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Milk Composition & Synthesis
Practice Quiz

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This is a sample of a quiz on the Milk Composition & Synthesis Module. Print is out and use it to help you study the material. This is a long module with a great deal of detailed information.


1. Whole milk is which of the following?

  1. a suspension of milk fat globules
  2. a suspension of lactose
  3. an emulsion of milk fat globules
  4. an emulsion of casein micelles

 

2. Which of the following best describes lactose?

  1. provides amino acids for the young
  2. is necessary for skeletal development
  3. a disaccharide of glucose and galactose
  4. a complex mixture of triglycerides

 

3. Which of the followingis true for casein?

  1. it is the major milk protein
  2. it is a complex of lipids
  3. it is a poorly digestible energy source
  4. it is made up of glucose and galactose

 

4. Milk fat is secreted by the mammary gland in what form?

  1. as skim milk
  2. as a fat globule
  3. as a micelle
  4. as a disaccharide

 

5. The serum phase of milk contains which of the following?

  1. milk fat and casein
  2. casein and lactose
  3. lactose and milk fat
  4. lactose and whey proteins

 

6. What is lactoperoxidase?

  1. an enzyme that hydrolyzes of hydrogen peroxide
  2. an immunoglobulin
  3. an enzyme that hydrolyzes iron
  4. a hormone
  5. a casein binding protein

 

7. Proteins include structural proteins which have roles in mammary tissue and cellular structure and in tissue and cellular function. An example of an structural protein involved in mammary cell cytoskeletal structure would be which of the following?

  1. serum albumin
  2. collagen
  3. plasmin
  4. casein
  5. actin

 

8. In most tissues, galactosyltransferase transfers galactose from the donor, which is UDP-galactose, onto the terminal N-acetylglucosamine acceptor on the oliogosaccharide complex of glycosylated proteins. In the presence of alpha-lactalbumin the reaction of galactosyltransferase is altered to which of the following?

  1. glucose as the acceptor molecule and UDP-glucose as the donor
  2. glucose as the acceptor molecule and UDP-galactose as the donor
  3. glucose as the donor molecule and UDP-galactose as the acceptor
  4. galactose as the acceptor molecule and UDP-glucose as the donor
  5. galactose the acceptor molecule and UDP-glucosamine as the donor

 

9. During the synthesis of palmitic acid (also known as n-hexadecanoic acid) in the mammary epithelial cell, which reaction involves NADPH2?

  1. elongation reaction
  2. activation pathway
  3. condensation reaction
  4. reduction reaction
  5. dehydration reaction

 

10. Which of the following substrates is essential for milk synthesis?

  1. sucrose
  2. lactose
  3. acetate
  4. fructose
  5. glucose

 

11. The major milk lipid component is triglyceride (also called triacylglyceride), which accounts for 98% of all milk lipid. Approximately what proportion of total milk lipid is cholesterol?

  1. 3%
  2. 0.03%
  3. 0.3%
  4. 0.9%
  5. 0.09%
  6. 9%

 

12. Amino acid utilization by mammary tissue is dependent upon intracellular metabolism of the amino acid. Which of the following occurs as part of the intracellular metabolism of an amino acid in the mammary tissue?

  1. incorporation into muscle fibers
  2. retention of the amino acid in the cell as a structural protein
  3. rate of mammary blood flow
  4. arterial blood concentrations of the amino acid

 

13. Comparing milk and blood plasma, how much protein does milk have?

  1. 3 times as much as blood
  2. 5 times as much as blood
  3. 10 times as much as blood
  4. one tenth times as much as blood
  5. one half as much as blood

 

14. The synthesis of lauric acid (C12:0, or n -dodecanoic acid) in the mammary epithelial cell requires which of the following?

  1. 7 acetyl CoA, 5 malonyl CoA, and 14 NADPH2
  2. one acetyl CoA, 5 malonyl CoA, and 10 NADPH2
  3. 14 acetyl CoA, 12 malonyl CoA, and 12 NADPH2
  4. 2 acetyl CoA, 10 malonyl CoA, and 12 NADPH2
  5. one acetyl CoA, 10 malonyl CoA, and 10 NADPH3
  6. no acetyl CoA, 7 malonyl CoA, and 14 NADPH2

 

15. Selenium is an important trace element in animal nutrition. Soils in the midwest are somewhat deficient in selenium, and so crops used for animal feeds are low in selenium. Supplementing selenium in the diet of dairy cattle will have what effect on selenium levels in the milk ?

  1. increase selenium concentration in milk
  2. decrease selenium concentration in milk
  3. have no effect on selenium concentration in milk

Milk Compostition & Synthesis Module