Download BIOCHEM MID SEM EXAM 2014 The Foundations of Biochemistry

BIOCHEM MID SEM EXAM 2014 The Foundations of Biochemistry: From Cells to Chemical Laws of Biochemistry (lec 1) Qu. What is Biochemistry? Provide a brief definition in 30 words or less.
The study of biomolecules inside & outside of cells from living systems and how
they interact to maintain & perpetuate life via universal physical & chemical laws.
Qu. What are the cellular foundations of biochemistry?
- Cells are the biochemical factories of living systems
- 2 main types of cells: prokaryotes + eukaryotes
Qu. Compare the structural features of Gram –ve/+ve prokaryotic, plant &
animal cells.
PROKARYOTIC CELL
GRAM +
- Stain purple
- No outer
membrane
- Thicker
Peptidoglyca
n layer
-
GRAM - Stain pink/red
- Have outer
membrane
- Peptidoglycan
layer
Ribosomes
Cell envelope
- Nucleoid
- Pili
- Flagella
EUKARYOTIC CELL
PLANT CELL
- Larger
- Chloroplasts
- Cell wall
- Plasticids
- Visible vacoules
-
ANIMAL CELL
- More lysosomes
- Centrosome
- No cell wall
- Peroxisome
Ribosomes
Cytoskeleton
Golgi complex
Plasmodesma
Smooth + rough ER
Nucleus
Nucleolus
Mitochondria
Plasma membrane
Starch granule
Qu. Describe the chemical foundations of biochemistry.
1. Colourà CPK model
2. Speedà enzymes
3. Strengthà equilibrium dissociation constant
4. Geometryà cis and trans
5. Stereospecificityà L and D
Qu. What are enzymes?
Biological catalysts that speed up the conversion of substrate to product.
Qu. What is the equilibrium dissociation constant (KD)?
- A thermodynamic parameter describing ‘strength of interactions’ in biochem
Qu. What is cis and trans?
- Cisà same groups are on the same side of the double bond
- Transà same groups on opposite side of double bond
Qu. Allocated stereospecifity for AAs and sugar.
- AAsà L (life)
- Sugarsà D (daily)
The Foundations of Biochem:
Biomolecules and Physical, Genetic &
Evolutionary Foundations (Lec 2)
Qu. Describe the physical foundations of biochemistry.
1. Energyà ATP àADP + Pi, ΔG = ΔH –T.ΔS
Qu. How is ATP produced?
1. Glycolysisà occurs in the cytosol. It’s the pathway that converts glucose into
pyruvate.
o The energy released in this process is used to form ATP and NADH
2. Krebs cycleà occurs in the inner mitochondrial membrane protein complex
(ATP Synthase)
Qu. Which enzyme is responsible for producing the most ATP?
- ATP synthase in the inner inner mitochondrial membrane protein complex
Qu. Which has more energy, ATP, ADP or AMP?
- ATP because it has 3 phosphates and more bonds. When you break bonds, you
release energy
Qu. What is ΔG? The change in the free energy of the system Qu. What is ΔH? - Change in enthalpyà the number and nature of bones (ie. Heat emitted or absorbed) Qu. What is ΔS? - Entropy à the change in the randomness of the system Qu. What does it mean if ΔG is + and -­‐? - +à unfavourable reaction, energy needs to be put in - -­‐ à favourable reaction, energy is released - 0à Equilibrium, freely reversible reaction Qu. Name the 5 major classes of biomolecules in living systems & briefly
describe their structure & role in biology.
1. Deoxyribonucleic acid (DNA)
2. RiboNucleic Acid (RNA)
3. Proteins
4. Carbohydrates
5. Lipids
Qu. Define DNA.
- Deoxyribonucleic acid, a self-replicating material which is present in nearly
all living organisms as the main constituent of chromosomes. It is the carrier
of genetic information (hereditary material)
- It makes up the ‘genome’ of an organism that contains genes encoding RNA +
proteins
Qu. Where is DNA found in prokaryotic cells and eukaryotic cells?
- Prokaryotic cellà cytoplasm
- Eukaryotic cellà Nucleus
Qu. What are 3 major RNA molecules?
1. mRNA (messenger RNA)
2. tRNA (transfer RNA)
3. rRNA (ribosomal RNA)
Qu. What’s the importance of mRNA?
- It’s the product of transcription
- It’s what will then be encoded to a protein during translation