Bio Paper 1 Flashcards
Monomer
The smaller units from which larger molecules are made
e.g. glucose, fructose, galactose
Polymer
Molecules made from a large number of monomers joined together
Monosaccharide
The monomers from which larger carbohydrates are made
e.g. glucose, fructose, galactose
Disaccharide
Formed by the condensation of two monosaccharides
e.g. maltose, sucrose, lactose
Polysaccharide
Formed by the condensation of many glucose units held by glycosidic bonds
e.g. starch, glycogen, cellulose
Cellulose
Polysaccharide in plant cell walls formed by the condensation of β-glucose
Glycogen
Polysaccharide in animals formed by the condensation of α-glucose
Starch
Polysaccharide in plants formed by the condensation of α-glucose contains two polymers - amylose and amylopectin
Glycosidic bond
C–O–C link between two sugar molecules formed by a condensation reaction it is a covalent bond
Amylose
Polysaccharide in starch made of α-glucose joined by 1,4-glycosidic bonds coils to form a helix
Amylopectin
Polysaccharide in starch made of α-glucose joined by 1,4 and 1,6-glycosidic bonds branched structure
Condensation reaction
A reaction that joins two molecules together with the formation of a chemical bond involves the elimination of a molecule of water
Hydrolysis reaction
A reaction that breaks a chemical bond between two molecules involves the use of a water molecule
Fibrils
Long, straight chains of β-glucose glucose held together by many hydrogen bonds
Triglyceride
Formed by the condensation of one molecule of glycerol and three molecules of fatty acids forming 3 ester bonds
Phospholipid
Formed by the condensation of one molecule of glycerol and two molecules of fatty acid held by two ester bonds a phosphate group is attached to the glycerol
Induced-fit model
The enzyme active site is not initially complementary to the substrate the active site moulds around the substrate this puts tension on bonds lowers the activation energy A molecule that is the same/similar shape as the substrate binds to the active site prevents enzyme-substrate complexes from forming
Competitive inhibitor
A molecule that binds to an enzyme at the allosteric site causing the active site to change shape preventing enzyme-substrate complexes from forming
Non-competitive inhibitor
A molecule that binds to an enzyme at the allosteric site causing the active site to change shape preventing enzyme-substrate complexes from forming
Primary structure
The sequence of amino acids on a polypeptide chain
Secondary structure
The folding or coiling to create a β pleated sheet or an α helix held in place by hydrogen bonds
Tertiary structure
The further folding to create a unique 3D shape held in place by hydrogen, ionic and sometimes disulfide bonds
Quaternary structure
More than one polypeptide chain in a protein
Peptide bond
Covalent bond joining amino acids together in proteins C–N link between two amino acid molecules formed by a condensation reaction
What is the effect of temperature on enzyme-controlled reaction
At low temperatures, there is not enough kinetic energy for successful collisions between the enzyme and substrate. At too high a temperature, enzymes denature, the active site changes shape and enzyme- substrate complexes cannot form.
What is the effect of pH on enzyme-controlled reaction
Too high or too low a pH will interfere with the charges in the amino acids in the active site. This breaks the ionic and hydrogen bonds holding the tertiary structure in place therefore the active site changes shape and the enzyme denatures Different enzymes have a different optimal pH
What is the effect of substrate concentration on enzyme-controlled reaction
At low substrate concentrations, there will be fewer collisions between the enzyme and substrate. At high substrate concentrations, the rate plateaus because all the enzyme active sites are saturated
What is the effect of enzyme concentration on enzyme-controlled reaction
At low enzyme concentrations, there will be fewer collisions between the enzyme and substrate. At high enzyme concentrations, the rate plateaus because there are more enzymes than the substrate, so many empty active sites.
Ester bond
–COO– chemical bond formed between glycerol and fatty acids
Hydrophilic
The ability to mix, interact or attract water
Hydrophobic
The tendency to repel and not mix with water
Glucose
Monosaccharide that exists as two isomers α glucose β glucose
Galactose
An example of a monosaccharide that forms lactose
Fructose
An example of a monosaccharide that forms sucrose
Isomer
Molecules with the same molecular formula
What does ‘philic’ refer to?
The ability to mix, interact or attract water
Example: Hydrophilic substances dissolve easily in water.
What does ‘hydrophobic’ mean?
The tendency to repel and not mix with water
Example: Hydrophobic molecules cluster together and repel water.
What is glucose?
Monosaccharide that exists as two isomers β glucose and α glucose
Example: Glucose is a simple sugar used for energy by cells.
What is ‘Galactose’ an example of?
An example of a monosaccharide that forms lactose
What is ‘Fructose’ an example of?
An example of a monosaccharide that forms sucrose
What is an ‘Isomer’?
Molecules with the same molecular formula but the atoms are arranged differently
What is ‘Maltose’?
Disaccharide formed by the condensation of two glucose molecules
What is ‘Lactose’?
Disaccharide formed by the condensation of a glucose molecule and a galactose molecule
What is ‘Sucrose’?
Disaccharide formed by the condensation of a glucose molecule and a fructose molecule
What is a ‘Polypeptide’?
Polymer chain of a protein made up of amino acids bonded together by peptide bonds following condensation reactions
What is an ‘Amino acid’?
The monomer of a protein formed from C,H,O,N contains a carboxyl group, amine group and an R group
What is a ‘Carboxyl group’?
COOH group made up of a C with hydroxyl (OH) and carbonyl (double-bonded O) group bonded to it found in amino acids and fatty acids
What is an ‘Amine group’?
NH2 group found on amino acids
What is the ‘R group’ on amino acids?
The variable group, the part of each of the 20 amino acids that is different
What is an ‘α helix’?
A secondary structure in proteins a coiled shape held in place by hydrogen bonds
What is a ‘β pleated sheet’?
A secondary structure in proteins a folded, pleated shape held in place by hydrogen bonds
What are ‘Hydrogen bonds’?
Weak bond forms between H and O in many biological molecules e.g. proteins, water, DNA, tRNA
What are ‘Ionic bonds’?
A bond that forms between the R groups of different amino acids in the tertiary structure of proteins
What are ‘Disulfide bonds’?
A strong covalent bond between two sulfur atoms in the R groups of different amino acids in the tertiary structure of proteins
What is an ‘Active site’?
Unique-shaped part of an enzyme that the substrate binds to
What is ‘Activation energy’?
The minimum amount of energy required for a reaction to occur
What is an ‘Enzyme-substrate complex’?
Forms when an enzyme and substrate collide and bind resulting in a lowered activation energy
What does it mean to ‘Denature’?
When the active site changes shape so the substrate can no longer bind
What is an ‘Enzyme-inhibitor complex’?
The structure that forms when an enzyme and inhibitor collide and bind prevents enzyme-substrate complexes from forming
What is a ‘Saturated fatty acid’?
A long hydrocarbon chain with a carboxyl group at one end, only single bonds between carbon atoms
What is an ‘Unsaturated fatty acid’?
A long hydrocarbon chain with a carboxyl group at one end, at least one double bond between carbon atoms
What is a ‘Polar molecule’?
A molecule that has an uneven distribution of charge
What is a ‘Phospholipid bilayer’?
Phospholipids have two charged regions, in water, they are positioned so that the heads are exposed to water and the tails are not
What is the ‘Plasma membrane’?
Phospholipid bilayer cell surface membranes and organelle membranes
What are ‘Reducing sugars’?
Sugars that can reduce Cu ions in Benedict’s reagent to Cu ions in the form of copper (I) oxide which forms a brick-red precipitate
What is the ‘Test for reducing sugar’?
Add Benedict’s reagent, heat, observe green/yellow/orange/brick red precipitate
How does the structure of a triglyceride relate to its function?
Large ratio of energy-storing carbon-hydrogen bonds compared to the number of carbon atoms; a lot of energy is stored in the molecule, high ratio of hydrogen to oxygen atoms they act as a metabolic water source, do not affect water potentials and osmosis, have a relatively low mass
How does the structure of a phospholipid relate to its function?
Phospholipids have two charged regions, so they are polar. In water, they are positioned so that the heads are exposed to water and the tails are not. This forms a phospholipid bilayer which makes up the plasma membrane around cells.
How does the structure of a triglyceride and phospholipid differ?
A phospholipid has one fewer fatty acid chain which is replaced by a phosphate group
What is the difference between saturated and unsaturated fatty acid?
A saturated fatty acid has no double bonds between carbon atoms where as unsaturated fatty acids have at least one double bond between carbon atoms
What are ‘Non-reducing sugars’?
A sugar unable to reduce Cu2+, the glycosidic bond must be hydrolysed to expose the reducing group e.g. sucrose. Following a negative Benedict’s test boil the sample in acid and then neutralize with alkaline, add Benedict’s reagent and heat, observe orange/brick red color
What is the ‘Test for non-reducing sugar’?
Following a negative Benedict’s test, boil the sample in acid and then neutralize with alkaline, add Benedict’s reagent and heat, observe orange/brick red color
What is the ‘Test for starch’?
Add iodine, turns blue
What are the characteristics of saturated fatty acids?
Saturated fatty acids have single bonds between carbon atoms.
Example: Palmitic acid
What are the characteristics of unsaturated fatty acids?
Unsaturated fatty acids have at least one double bond between carbon atoms.
Example: Oleic acid
What is a non-reducing sugar?
A non-reducing sugar is a sugar unable to reduce Cu2+. The glycosidic bond must be hydrolysed to expose the reducing group.
Example: Sucrose
What is the test for non-reducing sugar?
To test for non-reducing sugar, boil the sample in acid, then neutralize with alkaline. Add Benedict’s reagent and heat, observe orange/brick red color.
What is the test for starch?
To test for starch, add iodine. It turns blue/black.
How to test for lipids?
To test for lipids, add ethanol and shake to dissolve, then add water. A white emulsion forms.
How to test for protein?
To test for protein, add biuret. It turns purple.
What is a nucleotide?
A nucleotide is the monomer of DNA and RNA, containing a pentose sugar, a phosphate group, and a nitrogenous base.
What are the complementary base pairs?
Complementary base pairs align opposite each other and form hydrogen bonds. Adenine pairs with thymine/uracil, guanine pairs with cytosine.
What is a polynucleotide?
A polynucleotide is a DNA polymer with many nucleotides joined together via a condensation reaction, joined by phosphodiester bonds.
What is the structure of water?
Water is a polar molecule, with the oxygen atom slightly negative and the hydrogen atoms slightly positive.
What is the role of ATP synthase?
ATP synthase is an enzyme that catalyzes the synthesis of ATP from ADP + Pi.
What is the role of ATP hydrolase?
ATP hydrolase is an enzyme that catalyzes the hydrolysis of ATP into ADP + Pi.
What is phosphorylation?
Phosphorylation is the addition of a phosphate group to a molecule, making the molecule more reactive/gaining energy.
What is a dipeptide?
A dipeptide is two amino acids bonded together by a peptide bond, formed by a condensation reaction.
What is the role of hydrogen ions?
Hydrogen ions determine the pH, with more ions indicating more acidic conditions and playing a role in chemiosmosis in respiration and photosynthesis.
What is the role of iron ions?
Iron ions are a compound of haemoglobin involved in oxygen transport.
What is the role of sodium ions in co-transport?
Sodium ions are involved in co-transport for the absorption of glucose and amino acids in the ileum.
What is the role of phosphate ions?
Phosphate ions are a component of DNA, RNA, and ATP, forming phosphodiester bonds in DNA and RNA between the phosphate group and the pentose sugar.
What is co-transport involved in?
Absorption of glucose and amino acids in the ileum
Example: Co-transport is involved in the absorption of glucose and amino acids in the ileum.
What is the role of phosphate ions?
As a component of DNA, RNA, and ATP
Phosphate ions play a crucial role as a component of DNA, RNA, and ATP.
What forms the phosphodiester bond in DNA and RNA?
Between the phosphate group and the pentose sugar
The phosphodiester bond in DNA and RNA forms between the phosphate group and the pentose sugar.
What is the structure of a fatty acid?
It has a carboxyl group and a long hydrocarbon chain
Fatty acids consist of a carboxyl group and a long hydrocarbon chain.
Can fatty acids be saturated or unsaturated?
Fatty acids can exist in saturated or unsaturated forms.
