Cells at Work

Question 1

What is Transcription? (Protein synthesis step 1)

Answer 1

mRNA is created based on information encoded in DNA (each nucleotide has a matching nucleotide)
3 nucleotides code for 1 piece of info
3 Events
- A portion of DNA unwinds and seperates
- One strand of DNA is used as a blueprint for the complementary strand of RNA
- A special enzyme (RNA polymerase) creates the complementary RNA

Question 2

What is Translation? (step 2 of protein synthesis)

Answer 2

mRNA travels to the ribosomes where the RNA is matched to tRNA which gives the corresponding amino acid
Amino acids are joined by peptide bonds
Endoplasmic reticulum folds the protein into the correct shape

Question 3

What are the 4 Steps of an enzymatic reaction?

Answer 3

1. Enzyme bonds to a specific substrate (different enzyme for each type of reaction)
2. The active site of the enzyme changes shape to accommodate the substrate
3. as the reaction progresses, the enzyme-substrate complex turns into an enzyme-product complex
4. The products are released and the enzyme is ready to be used again

Question 4

Explain the process of lysosomal digestion.

Answer 4

Lysosomes contain digestive enzymes which are used to break down food molecules
Lysosomes merge with food molecules, break down the food and release the nutrients into the cytoplasm
Waste is expelled through a vacuole
Lysosomes can release their enzymes into the cell when the cell is old or diseased causing it to ‘self-destruct’

Question 5

Describe the 3 processes of Aerobic Cellular Respiration.

Answer 5

Requires oxygen
Glycolysis: glucose is broken down to form 2 pyruvic acid molecules and the energy released is used to combine 2 ADP and 2 Phosphate into 2 ATP
Krebs Cycle: pyruvic acid is broken down in the mitochrondria removing hydrogen and producing CO2
Electron Transport: hydrogen atoms are passed along a series of electron carriers, hydrogen reacts with oxygen to form water and energy is released to make 34 ATP

Question 6

Describe Anaerobic Cellular Respiration.

Answer 6

Does not require oxygen, Aerobic is preferred but Anaerobic is used when oxygen is limited
Glycolysis does not require oxygen, glucose + 2 ADP + 2 Phosphate = 2 pyruvic acid + 2 ATP
Humans cannot survive on Anaerobic alone