Module 2 - Biochemistry Flashcards
What are the 3 different ways a sugar can be classified?
- Position if carbonyl group - aldoses or ketoses
- Length of carbon chain
- Spatial arrangement - linear or cyclic
What is the difference between starch and cellulose? Which is easier to break down?
Both are storage polysaccharides
alpha 1-4 bonds =starch, beta 1-4 = cellulose
Cellulose is easier to break down
How can the rate of a reaction be measured?
Kcat = molecules broken down / second
Describe the 4 levels of protein structure.
- Primary - amino acid sequence
- Secondary - alpha helices and beta sheets
- Tertiary - 3D shape of protein - due to interactions between R groups of amino acids
- Quarternary Structure - assembly of polypeptides to form a complete protein
What is the function and structure of myoglobin?
Stores oxygen in muscle cells
Single polypeptide monomer
What is the structure and function of hemoglobin?
Transports oxygen through veins and arteries
It is a tetramer with 4 subunits
What gives myoglobin and hemoglobin the ability to bind to oxygen?
The heme group - a molecule with an iron atom at its centre
What are the similarities and differences of myoglobin and hemoglobin?
They are homologous, meaning they have a similar primary, secondary and tertiary structure - this also means they have similar functions
Due to its tetrahedral shape, hemoglobin can bind to 4 oxygens, whereas myoglobin can only bind to one
What is sickle cell anemia?
There is a single amino acid mutation resulting in a different protein formation. The red blood cell is sickle shaped which affects its ability to carry oxygen.
What role does insulin play?
Insulin is the key that unlocks the glucose channel
What is a denatured protein?
Inactive protein - can be caused by alterations in pH, temperature, etc
- unravelled protein
How many different types of collagen are there? What are the differences between them?
- Most common - found in skin, tendon, bones and organs
- Cartilage
- Connective tissue around the liver
What is collagen?
Most abundant protein in the body - it is insoluble
Procollagen = inactive form Tropocollagen = active
Describe the shape and structure of collagen.
Elongated shape, held tightly together and is very crowded with atoms
What is osteogenesis imperfecta?
Brittle bone disease
Glycine side changes of collagen are replaced with cysteine - cysteine is too large for the dense helical collagen, and the helical arrangement becomes unstable
Results in more fragile bones that break very easily
What are vitamins and why are they so important?
Vitamins are organic compounds that are vital nutrients for our body. They cannot be synthesised by the body, and therefore must come from our diet
Example: vitamin c strengthens collagen and without it, the collagen is much weaker
Name 3 different categories of lipids.
- Phospholipids
- Fats
- Steroids
What are fats made from?
Glycerol + fatty acids
Glycerol = a 3 carbon alcohol with a hydroxyl group on each carbon
Fatty acids = carboxyl group attached to a long carbon skeleton
What is the bond that joins glycerol to fatty acids?
Ester link
Describe the structure and function of a phospholipid, and why they self-assemble into bilayers in water.
Phospholipids are composed of a hydrophobic head (phosphate group and glycerol) and a hydrophilic tail (2 fatty acids)
When placed into water, they assemble into a bilayer with the heads facing out and tails facing in. This allows the polar heads to interact with the water.
List 3 properties of steroids
- mostly non-polar
- hydrophobic
- 4 rings in their structure
What are some functions of steroids?
- signalling
- cell membrane
- hormones
- vitamin D
- anabolic steroids (natural or synthetic - can stimulate muscle growth and other functions)
Describe the structure of a nucleotide.
Phosphate group + nitrogenous base + pentose sugar
Name either the 2 purines or the 3 pyrimadines
Pyrimidines = cystosine, thymine and uracil
Purines = adenine and guanine
