Lecture 2 Flashcards
What are the 4 main elements of biological importance?
Carbohydrates, lipids, nucleic acids, and proteins
Why are the biological elements important?
Makes up the structure of cells/tissues,
transmits info, regulates and participates metabolic reactions, and provides energy for life
What do carbohydrates include?
Sugars, starches and glycogen, cellulose, and chitin
What is the main function of a starch?
Energy source found in plants
What is the main function of sugars (glycogen)?
Energy source for animals
What are amyloplasts and what is stored in them?
Where plants store their starch (a-amylose and amylopectin)
What is the structure of a-amylose?
It is a single long unbranched chain of glucose, linked by a(1-4) bonds
What are micelles?
Balls of water, formed by a-amylose
How does the starch, a-amylose, get broken down in animals?
It first gets broken down (hydrolysed) by the a-amylase enzyme. The products from this are glucose and single maltose units. The enzyme, B-amylase, then breaks down the single maltose units to glucose.
How does the starch, amylopectin, get broken down in animals?
It first gets broken down (hydrolysed) by the a-amylase enzyme. The products from this are glucose, single maltose units, and dextrin. The enzyme, B-amylase, then breaks down the single maltose units to glucose, and the enzyme glucosidase breaks down dextrin into limit dextrin
What is the structure of amylopectin?
Highly-branched polymer
Monosaccharide?
Single sugar unit (glucose)
Two sugar units?
Disaccharide (sucrose)
Polysaccharide?
Many sugar units (glycogen and starch) joined by glycosidic linkages
What is the most abundant monosaccharide?
Glucose
Glycosidic bonding?
Joins/links sugars together through hydrolysis
What two monosaccharides make up sucrose?
glucose-a(1-2)-fructose
What two monosaccharides make up lactose?
galactose-B(1-4)-glucose
What two monosaccharides make up maltose?
glucose-a(1-4)-glucose
- A homodimer of glucose units
- Occurs as a byproduct of starch hydrolysis
What does the alpha and beta mean?
If the OH group is pointing down (alpha), and if the OH group is pointing up (beta)
What enzymes hydrolysis sucrose, maltose, and lactose?
Sucrose=invertase
Maltose=maltase
Lactose=lactase
All breakdown through hydrolysis (breaking bonds using water)
Where is amylase, which is used to break down starch, found in humans?
In our saliva and pancreatic juices
What is the function of cellulose and chitin?
Cellulose (plant) and chitin (animal) are both structural components
Homopolysaccharides?
One type of monosaccharide linked together
Heteropolysaccharides?
Different types of monosaccharide linked together
How do polysaccharides get broken down into monosaccharides? What one is more effective?
Either through enzymatic or acid hydrolysis. Enzymatic is more effective
What are glycoproteins? What is the process of making a glycoprotein called?
When a sugar (oligosaccharide) links to a protein through glycosidic linkage. This process is called glycosylation
What is the purpose of glycoproteins?
To provide protection or adhere to produce mucus (waste removal)
Phosphorylation?
This makes sugars anionic and allows some of them to participate in glycosidic bonding as reactive intermediates
What are glycolipids?
Carbohydrate combined with lipids to form glycolipids - compounds on the surfaces of animal cells that allow cells to recognise and interact with one another
How are cellulose and starch different?
Cellulose contains beta glucose monomers joined by beta 1-4 linkages where as glucose subunits are joined by alpha 1-4 glycosidic linkages
What is glucose?
- Most abundant monosaccharide
- A hexose sugar (C6H12O6)
- Energy source in most organisms
- Used as a component in the synthesis of other compounds like fatty acids and amino acids
What are two storage polysaccharides and where can you find them?
Plants - starch
Animals - glycogen
Deposited as granules in the cytoplasm
What is a starch?
- homopolymer of alpha-glucose units joined by glycosidic bonds
- storage polysaccharide
- in plants
- a-amylose and amylopectin
Can animals break down cellulose?
No, bc we don’t have the enzymes needed to break the bonds. Cellulose only provides roughage in the diet
Where is chitin found?
The cell wall of fungi, the external skeleton of insects (arthropods) and as various structural components in animals
Where is glycogen stored?
Liver and muscle cells
What digests glycogen?
alpha-glucosidase enzyme
