2.3 Nucleotides and nucleiC acid

What type of reaction leads to the formation of nucleotides

Condensation reactions

3 main elements of a nucleotide

Deoxyribose sugar, phosphate group, base

Name the 5 types of base.

Adenine, trypsine (uracil)

Guanine, cytosine

Describe a purine

Has 2 rings

Example: adenine or guanine

Describe a pyrimidine

One ring

Examples: thymine, cytosine, uracil

Bonds between base pairs described

DNA: 2 h bonds between A+T

RNA: 2 h bonds between A+U

Both have 3 h bonds between G+C

What is a polynucleotide.

When nucleotides (monomers) are linked together to form nucleic acid/ polynucleotides (polymers). The nucleotides are bonded by phosphodiester bonds.

Name the structure inside the cell nucleus that contains DNA.

Chromosomes or chromatin

What type of substance does a gene code for.

Protein

State the definition and role of a gene.

A gene is a specific section of DNA

It codes for a characteristic

RNA vs DNA

Ribose sugar vs deoxyribose sugar

Uracil vs thymine

Single stranded vs double helix

Two types of pentose sugar and what identifies them

Ribose (RNA) and deoxyribose (DNA)

They contain 5 carbons each

What do helicase and gyrase do

Helicase - breaks the hydrogen bonds between bases to disconnect the strands of DNA.

Gyrase- straightens the double helix strands found in DNA so that it is no longer coiled

describe semiconservative replication

gyrase and helical seperate the dna strand to form a leading and lagging. Leading strand binds to free complimentary bases in cytoplasms by condensation reaction. Lagging strand also binds to form new double helix so you end up with two identical double helixes.

3 bases on DNA, 3 bases on mRNA, 3 bases on tRNA ‘

DNA - triplets.

mRNA - codons

tRNA- anticodons

What does the term non-overlapping refer to in terms of genes

Genes that code for a characteristic cannot overlap er crossover with one another at any point

What enzyme constructs mRNA and how

RNA polymerase builds mRNA during transcription by forming phosphodiester bonds between the mRNA molecules.

What do the small letters stand for in: mRNA, tRNA, rRNA

mRNA -messenger

tRNA — transfer

rRNA -ribosomal

What does ATP/ ADP stand for and consist of

Adenosine triphosphate- A nucleotide consisting of a molecule of ribose joined to the nitrogenous base adenine and 3 phosphate groups

Adenosine diphosphate- a nucleotide consisting of a molecule of ribose joined to the nitrogenous base adenine and 2 phosphate groups

Degenerate definition (regarding amino acids)

Some amino acids can be coded for by multiple different codons (group of 3 bases on mRNA )

What are ribosomes mostly made up of

rRNA -ribosomal RNA

Universal (genetic code)

The fact that the same codons code for the same amino acids in all organisms

Examples of macromolecules

DNA, carbohydrate, triglycerides, protein, amylose

What bond holds 2 complimentary bases together

Hydrogen bonds.

What is an isotope.

A slightly heavier or lighter atom than it typically is due to A differing number of neutrons. The bigger the number of neutrons, the heavier the atom

How do free bases become attracted to the single strands of DNA

They are activated by ATP which is a source of energy that derives from glucose.

Name 2 hexose sugars and their identifier.

Glucose, fructose

They have 6 carbons each

What 5 elements is DNA made up of

Carbon, oxygen, hydrogen, phosphorus, nitrogen

What is splicing in reference to the transcription process

When the intron section (non-coding section) is removed from mRNA before it’s sent out of the nucleus to improve efficiency when translation occurs. The remaining sections of the mRNA (extron /coding sections) are bonded back together and sent out of the nucleus

Extron vs intron

Extron- coding parts of a gene

Intron-non-coding parts of a gene

What is {1} mRNA molecule made up of

A gene

How many amino acids are there in nature

20

Which bases in a codon don't affect the primary structure of a protein (the amino acid chain )

The 3rd base

Name two pentose sugars and their identifiers

Ribose, deoxyribose

Have 5 ring base

How can DNA be purified by precipitation④

Add ethanol and salt to aqueous solution

Nucleic acids precipitate out of solution

Centrifuge to obtain pellet of nucleic acid

Wash pellet with ethanol and centrifuge again

Transcription, occurrence and products

Inside the nucleus, produces mRNA

Outline the process before transcription ④

RNA polymerase binds to promoter region on a gene.

Section of DNA uncoils into 2 strands with exposed bases, antisense strand acts as template

Free nucleotides are attracted to their complimentary base

RNA polymerase joins adjacent nucleotides to form phosphodiester bonds

Outline the process of transcription ③

H bonds reform and DNA rewinds

Splicing occurs, removing introns from pre-mRNA in eukaryotic cells

MRNA moves out of nucleus via nuclear pore and attaches to ribosome

Translation, occurrence and products

In cytoplasm on ribosomes , produces protiens

Outline the process of translation ④

Ribosome moves along mRNA until ‘start’ codon

tRNA anticodon attaches to complimentary bases on mRNA

Condensation reactions between amino acids on tRNA form polypeptide bonds which requires energy from ATP hydrolosis

Process continues to form polypeptide chain until ‘stop’ codon is reached