Q In Class

Question 1

Describe the biochemical processes that are important in fat synthesis in milk production?

Answer 1

The dominant fat in milk is triacyglycerol. Short chain fatty acids are synthesised within mammary glands and long chain acids are derived from blood plasma fatty acids. Intermediate chains are from both.

Fatty acids are synthesised in the mammary gland via Malonyl Coenzyme. A pathway then form Le into triacyglycerol which are then synthesised in the endoplasmic reticulum and are released into the lumen.

Fat contents vary between different cow breeds and also stages of lactation.

Question 2

Describe the biochemical processes that are important in protein synthesis in milk production?

Answer 2

There is mostly the protein casein in milk. Protein synthesis occurs in mammary alveolar cells where DNA controls the process. MRNA carries encoded DNA messages from the nucleus to the ribosomes on the rough endoplasmic reticulum and cytoplasm. This combined amino acids into peptide chains to elongate and form protein. Then it is passed to the lumen and into the Golgi apparatus where there accumulate and polymerise into different milk proteins. Milk protein percentage differs with breeds, age (younger than 3 produce more protein). Early stages of lactation produce more milk.

Question 3

Describe the biochemical processes that are important in carbohydrate synthesis in milk production?

Answer 3

Carbohydrates are in the form of disaccharide lactose. It is revukates by water content. Glucose is the primary substrate in lactose synthesis, provided mainly from the blood. Starts in the Golgi apparatus where lactose is formed under the action of enzyme lactose synthetase. Uses glucose and UDP-galactose as inputs.

Question 4

Why are there such large numbers of mitochondria in Mammary cells

Answer 4

All biochemical processes involved with making milk require ATP from the mitochondrial TCA cycle

Question 5

Describe the biochemical processes by which Acetyl CoA consumption is used to drive aerobic ATP synthesis in the mitochondria?

Answer 5

Acetyl CoA from glycolysis goes into the TCA cycle where it makes the proton donors in the matrix. The mitochondria is surrounded by 2 membranes where the ETC sits on the inner-membrane. The gradient is formed between the 2 membranes and that is why the ETC is on the inner. It grabs protons from the proton donors supplied by the TCA cycle and sends It across the ETC. Protons are H+ and therefore make it more acidic. This causes an acid-base gradient and protons move around. The positive charge of the proton donors create an electrical charge. Because there is both electricity and chemistry there is an electro-chemical gradient.

Stored power in the mitochondria chars the protons to fly through the enzyme ATPsynthase pore. This makes ATP. The ETC have enzymes