DNA and proteins - lecture 1 Flashcards Preview

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Flashcards in DNA and proteins - lecture 1 Deck (20)
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1

Who discovered nuclein and cells?

Friedrich Meischer. He washed pus bandages in salt then soaked them in weak alkaline solution. There was a ppt at the bottom, the cells has lysed ad the nuclein was at the bottom

2

What are the two types of Streptococcus pneumonia ?

- Smooth virulent strain ( polysaccharide coat protects it from immune system)
- Rough nonvirulent ( lacks polysaccharide coat)

3

What is the transforming principle?

DNA

4

How was the transforming Principe discovered?

- Smooth virulent strain when killed by heat the mouse can still survive
- When heat killed smooth virulent strain is mixed with living rough non-virulent strain , mouse is still killed .

5

Who discovered the transforming principle first?

Frederick Griffith in 1928

6

who determined that the ' transforming principle' is DNA?

- Oswald Avery
- Colin MacCleod
-Maclyn McCarty

7

Who determined the base ratios and when?

Erwin Chargaff in 1949

8

When did Rosalind Franklin and Maurice Wilkins produce their X-ray diffraction patterns?

1952

9

When did Francis and Crick discover the structure of DNA

1953

10

Structure of a nucleotide

5 carbon pentose sugar + nitrogenous base + phosphate base

11

Structure of a nucleoside

5 carbon pentose sugar and nitrogenous base

12

What are purines?And what are their names?

nucleotide with a 2 carbon nitrogenous base . Adenine and Guanine.

13

What are pyrimidines? And what are their names?

nucleotides with 1 carbon nitrogenous base. Cytosine , thymine and uracil

14

how are carbons labelled in a ring?

the carbons on the sugar are termed 3 prime or 4 prime etc ...

15

What are the two bonds in DNA strands?

N-glycosidic bonds and phosphodiester bonds.

16

What is a N- glycosidic bond made of?

Links nitrogenous base to the C1 pentose

17

What is the phosphodiester bond made of?

links the 5' and 3' pentose sugars

18

Features of DNA

- Right handed helix
- wide and deep major groove
- narrow and deep minor groove
- tiny central axis

19

Differences between RNA and DNA

- less pronounced grooves
- uracil instead of thymine

20

Types of RNA ( which are uncommon)

- Micro RNA ( regulatory)
-Imprinted associated RNA (genomic imprinting)
- Telomerase RNA ( telomere formation)