what are carbohydrates main function, their monomers, the bond that holds the monomers together, their elements and an example
Primary source of energy.
Monomers: monosaccharides
Bond: Glycosidic bond
Elements: C,H,O
Ex: Starch
What are the four key biomolecules, and their percentage in a cell?
Water - 70%
Proteins – 18%
Carbohydrates – 4%
Lipids – 3%
Nucleic acids – 1.35%
what are lipids main function, their monomers, the bond that holds the monomers together, their elements and an example
Secondary source of energy, insulation
Monomers: Fatty acids and glycerol
Bond: Ester bond
Elements: C,H,O
Ex: Fats
what are protein main function, their monomers, the bond that holds the monomers together, their elements and an example
Protein:
Structural and functional units of the human body
Monomers: Amino acids
Bond: Peptide bond
Elements: CHONS
Ex: Collagen
what are nucleic acids main function, their monomers, the bond that holds the monomers together, their elements and an example
Nucleic acids:
Stores genetic information
Monomers: Nucleotides
Bond: Phosphodiester bonds
Elements:CHONP
Ex: DNA and RNA
Why is Protein hydrolysis important in protein metabolism?
Or protein denaturation
pH: influences protonation of charged side groups, hydrolysis of peptide bonds
Temperature: disrupts H-bonding through increased molecular vibration (become ‘sticky’ and aggregate)
list the digestive enzymes that break down biomolecules
Carbohydrates: amylase, sucrase,
maltase, lactase
Lipids: lipase
Protein: pepsin, protease-trypsin, peptidase.
What are the differences between monosaccharides, disaccharides and polysaccharides, and provide examples
Monosaccharides: The simplest form of carbohydrates (single sugar units). Examples include glucose, fructose, and galactose.
Disaccharides: Two monosaccharides through a glycosidic bond. Examples include maltose, sucrose, and lactose.
Polysaccharides: Long chains of monosaccharides linked together. Examples include starch, glycogen, and cellulose.
Describe the digestion and absorption of carbohydrates in the digestive tract, beginning in the mouth. Include of types of enzymes involved at each organ, and the end molecules produced. meow
- Mouth – chemical digestion from salivary amylase
- Stomach – Hydrochloric acid inhibits amylase, halting biochemical digestion.
- Pancreas: Secretes pancreatic amylase into the small intestine.
- Small intestine – the primary site of carbohydrate digestion. Pancreatic amylase continues breaking down starch into disaccharides. Brush border enzymes in the small intestine (e.g., lactase) further break down disaccharides into monosaccharides.
- Liver: Processes absorbed monosaccharides and helps regulate blood glucose levels.
- End molecules = disaccharides and monosaccharides
Describe the process of monosaccharide absorption of glucose, galactose, fructose, and how they enter the capillary.
- Absorption: Monosaccharides are absorbed by the enterocytes in the small intestine.
Glucose and galactose are absorbed via sodium-glucose cotransporter (SGLT) using active transport.
Fructose is absorbed through facilitated diffusion via GLUT-5. - The monosaccharides then exit the enterocytes and enter the capillaries via GLUT-2 by simple passive diffusion.
How does carbohydrate metabolism differ from carbohydrate digestion?
- Metabolism = set of metabolic pathways which break down molecules into smaller units and release energy
- Digestion = process by which the body breaks down food so it can be absorbed by the blood stream
what are the accessory organs
- salivary glands
- Pancreas
- Liver
- Gall bladder
Identify the 5 classes of lipids and describe their biochemical functions
- Free Fatty Acids: Used primarily as fuel and components of membrane lipids.
- Triacylglycerols: The storage form of fatty acids.
- Phospholipids: Key components of cell membranes, consisting of a polar head and nonpolar tails.
- Glycolipids: lipids that are bound to carbohydrates.
- Steroids: secreted by the endocrine system and function as hormones (e.g., estrogen, testosterone), and cholesterol.
Function of emulsification
- Mechanical processing in stomach creates large drops of lipids.
- Bile salts break droplets apart in a process called emulsification.
- Emulsifiers break large fat globules into smaller droplets.
- Emulsification makes lipids more accessible to digestive enzymes.
The meaning of micelles and chylomicrons.
- Micelles: Structures formed by bile salts surrounding the products of fat digestion (fatty acids and monoglycerides). Micelles help transport these products to the intestinal cells for absorption.
- Chylomicrons: one type of lipoprotein— Transports dietary lipids from intestinal cells to elsewhere in the body
What molecules do the 3 steps of the energy cycle of the cell each produce?
- Glycolysis: net gain of 2 ATP molecules, 2 pyvurate, 2 NADH molecules per glucose molecule
- Krebs Cycle (Citric Acid Cycle): Each cycle generates 1 ATP, 3 NADH, 1 FADH2, and 2 CO2 per Acetyl-CoA molecule.
- Electron Transport Chain (ETC): approximately 34 ATP molecules per glucose molecule.
The fate of pyruvate molecules in relation to Energy cycle
- With Oxygen (Aerobic Respiration): Pyruvate moves into the mitochondria, where it’s oxidised into Acetyl-CoA. Acetyl-CoA then goes into the Krebs Cycle, which helps produce more ATP as it goes through the ETC.
- Without Oxygen (Anaerobic Respiration): Pyruvate is turned into other substances through fermentation (eg lactic acid in muscles or alcohol in yeast) to keep producing NAD+ to keep making ATP without needing oxygen
Compare and contrast anaerobic respiration and aerobic respiration
- Aerobic Respiration:
o The process of producing cellular energy in the presence of oxygen
o Produces up to 36 ATP per glucose molecule. - Anaerobic Respiration:
o The process of producing cellular energy in the absence of oxygen
o Produces only 2 ATP per glucose molecule, as it relies solely on glycolysis.
Enzymatic digestion of lipids occurs in which of the organs of the digestive system?
mouth, stomach, small intestine
Which of the following metabolic processes does NOT require oxygen for the catabolism of glucose into cellular energy (ATP)
a. Glycolysis
b. The Citric Acid cycle
c. The Electron Transport Chain
d. All metabolic processes require oxygen to produce ATP
glycolysis
