Biological Macromolecules

Question 1

What is a ‘macromolecule.’

Answer 1

A large molecule - long polymers made up of smaller repeating units called monomers.

Question 2

What are the four classes of macromolecules?

Answer 2

Carbohydrates, lipids, proteins and nucleic acids.

Question 3

Give 2 examples of carbohydrates.

Answer 3

Glycogen and starch.

Question 4

What are carbohydrates composed of?

Answer 4

Carbon, hydrogen and oxygen atoms.

Question 5

Why is it better to consume complex carbohydrates as opposed to simple carbohydrates?

Answer 5

Because simple carbohydrates tend to cause quick rises in our blood sugar that are bad for our health, while complex carbohydrates provide a more slow, sustained source of energy.

Question 6

What are monosaccharides and give 3 examples?

Answer 6

The most basic units of carbohydrates. They are important in the storage of energy and are the building blocks of more complicated carbohydrates. Examples include glucose, fructose and galactose.

Question 7

What are disaccharaides?

Answer 7

As the name suggests, disaccharides are made up of two monosaccharide units joined together. For example, a reaction between a glucose and fructose monomer produces the disaccharide sucrose (sugar).

Question 8

List two more examples of disaccharides.

Answer 8

Lactose, maltose.

Question 9

What are polysaccharides?

Answer 9

Complex carbohydrates composed of thousands of repeating monosaccharide units, most commonly glucose. They can also be used for short-term energy storage in two forms: starch and glycogen.

Question 10

Why might glycogen be used by the mitochondria of some animal cells?

Answer 10

To use for ceullar respiration to generate ATP (chemical energy).

Question 11

What are lipids used for?

Answer 11

Long-term energy storage.

Question 12

What is the role of glycogen in the body?

Answer 12

Glycogen breaks down to release glucose into the bloodstreeam to be used as fuel for cells when the body needs a quick boost of energy, or is not receiving glucose from food.

Question 13

Which 2 macromolecules contain carbon, oxygen and hydrogen?

Answer 13

Carbohydrates and lipids.

Question 14

What is the difference between the roles of DNA and RNA in protein synthesis?

Answer 14

DNA stores the genetic information, where as RNA uses the information to help the cell produce the protein.

Question 15

What are some roles of lipids?

Answer 15

• Molecules that provide long-term energy storage.
• Form parts of cell membrane.
• Form a major component in some hormones.

Question 16

What are the building blocks of protein?

Answer 16

Amino acids.

Question 17

Give some properties of nucleic acids.

Answer 17

• They are made up of carbon, hydrogen, oxygen, nitrogen and phosphorous.
• They are long polymers of nucleotides.

Question 18

Which macromolecule is involved in catalysing chemical reactions that occur in the body?

Answer 18

Proteins.

Question 19

Describe the composition of proteins.

Answer 19

Amino acids join together to form a long polypeptide chain - the primary structure of a protein. This chain folds and forms repeating strucutres, such as helices and sheets, constituting the seconday structure of the protein. The polypeptide chain can keep folding to form a large 3D structure, the **tertiary structure ** of a protein. Two or more polypeptide chains can fold together to form the functional protein. This is the quaternary structure.

Question 20

Give examples of proteins.

Answer 20

1. Immunoglobins (or antibodies) - for immunological defence.
2. Enzymes - speed up and faccilitate reactions in the body.
3. Haemoglobin - transports oxygen around to our tissues.
4. Keratin - contributes to the structure of hair and nails.
5. Hormones - for growth.

1) Structural (e.g keratin). 2) Catalysing chemical reactions (e.g enzymes). 3) Transporting things (e.g haemoglobin).

Question 21

Compare the way DNA is stored in prokaryotes and eukaryotes.

Answer 21

Prokaryotes store DNA in loops, and eukaryotes store DNA in strands.

Question 22

List the 3 main differences between DNA and RNA.

Answer 22

1. DNA is double stranded, while RNA is singled stranded.
2. RNA has uracil as a base while DNA has thymine.
3. DNA’s backbone is composed of deoxyribose, while RNA’s backbone is composed of ribose.

Question 23

Describe how DNA is used for making proteins.

Answer 23

1. Genes are copied onto mRNA (messenger RNA) to be transported into a ribosome.
2. Ribosomes interpret the nucleotide sequence of the mRNA and translate it into polypeptide chains.

Question 24

What are proteins composed of?

Answer 24

Carbon, hydrogen, nitrogen and oxygen.

Question 25

What are nucleic acids composed of?

Answer 25

Carbon, hydrogen, nitrogen, oxygen and phosphorous.