3.3 - Carbohydrates

What is a disaccharide?

2 monosaccharides linked together

How many carbons in glucose?

6

What is the name of the bond formed in the maltose molecule, after the condensation of 2 glucose molecules?

A 1,4 glycosidic bond

When 2 glucose molecules react in a condensation reaction, they form a maltose molecule and water molecule. Describe the bond formed in the maltose molecule.

A covalent bond called a glycosidic bond, between carbons 1 and 4

When 2 monosaccharides link together, the result is called a what?

A dissacharide

What is a polymer?

A large complex molecule, composed of a long chain of many monomers joined together

What products are formed by the condensation of two alpha glucose molecules?

A maltose molecule, and a water molecule

What is a single sugar unit called?

A monosaccharide

What is formed when many (more than 2) monosaccharides link together?

A polymer called a polysaccharide

What is a condensation reaction?

A reaction where two molecules combine to form a larger molecule, together with the loss of a small molecule. Possible small molecules lost are water, hydrogen chloride or methanol, but most commonly in a biological reaction it is water.

Monomer or polymer? Amino acids

Amino acids are monomers

Name 2 disaccharides

Any 2 of: lactose, sucrose, maltose

What is the formula for glucose?

C6H12O6

Sugars are also known as what?

Carbohydrates or saccharides

Saccharides are known as what?

Carbohydrates or sugars

If you had a bag of sugar. What would this sugar be called, and what would this sugar be classed as?

Common sugar is sucrose, which is a disaccharide

Why does glucose dissolve in the cytosol of the cell?

Cytosol contains water. Glucose molecules have polar OH groups, which forms hydrogen bonds with the water molecules, making glucose molecules soluble in water, and therefore soluble in cytosol.

True or false? A maltose molecule has a glycosidic bond between carbons 1 and 3.

False

True or false? A maltose molecule has a glycosidic bond between carbons 1 and 6.

False

True or false? A maltose molecule has a glycosidic bond between carbons 2 and 4.

False

True or false? A maltose molecule has a glycosidic bond between carbons 3 and 4.

False

True or false? A maltose molecule has a glycosidic bond between carbons 4 and 5.

False

True or false? A maltose molecule has a glycosidic bond between carbons 5 and 6.

False

True or false? Glucose is a butose monosaccharide

False

True or false? Glucose is a heptose monosaccharide

False

True or false? Glucose is a monosaccharide composed of 3 carbons?

False

True or false? Glucose is a monosaccharide composed of 4 carbons?

False

True or false? Glucose is a monosaccharide composed of 5 carbons?

False

True or false? Glucose is a pentose monosaccharide

False

True or false? Glucose is an octose monosaccharide

False

True or false? The reaction between two alpha glucose molecules to form a maltose and water molecule is a hydrolysis reaction

False

True or false? Two glucose molecules react in a condensation reaction to form a polysaccharide

False

True or false? When two alpha glucose molecules react, one of the products formed is a glycogen molecule

False

True or false? When two alpha glucose molecules react, one of the products formed is a hydrogen chloride molecule

False

True or false? When two alpha glucose molecules react, one of the products formed is a lactose molecule

False

True or false? When two alpha glucose molecules react, one of the products formed is a methanol molecule

False

True or false? When two alpha glucose molecules react, one of the products formed is a sucrose molecule

False

True or false? The bond formed between two glucose molecules to form a maltose molecule is Ionic

False, glycosidic bonds are a type of covalent bond

What is sweeter: Fructose or galactose?

Fructose

What is sweeter: Fructose or glucose?

Fructose

Name the main sugar found in fruit. What would this sugar be classed as?

Fructose is the main sugar found in fruit, and is a hexose monosaccharide

Fructose naturally occurs in fruit, often in combination with what?

Fructose naturally occurs in fruit, often in combination with glucose

Where does fructose naturally occur?

Fruit

What is C6H12O6?

Glucose

What is sweeter: Glucose or galactose?

Glucose

Where does lactose naturally occur?

In milk and milk products

Glucose is a hexose monosaccharide. What does this mean?

It is composed of 6 carbons

Name the main sugar found in milk and milk products. What would this sugar be classed as?

Lactose is the main sugar found in milk and milk products, and is a disaccharide

What is a polysaccharide?

Many monosaccharides linked together

Monomer or polymer? Monosaccharides (such as glucose and fructose)

Monosaccharides are monomers

Monomers join together to form what?

Polymers

There are two pentose sugars that are important components of biological molecules. What are these two sugars, and in what biological molecules are they present?

Ribose- the sugar present in RNA nucleotides Deoxyribose- the sugar present in DNA nucloetides

Carbohydrates are also known as what?

Saccharides or sugars

Sucrose is commonly known as what?

Sugar

What are pentose monosaccharides?

Sugars that contain 5 carbon atoms

Imagine you are looking at the molecular structure diagrams for alpha glucose and beta glucose. What is the difference between the alpha glucose diagram and the beta glucose diagram?

The OH (hydroxyl) group on carbon 1 is on opposite positions. On an alpha glucose diagram the OH group is below the carbon 1, and on the beta glucose diagram the OH group is above the carbon 1

How many structural variations are there of the glucose molecule? What are they?

There are two structural variations of the glucose molecule, alpha glucose and beta glucose

Describe how the carbons are numbered in a molecular structure diagram of glucose

They are numbered clockwise, beginning with the carbon to the right (clockwise) of the oxygen atom that is within the ring

True or false? A maltose molecule has a glycosidic bond between carbons 1 and 4.

True

True or false? Glucose is a hexose monosaccharide

True

True or false? Glucose is a monosaccharide composed of 6 carbons?

True

True or false? Glucose molecules are polar

True

True or false? Glucose molecules are soluble in water

True

True or false? The bond formed between two glucose molecules to form a maltose molecule is called a glycosidic bond

True

True or false? The bond formed between two glucose molecules to form a maltose molecule is covalent

True

True or false? The reaction between two alpha glucose molecules to form a maltose and water molecule is a condensation reaction

True

True or false? Two glucose molecules react in a condensation reaction to form a disaccharide

True

True or false? When two alpha glucose molecules react, one of the products formed is a maltose molecule

True

True or false? When two alpha glucose molecules react, one of the products formed is a water molecule

True

True or false? alpha glucose molecules are polar

True

True or false? beta glucose molecules are polar

True

True or false? beta glucose molecules are soluble in water

True

Explain how a condensation reaction occurs between two alpha glucose molecules

When two alpha glucose molecules are side by side, the two polar hydroxyl groups react. When this happens the bonds are broken and reformed in different places, producing new molecules. 2 key things happen. 1) Two hydrogen atoms and an oxygen atom are removed from the alpha glucose monomers and join together to form a water molecule. 2) A glycosidic bond forms between carbons 1 and 4 on the glucose molecules and the molecules are now joined.

What sugars form Sucrose?

a glucose and b fructose

What sugars form lactose?

b galactose and b glucose

What elements do carbohydrates contain?

carbon, hydrogen and oxygen only

Which carbons of the glucose molecules bond to one another, in order to form a maltose molecule?

carbons 1 and 4

Which sugar is present in DNA nucleotides?

deoxyribose

monosaccharide, disaccharide or polysaccharide? lactose.

disaccharide

monosaccharide, disaccharide or polysaccharide? sucrose.

disaccharide

Name 3 hexose monosaccharides

fructose, galactose and glucose

Give 3 examples of monosaccharides

glucose, fructose, ribose

Name 3 monosaccharides

glucose, fructose, ribose

Name 3 polysaccharides

glycogen, cellulose, starch

What does carbohydrate literally mean?

hydrated carbon (carbon and water)

b glucose and b galactose form what sugar?

lactose

Give 2 examples of disaccharides

lactose, sucrose

a glucose and a glucose form what sugar?

maltose

monosaccharide, disaccharide or polysaccharide? fructose.

monosaccharide

monosaccharide, disaccharide or polysaccharide? galactose

monosaccharide

monosaccharide, disaccharide or polysaccharide? glucose.

monosaccharide

monosaccharide, disaccharide or polysaccharide? ribose.

monosaccharide

monosaccharide, disaccharide or polysaccharide? cellulose.

polysaccharide

monosaccharide, disaccharide or polysaccharide? glycogen.

polysaccharide

monosaccharide, disaccharide or polysaccharide? starch.

polysaccharide

Which sugar is present in RNA nucleotides?

ribose

Name 2 pentose sugars

ribose and deoxyribose

a glucose and b fructose form what sugar?

sucrose

Fructose naturally occurs in fruit, often in combination with glucose, forming what?

the disaccharide sucrose