Processes

Question 1

Making and secreting protein

Answer 1

1. Gene transcribed into mRNA in the nucleus
2. mRNA leaves through nuclear pore
3. mRNA attaches to ribosome
4. Ribosomes translate the code to a protein
5. Protein molecules are in pinched off vesicles and travel to Golgi apparatus
6. Vesicle fuse with Golgi apparatus
7. Golgi apparatus packages and processed the proteins
8. Packaged protein pinched off vesicles
9. Vesicles fuse with plasma membrane
10. Plasma membrane opens releasing protein

Question 2

Dna Replication (continuous)

Answer 2

1. DNA Helicase unwinds and unzips the double helix giving the replication fork
2. Free nucleotides bind to exposed bases
3. H bonds form
4. DNA Polymerase forms phosphodiester bonds between nucleotides
5. DNA ligase seals everything up to form 2 double helices

Question 3

Discontinuous replication (lagging strand)

Answer 3

1. Primase adds RNA primer
2. DNA Polymerase bonds to primer then adds bases up to the prev RNA primer
3. Exonuclease gets rid of RNA (forming Okazaki fragments)
4. DNA Polymerase fills in the gaps
5. DNA ligase seals everything up to form 2 double helices

Question 4

Translation

Answer 4

1. Minor then major sub-units of ribosome fit onto the mRNA at the start codon
2. tRNA with an anticodon of complementary bases will be attracted to the codon
3. tRNA binds to mRNA codon
4. 2nd tRNA molecules is attracted and binds
5. The bond between the first tRNA and the amino acid are broken
6. The energy is used by the enzyme peptidyl transferase to form a peptide bond between the 2 amino acids in the ribosome
7. The tRNA is freed and the ribosome moved along the mRNA

Question 5

Interphase:

Answer 5

1. G1- organelles duplicate, protein synthesis to make proteins required for replication, cell differentiation
2. S - DNA replication, rapid, chromosomes into 2 chromatids
   3 - G2 - Produces proteins that cause condensing of chromosomes, cytoskeleton break down, microtubules reassemble into spindle fibres, tubulin produced

Question 6

Mitosis

Answer 6

1. Prophase - chromosomes condense, nuclear envelope breaks down, centrioles love to opposite ends of the cell, spindle fibres extend to equator
2. Metaphase - Centrosomes reach poles, chromosomes line up down the equator (metaphase plate), spindle fibres attach to centromeres of chromosomes, each sister chromatid attached from a spindle fibre
3. Anaphase - Spindle fibres contract, centromeres spilt and sister chromatids split, carried in a ‘V’ shape with centromere leading, set of chromosomes at each pole
4. Telophase - chromosomes uncoil and become long, spindle fibres break down, nuclear envelope forms around each new group of chromosomes, new nucleoli fired within each nucleus

Question 7

Meiosis