Biological Molecules- enzymes and more Flashcards
What is ATP?
Adenosine triphosphate
What does ATP contain?
3 phosphate groups
One molecules of ribose
Adenine
What hydrolyses ATP?
ATP hydralase
What is released when ATP is hydrolysed?
Energy
What type of reaction is it when ATP is hydrolysed?
Exergonic
What are the products when ATP is hydrolysed?
ADP and a phosphate group
How do you get from ADP + Pi back to ATP?
Condensation reaction
What is need to get from ADP + Pi back to ATP?
Energy
What is the reaction needed for energy?
Endergonic
What is the energy released used for?
Movement/ muscle contraction Active transport Breakdown + synthesis of new molecules Enzyme controlled reactions Polymer synthesis
What is high surface tension?
The uneven distribution of force at a boundary interface caused by molecular bonding
What is the biological importance of water having a high surface tension?
Allows water to form a skin that supports small aquatic organisms to walk over it
What is density?
A measure of mass per unit volume
What is the biological importance of water having a lighter density when it is a solid?
In winter it acts as an insulator for organisms living below it in the water
What is a universal solvent?
A liquid substance that can dissolve a wide range of molecules
What is the biological importance of water being a universal solvent?
It can act as a transport medium
What is high specific heat capacity?
The amount of heat needed to raise 1 kg of water by 1 degree
What is the biological importance of water having a high specific heat capacity?
Helps maintain a constant temperature needed for cells and acts as a temperature buffer
What is cohesion?
The tendency of molecules of a substance to attract one another
What is the biological importance of water being cohesive?
Molecules are pulled upwards through the xylem’s tissue
What is adhesion?
The tendency of molecules to be attracted to other molecules of a different type
What is the biological importance of water being adhesive?
Strong force of attraction between water molecules and walls of xylem so transpiration takes place
Why do we need DNA replication?
Growth
Development/specialisation
Reproduction
What is conservative replication?
One daughter molecules contains both parental DNA
Other contains DNA strands of new synthesised DNA
What is dispersive replication?
Parental DNA is interspersed between two daughter molecules
What is semi-conservative DNA?
Both DNA helices consist of one parental and one new strand
Which way does our DNA replicate by?
Semi-conservative
How does semi-conservative replication work?
DNA helicase breaks H bonds in helix
Each exposed strand acts as a template
Free nucleotide attracted to complementary bases
Free nucleotides line up and reform H bonds
DNA polymerase catalyses polymerisation of nucleotides to form nucleotide chain with phosphodiester bond
Two new DNA molecules formed each with original strand of parental DNA
How do we know our DNA replicates by semi-conservative replication?
Grew cells in N15
Used a centrifuge to separate according to weight
Mixed N15 and N14
Half DNA contained half heavy and half light = disproved conservative
Second division disproved dispersive
What is RNA?
Polymer of nucleotides
What sugar is present in DNA?
Deoxyribose
What sugar is present in RNA?
Ribose
What is the structure of DNA?
Double helix
What is the structure of RNA?
Single stranded
What is the base pairing of DNA?
Thymine to adenine
Guanine to cytosine
What is the base pairing of RNA?
No base pairing but uracil replaced thymine
What is the length of DNA?
Larger molecule
What is the length of RNA?
Smaller molecule
Can you predict percentage of base pairs in DNA?
Yes
Can you predict percentage of base pairs in RNA?
No because it is single stranded
What is messenger RNA?
Copies of DNA, they leave the nucleus through nuclear pores in the membrane and give instructions to the ribosomes
What is ribosomal RNA?
Makes up part of ribosome structure
What is transfer RNA?
Used to carry specific amino acids during the process of protein synthesis
How does protein synthesis work?
DNA helicase breaks H bonds
mRNA makes copy of DNA template strand
mRNA leaves through nuclear pores
Ribosome attaches to mRNA
tRNA molecules attach to complementary anti-codon
Each amino acid joins to form a polypeptide
What is transcription?
Steps involved in protein synthesis that happens inside of the nucleus
What is translation?
Steps involved in protein synthesis that happens outside of the nucleus
What is a polymer?
A large molecule made up of smaller repeating units called monomers
What makes up a nucleotide?
Deoxyribose sugar
Phosphate group
Organic base
What is the bond between a phosphate group and sugar?
Ester bond
What is the bond between a base and sugar?
Glycosidic bond
What are the bases?
Adenine
Thymine
Guanine
Cytosine
What is the bond created when a sugar from one nucleotide is condensed to a phosphate group from another nucleotide?
Phosphodiester
How many H bonds are between cytosine and guanine?
3
How many H bonds are between adenine and thymine?
2
How is the sugar backbone created?
By the condensing a sugar from one nucleotide with a phosphate group from another nucleotide
What are the advantages of the lock and key model?
Shows the active site is complementary to the substrate
Correctly identifies the concept of the active site and substrate binding and a catalysis occurs
What are the disadvantages of the lock and key model?
Doesn’t show the products produced
Doesn’t show how some enzymes can act on a small number of similar structures
What does the induced fit model show?
Active sit changes shape as the substrate binds, causing a change in shape of substrate
Change in shape induces a strain in the substrate bonds, which lowers the activation energy
What are the advantages of the induced fit model?
Explains how enzyme substrate complex lowers the activation energy
Explains how the products are released
Flexibility of active site explains how an enzyme can act on two similar substrates
Flexibility of proteins provide a better explanation of non-competitive inhibition
What are the factors that effect enzymes?
pH
Temperature
Enzyme conc
Substrate conc
What happens at a low temp?
Slow rate as enzymes don’t have enough KE so there is less successful collisions
What happens at a optimum temp?
Fastest rate as enzymes have lots of KE so there is more successful collisions
What happens at a high temp?
Slow rate as the temp is too hot so H bonds in active site has broken so it has denatured
What happens at low pH?
Slow rate as there is a high amount of H+ ions so bonds break so active site denatures
What happens at optimum pH?
Fastest rate as creates perfect conditions for successful collisions
What happens at high pH?
Slow rate as bonds are broken so active site denatures
What happens when you change the pH?
Change the charge of amino acids that form the active site so the substrate isn’t complementary
What does the graph of enzyme and substrate conc look like?
Increases then plateaus
What happens at low substrate conc?
Slow rate as less substrates to occupy active sites so less successful collisions
What happens at optimum substrate conc?
Fast rate as there is enough substrates for enzymes so there is more successful collisions
What happens at high substrate conc (Vmax)?
Plateaus as too may substrates for enzymes
What happens at low enzyme conc?
Slow rate as less enzymes than substrates so there is less successful collisions
What happens at optimum enzyme conc?
Fast rate as enough enzymes to collide with all substrates so more successful collisions
What happens at high enzyme conc?
Rate plateaus as too many enzymes for substrates
What is an ion?
An atom that carries a charge
What are the ions you need to know about?
Hydrogen Iron Sodium Phosphate Calcium Magnesium Nitrogen
What are hydrogen ions used for?
Controlling and altering pH
Why are hydrogen ions are important?
Because if the pH is incorrect proteins will become denatured
What are hydrogen ions important for?
Proteins require optimum pH
Proteins denature in incorrect pH
Enzymes are required for metabolic processes
Channel proteins
What is iron a component of?
Haemoglobin
What is iron content mainly controlled by?
Diet
What is iron involved in?
Electron transport chain in respiration
What is sodium important for?
Sodium potassium pump- co-transport
What does sodium control?
Movement of glucose in/out of the cell
Amino acids moving in/out of the cell
Establishes nervous impulse
What are phosphate ions components of?
Nucleic acids (DNA + RNA)
ATP
Phospholipids
NAD + NADP in photosynthesis
What is calcium important for?
Strong bones and teeth
What is magnesium important for?
Component of chlorophyll
What is nitrogen important for?
Protein synthesis in plants
Nitrogenous bases in nucleotides