2.3 Nucleic acids

Question 1

What are nucleotides?

Answer 1

Monomers of nucleic acids, DNA and RNA.

Question 2

What is the sugar in RNA?

Answer 2

ribose pentose sugar

Question 3

What is the sugar in DNA?

Answer 3

deoxyribose pentose sugar

Question 4

What is a nucleotide called when it has more than one phosphate group?

Answer 4

Phosphorylated

Question 5

What are 2 examples of phosphorylated nucleotides?

Answer 5

ADP (adenosine diphosphate) and ATP (adenosine triphosphate). ATP is an energy-rich end-product of most energy releasing biochemical pathways and drives most energy-requiring metabolic pathways.

Question 6

What role do nucleotides play in NADP?

Answer 6

Nucleotides are found in the coenzyme NADP (nicotinamide adenine dinucleotide phosphate) which is used during photosynthesis.

Question 7

What other coenzymes contain nucleotides?

Answer 7

NAD and FAD, used in respiration

Question 8

What are the 4 DNA nitrogenous bases?

Answer 8

T - Thymine
A - Adenine
C - Cytosine
G - Guanine

Question 8

What does the structure of a nucleotide look like?

Answer 8

Refer to textbook (page 86)
A nitrogenous base is attached to the pentose sugar at Carbon 1 and a phosphate molecule attached at either carbon 3 or carbon 5

Question 9

idk how to word this but DNA is a macromolecule in all living organisms

Answer 9

sorry

Question 9

What is the overall structure of DNA?

Answer 9

DNA is made up of repeating monomeric units in 2 polynucleotide chains

Question 10

What is it called when the 2 polynucleotide chains run in opposite directions?

Answer 10

antiparallel

Question 11

What is the covalent bond between the sugar residue and the phosphate group called?

Answer 11

phosphodiester bond

Question 12

Which bases are purine bases?

Answer 12

Adenine and Guanine

Question 13

What are purine bases?

Answer 13

Bases with only one ring

Question 14

What are pyrimidine bases?

Answer 14

Bases with two rings

Question 15

Which bases are pyrimidine bases?

Answer 15

Thymine and Cytosine

Question 16

How many hydrogen bonds are there between Adenine and Thymine?

Answer 16

2 hydrogen bonds

Question 17

How many hydrogen bonds are there between Cytosine and Guanine?

Answer 17

3 hydrogen bonds

Question 18

Why are the hydrogen bonds between bases useful?

Answer 18

They can unzip for transcription and replication

Question 19

What does a 5’ (5 prime) chain mean?

Answer 19

The phosphate group is attached to the 5th carbon of the deoxyribose sugar.

Question 20

What does a 3’ (3 prime) chain mean?

Answer 20

The phosphate group is attached to the 3rd carbon of the deoxyribose sugar.

Question 21

How does DNA exist within eukaryotic cells?

Answer 21

• in the nucleus
• wraps around histone proteins
• one loop of DNA does not have histone proteins

Question 22

How does DNA exist within prokaryotic cells?

Answer 22

• DNA is a loop in the cytoplasm (no nucleus)
• not wound around histone proteins (aka naked)

Question 23

What is the process of semi-conservative replication?

Answer 23

- unwinds (gyrase enzyme) - unzips (DNA helicase) - free phosphorylase bases attach to exposed bases - DNA polymerase catalyzes - leading strand synthesized continuously, lagging strand discontinuously

Question 24

Why is it called semi-conservative replication?

Answer 24

One strand of OG DNA is kept within each new helix of DNA.

Question 25

How often do mutations occur?

Answer 25

every 1 in 10^8. Certain enzymes can proofread and limit mutations, however not all mutations are harmful.

Question 26

How is RNA different to DNA?

Answer 26

sugar molecule is called ribose sugar nitrogenous pyrimidine base uracil replaces thymine polynucleotide is often single stranded polynucleotide chain is shorter mRNA (messenger), tRNA (transfer), rRNA (ribosomal)

Question 27

What are examples for need of specific genetic code?

Answer 27

enzymes need a specific active site antibodies need a complementary shape to the pathogen

Question 28

Why is tRNA (messenger) needed?

Answer 28

DNA code cannot pass through the nucleus

Question 29

Why is genetic code referred to as universal?

Answer 29

In almost all living things, a DNA codon codes for the same amino acids

Question 30

Why is genetic code referred to as degenerate?

Answer 30

For most amino acids, except methionine and tryptophan, a change in the base triplet can still code for the same amino acid

Question 31

Why is genetic code referred to as non-overlapping?

Answer 31

The genetic code is only ever read from a fixed point.

Question 32

What are ribosomes made of?

Answer 32

Ribosomal RNA and proteins in almsot equal parts

Question 33

What is tRNA (transfer)?

Answer 33

Made in the nucleolus, they are single stranded polynucleotides which can twist into a hairpin shape. It has an anticodon at one end which is complementary to the codon on the mRNA.

Question 34

What do ribosomes do?

Answer 34

They catalyse the formation of polypeptides

Question 35

What energy is needed during protein synthesis?

Answer 35

ATP

Question 36

How does the polypeptide form its 3D shape?

Answer 36

chaperone proteins in the cell help form its shape into a tertiary structure.