E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |1
A Level Biology Edexcel B Questions &
100% correct Answers- Latest Test |
Graded A+ | Passed
Features and function of the Nucleus
Ξ -:- - Present in all eukaryotic cells
Ξ - Surrounded by double membrane (nueclear envelope)
Ξ - Membrane contains nuclear pores to allow movement of mRNA and ribosomes
out of nucleus, and enzymes into nucleus
Ξ - Stores genetic material as chromatin
Ξ - nucleolus (site of ribosome production)
Where is the site of ribosome production?
Ξ -:- Nucleolus
Features and Function of Rough Endoplasmic Reticulum
Ξ -:- - Folds of membrane with it's surface covered in ribosomes
- Folds and processes proteins made on the ribosomes
Features and Function of Smooth Endoplasmic Reticulum
Ξ -:- - Folds of membrane (no ribosomes)
- Production, processing and storage of lipids, carbohydrates and steroids
How to distinguish between smooth or rough endoplasmic reticulum?
Ξ -:- Observe under electron microscope
If ribosomes present, it is RER
If ribosomes not present, it is SER
26/08/2024 | © Copyright- This work may not be copied for profit.
, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |2
Features and function of Golgi Apparatus
Ξ -:- - Flattened Fluid filled curved sacs called cisternae
- Sorts and modifies proteins and lipids before packaging them into vesicles to be transported.
Features and function of mitochondria
Ξ -:- - Site of aerobic respiration
- Surrounded by a double membrane (envelope)
- Inner membrane folded to form cristae
- Matrix contains enzymes needed for aerobic respiration
- Also contains ribosomes and small pieces of DNA needed for replication of mitochondria before
cell division
Features and function of centrioles
Ξ -:- - Not found in plant or fungi cells
- Made out of hollow fibres called microtubules
- Microtubules are filaments of a protein that is used to move substances inside the cell and
supports shape of cell
- Two centrioles at a right angle to each other form a centrosome
- Organises spindle fibres during cell division
Features and function of 80s Ribsosomes
Ξ -:- - Found in eukaryotic cells only
- Site of protein synthesis and translation
- Made up of large 60s subunit, and small 40s subunit
Features and function of lysosomes
Ξ -:- - Bound by single membrane
- Form of vesicle containing hydrolytic enzymes
- Used by cells of immune system for programmed cell death
Features and function of vacuole
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, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |3
Ξ -:- - Large and central in plants (animal cells may have one, but they are often small
and temporary)
- Fluid filled cavity surrounded by a membrane (tonoplast)
- Helps maintain hydrostatic pressure and store cell sap
Features and function of plasmids
Ξ -:- - Small loops of DNA sometimes found in bacterial cells
- Contain genes that can be passed between prokaryotes (antibiotic resistance)
Features and function of slime capsule
Ξ -:- - Help keep bacteria moist and prevent them from drying out
- Help protect bacterial cells from attack of host organisms immune system cells
Features and function of Nucleoid
Ξ -:- - Area in which circular DNA is found
- Genetic material in prokaryotic cells often found as single circular strands
Features and function of Pilus
Ξ -:- - Thread like structures found on cell surface membrane
- Enables bacteria to attach to other cells and surfaces
- Allows plasmids to be passed from cell to cell
Features and function of 70s Ribosomes
Ξ -:- - Large 50s subunit
- Small 30s subunit
- Site of protein synthesis
Features and function of cell wall (prokaryotic)
26/08/2024 | © Copyright- This work may not be copied for profit.
, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |4
Ξ -:- - Made of peptidoglycan
- Provides strength and support to the cell
Difference in structure of Gram negative and Gram positive bactera
Ξ -:- Gram positive:
- Thick layer of peptidoglycan
- Inner plasma membrane
Gran negative:
- Thin layer of peptidoglycan
- Outer lipopolysaccharide membrane
Gram Staining Test Procedure + Results
Ξ -:- 1. Crystal violet solution for 1 minute, then wash with water
2. Iodine solution for 1 minute, wash with water
3. Alcohol added for 1 minute (lipopolysaccharide soluble in alcohols so outer membrane dissolves)
4. Red safranin for 1 minute, then dried
Gram positive: Purple
Gran negative: Pink/Red
Resolution
Ξ -:- Minimum distance between two objects where they can still be seen as two
separate objects
Features of transmission electron microscope
Ξ -:- Beams of electrons transmitted through the object, producing a 2D image.
Resolution 2000x better than light microscope
Features of Scanning electron microscope
26/08/2024 | © Copyright- This work may not be copied for profit.
A Level Biology Edexcel B Questions &
100% correct Answers- Latest Test |
Graded A+ | Passed
Features and function of the Nucleus
Ξ -:- - Present in all eukaryotic cells
Ξ - Surrounded by double membrane (nueclear envelope)
Ξ - Membrane contains nuclear pores to allow movement of mRNA and ribosomes
out of nucleus, and enzymes into nucleus
Ξ - Stores genetic material as chromatin
Ξ - nucleolus (site of ribosome production)
Where is the site of ribosome production?
Ξ -:- Nucleolus
Features and Function of Rough Endoplasmic Reticulum
Ξ -:- - Folds of membrane with it's surface covered in ribosomes
- Folds and processes proteins made on the ribosomes
Features and Function of Smooth Endoplasmic Reticulum
Ξ -:- - Folds of membrane (no ribosomes)
- Production, processing and storage of lipids, carbohydrates and steroids
How to distinguish between smooth or rough endoplasmic reticulum?
Ξ -:- Observe under electron microscope
If ribosomes present, it is RER
If ribosomes not present, it is SER
26/08/2024 | © Copyright- This work may not be copied for profit.
, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |2
Features and function of Golgi Apparatus
Ξ -:- - Flattened Fluid filled curved sacs called cisternae
- Sorts and modifies proteins and lipids before packaging them into vesicles to be transported.
Features and function of mitochondria
Ξ -:- - Site of aerobic respiration
- Surrounded by a double membrane (envelope)
- Inner membrane folded to form cristae
- Matrix contains enzymes needed for aerobic respiration
- Also contains ribosomes and small pieces of DNA needed for replication of mitochondria before
cell division
Features and function of centrioles
Ξ -:- - Not found in plant or fungi cells
- Made out of hollow fibres called microtubules
- Microtubules are filaments of a protein that is used to move substances inside the cell and
supports shape of cell
- Two centrioles at a right angle to each other form a centrosome
- Organises spindle fibres during cell division
Features and function of 80s Ribsosomes
Ξ -:- - Found in eukaryotic cells only
- Site of protein synthesis and translation
- Made up of large 60s subunit, and small 40s subunit
Features and function of lysosomes
Ξ -:- - Bound by single membrane
- Form of vesicle containing hydrolytic enzymes
- Used by cells of immune system for programmed cell death
Features and function of vacuole
26/08/2024 | © Copyright- This work may not be copied for profit.
, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |3
Ξ -:- - Large and central in plants (animal cells may have one, but they are often small
and temporary)
- Fluid filled cavity surrounded by a membrane (tonoplast)
- Helps maintain hydrostatic pressure and store cell sap
Features and function of plasmids
Ξ -:- - Small loops of DNA sometimes found in bacterial cells
- Contain genes that can be passed between prokaryotes (antibiotic resistance)
Features and function of slime capsule
Ξ -:- - Help keep bacteria moist and prevent them from drying out
- Help protect bacterial cells from attack of host organisms immune system cells
Features and function of Nucleoid
Ξ -:- - Area in which circular DNA is found
- Genetic material in prokaryotic cells often found as single circular strands
Features and function of Pilus
Ξ -:- - Thread like structures found on cell surface membrane
- Enables bacteria to attach to other cells and surfaces
- Allows plasmids to be passed from cell to cell
Features and function of 70s Ribosomes
Ξ -:- - Large 50s subunit
- Small 30s subunit
- Site of protein synthesis
Features and function of cell wall (prokaryotic)
26/08/2024 | © Copyright- This work may not be copied for profit.
, E x c e l l e n c e i s k e y | 2 0 2 0 2 5 ~ P a g e |4
Ξ -:- - Made of peptidoglycan
- Provides strength and support to the cell
Difference in structure of Gram negative and Gram positive bactera
Ξ -:- Gram positive:
- Thick layer of peptidoglycan
- Inner plasma membrane
Gran negative:
- Thin layer of peptidoglycan
- Outer lipopolysaccharide membrane
Gram Staining Test Procedure + Results
Ξ -:- 1. Crystal violet solution for 1 minute, then wash with water
2. Iodine solution for 1 minute, wash with water
3. Alcohol added for 1 minute (lipopolysaccharide soluble in alcohols so outer membrane dissolves)
4. Red safranin for 1 minute, then dried
Gram positive: Purple
Gran negative: Pink/Red
Resolution
Ξ -:- Minimum distance between two objects where they can still be seen as two
separate objects
Features of transmission electron microscope
Ξ -:- Beams of electrons transmitted through the object, producing a 2D image.
Resolution 2000x better than light microscope
Features of Scanning electron microscope
26/08/2024 | © Copyright- This work may not be copied for profit.
