Chapter 2 Flashcards
(24 cards)
What is the function of DNA
- its a stable structure that is passed from generation to generation
- it is able to separate during replication + protein synthesis
- it carries a large amount of genetic info
- due to its structure its protected from being corrupted by outside chemicals
How is DNA a stable molecule
- the phosphodiester backbone - protects more reactive organic bases
- H-bonds - link bases forming bridges
C-G = more stable as they have 3 h-bonds
The synthesis of ADP involves the addition of phosphate this occurs in 3 ways what are they?
- in chlorophyll containing plants during photosynthesis
- in plant and animal cells during respiration
- in plant and animal cells when phosphate groups are transferred from donor molecules to ADP
How does ATP store energy
- it has 3 phosphate groups that store energy
what are the 4 requirements of semi-conservative replication
- the 4 types of nucleotides and there bases
- both strands of DNA
- the enzyme DNA polymerase
- a source of chemical energy
how was DNA structure discovered
- in 1953, Crick and Watson figured out the DNA structure following the work by Rosalind Franklin on the X-Ray diffraction patterns of DNA
- this opened further doors in developments of biology over the next century
explain the process of semi-conservative replication
- DNA helicase breaks the H-bonds linking the bases - the double helix unwinds and seperates
- the exposed strand acts as a template strand for the free nucleotides to bind to - nucleotides are joined by a condensation reaction via DNA polymerase to form the new strand
- each DNA molecule contains 1 original strand and 1 new strand
Who discovered the DNA structure
- Watson
- Crick
- Rosalind Frankiln
what is the rule of DNA base pairing
- base pairing are complementary
- A-T
- C-G
what is RNA
a polymer made of a ribose sugar, base and a phosphate
how are nucleotides joined to form a di or polynucleotide
2 nucleotides are joined as a result of a condensation reaction between the pentose sugar of one nucleotide and the phosphate group of another
what components are nucleotides made of
- a pentose sugar
- a phosphate
- an nitrogenous base
how is ATP synthesized
- it is a reversible reaction therefore energy can be used to add Pi to ADP reforming ATP
- this is catalysed by atp-synthase and is a condensation reaction
how is ATP hydrolysed
- catalysed by ATP hydrolase and is a hydrolysis reaction
what is ATPs structure
- adenine
- ribose
- 3 phosphates
what is the bond formed between 2 nucleotides called
- a phosphodiester bond
what are the 4 bases in RNA
- adenine
- uracil
- cytosine
- guanine
how are bases in DNA joined
hydrogen bonds
what are the 4 bases in DNA
- adenine
- thymine
- guanine
- cytosine
explain 5 properties of water that make it important for organisms
- high specific heat capacity - buffers temp changes
- cohesion between H2O - produces surface tension through h-bonds
- a metabolite in hydrolysis/condensation reactions
- a solvent allowing transport of substances and metabolic reactions to occur
- large latent heat of vapourisation - provides a cooling effect through evapouration
state and explain the property of water that helps to prevent temp increases in a cell
a high specific heat capacity
- buffers changes in temp
Give two properties of water that are important in the cytoplasm of cells
for each property of water explain its important in the cytoplasm
- polar molecule - acts as a universal solvent
- universal solvent - metabolic reactions occur faster in solution
use your knowledge of water potential to suggest how high sodium concentrations in the medicines taken could affect blood volume
- Na+ lowers the water potential of blood
- water would move into the blood by osmosis
- increasing the blood volume
describe the roles of iron ions, sodium ions and phosphate ions in cells
Fe+:
- haemoglobin binds with O2
Na+:
- co-transport of glucose
- creates diffusion gradient
- affects water potential
phosphate ions:
- phosphodiester bonds + backbone
- phospholipid bilayer
- used to produce ATP
