Macromolecules and nutrients (wk2)

Question 1

Main classes of carbohydrates and lipids and how they’re structured
-Carbohydrates -> monosaccharides and oligosaccharides

Answer 1

-Carbohydrates:
* Contain at least 2 hydroxyl groups
* Great source of energy
* Offer cells external production e.g. cellulose
* Assist cells in recognising molecules when attached to proteins and lipids
* In the form of ribose/deoxyribose, part of every building block of nucleic acids and DNA which is fundamental in a lot of biological processes
-Monosaccharides - the simplest carbohydrates
-Oligosaccharides ->
* When 2-10 monosaccharides link covalently, they are referred to as oligosaccharides
* Linkages are called glycosidic.

Question 2

Main classes of carbohydrates and lipids and how they’re structured
-Carbohydrates -> Disaccharide and Polysaccharide

Answer 2

-Disaccharide -> When 2 sugar monomer are joined together by a glycosidic bond
-Polysaccharides ->
* Formed from >10 (greater than 10) monosaccharides
* Cellulose is a polymer (like a product) of glucose
* Found in plants and is the main solid constituent providing support
* A major constituent of dietary fibre

Question 3

Main classes of carbohydrates and lipids and how they’re structured
-Starch

Answer 3

-Starch ->
* Major form of carbohydrate and good source of energy
* Found in the seeds of plants (cereals, nuts, legumes)
* Mixture of amylose and amylopectin
* Structurally similar to Amylopectin, glycogen is the major source of stored carbohydrate in the body (in the liver and muscles)

Question 4

Draw the carbohydrate classification table

Question 5

Describe lipids and fatty acids

Answer 5

-Lipids (fatty acids and glycerol)-> Exists as large tissue (adipose). Also vital constituent of membranes, hormones and vitamins. Common feature is low solubility in water.
-Fatty acids -> Organic acids containing a relatively large number of carbon atoms (12-26). Consist of a long carbon chain with hydrogen atoms all around and a carboxyl at one end.

Question 6

Describe saturated and unsaturated fatty acids

Answer 6

• When all carbons are linked by single bonds (e.g. palmitate), it is called saturated, as there is no room for more hydrogen atoms
• Conversely, presence of double bonds means they can receive two H to become single – ‘unsaturated’ (examples ae oleate and elaidate)

Question 7

Describe triacylglycerols and triglycerides

Answer 7

• The most abundant lipid category, constituting 95% dietary fat
• Serve as energy depots
• Consist of a glycerol unit and three fatty acids connected via Ester links

Question 8

Describe what steroids and phospholipids are

Answer 8

-Steroids and phospholipids – key components of cell membranes
+Hydrophobic tails face inwards as they do not want to interact with water

Question 9

Contribution of vitamins and minerals to biological function
-Vitamins and minerals

Answer 9

-Vitamins and minerals:
* Complement carbohydrates, fats and protein in nutrition
* No energy value
* Vital regulators of numerous bodily functions
* Involved in energy provision during exercise
* Vitamins classified as water or fat soluble

Question 10

Contribution of vitamins and minerals to biological function
-Types of vitamins and minerals

Answer 10

-Types of vitamins and minerals:
* B1 (Thiamine) – Found in active site of pyruvate dehydrogenase
* B2 (Riboflavin) – Precursor of coenzymes for redox reactions
* B6 6 – Coenzymes for aminotransferases and neurotransmitters
* B12 – Serves as enzyme in fatty acid processing
* Vitamin A – Contained within retinas of the eye
* Vitamin D – Involved in calcium absorption (bone health)
* Pantothenate – Contributes to Coenzyme A, a key molecule in metabolism
* Folate – Involved in the synthesis of DNA
* Niacin – Precursor of NAD and NADP (good mediators for metabolism)

Question 11

Contribution of vitamins and minerals to biological function
-Minerals

Answer 11

• Sodium -> Main cation in extracellular fluids. Essential for electrical transmission in nerves and muscle. Maintains water content in various compartments of the body. Hyponatea can arise when an athlete sweats so much that they lower their sodium levels in their body by a dangerous amount and can affect their cognitive function.
• Potassium (K+) -> Interacts with Na+ to maintain fluid balance and electrical impulses
• Calcium (Ca2+) -> Critical component of bones and blood clotting
• Magnesium (Mg2+) -> Cofactor for hundreds of enzymes
• Iron (Fe2+) -> Embedded in proteins handling oxygen and the electron transport chain
• Copper -> Cofactor for cytochrome c, a component of the electron transport chain I oxidative metabolism
• Zinc (ZN2+) -> Sits in the active sites of around 200 enzymes, including carbonic anhydrase that helps rid CO2
• Manganese -> Cofactor for over 100 enzymes involved in metabolism

Question 12

Contribution of vitamins and minerals to biological function
-Non-metal minerals

Answer 12

• Chlorine –> Chloride (CL-) is the main anion in extracellular fluids, where it interacts with Na in the maintenance of fluid balance and electrical charges across cell membranes. It is also used in the production of digestive hydrochloric acid
• Phosphorus -> Phosphoryl groups are covalently attached to a vast array of biological compounds (nucleic acids, high energy phosphates)