DNA & RNA

Question 1

Nucleotides consist of three elements

Answer 1

Nucleobase Deoxyribose sugar Phosphate group(s)

Question 2

What is a nucleoside?

Answer 2

Is the nucleobase plus the deoxyribose sugar (i.e. without the phosphate).

Question 3

Difference between nuceleotides and nucleocides?

Answer 3

Nucleotides have a phosphate group.

Question 4

DNA is turned into RNA What is this called?

Answer 4

Transcription

Question 5

RNA is turned into proteins What is this called?

Answer 5

Translation

Question 6

Transfer RNA Ribosomal RNA What happens?

Answer 6

Transcribed from genes but used to translate mRNA into proteins

Question 7

What is Pyrimidine?

Answer 7

Nitrogen containing aromatic ring

Question 8

What is Purine?

Answer 8

Pyrimidine ring fused to imidazole ring

Question 9

What nucleobase is this?

Answer 9

Purine

Question 10

What nucleobase is this?

Answer 10

Pyrimidine

Question 11

Types of Nucleobases

Purines

Answer 11

Adenine

Guanine

Question 12

What nucelobase is this?

Answer 12

Adenine

Question 13

What nucleobase is this?

Answer 13

Guanine

Question 14

What nucleobase is this?

Answer 14

Cytosine

Question 15

What nucleobase is this?

Answer 15

Thymine

Question 16

Nucleosides and Deoxyribose

Answer 16

Deoxyribose binds to the nucelobase on a nitrogen atom of the pyrimidine or imidazole (for purine) ring

Question 17

What is this nucleoside?

Answer 17

Deoxyribose

Question 18

What is this nucleoside?

Answer 18

D-ribose

Question 19

What is this nucleoside?

Answer 19

Adenosine

Question 20

What is this nucleoside?

Answer 20

Guanosine

Question 21

What is this nucleoside?

Answer 21

Cytidine

Question 22

What are nucleotides?

Answer 22

Nucleotides are the building blocks of nucleic acids

Question 23

What is this nucleoside?

Answer 23

Thymidine

Question 24

Where does the Phosphate group bind?

Answer 24

It binds to the 5’ position of the deosyribose group.

Additional phosphate groups bind to existing phosphate groups.

e.g. Adenosine monophosphate

Question 25

Other functions of Nucleotides ATIP \> GTP \> UTP / CTP

Answer 25

Used for intracellular energy & metabolism

Question 26

Other functions of Nucleotides ATP & GTP

Answer 26

Intracellular signalling

Question 27

Other functions of Nucleotides ATP

Answer 27

Intracellular signalling

Question 28

Other functions of Nucleotides Adenosine

Answer 28

Also a transmitted in the brain and CVS Sleep / wake (e.g. coffee) Vasodilator Antiarrhymthic for heart

Question 29

Basics of DNA

Answer 29

Core nuclear material eukaryotes Deoxyribose - missing the 2' -OH group on the ribose group "Double helix" conformation for polymer

Question 30

Phosphodiester bond

Answer 30

Question 31

Nucleobase H-bonds Type?

Answer 31

Guanosine pairs with cytosine 3 H-bonds \*H = hydrogen

Question 32

Nucleobase H-bonds Type?`

Answer 32

Adenosine pairs with thymidine 2-H bonds

Question 33

What is the structure of DNA?

Answer 33

- sugar phosphate backbone - Nucleobase pairs linked - Hydrophobic bases on inside - Antiparallel strands - Read from 5' - 3'

Question 34

DNA helix structure

Answer 34

Anti-parallel double helix 3.4nm per turn, 2nm wide Glycosidic bonds of nucleobase and deoxyribose not at 90 degrees creates "major" and "minor" grooves. Easier for proteins and other molecules to access DNA through major groove.

Question 35

What are some intercalating agents?

Answer 35

Hydrophobic heterocyclic ring molecules - resemble ring structure of base pairs. Distort DNA double helix and interfere with transcription Acridine orange, ethidium bromide - flourescent staining of DNA Actinomuin D - inteferes with DNA replication. Cancer chemotherapy (also quite toxic)

Question 36

What is supercoiling of DNA?

Answer 36

Total length of human DNA molecule = 3m DNA must be "wound" - can strain the DNA helix Negative supercoiling relaxes DNA (and increases exposure to polymerases and transcription factors.) Topoisomerase I and II: cleave DNA, twist strands round and reanneal.

Question 37

Supercoiling and histones

Answer 37

Question 38

What are histones?

Answer 38

any of a group of basic proteins found in chromatin.

Question 39

What is a chromatin?

Answer 39

the material of which the chromosomes of organisms other than bacteria (i.e. eukaryotes) are composed, consisting of protein, RNA, and DNA.

Question 40

Denaturing DNA

Answer 40

Strands seperated by splitting H-bonds pH: spontaneous denaturing outside pH 2.3 - 11.5 Heat (~60 degrees) Ionic strength Can renature if restored through "annealing"

Question 41

Structure of RNA

Answer 41

Single stranded polyribonucleotide. Uridine not thymidine. ~30-50% of residues form intrastrand H-bonds Also helical 2' hydroxyl group attached to ribose group - less stable Shorter lifespan (~30 minutes)

Question 42

RNA tertiary structure

Answer 42

Complex tertiary structure is vital for function

Question 43

What is transcription?

Answer 43

First step of gene expression. RNA is transcribed from DNA by RNA. Polymerase complex Occurs in the nucleus

Question 44

What is translation?

Answer 44

Second step of gene expression. mRNA is translated into proteins by ribosomes. Occurs in cytosol / endoplasmic reticulum

Question 45

Example of DNA transcription

Answer 45

New proteins created from 5' end to 3'

Question 46

Translation of ribosomes

Answer 46

Protein / RNA complex with numerous different individual proteins and rRNA units. tRNA matches amino acid to nucleotide triplet and ribosome catalyses peptide bond formation.