Topic 8: Cell Physiology

Question 1

Cell Physiology Overview

Answer 1

• Cells = living building blocks of body
• Chemical processes in body (performed by ells) = metabolism
• Anabolism = building molecules
• Catabolism = breakdown of molecules

Question 2

Basic Cell Processes

Answer 2

1) Protein Synthesis
2) ATP Catabolism
3) Cellular Respiration

Question 3

Protein Synthesis

Answer 3

• Proteins can be enzymes, structural etc.
• Process of protein synthesis involves:
  1) DNA Transcription
  2) Translation
  3) After Translation

Question 4

DNA Transcription

Answer 4

• DNA –> mRNA
• Steps:
  1) DNA uncoils at site of gene to expose gene base sequence
  2) RNA strand is formed, using code on DNA template to add complementary RNA nucleotides

Question 5

Translation

Answer 5

• mRNA => Proteins
• Steps:
  1) mRNA associates with ribosomes
• 3 bases on mRNA = base triplet = a codon
• Each codon codes for 1 amino acid (aa’s can have more than one codon)
  2) Transfer RNA (tRNA) with specific aa and anticodon (complimentary bases to codon) binds to matching RNA)
  3) Peptide bond is formed to attach aa to growing peptide chain
• SO overall: sequence of DNA bases determines mRNA sequence -> determines sequence of protein

Question 6

After Translation

Answer 6

• Proteins produced on free ribosomes - released into cytosol or go to nucleus or mitochondria
• Proteins produced by ribosomes on ER (RER) -released into ER lumen
• Modified by addition of sugars (glycoprotein)
• Transferred to Golgi complex in vesicles
• Glogi Complex:
  1) Further modifies protein by
• carb changes/additions (act as an address to send them to the right destination)
• Lipid additions
  2) Packages modified proteins (in vesicles) and sends to destination: cell membrane, section, lysosomes

Question 7

Enzymes

Answer 7

• Names end in -ase
• Increase reaction rates
• Not used up in reaction
• very sensitive to pH, temperature
  Synthesis controlled by cell (proteins) - cell can vary activity
• Very specific

Question 8

ATP Catabolism

Answer 8

• Adenosine Triphosphate (ATP)
• adenine + ribosome (= adenosine) + 2 phosphates
• Energy stored in phosphate bonds (covalent)
• Energy produced used for reactions (protein synthesis, active membrane transport, muscle contraction etc)
• Little ATP is stored, so constantly have to make it

Question 9

Cellular Respiration

Answer 9

• Produced of ATP using glucose - glucose enters mostt cells by facilitated transport (Amy be higher in some cells by insulin)
• DIAGRAM
• Steps:
  1) Glycolysis (anaerobic) in cytosol
  2) Enters mitochondria - becomes aerobic
  3) Kerbs Cycle
  4) Electron Transport Chain

Question 10

Cellular Respiration: In the body

Answer 10

1) Glycogen –> glucose –> ATP
2) Proteins
- Some aa can be converted to pyretic acid or enter Kerbs cycle
- Depending on body’s need may form new glucose (liver, kidney) or ATP (most cells)
3) Fats
- Primary storage form of energy in the body (triglycerides)
- Broken down to form acetyl CoA –> ATP