Topic 1 - Bio Molecules Flashcards
What causes water to be a dipole
The electrons between the covalent bonds are closer to oxygen, giving the O side a negative charge and the H2 side a positive charge
What is the significance of the following properties of water:
1) high specific heat capacity
2) cohesion and adhesion
3) latent heat of vaporisation
4) ice is less dense than water
5) transparency
1) means water is available to organisms across a wide range of temperatures
2) coh- water molecules flow together adh- water is attracted to move up walls
3) used in cooling effect using body heat to vaporise water
4) ice floats to surface to insulate habitat beneath
5) light can penetrate so plants and algae can photosynthesise
What are sodium ions used for?
Nerve impulses, uptake of glucose and amino acids into gut, kidney tubule function
What are phosphate ions used for?
Strengthen bones, used in ATP, DNA and RNA
What are iron ions used in?
Haemoglobin
What are iodine ions used for?
Production of thyroxine, involved in IQ levels and development
Iodine = trace element only need small amount daily
What are some monosaccharides?
Trioses,
Pentoses e.g ribose and deoxyribose, Hexoses e.g fructose, glucose and galactose
What is the formula for glucose and the difference between beta and alpha glucose?
Formula: C6 H12 O6
Alpha = OH group on first carbon is on bottom
Beta = OH group on first carbon is on top
ABBA
What are the disaccharides and what are they composed of?
Maltose - 2 alpha glucoses
Sucrose - alpha glucose and fructose
Lactose - alpha glucose and galactose
What is the reaction between glucose and what bond does it form? How do you break down these bonds?
A condensation reaction that forms glycosidic bonds. Bonds are broken down in a hydrolysis reaction
What are features of polysaccharides? What are the 3 main polysaccharides?
Larger molecules
Compact
Chemically inert
Lots of glycosidic bonds
3 main polysaccharides are starch, glycogen and cellulose
Others are : chitin and murein
What are the components of starch and features of them?
Amylose - long chain of alpha glucose twisted into alpha helix shape by hydrogen bonds contains only 1,4 glycosidic bonds
Amylopectin - branches chain of alpha glucose contains both 1,4 and 1,6 glycosidic bonds
What is the test for reducing sugars?
Add Benedict’s solution and heat at 80• for 5 mins. Copper precipitates to form a red colour from original blue
What is the test for non-reducing sugars?
Heat with HCl at 80•
Cool and neutralise (with sodium hydrogen carbonate)
Test with Benedict’s
Should turn from blue to red
What is the test for starch?
Add potassium iodide solution
Will turn from brown to blue/black
What is the structure and features of glycogen?
Polymer of alpha glucose
Animal energy reserve
Found in muscles and around liver
Very compact grain - more 1,6 glycosidic bonds
Chemically inert unless broken into glucose by hydrolysis
Insoluble
What enzyme breaks down starch and how does that then become glucose?
Starch is broken down by amylase into maltose
Maltose is broken down by maltase into glucose
What are features and the structure of cellulose?
Is a polymer of beta glucose
Creates a straight chain of microfibril
Is a component in the cell wall- microfibril is layered and held together by hydrogen bonds
Only 1,4 glycosidic bonds but the glucose molecules undergo an alternating 180• flip during bonding
What are features and the structure of cellulose?
Is a polymer of beta glucose
Creates a straight chain of microfibril
Is a component in the cell wall- microfibril is layered and held together by hydrogen bonds
Only 1,4 glycosidic bonds but the glucose molecules undergo an alternating 180• flip during bonding
What structure are lipids made out of? And what part of this is hydrophobic
Triglycerides
The fatty acid tails are hydrophobic
What are the two components of a fatty acid?
The carboxyl group and the hydrocarbon tail
What is the reaction between a glycerol and a fatty acid and what bond does it form?
A condensation reaction that forms a ester bond
What happens is a fatty acid is unsaturated?
It has less hydrogen atoms due to a carbon-carbon double bond which causes a kink in the chain
What happens is a fatty acid is unsaturated?
It has less hydrogen atoms due to a carbon-carbon double bond which causes a kink in the chain which makes the lipid a liquid (oil)
What are the uses of lipids?
Energy reserve used after carbohydrates in both plants and animals
Used in hormone production
Insulation
Rich in vitamins and aids uptake
Protects vital organs
Buoyancy
What are the two types of unsaturated fatty acids acids and what is the difference between them?
Monounsaturated - single C=C bonds
Polyunsaturated - multiple C=C bonds
What is a phospholipid and where is it found?
Made up of 1 glycerol, 2 fatty acid tails and 1 phosphate group
Make up cell membrane in a phospholipid bilayer
What is a glycolipid and what does it do?
1 glycerol, 2 fatty acid tails and 1 carbohydrate
Hold cells together in a tissue and act as a receptor for hormones
What is cholesterol and what is it used for?
4 hydrocarbon rings and 1 hydrocarbon tail
It fits in cell membrane and strengthens it and helps make hormones
What is the test for a lipid?
Emulsion test - add ethanol and shake add distilled water and shake should form a cloudy emulsion
What are the uses of protein?
Make up enzymes that catalyse reactions
Make up antigens that act as immunological markers
Collagen which is a component of tendons
Coats cholesterol to form lipoprotein
Make antibodies
Make pigments e.g. haemoglobin
How many naturally occurring amino acids are there? How many do humans gain from their diet? What foods provide these?
20 naturally occurring
Humans gain 10 from their diet
Meats provide all 10, different plants provide a different 8, pulses, nuts and grains provide all 10 when combined
What 3 groups do amino acids contain?
Amine group, carboxyl group and variable group
What reaction occurs between 2 amino acids, what bond does it form and what does it produce?
A condensation reaction which forms a polypeptide bond. Produces a dipeptide
What is the primary structure of protein?
The sequence of amino acids in polypeptides
What is the secondary structure of protein?
Either an alpha helix or a beta pleated sheet is formed due to hydrogen bonds between amino acids
What is the tertiary structure of protein?
A globular molecule is created due to bonds between R groups using:
Hydrogen bonds
Ionic bonds
Dipeptide bridges - only with [Cys]
Hydrophobic interaction
What is the quaternary structure of protein?
A protein consists of 2+ polypeptides joined together by hydrogen bonds
E.g. Haemoglobin consists of 2 alpha and 2 beta polypeptides
What is in the middle of the polypeptides making up Haemoglobin?
A haem group (prosthetic group)which contains 1 iron ion
How many oxygen atoms can one Haemoglobin carry?
8 oxygen atoms
Each haem can bind to 1 oxygen molecule (diatomic)
Each Haemoglobin contains 4 haems
What is collagen made up of
3 interwoven polypeptide strands
Each strand is made up of chains which are joined together in a staggered pattern to strengthen stand
What is the test for a protein?
Add biuret reagent
Will turn from blue to purple
What reactions do enzymes catalyse?
Metabolic reactions
Intracellular and extracellular
What reactions do digestive enzymes catalyse?
Hydrolysis reactions
What are the two enzymes that join nucleotides to make a polymer
DNA polymerase
RNA polymerase
What is formed when a substrate fits into an enzymes active site?
An enzyme-substrate complex
What bonds do the substrates form with the active site and why?
Temporary bonds
Very few so they are easily broken
What are the 3 steps of enzymes catalysing reactions?
1) substrate collided with sufficient energy to form product molecules
2) free energy of products must be less than that of substrate
3) may need energy to start reaction
What does the induced fit model state?
Enzymes are not complementary to substrate, substrate changes active site
This change weakens bonds in substrate which lowers the activation energy
Put ionic bonds, hydrogen bonds and disulphide bonds in order of strength (weakest to strongest)
Hydrogen, ionic, disulphide
Write a statement about the enzymes active site
Enzymes have an active site that can become complementary to a specific substrate
What are the 3 ways of calculating rate?
Product/time
Decrease in substrate/time
1/reaction time
What factors affect rate of enzyme reactions?
Concentration of substrate
Concentration of enzyme
Temperature
pH
Presence of inhibitors
What is a nuceotide of DNA composed of?
A phosphate group, pentose sugar (deoxyribose), and an organic nitrogenous base
What are the two kinds of bases and 2 of each?
Purines - adenine and guanine
Pyrimidines - cytosine and thymine
What are the phosphodiester bonds in DNA between?
Carbon 3 of the pentose sugar and the phosphate group
What is formed due to the phosphodiester bonds? How does this help DNA?
Sugar-phosphate backbone - makes DNA more stable and more resistant to mutations
What bonds form between complementary bases? What does this do for DNA?
Hydrogen bonds. 2 between A-T. 3 between C-G.
Makes DNA more stable, bonds can be broken when needed, bonds act as template during replication
What shape does DNA form?
A double helix - DNA = anti parallel
What is an RNA nucleotide made from?
A phosphate group, a pentose sugar (ribose) with 5 carbons, organic nitrogenous base
What are the 3 types of RNA?
Messenger RNA - copies base sequence of coding strand of 1 gene
Transfer RNA - carries amino acids to ribosomes
Ribosomal RNA - makes up ribosomes
What are the components of the nucleus?
Nucleolus - makes rRNA
Nuclear pore - let’s mRNA out
Nuclear envelope
Nucleoplasm
Compare RNA and DNA nucleotides
Both contain phosphate groups
Both contain 5 carbon pentose sugars
Both contain organic nitrogenous bases
RNA = ribose DNA = deoxyribose
DNA = thymine RNA = uracil
Compare DNA and RNA molecules
Both have sugar-phosphate backbones
RNA = single stranded DNA = double stranded
RNA = shorter than DNA
3 types of RNA
RNA = uracil not thymine
What are hydrogen ions used for?
They determine the pH of a substance
What are hydrogen ions used for?
They determine the pH of a substance
