DNA and protein synthesis

• Describe and explain the arrangement of the genetic material shown in the image?

  -chromatins are condensing

  -into visible chromosomes

  -arranged randomly due to lack of spindle fibre activity
• The diploid number of chromosomes in the body cell of an insect species is four. tick box ABC or D.?

  A (4 chromosomes)
• Name the fixed position occupied by a gene on a DNA molecule?

  locus
• Describe how a gene is a code for the production of a polypeptide. Don’t include transcription or translation in your answer.?

  -A gene is a sequence of nucleotide bases

  -in a triplet code

  -sequence of bases determines the amino acid order
• What is a gene?

  A sequence of bases on a DNA that codes for a protein, which results in a characteristic
• Describe how the production of messenger mRNA in a eukaryotic cell is different from the production of mRNA in a prokaryotic cell.?

  Prokaryotes

  -transcription results in the direct production of mRNA

  Eukaryotes

  -transcription results in pre-mRNA

  -spliced (remove introns) to form mRNA
• Suggest how PNA affected the transcription of the section of DNA?

  -PNA forms base pairs with DNA

  -prevents RNA polymerase from binding with DNA for transcription
• Describe the role of ATP in the process of translation in protein synthesis?

  -tRNA amino acids need to be joined together with peptide bonds

  -via condensation reaction

  -requires energy from ATP hydrolysis
• Describe how mRNA is produced from an exposed template strand of DNA. Do not include DNA helicase or splicing in your answer?

  -free RNA nucleotides form complementary base pairs

  -phosphodiester bonds form

  -by action of DNA polymerase
• Define the term exon?

  Coding region of a gene for amino acids
• Use figure 1 to give amino acid sequence?

  serine, alanine, glycine, proline
• Mutation in the nucleotide sequence shown in figure 1. Does students conclusion support information?

  -substituting one base for another

  -CGT—>GCC to make glycine instead of alanine

  -does support
• Give three ways in which DNA in a chloroplast is different from DNA in the nucleus?

  -chloroplast DNA much shorter as less genes

  -no introns in chloroplast DNA

  -DNA in chloroplasts is coiled around histone proteins
• Difference between DNA nucleotide and RNA nucleotide?

  DNA nucleotide has deoxyribose pentose sugar whereas RNA has ribose sugar
• Structures labelled X and W?

  W=amino acid binding site

  X=anticodon
• Not all mutations cause change in structure of polypeptide. why?

  -mutation may have happened in intron which is not coded

  -degenerate-multiple sequences/ codons can produce the same amino acid
• Describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule?

  -condensation reaction

  -between phosphate and deoxyribose
• Maths Q?


  336/4=A +T

  84=

  84/2=42

  168+168+42+42=420/2=210

  210/3=70
• DNA protein associated with chromosome?

  histone
• Describe how the separation of strands occurs?

  enzyme Helicase breaks hydrogen bonds between nucleotide strands