Nucleic acids and their functions Flashcards
Nucleic acids are monomers/polymers
Polymers
What are the monomers of Nucleic acids?
Nucleotides
What is the name of a molecule containing many nucleotides?
Polynucleotides
they may be millions of nucleotides long
What are the 3 components of nucleotides?
- a phosphate group (same structure in all nucleotides)
- a pentose sugar
- an organic nitrogenous base
What is the pentose sugar in RNA?
What is the pentose sugar in DNA?
Ribose
Deoxyribose
What are the two groups of organic bases?
Pyrimidine & purine
What are the Pyrimidie bases?
Thymine and cytosine
What are the purine bases?
Adenine and guanine
In biological systems what energy makes the changes?
Chemical energy
What must happen for chemical reaction to occur?
Make or break bonds
Where does heterotrophic organisms (e.g. Animals) derive their chemical energy from?
Food
Where does autotrophic organisms (e.g. Plants) derive their energy from?
Light energy (which they convert to chemical energy in photosynthesis)
Where do organisms mainly tutors their chemical energy?
In lipids and carbohydrates
What is the molecule that makes energy available when it’s needed?
Adosine trophosphate (ATP)
How much ATP do we break down every day?
50g
The body only contains 5g of ATP, what does this suggest?
That ATP is not an energy store
When is ATP synthesised?
When energy is made available
When is ATP broken down?
When energy is needed
What are the components of ATP?
- Adenine
- ribose
- 3 phosphate groups
What is the enzyme that breaks down ATP?
How does it work?
ATPase
- It hydrolyses the bond between the second and third phosphate groups in ATP
- This removes the third phosphate group leaving only two
What is the ATP molecule hydrolysed into?
Adenosine diphosphte (ADP) and an inorganic phosphate ion
What is released when ATP is hydrolysed?
Chemical energy
How much energy is released when 1 mole of ATP is hydrolysed?
30.6KJ
What name is given to a reaction that releases energy?
An exergonic reaction
ADP + an inorganic phosphate ion (in a condensation reaction) =
(this requires energy inout)
What kind of reaction is it?
ATP + water
Endergonic reaction
The addition of phosphate to ADP is called?
Phosphorylation
How does ATP work?
- ATP transfers free energy from energy rich compounds like glucose to cellular reactions where it is needed
- but energy transfers are inefficient and some energy is always lost as heat
What would the incontrolled release of energy from glucose produce?
A temperature increase that would destroy cells
How to living organisms release energy?
Gradually in a series of small steps called respiration, producing energy in the form of ATP
Name 2 advantages in having ATP as an intermediate in providing energy compared with using glucose directly
- the hydrolysis of ATP to ADP involves a single reaction that releases energy immediately. The breakdown of glucose involves many intermediates and it takes longer for energy to be releaded
- only one enzyme is needed to release energy from ATP but many are needed to release energy from glucose
Name 2 other advantages in having ATP as an intermediate in providing energy compared with using glucose directly
- ATP releases energy in small amounts. When and where it is needed but glucose contains large amounts of energy which would be released all at once
- ATP provides a common source of energy for many different chemical reactions increasing efficiency and control by the cell
ATP provides the necessary energy for cellular activity: (MA)
- METABOLIC PROCESSES- to build large complex molecules from smaller, simpler molecules, such as DNA synthesis from nucleotides
- ACTIVE TRANSPORT- to change the shape of carrier proteins in membranes and allow molecules or ions to be moved against a concentration gradient
ATP provides the necessary energy for cellular activity: (MNS)
- MOVEMENNT- for muscle contraction
- NERVE TRANSMISSION- sodium potassium pumps actively transport sodium and potassium ions across the axon membrane
- SECRETION-the packing and transport of secretory products into vesicles in cells
What is the relative molecular mass of ATP?
507.2
Describe structure of DNA:
1) DNA is composed of two Polynucleotide stands wound around each other in a double helix
2) The pentose sugar in the nucleotides In deoxyribose
3) there are 4 organic bases in DNA: two purines (Adenine & guanine) and two Pyrimidines (Thymine and cytosine)
4) the deoxyribose sugar and phosphate groups are on the outside of the DNA molecules and form the ‘backbone’
5) the bases of the two strands face each other pointing inwards. Adenine always likes with Thymine and guanine always likes with cytosine. Hydrogen bonds join the bases and form complememtsry pairs. The hydrogen bonds between then bases maintain the shape of a double helix