OCR Biology: Amylose, Amylopectin and Glycogen Structure

Why are polysaccharides less soluble in water than monosaccharides?

Polysaccharides are less soluble due to their size and because regions that could hydrogen-bond with water are hidden inside the molecule.

What happens if many glucose molecules dissolve in the cytoplasm?

The water potential would reduce, leading to excess water diffusing in and disrupting normal cell functions.

What is amylose?

Amylose is a long chain of α-glucose molecules with glycosidic bonds between carbons 1 and 4.

What structural feature does amylose form?

Amylose coils into a spiral shape, stabilized by hydrogen bonds.

Where are the hydroxyl groups located in the amylose structure?

The hydroxyl groups on carbon 2 are situated on the inside of the coil.

What is amylopectin?

Amylopectin is similar to amylose but has branches formed by glycosidic bonds between carbons 1 and 6.

How does glycogen differ from amylopectin?

Glycogen is like amylopectin but has more branches and is more compact, making it easier to remove monomer units.

What type of glycosidic bonds are found in amylopectin?

Amylopectin has glycosidic bonds between carbons 1 and 4, and branches formed by bonds between carbons 1 and 6.

What is the significance of glycogen being stored in the liver and muscle cells?

Glycogen serves as a readily available energy store for animals.

What is a limit dextrin?

A limit dextrin is a core unit of glycogen or amylopectin that is resistant to hydrolysis by enzymes.

What is the role of hydrogen bonds in amylose?

Hydrogen bonds hold the coiled structure of amylose together.

What is the advantage of a polysaccharide having a branched chain?

Branched chains allow for more compact storage and easier access to monomer units.

How does the size of glycogen chains compare to those of amylopectin?

The 1-4 bonded chains in glycogen tend to be smaller than those in amylopectin.

What is the primary function of glucose in respiration?

Glucose serves as an energy source when used in respiration.

Why is it important that hydroxyl groups on carbon 2 of glucose are found on the inside of the amylose spiral?

This arrangement makes the molecule less soluble and allows hydrogen bonds to maintain the coil's structure.

What is the general structure of polysaccharides?

Polysaccharides are long chains of monosaccharides linked by glycosidic bonds.

What types of organisms store glycogen?

Glycogen is stored in animals, specifically in the liver and muscle cells.

What is the primary component of mucus related to polysaccharides?

Limit dextrins, which are resistant to hydrolysis, are major components of mucus.

What is the importance of the hydrophobic external surface of amylose?

The hydrophobic surface helps to minimize solubility in water.

What is the relationship between glucose polymers and energy storage?

Any polymer of glucose provides an energy store for the organism.

What type of bonding is crucial for the structure of amylopectin?

Hydrogen bonds are crucial for maintaining the coiled structure of amylopectin.

How does the structure of amylopectin affect its function?

The branched structure allows for rapid mobilization of glucose when energy is needed.

What is the significance of the 1-6 glycosidic bonds in amylopectin?

They create branches that enhance the molecule's solubility and accessibility.

What is the role of amylopectin in plants?

Amylopectin serves as a form of starch for energy storage in plants.

How does the branching in glycogen compare to amylopectin?

Glycogen has more branches than amylopectin, making it more compact.