Unit 1 - Biological Molecules Flashcards
Examples of of monomers
Monosaccarides
Amino acids
Nucleotides
Condensation reaction points
Molecules joining together
Water is formed as a byproduct
Reaction between OH’s and H
Hydrolysis
Large to small molecules
Water is required
Forms H+ and OH- ions
What are amino acids joined together by?
Peptide bonds
Examples of proteins
Insulin
Enzymes
Structural proteins (Keratin and Collagen)
Non polar amino acid points
Hydrophobic
On the inside of proteins
Polar amino acid points
Hydrophilic
Found on the outside of proteins
Electrically charged
Have a whole charge
Want to form ionic bonds
What is the primary structure
Sequential chain of amino acids joined by peptide bonds
What are the bonds found in secondary structures?
Hydrogen bonds
What are the bonds in Tertiary structure? (In order of strength)
(Covalent) Disulphide bridges
Ionic bonds
Hydrogen bonds
What are the bonds in Tertiary structure? (In order of strength)
(Covalent) Disulphide bridges
Ionic bonds
Hydrogen bonds
Bonds found in globular proteins
Ionic and hydrogen bonds
Bond found in fibrous proteins
Disulphide bonds
Fibrous protein properties
Insoluble in water
Alpha helicies or beta pleated sheets
Disulphide bonds
Structural proteins
Globular protein properties
Soluble in water
Alpha helicies and beta pleated sheets
Ionic and hydrogen bonds
Metabolic proteins
Shape: Roughly circular
Function: Physiological
Examples: Hemoglobin, enzymes, insulin
Why do substances move at different rates in chromatography?
Affinity to the stationary phase
Solubility in the solvent
Why do substances move at different rates in chromatography?
Affinity to the stationary phase
Solubility in the solvent
Enzyme definition
Biological catalysts which provide an alternative reaction pathway with a different activation energy.
Describe the structure of enzymes?
Globular proteins with a 3D tertiary structure
Hydrophilic side chains
Have an active site
Described the induced fit model
1) Enzymes and substrates have specific tertiary structures that are roughly complementary
2) Substrate goes into active site
3) Bonds form and active site bends around substrate forming and induced fit and putting strain on the bonds
4) Activation energy is therefore lowered- substrate breaks
5) Products are released
Equation for temperature coefficient
Temperature coefficient= Rare of reaction at (x+10)/ Rate of reaction at x
Describe enzyme and decreasing PH
- In a higher PH, there are (less) H+ ions
- This causes the hydrogen and ionic bonds to break in the tertiary structure
- The enzymes denature
- Substrate and active site are no longer a complementary fit
- The enzyme substrate complex can no longer be made
Describe enzyme activity and increasing temp
- Increase in the kinetic energy of substrate and enzyme
- The enzyme and substrate move faster
- Substrate and enzyme more likely to collide
- An optimym temp is reached where are there are many random collisions but the shape of the active site hasn’t changed
- Enzymes absorb so much energy that the ionic and hydrogen bonds within them break- changing the 3D tertiary structure
- The enzymes become denatured
- There is no longer a complementary fit between the substrate and active site
Describing the effect of change of substrate conc
- Initially the substrate is the limiting factor as the enzyme (active site) is in abundance
- As substrate conc increases- more substrates can bind with active sites- forming and induced fit and giving an alternative reaction pathway with a lower activation energy.
- Eventually, the substrate is no longer the limiting factor- it is enzyme conc
- Increasing substrate conc no longer increases the rate of reaction
What are carbs made out of and in what ratio are they found?
Carbon, Oxygen and Hydrogen in the ratio CH2O
General properties of sugars
Sweet Soluble in water White Crystaline All have the suffix of OSE
What are disaccarides?
Two monosaccarides joined together by a gylcosidic bond- they are insoluble in water
Examples of Disaccarides
Sucrose- Glucose and Fructose
Lactose-Glucose and Galactose
Maltose- Glucose and Glucose
How are polysaccharides formed?
Multiple monosaccarides joined together by glycosydic bonds
Methods of breaking down polysaccarides into monosaccarides
Enxyme hydrolysis- Mix enzyme with polysaccaride at room temp
Acid hydrolysis- Boil HCl with the polysaccaride
What are Reducing sugars
A sugar that is able to donate an electron to something else
Which ones are the reducing sugars?
Glucose
Fructose
Maltose
How to test for a reducing sugar
- Heat with benedicts solution at 70 degrees in a thermostatically controlled water bath
- If a reducing sugar is present- Will go from blue- green-yellow-orange-brick red
To find out if a solution has reducing sugars but no non-reducing sugars
- Heat with benedicts solution, should go blue to brick red
- Another sample, heat with HCL and neutralise- should go the same colour
To find out a solution has non reducing but no reducing sugars
- Heat a sample with benedicts-should stay blue
- Heat another sample with HCL and neutralise with sodium hydrogencarbonate- when benedicts is added- should go brick red
To find if a solution has both reducing and none reducing sugars
- Add Benedicts reagent - if negative result (stays blue negative result)
- Add dilute HCl then neutralise with sodium hydrogencarbonate
- Then carry out the benedicts test again
Starch adaptations
- Insoluble so it doesn’t affect water potential or diffuse
- Compact- Doesn’t take up too much space
- Forms glucose when hydrolysed- can easily be transported and used in respiration
- Branched form can be very efficient
Cellulose adaptations
- Makes cell walls strong due to parallel chains held together by hydrogen bonds
- Can resist tugor pressure- this means it stops the cell from swelling too much
- Resists digestion from enzymes and microorganisms
- Glycosydic- Bonds alternate due to the fact that it uses beta glucose- postition of H and OH- causing the cellulose to form fibres
Glycogen adaptations
Insoluble- Doesn’t affect water potential- doesn’t diffuse out of cells
Compact- A lot can be stored in a small volume
Efficient to break down- Easily accessible for enzymes to break it down as it has lots of branches which can be acted on simultaneously.
Types of RNA
tRNA
mRNA
rRNA
DNA structure
Double helix
The two polynucleotide chains are antiparallel- they run upside down from each other
Made up of monomers of nucleotides
The two strands of nucleotides are held together by hydrogen bonds between complementary base pairs
Structure of RNA
Short polynucleotide chain joined together by covalent bonds `
Uses uracil instead of thymine
Properties of DNA vs RNA
Stable- Unstable ATGC- AUGC Bigger- Smaller Double helix-Single strand Hydrogen bonds- No hydrogen bonds
What is the type of bond between nucleotides
Phosphodiester bonds
Reasons why bases always pair with complementary pairs
- Bases are too big to fit- causing DNA to bulge
Characteristics of lipids
- They contain carbon, hydrogen and oxygen
- There are more hydrogens and carbons for every oxygen then that of carbohydrates
- They are insoluble in water
- They are soluble in organic solvents
The effects of having unsaturated fats
The double bonds formed from unsaturated hydrocarbons cause a kink in the molecule
meaning they can’t form a tight side by side structure.
Thus they are more likely do be liquid at room temp
The functions of triglycerides relating to structure
- High ratio of energy storing carbon-hydrogen bonds relative to other atoms
- Low mass to energy ratio- good storage molecules- reduces mass that animals carry around
- Being large non-polar molecules, triglycerides are insoluble in water- water potential and osmosis isn’t affected
- Source of water due to high ratio of hydrogen oxygen atoms
Structure of phospholipids relating to properties
- Hydrophilic head and hydrophobic body- In an aqueous environment it forms a bilayer within the cell surface membrane- forming a hydrophobic bilayer.
- Hydrophilic phosphate heads help hold the molecules at the surface of the cells
- Phosphates allow them to form glycolipids by joining with carbs- glycolipids are used for cell recognition
- Contribute to the flexibility of membranes and the transfer of substances.
General functions of lipids
- Source of energy- High ratio
- Waterproofing- Lipids are insoluble- can be used for waxy cuticles
- Insulation- Poor conductors of heat- retain body heat
- Poor conductors of electricity- used for things like myelin sheath
Emulsion test for lipids
- Take a dry test tube
- Add a sample to ethanol in the ratio 2:5
- Shake thoroughly (dissolves lipids)
- Add 5cm cubed of water and shake gently
- If there is a milky white emulsion- lipids are present
- As a control- do the test with water
Semi-conservative replication requirements
- The 4 types of nucleotide and their bases
- The strands of DNA act as a template for the attatchment of the nucleotides
- The Enzyme DNA polymerase
- A source of chemical energy is required to drive the process
The process of DNA replication
- The enzyme DNA helicase, causes the two strands of the DNA to separate by breaking hydrogen bonds between the bases- resulting in the double helix separating into two separate strands.
- Each exposed polynucleotide acts as a template to which complementary bases bind by base pairing
- Free nucleotides that have been activated bind specifically to the complementary bases
- The nucleotides are joined together by DNA polymerase which makes phosphodiester bonds, forming the sugar-phosphate backbone
- Each of the new DNA molecules contains one of the original DNA strands- half of the original DNA has been saved and built into the new DNA molecules.
Constituent parts of ATP
- Nitrogenous base
- Ribose
- Phosphate
What are the three ways that synthesis of ATP occurs
- In chlorophyll- containing plant cells during photosynthesis (Phosphorylation)
- In plant and animal cells during respiration (Oxidative phosphorylation )
- In plants and animals when phosphate groups are transfered from donor molecules to ADP
ATP properties
- Each ATP molecule releases less energy than each glucose molecule- the energy of each reaction is lower- less waste of energy and more heat control.
- The hydrolysis of ATP to ADP is a single reaction that releases immediate energy. The breakdown of glucose is longer
- ATP cannot be stored- needs to be continuously made in the cells that need it.
Roles of ATP
- Metabolic processes (building up molecules)
- Movement- Contraction of muscles
- Active transport- Used to change the shape of carrier proteins to allow molecules to go through
- Secretion- used for forming lysosomes
- Activation of molecules- Phosphorylation of other molecules
Describe Specific heat capacity of water
- A lot of energy input is required to increase heat by a small amount
- Due to bond enthalpies between water molecules
- Large volumes of water change temp slowly
High latent heat of vaporisation
- Hydrogen bonds require a lot of energy to break and thus cause water to evaporate
- Lots of energy is used to evaporate a small amount of water
- High heat to water loss ratio
Cohesion
- Hydrogen bonds between water molecules means that they are attracted
- This keeps them attracted to each other so they stick together
Adhesion
- Water is attracted to other molecules and other water molecules
- This causes it to stick to surfaces
Surface tension
- There is a higher density of hydrogen bonds on the surface of water
- To break these bonds requires a lot of energy as they are collectively strong
Water as a Solvent
- Allows water to transport dissolved molecules over large distances
- Creates a place for reactions to happen
Water as a substrate/ metabolite
Water is needed for hydrolysis as it is needed to create OH groups
Water properties in real life
Surface tension- Creates habitats for creatures above water
Cohesion- Water moves up xylem
Water is less dense when solid- Creates habitats, insulating water beneath
High specific heat capacity-Water maintains a relatively constant temp- high heat loss to water loss ratio
Water is a solvent- Transports molecules in blood around the body- dissolves minerals which can be taken up by plants
Its immiscible with fat- Membranes separate cells from environment, creating different conditions
Roles of organic ions
Sodium
Potassium
Phosphate
Iron
H+
Na+- Cotransport in illeum
Fe2+- Component of haemoglobin
Phosphate ions PO4 3- - Component of DNA
H+ role in pH
Why are lipids not considered polymers
Consist of two different molecules
Polymers must be repeated monomers
