proteins at the ribosome
Regulator Gene: inhibits or enhances transcription by either producing molecules which repress molecules meaning proteins are produced to block the promoter or structural gene therefore RNA polymerase cannot find meaning no transcription occurs or it will produce proteins which in Hants RNA polymerase binds into jeans therefore increase transcription and protein synthesis can occur
Describe the process of DNA replication
Two strands of DNA are separated by enzyme heck delays this can be done due to the week hydrogen bonds each strand has each strand has been separated in half of the original information and is a template For the nucleotide which will form on the next new strand the new strand or form identical to the original the formation results and two identical strands are in a polymerase as the new nucleotides to the UK strand and DNA ligase joins the short sections of DNA together
Explain the process of transcription
Transcription is when genetic instructions are copied or transcribed from the DNA and mRNA molecule
Initiation: where transcription is initiated by a chemical messenger e.g. a hormone and binds to the relevant site forming part of the Epigenome RNA polymerase then binds to the promoter site
Elongation: RNA then moves from a 5 to 3 direction on the double helix unwinding it RNA polymerase as a complimentary free nucleotides to form an mRNA strand at the start sequence
Termination: RNA polymerase reaches a stop triplet in the DNA and stops copping mRNA strand is then released and undergoes splicing to remove entrance and join extras together mRNA leaves through the nuclear poor and the double helix reforms
Explain the process of translation
Translation is the production of proteins using information which is coded in the mRNA molecule of the cytosol
- Binds to ribosomes am I in a bind to ribosomes at the code on binding site the ribosome then moves along the RNA and when it reaches a star code on AUG and translation begins
- Translation TRNA in the cytoplasm has a complimentary anti-codon for the mRNA codons  anti-codons correspond to the specific amino acid and tRNA Kalex amino acids to bring to the ribosomes
- Peptide bonds amino acid delivered to the ribosome and I joined by peptide bonds which uses 1 ATP this forms a polypeptide chain
- Stop codon: when ribosome reaches a stop code on translation is complete and the mRNA strand is released and the polypeptide chain is sent to the Gogli apparatus for packaging
Explain the stages of the cell cycle
G1 phase the first growth phase where the cell produces new proteins grow normal tasks will end when the sale starts duplicating
S phase The synthesis phase the DNA molecule forms exact copies of each other
G2 phase: The second growth phase this is the prep for cell division 
M phase: This is the miotic phase when the cell divides into two daughters cells
Explain the process of mitosis
Interphase this is the period between nuclear divisions the sale will go through G1, S and G1 during S phase the DNA forms exact copies of themselves meaning quantity of DNA in the nucleus doubles
Prophase in the first phase 2 pairs of centrioles are visible and move to either side or polls of the cell the microtubules then radiate from the same time the nucleus disappears the nuclear membrane begins to breakdown the chromatin threats of DNA become tightly coiled this is seen as the chromosomes coil the long delicate DNA and makes the DNA easily distributed to the daughter cells to chromatids are identical the DNA molecules produced in interphase and the centrioles are A joint network called spindle fibres
Metaphase: chromatid pairs line in the middle attached the spindle fibres the spindle fibres contract and pull the chroma zones in a single alignment along the equator
Anaphase the pair of chromatids separate for you from The centromere due to the contractions the chromatids are independent and now known as chroma zones chroma zones pull away from each other and move to separate poles
Telophase: The chroma zones now will reach the polls and form tight groups the spindle fibres disappear and the chroma zones on coil becoming chromatin once again nuclear membrane reforms and the nucleus reforms
Cytokinesis division of the cytoplasm until cytoplasm develops between the two nuclei furrows deep in between the two cells pinching off making them to separate cells
Explain what differentiation is
When different jeans are activated during mitosis it causes the cells to differentiate into specialised cells so it can perform specific functions for example like muscle cells and stomach cells
Explain what a totipotent, pluripotent and multi potential stem cell all are
totipotent: they have the potential to create any cell necessary for embryonic development including the embryo and other cells which nourish the embryo
Pluripotent: gives rise to any of the cells in the body embryonic stem cells aporia potent as they differentiate to form or cells of the individual
multi potent: have the potential to form numbers of different cells for example blood cells and platelets
Explain the process of meiosis
 first division the homologous pairs separate and two daughters cells form with 23 chromosomes each with 2 chromatids the second division of chromatids separate
Prophase one the chromosomes become visible as long threads chroma zones have gone through replication so they each have two chromatids the chroma zones move so that the homologous chromosomes move next to each other and contract to become thicker
Metaphase one homologous pairs moved the equator with spindle fibres
Anaphase one each homologous chromosomes separates moving to separate ends of the spindle fibres resulting in 23 chromosomes moving to each end
Telophase 1: the chromosomes Decondense  and cytokinesis occurs forming to daughter cells
Prophase two: new spindle fibres for each new daughter cells have one chromosome
Metaphase two: sister chromatids moved to the centre of the cell and align on the metaphase plate
Anaphase two: spindle fibres contract causing chromatids to separate and are pulled to opposite poles
Telophase 2: spindle fibres contract sister chromatids are separated and move to opposite ends
Cytokinesis the cytoplasm splits into two and forms for haploid cells from the original cell
Explain what a stem cell is
They don’t have a pet any particular role they have the potential to develop into any cell
