Topic 8: Cell Physiology 2 Flashcards
What is anabolism and catabolism?
Anabolism: building molecules
Catabolism: breaking down of molecules
Explain the process of DNA transcription
DNA template is copied to mRNA:
-DNA uncoils at site of gene to expose gene base sequence
-RNA strand is formed, using code on DNA template to add complementary RNA nucleotides
Explain the process of mRNA translation
mRNA ~> proteins:
—mRNA associates with ribosomes
(3 bases on mRNA = base triplet = codon)
(Each codon codes for 1 amino acid)
—transfer RNA (tRNA) with attached specific A.A. and anticodon binds to matching RNA
—peptide bond is formed to attach A.A. to growing peptide chain
What happens after mRNA translation?
—Proteins produced on free ribosomes are released into cytosol or go to nucleus or mitochondria
—Proteins produced by ribosomes on rough ER are released into lumen of RER
What is ATP catabolism? How does it work?
The breakdown of ATP to release energy
—adenine + ribose (=adenosine) + 3 P
—energy stored in phosphate bonds
—energy produced is used for reactions
—little ATP is stored, so the body has to constantly make more
What are the steps of cellular respiration?
Glycolysis (anaerobic) in cytosol
Enters mitochondria ~> becomes aerobic
Krebs cycle
Electron transport chain
Proteins produced by ribosomes on the RER are released in to the lumen of the RER. There they are modified by the addition of sugars (glycoprotein). What happens to the proteins next?
Proteins are sent to the Golgi complex:
- They are further modified by:
- carb changes/additions
- lipid additions (lipoproteins) - Modified proteins are packaged in vesicles and sent to their destination
All enzymes are _______.
proteins
Why are enzymes important?
They are used to speed up chemical reactions within the body
What can alter the shape of an enzyme?
Temperature and pH
What is the chemical reaction of cellular respiration?
1 glucose (C6H12O6) + 6 O2
~~~~>
6 CO2 + 6H2O + 32 ATP + heat
What substrates in the body can be used to produce ATP?
Carbohydrates:
> stored as glycogen in the liver or ingested with diet are broken down to form glucose
Proteins:
> some AAs can be converted to pyruvic acid or enter Krebs cycle, they may be used to form glucose or ATP
Lipids:
> primary storage of energy in the body (triglycerides), broken down to ATP
Cellular respiration is the production of ATP using glucose. How does glucose enter most cells, and what are the exceptions?
Glucose enters most cells by carrier mediated facilitated diffusion (facilitated transport). There is usually a lower concentration of glucose within the cell because it is constantly being used up.
Exceptions are cells of the small intestine and certain kidney cells. In these cells glucose is transported into the cells using secondary active transport.
