Metabolism/biomolecules

Question 1

What is a biomolecule?

Answer 1

Any molecule made within an organism. e.g. proteins, lipids, hormones, carbs

Question 2

What are the different types of Carbohydrates (when broken down) ?

Answer 2

They are classified according to molecular size and solubility. They include: Monosaccharides, Disaccharides and Polysaccharides.

Question 3

What is a monosaccharide?

Answer 3

Single sugar molecule. They can combine to form disaccharides, e.g. glucose and fructose.

Question 4

What is a dissaccharide?

Answer 4

two sugar molecule. They are formed when two monosaccharides are joined and a molecule of water is removed. They are too large to pass through the cell membrane and must be digested via hydrolysis. e.g. maltose, sucrose and lactose

Question 5

What is a polysaccharide?

Answer 5

many sugar molecules linked. Chains of simple sugars linked together via dehydration synthesis, used as a storage product. e.g. starch, glycogen and cellulose.

Question 6

What is a lipids and what are types of Fats/Lipids (when broken down)?

Answer 6

Lipids: organic molecules which are insoluble in water e.g. triglyceride, phospholipid and cholesterol.

Question 7

What is a triglyceride?

Answer 7

It is a neutral fat (three fatty acid chains attached to a glycerol) that protects the internal organs, stores energy fuel and insulates.

Question 8

What is a phospholipid?

Answer 8

Modified triglyceride which have one fatty acid chain replaced by a phosphate group. They have two non polar fatty chain ends and a phosphate polar portion.

Question 9

What is cholesterol?

Answer 9

Most important molecule ingested in animal products, consist of 4 interconnected carbon rings and plays an important role in stabilising the cell membrane. Used to synthesise, steroid hormones such as vitamin d. (can be HDL = good or LDL = bad).

Question 10

What is a protein?

Answer 10

formation of 20 different amino acids and are responsible for multiple physiological functions.

Question 11

What are the structures of a protein?

Answer 11

Primary Structure:
- determined by the sequence of amino acids connected by peptide bonds.
Secondary:
- the protein may use hydrogen bonds to form a secondary structure consisting of coils or pleats.
Tertiary:
- the final dimensional shape that a protein assumes, determined by a variety of bonding interactions between
the “side chains” on the amino acids.
- These bonds can be stronger than the hydrogen bonds and thus the protein will bend, fold and loop.
Quaternary:
- the combination of two or more
chains, to form a complete unit..
- The interactions between the chains are distinguished only by being interchain rather than intrachain.

Question 12

Protein conformation can be affected by….

Answer 12

high temp, changed in pH, various chemicals and radiation.

Question 13

What are enzymes?

Answer 13

type of protein (globular mostly) . they have a unique 3D shape that binds with a small group of reacting molecules. They are much larger than their substrates.

Question 14

What are examples of polypeptides?

Answer 14

encephalins and endorphins (natural pain killers). These can bind to receptors in the brain and provide temporary relief. Endorphins may produce a sedative effect by preventing the release of substance P.

Question 15

What are the three main types of metabolic reactions?

Answer 15

Catabolism: 
- complex molecules broken down into smaller molecules
Anabolism: 
- build large molecules from small ones
Waste removal

Question 16

Stage 1 of catabolism is…

Answer 16

• where enzymes break down large molecules into smaller ones to be diffused across the bloodstream. e.g. proteins into amino acids

Question 17

Stage 2 of catabolism is ….

Answer 17

• where newly delivered nutrients are either built into lipids, proteins and glycogen (anabolism) or broken down to pyruvic acid and Acetyl into the cytoplasm (catabolism)
• the products are further broken down to yield 2 or 3 carbons

Question 18

Stage 3 of catabolism is …

Answer 18

the major production of energy in the mitochondria. Two acetyl group is oxides in the citric acid cycle producing= NADH and FADH2
as long as cells have oxygen the electrons and ions can be transferred to the electron transport chain to ADP then ATP

Question 19

Which vitamins are essential for mitochondrial function and aerobic respiration ?

Answer 19

• B1, B2, B3
  (Vit B1) thiamine (wherever CO2 is removed)
  – (Vit B2) riboflavin (forms flavin adenine dinucleotide (FAD) a redox
  cofactor – accepts and donates electrons)
  – (Vit B3) Niacin (forms part of Nicotinamide adenine dinucleotide
  (NADH) which is involved in redox reactions)

Question 20

Would the availability of oxygen impact on the amount of energy that is produced by the cell? Explain your answer.

Answer 20

During aerobic respiration (with O2) the cell produces between 36
ATP, whereas with anaerobic respiration (without O2) the cell only
produces 2 ATP.

Question 21

Explain why Hypoxia might lead to multiple system failure?

Answer 21

-Oxygen is needed for the electron transport chain (oxidative
phosphorylation)
– No oxygen means no regeneration of NAD and FAD which
ultimately leads to no ATP output which leads to cellular failure and
organ failure.

Question 22

What is glycogen synthesis and where does it take place?

Answer 22

Glycogen synthesis is the process by which excess glucose is
converted into glycogen for storage.
– The liver is the primary storage site of glycogen, although other
organs such as the skeletal muscle, heart, kidney and brain can also
synthesize glycogen as well as break it down.

Question 23

What is gluconeogenesis?

Answer 23

Gluconeogenesis is the process by which glucose is made from the biosynthesis of simpler non-carbohydrate precursors such as oxaloacetate or pyruvate.

Question 24

List three factors that can influence enzyme function and explain how they influence enzyme function

Answer 24

pH
– Enzymes function within a narrow pH range. Changes in pH can make and
break intra- and intermolecular bonds, leading to a change in shape of the
enzyme, disrupting its binding site.

Temperature
– Enzymes function best at their optimal temperature (usually 37.5 degrees in
humans). If the temperature exceeds this, the enzyme structure will begin to
denature (break down). This is due to the breakdown of intra- and intermolecular bonds due to the increased kinetic energy.

Initial concentration of the substrate and enzyme
– The reaction is dependant on the amount of substrate and enzyme. If the substrate concentration is high and that temperature and pH are kept constant, the rate of reaction is proportional to the enzyme concentration.