AQA A LEVEL Biology Paper 1 COMPLETE GUIDE WITH 100%
RATED 250+ QUESTIONS AND CORRECT ANSWERS| GRADED A+ |
2025 LATEST UPDATED | 2 LATEST VERSIONS
Water removed from the reactants joining two molecules together forming a chemical bond -
(ANSWER)Condensation
The addition of water to the reactants to break a chemical bond between 2 molecules -
(ANSWER)Hydrolysis
1. Add Benedict's reagent. 2. Heat the solution in a water bath for 5 minutes at 95 degrees
Celsius. 3. Change from blue to brick red as CuO formed - (ANSWER)Test for Reducing
Sugars (3)
Smaller units from which larger molecules are made - (ANSWER)Monomer
1. Add 2cm³ of food sample then add 2cm³ of dilute HCl and heat.
2. Add 2cm³ of NaHCO3 then do test for reducing sugars. - (ANSWER)Non-Reducing Sugars
(2)
Add drops of iodine to starch solution. Colour change to blue-black - (ANSWER)Test for
Starch (1)
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion - (ANSWER)Test for Lipids (3)
1. Obtain equal volumes of test solution and NaOH then add a few drops of biuret solution
(dilute copper (II) sulphate solution).
,2. Colour change to mauve/purple - (ANSWER)Test for Proteins (2)
1. Very high resolution.
2. Needs thin and dead specimen.
3. Artefacts can occur (remnant left on object during prep, such as air bubbles)
4. Uses magnets to focus on specimen
5. Uses electrons fired at sample.
6. Is not in colour - (ANSWER)Transmission Electron Microscope (5)
1. Inhibitor is similar in shape to substrate so it impermanently binds to the active site.
2. Prevents ESC from forming, slowing rate - (ANSWER)Competitive inhibition (2)
1. Molecule will bind to allosteric site.
2. Binding causes a change in active site.
3. Permanently preventing further ESC. - (ANSWER)Non-competitive inhibition (3)
1. DNA helicase breaks the hydrogen bonds between the base pairs
2. 2 single strands formed as the double helix "unzips".
3. Free DNA nucleotides in the nucleoplasm bond to the complementary bases on the strand.
4. DNA polymerase forms phosphodiester bonds between adjacent DNA nucleotides via
condensation reaction with the hydrolysis of ATP, forming the phosphate backbone -
(ANSWER)DNA Replication: Semiconservative (4)
1. ATP stores or releases only a small amount of energy at a time, so no energy is wasted as heat.
2. Small and soluble so easily transported
3. Easily broken down, so energy is released instantaneously
4. Can be quickly re-made
5. Can make other molecules more reactive via phosphorylation
,6. ATP can't pass out of cell, so the cell always has an immediate supply of energy. -
(ANSWER)Describe 6 properties of ATP that make it a good energy source. (6)
Prevents the cell from drying out. Allows bacteria to stick to each other - (ANSWER)Slime
capsule (2)
Used for attachment of a cell to a surface - (ANSWER)Fimbria
Involved in bacterial conjugation - (ANSWER)Pilli
Invagination of cell membrane. Site of cell respiration (prokaryotes) - (ANSWER)Mesosome
The ability to distinguish two points apart - (ANSWER)Resolution
1. Lower resolution than TEM
2. 3D image
3. Does not require thin samples - (ANSWER)Scanning Electron Microscope
The mass of organelles at the bottom of the test tube after centrifugation. - (ANSWER)Pellet
Cold. Low temperature slows enzyme activity, minimising self digestion by reducing metabolic
rate. Isotonic. Salt and sugar concentration kept the same, minimising organelle size change due
to osmosis. Buffered. Minimum changes in pH, so prevents enzymes in organelles denaturing. -
(ANSWER)Solution Required for cell fractionation (6 Marks)
1. Homogenisation. Breaking up cells by blending the sample to create a homogenate.
2. Filtering. Filtering the large, unwanted sil, producing the filtrate.
3. Ultracentrifugation. Spin in a centrifuge so components separate out by weight. Heavier near
the bottom of the tube.
, 4. Supernatant is removed and spun again at higher speed. - (ANSWER)Separation of
Organelles From The Cells (4)
The solution not including the pellet at the bottom of the test tube after centrifugation. -
(ANSWER)Supernatant
1. Cell wall forms, dividing the two genetically identical daughter cells.
2. Same circular DNA. - (ANSWER)Binary Fission 3
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes -
(ANSWER)Order of Organelles
(Pass me a taco chief) - (ANSWER)Mitosis acronym
Cell grows and carrys out its normal function - (ANSWER)Interphase
Cells grow to normal size. Organelles replicate and genes are expressed to make proteins needed.
- (ANSWER)Interphase G1
DNA and histones replicated. - (ANSWER)Interphase S
Spindle fibres are made - (ANSWER)Interphase G2
1. DNA winds up making chromosones from chromatin.
2. Centrioles appear at opposite poles of the cell. 3. Nucleolus disappears -
(ANSWER)Prophase (3)
1. Nuclear envelope disappears.
2. Chromosomes align along the equator of the cell.
RATED 250+ QUESTIONS AND CORRECT ANSWERS| GRADED A+ |
2025 LATEST UPDATED | 2 LATEST VERSIONS
Water removed from the reactants joining two molecules together forming a chemical bond -
(ANSWER)Condensation
The addition of water to the reactants to break a chemical bond between 2 molecules -
(ANSWER)Hydrolysis
1. Add Benedict's reagent. 2. Heat the solution in a water bath for 5 minutes at 95 degrees
Celsius. 3. Change from blue to brick red as CuO formed - (ANSWER)Test for Reducing
Sugars (3)
Smaller units from which larger molecules are made - (ANSWER)Monomer
1. Add 2cm³ of food sample then add 2cm³ of dilute HCl and heat.
2. Add 2cm³ of NaHCO3 then do test for reducing sugars. - (ANSWER)Non-Reducing Sugars
(2)
Add drops of iodine to starch solution. Colour change to blue-black - (ANSWER)Test for
Starch (1)
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion - (ANSWER)Test for Lipids (3)
1. Obtain equal volumes of test solution and NaOH then add a few drops of biuret solution
(dilute copper (II) sulphate solution).
,2. Colour change to mauve/purple - (ANSWER)Test for Proteins (2)
1. Very high resolution.
2. Needs thin and dead specimen.
3. Artefacts can occur (remnant left on object during prep, such as air bubbles)
4. Uses magnets to focus on specimen
5. Uses electrons fired at sample.
6. Is not in colour - (ANSWER)Transmission Electron Microscope (5)
1. Inhibitor is similar in shape to substrate so it impermanently binds to the active site.
2. Prevents ESC from forming, slowing rate - (ANSWER)Competitive inhibition (2)
1. Molecule will bind to allosteric site.
2. Binding causes a change in active site.
3. Permanently preventing further ESC. - (ANSWER)Non-competitive inhibition (3)
1. DNA helicase breaks the hydrogen bonds between the base pairs
2. 2 single strands formed as the double helix "unzips".
3. Free DNA nucleotides in the nucleoplasm bond to the complementary bases on the strand.
4. DNA polymerase forms phosphodiester bonds between adjacent DNA nucleotides via
condensation reaction with the hydrolysis of ATP, forming the phosphate backbone -
(ANSWER)DNA Replication: Semiconservative (4)
1. ATP stores or releases only a small amount of energy at a time, so no energy is wasted as heat.
2. Small and soluble so easily transported
3. Easily broken down, so energy is released instantaneously
4. Can be quickly re-made
5. Can make other molecules more reactive via phosphorylation
,6. ATP can't pass out of cell, so the cell always has an immediate supply of energy. -
(ANSWER)Describe 6 properties of ATP that make it a good energy source. (6)
Prevents the cell from drying out. Allows bacteria to stick to each other - (ANSWER)Slime
capsule (2)
Used for attachment of a cell to a surface - (ANSWER)Fimbria
Involved in bacterial conjugation - (ANSWER)Pilli
Invagination of cell membrane. Site of cell respiration (prokaryotes) - (ANSWER)Mesosome
The ability to distinguish two points apart - (ANSWER)Resolution
1. Lower resolution than TEM
2. 3D image
3. Does not require thin samples - (ANSWER)Scanning Electron Microscope
The mass of organelles at the bottom of the test tube after centrifugation. - (ANSWER)Pellet
Cold. Low temperature slows enzyme activity, minimising self digestion by reducing metabolic
rate. Isotonic. Salt and sugar concentration kept the same, minimising organelle size change due
to osmosis. Buffered. Minimum changes in pH, so prevents enzymes in organelles denaturing. -
(ANSWER)Solution Required for cell fractionation (6 Marks)
1. Homogenisation. Breaking up cells by blending the sample to create a homogenate.
2. Filtering. Filtering the large, unwanted sil, producing the filtrate.
3. Ultracentrifugation. Spin in a centrifuge so components separate out by weight. Heavier near
the bottom of the tube.
, 4. Supernatant is removed and spun again at higher speed. - (ANSWER)Separation of
Organelles From The Cells (4)
The solution not including the pellet at the bottom of the test tube after centrifugation. -
(ANSWER)Supernatant
1. Cell wall forms, dividing the two genetically identical daughter cells.
2. Same circular DNA. - (ANSWER)Binary Fission 3
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes -
(ANSWER)Order of Organelles
(Pass me a taco chief) - (ANSWER)Mitosis acronym
Cell grows and carrys out its normal function - (ANSWER)Interphase
Cells grow to normal size. Organelles replicate and genes are expressed to make proteins needed.
- (ANSWER)Interphase G1
DNA and histones replicated. - (ANSWER)Interphase S
Spindle fibres are made - (ANSWER)Interphase G2
1. DNA winds up making chromosones from chromatin.
2. Centrioles appear at opposite poles of the cell. 3. Nucleolus disappears -
(ANSWER)Prophase (3)
1. Nuclear envelope disappears.
2. Chromosomes align along the equator of the cell.
