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Flashcards in Nucleic acids Deck (51)
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1
Q

What is DNA?

A

Double stranded polymer of nucleotides which carry the info for protein synthesis

2
Q

What pentose sugar does DNA contain?

A

Deoxyribose

3
Q

What is RNA?

A

Single stranded polymer of nucleotides

4
Q

What sugar does RNA contain?

A

Ribose

5
Q

What is a polynucleotide?

A

Polymer of nucleotide monomers covalently bonded together

6
Q

What is an organic nitrogenous base?

A

An organic compound containing nitrogen, which is part of all nucleotides

7
Q

What is a nucleotide made up of?

A

A phosphate, 5-carbon sugar, and a nitrogenous base

8
Q

Why is the pentose sugar called 5-carbon sugar?

A

Either a ribose or deoxyribose molecule, both of these contain 5 carbon atoms

9
Q

What are the organic nitrogenous bases?

A
A - adenine 
C - cytosine 
G - guanine 
T - thymine 
U - uracil
10
Q

What are the complementary base pairs?

A

All teachers care gently
a - t
c- g
a - u

11
Q

In which type of nucleic acid is the base Pais a with u instead of t?

A

RNA

12
Q

What are the two types of bases?

A

Pyrimidines and purines

13
Q

How many carbon-nitrogen rings does pyrimidine bases consist of?

A

1

14
Q

How many carbon-nitrogen rings does purine bases consist of?

A

2

15
Q

Which bases are pYrimidines?

A

ThYmine (Also have Y)
CYtosine (Also have Y)
Uracil (replaces T)

16
Q

Which bases are purINE?

A

AdenINE

GuanINE

17
Q

How is a polynucleotide formed?

A

The phosphate group of one nucleotide bonds to the sugar molecule of another, forming one long continuous polynucleotide (half a DNA strand)

18
Q

How do we go from a polynucleotide to the nucleic acid - DNA?

A

Two polynucleotide chains join together with hydrogen bonds between both polynucleotides nitrogenous bases (hydrogen bonds)

19
Q

After two polynucleotide chains have joined to form the nucleic acid, how does it fully become DNA?

A

Once it contains a sugar deoxyribose and the base thymine

20
Q

What is complementary base pairing?

A

A will only pair with T (forming two hydrogen bonds), and C will only pair with G (forming three hydrogen bonds)

21
Q

What is important about complementary base pairing?

A

Molecule will become very stable and same width all the way down the chain (due to bases holding backbone same width apart)

22
Q

Describe antiparallel in terms of DNA?

A

The two polynucleotides and in opposite directions top one another so that the bases meet and bond together in the middle

23
Q

What is semi-conservative replication?

A

Each new DNA molecule is made up of 1 conserved stand from original template, and 1 new strand of nucleotides

24
Q

What does the enzyme DNA helicase do in the first stage of DNA semi-conservative replication?

A

Unwinds and unzips the double stranded helix, breaking the hydrogen bonds, leaving 2 individual strands

25
Q

Into what shape is the now 2 singular strands of nucleotide, unzipped into?

A

A fork, one end becomes the leading strand and the other, the lagging strand

26
Q

Which strand is the lagging strand?

A

The one the wrong way up

27
Q

How does complementary base pairing occur once unzipped, in the second stage of S-CR?

A

New and free nucleotides in nucleus attach to exposed bases, forming hydrogen bonds

28
Q

What does DNA polymerase do?

A

Catalyses the condensation reaction which covalently bonds the new nucleotides to the adjacent base

29
Q

In stage 3 of S-CR what happens to the leading strand?

A

DNA polymerase zooms down the strand (in same direction as unzipping) , base pairing is an efficient and continuous process

30
Q

In stage 3 of S-CR what happens to the lagging strand?

A

Due do DNA polymerase moving in opposite direction to unzipping, process is a lot slower

31
Q

What is the triplet code?

A

The three nitrogenous bases read along the DNA strand that code for DNA

32
Q

What is the definition of transcription?

A

The process of exactly copying the genetic code to form a template of mRNA

33
Q

What is the genetic code?

A

The triplet code, 3 bases coding for an amino acid

34
Q

How is mRNA structured?

A

Single stranded, contains ribose (instead of deoxyribose) and contains uracil instead of thymine

35
Q

What are the two processes in protein synthesis?

A

Transcription and translation

36
Q

What is a gene?

A

A short length of DNA, a sequence of bases that code for the amino acids which make up an individual protein

37
Q

What are the two separate strands in a gene?

A

The coding strand and the template strand

38
Q

Why does protein synthesis occur?

A

When the cell needs to produce a specific protein

39
Q

What is the first stage of protein synthesis?

A

Enzyme RNA polymerase binds to the gene and unzips the two DNA strands

40
Q

What direction does the RNA polymerase move?

A

In the 3’ to 5’ direction

41
Q

What is the second thing the RNA polymerase does in protein synthesis?

A

Pairs free RNA nucleotides with complementary nucleotides on the DNA template strand (covalently linked by phosphodiester bonds)

42
Q

How is the mRNA formed from the RNA?

A

The complementary RNA nucleotides covalently link to those on the template strand by phosphodiester bonds, making a polynucleotide chain, growing in the 5’ to 3’ direction

43
Q

Whats the first stage of translation?

A

mRNA leaves the nucleus via the nuclear pore with small sub unit of ribosome and act as a template for proteins to be synthesised

44
Q

What is a codon?

A

A triplet

45
Q

What is an anticodon?

A

The complementary triplet to the mRNA codon

46
Q

What is a tRNA molecule?

A

Transfer molecule, has an anticodon one end, the sugar-phosphate backbone, and the other is the region for the particular amino acid to attach

47
Q

What happens after tRNA molecules attach to a ribosome?

A

The anti codon which is complementary to the codon, pair up on the mRNA

48
Q

What happens to amino acids transported by tRNA?

A

They join together by a condensation reaction forming peptide bonds

49
Q

When does translocation stop?

A

When tRNA molecules go back to cytoplasm, ribosome has moved along whole mRNA strand and all amino acids have joined, ending with a stop codon

50
Q

What is rRNA (ribosomal)?

A

Site of protein synthesis, when RNA molecules are attached to ribosomal protein molecules

51
Q

Whats the helical structure of RNA?

A

A polynucleotide chain twists into helix and coils back on itself, some sections of the chain join to other parts for tRNA/mRNA, however mRNA is linear