Aqa A Level Biology Paper 1 Exam Questions And Correct
Answers 2024/2025 Correct Verified Answers Best Graded
A+ For Success
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 - CORRECT ANSWERS
Test for Reducing Sugars (3)
Smaller units from which larger molecules are made - CORRECT ANSWERS 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. - CORRECT ANSWERS Non-
Reducing Sugars (2)
Add drops of iodine to starch solution. Colour change to blue-black - CORRECT
ANSWERS Test for Starch (1)
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion - CORRECT ANSWERS 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 - CORRECT ANSWERS 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 - CORRECT ANSWERS 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 - CORRECT ANSWERS Competitive
inhibition (2)
,Aqa A Level Biology Paper 1 Exam Questions And Correct
Answers 2024/2025 Correct Verified Answers Best Graded
A+ For Success
1. Molecule will bind to allosteric site.
2. Binding causes a change in active site.
3. Permanently preventing further ESC. - CORRECT ANSWERS 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 -
CORRECT ANSWERS 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. -
CORRECT ANSWERS 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 - CORRECT
ANSWERS Slime capsule (2)
Used for attachment of a cell to a surface - CORRECT ANSWERS Fimbria
Involved in bacterial conjugation - CORRECT ANSWERS Pilli
Invagination of cell membrane. Site of cell respiration (prokaryotes) - CORRECT
ANSWERS Mesosome
,Aqa A Level Biology Paper 1 Exam Questions And Correct
Answers 2024/2025 Correct Verified Answers Best Graded
A+ For Success
The ability to distinguish two points apart - CORRECT ANSWERS Resolution
1. Lower resolution than TEM
2. 3D image
3. Does not require thin samples - CORRECT ANSWERS Scanning Electron Microscope
The mass of organelles at the bottom of the test tube after centrifugation. - CORRECT
ANSWERS 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. - CORRECT ANSWERS 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. - CORRECT ANSWERS
Separation of Organelles From The Cells (4)
The solution not including the pellet at the bottom of the test tube after centrifugation. -
CORRECT ANSWERS Supernatant
1. Cell wall forms, dividing the two genetically identical daughter cells.
2. Same circular DNA. - CORRECT ANSWERS Binary Fission 3
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes -
CORRECT ANSWERS Order of Organelles
(Pass me a taco chief) - CORRECT ANSWERS Mitosis acronym
, Aqa A Level Biology Paper 1 Exam Questions And Correct
Answers 2024/2025 Correct Verified Answers Best Graded
A+ For Success
Cell grows and carrys out its normal function - CORRECT ANSWERS Interphase
Cells grow to normal size. Organelles replicate and genes are expressed to make
proteins needed. - CORRECT ANSWERS Interphase G1
DNA and histones replicated. - CORRECT ANSWERS Interphase S
Spindle fibres are made - CORRECT ANSWERS Interphase G2
1. DNA winds up making chromosones from chromatin.
2. Centrioles appear at opposite poles of the cell. 3. Nucleolus disappears - CORRECT
ANSWERS Prophase (3)
1. Nuclear envelope disappears.
2. Chromosomes align along the equator of the cell.
3. Spindle fibres connect centrioles to chromosomes - CORRECT ANSWERS Metaphase
(3)
1. Spindle fibres contract pulling daughter chromosomes to opposite poles of the cell. -
CORRECT ANSWERS Anaphase (1)
1. Cytoplasm constricts separating the cells into two.
2. Membrane forms creating two new genetically identical daughter cells. - CORRECT
ANSWERS Cytokinesis (2)
number of cells in mitosis/total number of cells - CORRECT ANSWERS Mitotic index
1. Circular DNA replicates and both copies attach to the cell membrane.
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