DNA & RNA

Question 1

What are the two kinds of nucleic acid?

Answer 1

Deoxyribonucleic acid (DNA)

Ribonucleic acid (RNA)

Question 2

What are the subunits of DNA?

Answer 2

• sugar (pentose)
• phosphate group
• nitrogenous bases

Question 3

Describe genes

Answer 3

Composed of nucleic acids

Hundreds-thousands of nucleotides long

Question 4

Describe nucleic acids

Answer 4

Macromolecules that exist as polymers (called polynucleotides)

They are made up of the monomers called nucleotides that store, transmit and express hereditary information

Question 5

Describe nucleotides

Answer 5

Monomers that when linked make up nucleic acids.

They are composed of

• nitrogenous bases
• pentose (5-C sugar)
• 1 or more phosphate groups

Question 6

Describe DNA

Answer 6

the genetic material that organisms inherit from their parents

It directs RNA synthesis and through RNA it controls protein synthesis

Question 7

Describe chromosomes

Answer 7

They contain one long DNA molecule that carries hundreds of genes

Question 8

T or F: DNA implements genetic programming by itself

Answer 8

FALSE. Proteins are required for this

Question 9

Where is DNA located in eukaryotic cells?

Answer 9

In the nucleus

Question 10

Describe nitrogenous bases

Answer 10

A nitrogen-containing molecule that is also basic because the nitrogen atoms tend to absorb H+

Question 11

What are the nitrogenous bases?

Answer 11

DNA:

• Adenine
• Thymine
• Cytosine
• Guanine

RNA:

• Adenine
• Uracil
• Cytosine
• Guanine

Question 12

What are the two families of nitrogenous bases? Which base is in which family?

Answer 12

1. Purine:
   - Adenine
   - Guanine
2. Pyrimidine:
   - Cytosine
   - Thymine (in DNA)
   - Uracil (in RNA)

Question 13

Describe the structures of purines and pyrimidines

Answer 13

Purine: 2 rings

Pyrimidines: 1 ring

Question 14

What kind of sugar is found in nucleotides?

Answer 14

A 5-carbon sugar (PENTOSE)

• deoxyribose in DNA
• ribose in RNA

Question 15

How are sugar carbons numbered vs nitrogenous base carbons?

Answer 15

Carbons in the sugars are numbered as primes - ex. 1’

Question 16

Where are the phosphate groups attached on the nucleotide?

Answer 16

one or more phosphate group is attached to the C5’ of the sugar

in a polynucleotide, each monomer only has one phosphate group

Question 17

Describe a nucleoside

Answer 17

The portion of a nucleotide that is lacking a phosphate group

composed of just the pentose sugar and the nitrogenous bases

Question 18

If nucleotides are monomers, what are the polymers?

Answer 18

polynucleotides AKA nucleic acids

Question 19

What are the covalent bonds called that connect nucleotides?

Answer 19

Phosphodiester linkages

A phosphate group links the sugars of two nucleotides

Question 20

What is the result of a phosphodiester linkage?

Answer 20

the sugar-phosphate backbone (the non-variable part of the DNA) with

a 5’ end: phosphate attached to the 5’C
a 3’ end: -OH attached on the 3’ C

Question 21

Which direction does the sugar-phosphate backbone run?

Answer 21

5’ - 3’

Question 22

Describe the structure of a DNA molecule

Answer 22

Contains two polynucleotides (nucleic acids) that wind around in a double helix. In the helix, the nitrogenous bases are paired.

The helix is surrounded by two sugar-phosphate backbones that run in opposite 5’-3’ directions (antiparallel)

Question 23

T or F: each of the two strands are complimentary to the other and can therefore be used as a template to generate the other

Answer 23

TRUE

Question 24

Describe the structure of RNA molecules

Answer 24

Exist as single strands with complimentary base pairings occurring between regions of two RNA molecules

Question 25

Describe why replication is semi-conservative

Answer 25

In the new double helix/DNA molecule, one strand is new and one is conserved from the parental molecule

Question 26

What is the function of the enzyme helicase in DNA replication

Answer 26

It attaches to the DNA at the origins and separates the two strands to open the replication bubble

Question 27

Which direction does DNA replication occur in?

Answer 27

Both directions until the entire molecule is copied

Question 28

What is the function of DNA polymerase?

Answer 28

It catalyzes the synthesis of nucleic acids for chromosomes by adding nucleotides to a template chain and makes a daughter strand

Question 29

What are the names for the two strands of DNA produced?

Answer 29

1. Leading strand | 2. Lagging strand

Question 30

How is the leading strand produced?

Answer 30

Continuously because the enzyme is running 5'-3' TOWARDS the replication fork

Question 31

T or F: the leading strand's enzyme is running towards the replication fork

Answer 31

True

Question 32

How is the lagging strand produced?

Answer 32

In series of segments because the enzyme is running 5'-3' AWAY from the replication fork The enzyme synthesizes segments and links them after

Question 33

Define the replication fork

Answer 33

Where the two strands of DNA separate at the end of each replication bubble

Question 34

What are the segments of lagging strands called?

Answer 34

Okazaki fragments

Question 35

T or F: the enzyme Polymerase can only add nucleotides in one direction

Answer 35

TRUE

Question 36

Define RNA and its structure

Answer 36

A nucleic acid polymer composed of nucleotides, sugars, and nitrogenous bases. It is usually single-stranded but can fold into 3D shape by hydrogen bonding and base pairing

Question 37

What is the sugar in RNA?

Answer 37

Ribose

Question 38

What are the nitrogenous bases in RNA?

Answer 38

Uracil and Adenine | Guanine and Cytosine

Question 39

Define transcription

Answer 39

The process in which RNA molecules are made from DNA

Question 40

What are the 4 types of RNA?

Answer 40

All made by transcription: 1. mRNA: Messenger RNA 2. rRNA: Ribosomal RNA 3. tRNA: transfer RNA 4. hnRNA: heterogenous nuclear RNA (not important for this course)

Question 41

What is the function of mRNA?

Answer 41

Messenger RNA contain information from a gene to command amino acids to them

Question 42

What is the function of rRNA?

Answer 42

Ribosomal RNA is a major structural and functional component of ribosomes which work in protein synthesis They also read the mRNA

Question 43

What is the function of tRNA?

Answer 43

They bring amino acids to ribosomes during translation (making a protein)

Question 44

What are other functions of small RNAs?

Answer 44

processing mRNAs intracellular transport ribozymes (RNA-based enzymes)

Question 45

What is the overall function of RNAs?

Answer 45

To make proteins

Question 46

What are the 3 structural differences between DNA and RNA?

Answer 46

1. DNA consists of deoxyribose sugar, whereas RNA consists of ribose sugars 2. DNA consists of A-T, C-G nitrogenous pairs, whereas RNA consists of A-U, C-G pairs 3. DNA is a double stranded helix, whereas RNA is a single strand