Lesson 5: DNA Structure

Question 1

What is DNA made from?

Answer 1

• Repeating nucleotide units.
• Four different types of nucelotides make up DNA.
• Each nucleotide consists of a common sugar and phosphate group with one of 4 different bases attached to the sugar: A,C,T,G.

Question 2

What is a nucleotide?

Answer 2

• A molecule that makes up DNA.
• Contains: a phosphate group attached to a sugar molecule. The sugar molecule is attached to the base.

Question 3

How do the bases on each DNA strand complement each other to form the double helix structure?

Answer 3

A - T
C- G

Question 4

What is the code for a particular amino acid?

Answer 4

• A sequence of three bases is the code for a particular amino acid.

Question 5

What controls the order in which amino acids are assembled/ therefore the protein that is formed?

Answer 5

• The order of bases controls the order in which amino acids are assembled to produce a particular protein.
• The order of amino acids affects the shape of the protein formed.

Question 6

What does the shape of a protein affect?

Answer 6

• The shape of a protein affects the protein’s function.

Question 7

What are 3 uses of proteins in the body?

Answer 7

1.) Enzymes.
2.) Hormones
3.) Forming structures in the body (ie. collagen.)

Question 8

What is the 1st stage of protein synthesis?

Answer 8

• Gene is copied onto a template molecule.
• This template is called mRNA.
• mRNA is a single- stranded molecule.
• mRNA passes out of nucleus –> into cytoplasm.

Question 9

What is the 2nd stage of protein synthesis?

Answer 9

• mRNA molecule is attached to ribosome.
• Amino acids are bought to the ribosome on carrier molecules (known as tRNA.)
• Ribosome reads the triplets of bases on mRNA to join together the correct amino acids in the correct order.

Question 10

What is the 3rd stage of protein synthesis?

Answer 10

• When the protein chain is complete, it folds up to form a unique shape.
• This unique shape allows the protein to do its specific job.