Comp 12: DNA, Protein and Cell Divison

Question 1

What are nucleic acids

Answer 1

Organic macromolecules (C, H, O, N, P) present in living cells especially in DNA and RNA

Question 2

What are polynucleotides?

Answer 2

Chain of repeating monomers called nucleotide

• monomers: molecules that bond to other identical molecules to form poly
• nucleoside: pentose sugar + nitrogenous base
• nucleotide: nucleoside + phosphate groups

Question 3

Difference between DNA and RNA?

Answer 3

DNA: double-stranded polymer, contain sugar deoxyribose, uses ACG, A-T and G-C
RNA: single-stranded polymer, contain sugar ribose, uses ACG, A-U and G-C

Question 4

What are proteins and the chemical components of it

Answer 4

• proteins are important macromolecules and about 10,000 in our body
• contain carbon, hydrogen, oxygen, nitrogen and MAY contain sulphur, ion, phosphorous or iodine.

Question 5

Function of proteins

Answer 5

• regulation
• transport
• protect
• contract
• structure
• energy

Question 6

Transcription and Translation explanation

Answer 6

Transcription: Transcription is the process of producing a strand of RNA from a strand of DNA

Translation: Translation is the process where the information carried in mRNA molecules is used to create protein

Question 7

What are codons?

Answer 7

• codons are sequences of 3 nucleotides forming genetic code in DNA or RNA
• 64 codons in mRNA, 20 naturally occurring aa

Question 8

What is post-translational modification?

Answer 8

• chemical modification of protein after translation
• one of the last steps in protein synthesis
• proteins can be modified by attaching other functional groups > can change or extend its functions e.g. lipids and cords

Question 9

Distinguish between somatic, germ and gamete cells

Answer 9

• somatic: any cell of an organism that isn’t a reproductive cell
• germ: cells that become embryo developing into a child
• gamete: cells that fuse during sexual reproduction

Question 10

Explain the mitosis division

Answer 10

• interphase: replication of DNA preparing for division
• prophase: break and build structures to prep for chromosome division
• metaphase: chromosomes aligned at the nuclear equator
• anaphase: 2 identical chromosomes to end of the cell, cytokinesis begins
• telophase: starts to re-establish its normal structures

Question 11

Explain the meiosis division

Answer 11

• Early prophase: duplicate chrom. become visible chromatids
• Middle prophase: homologous chrom. synapse to form tetrads
• Metaphase 1: homo-chrom align @ centre of the cell
• Anaphase 1: homo-chrom move apart opposite sides of the cell
• Telophase 1: new nuclei form and the cell divides
• Prophase 2: each chrom consists of 2 chromatids
• Metaphase 2: chrom align along centre of cell
• Anaphase 2: chromatids separate and each is now chromosome
• Telophase 2: new nuclei + cell divides to make 4 daughter cells