Biological Molecules : Neuclotides + Water Flashcards
What are nucleic acids ?
Group of the most important molecules
Best known nucleic acids
RNA and DNA
What does RNA stand for ?
Ribonucleic acid
What does DNA stand for ?
Deoxyribonucleic acid
What makes DNA recognisable ?
Double helix structure
What is a polynucleotide ?
Strand of DNA or RNA made from mononucleotides
Nucleotide structure: 3 components
- pentose sugar
- phosphate group
- a nitrogen containing organic base
Nucleotide structure: How are the 3 components joined ?
Condensation reaction to form.a mononucleotid e
Nucleotide structure: Bond when 2 mononucleotides join ?
Phosphodiester bond
Nucleotide structure: order of nucleotides
Mononucleotides + dinucleotide + polynucleotide
RNA : What is RNA ?
- A polymer made of nucleotides which transfers genetic material from DNA to ribosomes
- ribosomes made of protein and another type of RNA
- 3rd type involved in protein synthesis
RNA : Bases
Adenine
Uracil
Cytosine
Guanine
RNA : Pentose sugar
Ribose
DNA : who worked out the structure of DNA ?
James Watson and Francis Crick
DNA : Whose work did crick and Watson follow ?
Rosalind franklin
DNA : Bases
Adenine
Thymine
Cytosine
Guanine
DNA : pentose sugar
Deoxyribose
DNA : What is DNA made of ?
Double helix with 2 polynucleotide chains joined by hydrogen bonds between complimentary bases
Base pairing : specific pairing
A-T
G-C
Base pairing : Adenine is said to be ….. to thymine
Complimentary
Double helix : how is it formed ?
Uprights of phosphate and deoxyribose wind around
Function : phosphodiester backbone
Prevents organic bases reacting with the environment
Function : Long molecule
Store lots of information
Function : Double helix
Makes DNA compact
Function : Weak H bonds join base pairings
Easily broken for DNA replication
Function : Double stranded
Allow replication from template strands to occur
Function : Base sequence
Allows information to be stored
Function : Base stacking
Makes DNA stable
How is DNA replicated
- dna helical causes strands separate when H bonds break
- both strands act as templates
- free nucleotides attract and H bonds reform to complimentary base pairings
- DNA polymerase joins adjacent nucleotides
- semi conservative replication ( one old an one new)
Cell division : nuclear division
Nucleus divides (mitosis/meiosis)
Cell division : Cytokinesis
Whole cell divides
Cell division : What should happen before nucleus divides
DNA replication
Semi conservative replication : 4 requirements
- 4 types of nucleotide with bases
- both dna strands to act as a template
- enzyme DNA polymerase
- source of chemical energy
Who conformed the semi conservative model
Meselson and stahl
What are the 3 models
Fully conservative . Semi conservative and dispersive model
Proof it was semi conservative
2 bands formed : lighter N14 and heavier N14 and N15 mixed
ATP : What does it stand for ?
Adenosine triphosphate
Main energy source to carry out processes in cells
ATP
Uses of ATP
- provide energy for processes like a.t
2. add phosphates to other substances to make them more reactive
Structure of ATP : 3 parts
Adenine
Ribose
3 phosphates
ATP storing energy:describe bonds between phosphate groups
Unstable so they have a low activation energy = easily broken
ATP storing energy : what happens when bond is broken between phosphate groups
Removal of last phosphate releases energy
Releasing energy (ATP) : equation
ATP + H20 = ADP + Pi
Releasing energy (ATP) : equation (Pi)
Inorganic phosphate (doesn’t contain carbon )
Releasing energy (ATP) : what is required to convert ATP to ADP
Water through hydrolysis reaction
Releasing energy (ATP) : which enzyme catalysts the reaction
ATP hydrolase
Synthesis of ATP : what type of reaction is conversion of ATP and ADP
Reversible reaction
Synthesis of ATP : Which enzyme catalyses this reaction
ATP synthase
Synthesis of ATP : What is removed in this reaction
Water
Synthesis of ATP : Condensation or hydrolysis reaction ?
Condensation reaction
Synthesis of ATP : What does synthesis of ATP from DP require
Addition of a phosphate molecule to ADP
Roles of ATP : Why is ATP a better immediate source of energy than glucose
- each atp mol releases less energy so is in more manageable quantities
- hydrolysis of ATP to ADP is a single reaction that releases immediate energy
Roles of ATP : Why do humans need to make a lot of ATP everyday
ATP cannot be stored and it’s released in small amount so you need a constant supply from mitochondria of cell
Suitable energy for cells : released in small amounts (s)
Less energy wasted as heat
Suitable energy for cells : Doesn’t leave cell (s)
Highly reactive
Suitable energy for cells : soluble in cytoplasm (s)
Most chemical reaction in solution so its more likely to cause a reaction
Suitable energy for cells : Rapidly resynthesised (s)
Only add 1 phosphate
Suitable energy for cells : Instant energy (s)
Only a single reaction where one bond is broken
What is water made up of ?
2 hydrogen atoms covalently bonded to 1 oxygen atom
Water : polar on non-polar
Polar / dip Olaf
Water : Electric charge ?
Neutral but electrons are not distributed uniformly
Water : attractive force between opposite charges
Hydrogen bond which allow water to stick together
Water : Permanent or non permanent structure
-Not permanent. -bonds break and reform as H20 molecules move around
Water properties : polar
Acts as a good solvent so chemical reactions can occur faster
Water properties : Reactive
Used in hydrolysis reactions
Water properties : High SHC
Acts as a buffer against sudden temperature variations making the environment stable
Water properties : adhesive and cohesive
Movement through xylem
Water importance: metabolism
- break many complex molecules via hydrolysis
- raw material in photosynthesis
Water importance: solvent
Readily dissolves in other substances
Other water properties
- transparent
- variable density
Inorganic ions : iron
Haemoglobin where they transport o2
Inorganic ions : Phosphate
Structural role in dna and storing ATP molecules
Inorganic ions : H ions
Determining PH of solutions and function of enzymes
Inorganic ions : Sodium
Transport of glucose and amino acids across plasma membranes
Similarities between moveenment of water and inorganic ions
- move against a concentration gradient
- both move through (protein) channels in the membrane
Contrast between movement of water and ions
Ions can move against a concentration gradient via a.t.