DNA 1.1- DNA

Question 1

What is DNA?

Answer 1

DNA stores and transmits genetic information and is a helical double-stranded molecule

Question 2

What are chromosomes made out of?

Answer 2

A very long strand of helical DNA

Question 3

What is Chromatin?

Answer 3

A long and thin, tangled strand of DNA (when the cell is not dividing)

Question 4

What is a Chromatid?

Answer 4

Condensed, strong, thicker strands of DNA (in cell division)

Question 5

Compare chromosomes in prokaryotes and eukaryotes.

Answer 5

Prokaryote DNA (including mitochondria and chloroplasts) is circular, unbound, found in the cytosol and has no introns. Eukaryotic DNA is linear, bound to histones (proteins), found in the nucleus, and has introns and exons.

Question 6

What are the four nucleotide bases and their pairings?

Answer 6

Adenine, Thymine, Cytosine, and Guanine (A+T & C+G)

Question 7

What is DNA made of?

Answer 7

DNA is made of nucleotides which have a nitrogenous base (A T C G), attached to a deoxyribose sugar. Said sugar is linked to a phosphate group, which then forms the sugar-phosphate backbone.

Question 8

What are weak hydrogen bonds and why are they weak?

Answer 8

Weak hydrogen bonds hold the two strands of DNA together between complementary bases; and are weak so they can easily be broken apart for transcription and replication.

Question 9

Describe and represent the process of semi-conservative replication of DNA.

Answer 9

1. DNA unwinds and DNA helicase breaks weak hydrogen bonds, splitting the DNA strands.
2. Free DNA nucleotides link into position and complementary base pair.
3. DNA polymerase links the nucleotides to form new strands and Ligase seals the sugar-phosphate backbone.
4. Two new DNA molecules are created which are replicas of the original. This is “semi-conservative” because each strand contains 1 old and 1 new strand.

Question 10

Which enzyme separates weak hydrogen bonds?

Answer 10

Helicase

Question 10

Which enzyme links nucleotides during DNA replication

Answer 10

Polymerase

Question 11

Which enzyme seals the nucleotides during DNA replication to form the sugar-phosphate backbone?

Answer 11

Ligase

Question 12

Explain the importance of complementary base pairing for DNA replication.

Answer 12

Complementary base pairing is important so that DNA can accurately replicate itself, and accurately be transcribed into RNA and then amino acids.