Biology 3.3 Dna Structure

3. 3 & 7. 1 desoxyribonucleic acid Structure Worksheet 1. Draw and distinguish the structure of a simplify single nucleotide, including sugar, phosphate and bottom. 2. Complete the tabularize below to show the pairings of the secondarys in DNA Purine Pyrimidine Adenine Thymine grand Cytosine 3. Where would one find the base uracil? RNA, it replaces thymine 4. In the space below, manoeuvre a single concatenation of trinity nucleotides, assigning the bonds amidst them and showing the correct relative position of these bonds. The eon of these bases makes up the communicable code. The red linesrepresent covalent bonds.They are read in groups of three called triplets. These triplets arethen used to send instructions in the stall to switch genes on and off. 5. Define the term double helix. The term double helix is cardinal strands of DNA that twist around distributively other. Anti-Parallel 6. In the space below, draw a section of DNA, showing two anti-parallel strands of t hree nucleotides. Label the bonds which sustenance the bases together as well as the correct complementary base pairs. Also include the 3 and 5 linkages (and ends), and the distinction between purines and pyramidines. . rationalize the relevance of the following in the double-helix structure of DNA a. Complementary base pairing Complementary base pairing is when G only bonds with C and T only bonds with A and these are found on each strand of the double helix b. Hydrogen bonds Hydrogen bonds between the bases curb together the strands of DNA c. Relative billet of the sugar-phosphate backbone and the bases The relative positioning of the sugar-phosphate backbone are on the outside and the bases are on the inner of the double helix 8.In the space below, draw the structure of a simplified nucleosome, including the H1 linker and histone proteins. 9. Nucleosomes allow the DNA to be supercoiled. a. What is the approximate length of the DNA strand in one chromosome? The length is (len gth of 1 bp) (number of bp per cubicle) which is 2 meters. b. During which phase of the cell cycle is DNA most likely to be supercoiled? Prophase c. Outline how nucleosomes divine service regulate transcription. 10. Distinguish between unique or single-copy genes and highly instant sequences Single-copy genes Highly-repetitive sequences . 5% of genome makes polypeptides. Each codon (mRNA) (3 bases) codes for one amino acid. 3% codes for on/off gene switches. Within each eukaryotic genes there areExons (coding regions)Introns (non-coding regions which are edited out)Every gene has a switch, for example a skin cell will turn off unnecessary genes so it does not suffice the wrong activity (e. g. producing blood) Makes up about 5% 45% of the genome. in one case called junk DNAAlso known as satellite DNA, each repeated sequence can be 5-300 base pairsHRSs are used in genetic fingerprinting.This is because they accumulate mutations rapidly Not all of the base sequences in DNA are tra nslated. Highly repetitive base sequences are not translated. They brood of sequences of between 5 and 300 bases that may be repeated up to 10 000 times. They lay down 5-45% of eukaryotic DNA. Single-copy genes or unique genes are translated and constitute a surprisingly small proportion of eukaryotic DNA. 11. Distinguish between introns and exons in eukaryotic genes. Exons (coding regions) Introns (non-coding regions which are edited out)