5.1 DNA Structure and Organization (CQ - exam)

Question 1

What is the shape of DNA referred to as?

Answer 1

Double helix, a twisting ladder

Question 2

DNA stands for…

Answer 2

deoxyribonucleic acid

Question 3

DNA uses which nitrogenous bases

Answer 3

adenine, guanine, cytosine, thymine

Question 4

Sugar in DNa

Answer 4

• deoxyribose
• 5 carbon
• connected to appear like a ring

Question 5

what type of bonds hold the 2 DNA strands together

Answer 5

hydrogen bonds

Question 6

What types of bonds hold the nucleotides together?

Answer 6

• Hydrogen bonds are formed between nitrogenous bases in both DNA and RNA
• Covalent bonds are formed in nucleotides between the carbon atoms

Question 7

how is the binding of A to T different from binding of C to G?

Answer 7

• 3 hydrogen bonds formed between C and G
• only 2 between A and T

Question 8

purines vs pyrimidines

Answer 8

pyrimidines
- single rings
- thymine and cytosine

purines
- 2 rings
- adenine and guanine

Question 9

chargaff’s rule

Answer 9

guanine is of equal amount to its cytosine and its adenine is equal to the amount of thymine

Question 10

antiparallel strands

Answer 10

Antiparallel strands means each strand has a 5’ end and a 3’ end from the numbering of the carbons in the deoxyribose sugar

Question 11

complementary base pairing

Answer 11

the linking between specific nitrogenous bases in strands of genetic material.

Question 12

Why is one end of DNA called the 5’ end and the other the 3’ end? What do these numbers refer to?

Answer 12

One end of DNA is called 5’ because it refers to how the phosphate group is attached on the 5 carbon. The other end is called 3’ because the OH- group is attached on the 3 carbon. The numbers are the carbon the group is attached to in the deoxyribose sugar.

Question 13

gene vs genome

Answer 13

Gene
- Segment of a portion of DNA
- Codes for proteins
- Consists of few base pairs
- Study of properties of genes is called genetics
- Individual has thousand of millions

Genome
- Total of DNA content in cell
- Cannot code for proteins
- Consists of all base pairs in cell
- Study of properties of genome is called genomics
- Individual has one

Question 14

DNA in prokaryote vs eukaryotes

Answer 14

prokaryotes
- circular
- packed in nucleoid
- no nuclear membrane
- little junk DNA
- found in cytoplasm
- replication happens in cytoplasm

eukaryotes
- linear
-more compact
- found in nucleus and organelles
-lots of junk DNA
- replication happens in mitochondria

both
- double stranded

Question 15

Would a mutation in a protein-coding region of DNA be more detrimental than a mutation in a non-coding region?

Answer 15

• Coding region is where DNA codes for proteins/traits
• Non-coding region is all the junk DNA between the coding regions
• Mutation is where DNA code has been altered
• A mutation in the coding region would be more detrimental because it might prevent an essential protein from being made
• Non-coding regions do not code for proteins so a mutation might not affect the cell at all