Biological Molecules

Question 1

Define monomers

Answer 1

Monomers are small units from which larger molecules, polymers are made from.

Question 2

Define polymers

Answer 2

Polymers are larger molecules made up from many smaller units joined called monomers.

Question 3

Define monosaccharide (Give examples)

Answer 3

The monomers from which larger carbohydrates are made.
Glucose, galactose and fructose

Question 4

Define disaccharides (Give examples)

Answer 4

Formed by condensation of two monosaccharides joined by glycosidic bonds
Maltose, Sucrose, Lactose

Question 5

Define polysaccharides (Give examples)

Answer 5

Macromolecules formed by many monosaccharides joined by glycosidic bonds in a condensation reaction to form chains
Starch, glycogen and cellulose

Question 6

Describe and explain the structure of glycogen and how it helps with its function?

Answer 6

1. Made from alpha glucose (1-4,1-6 glyco bonds)
2. Highly branched - allows for rapid hydrolysis to provide high levels of glucose
3. Compact structure - stored in large amounts without taking up too much space

Question 7

Describe and explain the structure of starch and how it helps with its function?

Answer 7

1. Made from alpha glucose (1-4 glyco bonds)
2. Amylose - unbranched in a coiled helical structure so compact so more storage
3. Amylopectin - branched means glyco bonds are much more available to break down by enzymes to release glucose

Question 8

Describe and explain how the structure of cellulose helps with its function

Answer 8

1. Made from beta glucose (1-4,1-6 glyco bonds)
2. Contains microfibrils held together by hydrogen bonds for strength

Question 9

Explain the differences between DNA and RNA

Answer 9

1. DNA has deoxyribose and mrna has ribose
2. DNA has thymine mrna has uracil
3. DNA is double stranded mRNA is single stranded
4. DNA has hydrogen bonds mRNA doesn’t
5. DNA is long mRNA is short

Question 10

What happens during transcription?

Answer 10

The base sequence of a gene is copied into the complementary base sequence of a molecule called mRNA. (Happens in the nucleus) mRNA molecules moves to the cytoplasm where translation occurs

Question 11

What happens during translation?

Answer 11

mRNA is used to determine the amino acid sequence of the polypeptide.
mRNA attaches to a ribosome.
There are free molecules of tRNA in the cytoplasm
These have a triplet of unpaired bases at one end (anticodon) and a region where a specific amino acid can attach at the other
The tRNA molecules bind with there specific amino acids and bring them to the mRNA molecule on the ribosome
The triplet of bases on each tRNA molecule (anticodon) pair with a complementary triplet (codon) on the mRNA molecule
The tRNA molecules fit onto the ribosome bringing the amino acid they are carrying
Peptide bonds are formed between the amino acids