Nucleotides

Question 1

what is there monomer of dna

Answer 1

nucleotides

Question 2

What is the difference between tap and add

Answer 2

Different levels of phosphorylation ( try vs bi phosphate )

Question 3

Structure of nucleic acids

Answer 3

Phosphate group - pentose sugar - nitrogenous base

Question 4

Structure of DNA

Answer 4

DNA is a polymer made of nucleotides
Two strands run antiparralel to one and other
Each nucleotide has a phosphate pentose and base
The booing between each nucleotide is called phosphodiestar bond
They cary genetic info

Question 5

What is the name of the bind between nucleotides

Answer 5

Phosphodiestar

Question 6

What is the difference between a purine and a pyrimidine

Answer 6

Short name long molecule
Purine (A/G)

Long name short molecule
Pyrimidine (C/T/U)

Question 7

What is the importance of hydrogen bonding in DNA

Answer 7

Each strand is held together by hydrogen bonding. This is important as these bonds need to be broken during replication but need to be strong enough

Question 8

how many bonds between G/C

Answer 8

3

Question 9

How many bonds between A/T

Answer 9

2

Question 10

What shape is DNA

Answer 10

Double Helix

Question 11

What is antiparallel

Answer 11

When each strand is parallel to one and other on the double helix but is running in different directions

Question 12

How is DNA organised in cells

Answer 12

The majority of thew genome is in the nucleus

Each molecule of Dna is tightly wound around histones and forms a chromosome.
A chromosome is therefore one molecule of DNA

A gene codes for a protein

There is a loop of Dna in mitochondria

In Prokaryotes:

DNA is in a loop in the cytoplasm not in a nucleus

Question 13

Why is DNA described as self replicating

Answer 13

Because the dna in any cell is coded to maintain that organism and therefore has the genetic code to make more of its self

Question 14

What I semi conservative replication

Answer 14

The idea that each new molecule of DNA made in DNA replication contains one new and one old strand

Question 15

DNA Replication

Answer 15

DNA unwinds and unzips using helicase

Free nitrogen containing bases in the cytoplasm and bonded to the exposed bases using complementary base pairing theory – This is catalysed by DNA polymerase which walks along the strands 5’ to 3’ direction and picks the correct bases to the one it has just read. The leading strand is synthesised continuously whereas the lagging strand is synthesises in Okazaki fragments that are joined by ligase.

Question 16

Mutations to DNA

what does it do that is bad

Answer 16

During DNA Replicaton, mutations may occur and the wrong base may be added to the chain. This rarely occurs and due to the genetic code being a degenerate code it may not make a difference

If the wrong base is placed then the gene may be wrong. This would code from the wrong amino acid to be fetched and therefore could alter things like active sites in enzymes rendering them useless. Receptors may be the wrong shape
Antibodies may be the wrong shape

Question 17

How is RNA different to DNA

Answer 17

The sugar is ribose
One extra oxygen
Uracil replaces Thymine
Single stranded
shorter

Question 18

The nature of the genetic code

Answer 18

universal – used in all organisms

Degenrate – There is more than one base triplet that codes for each amino acid

Non overlapping – Starts reading from a foxed points in groups of three so avoids overlaps causing error

Question 19

Protein synthesis

Answer 19

Transcription:
A Short section of DNA (Gene) unzips and unwinds. The hydrogen binds break between complementary use pairs
RNA polymerase forms temporary hydrogen bonds between RNA bases and their complementary DNA ones
A length of RNA forms
This passes out of the nucleus via a nuclear pore

Translation:

mRNA enters the ribosome
tRNA brings an amino acid and reads along the codon until it matches its anticodon
As amino acids are brought together, peptide bonds form between them and folds into its 3d shape