BIOLOGY – KEY CONCEPTS c bacteria – chromosomal DNA, plasmid DNA, cell membrane,
1.1 Explain how the sub-cellular structures of eukaryotic and ribosomes and flagella
prokaryotic cells are related to their functions, including: Organelles in BACTERIAL CELL
Eukaryotes: Cells that contain their genetic material in their Contains: cell membrane, ribosomes, cytoplasm & cell wall
nucleus. Plant & Animal cells. Do NOT contain: Mitochondria, Chloroplasts, nucleus
Prokaryotes: Genetic material is not enclosed in a nucleus and are CHROMOSOMAL DNA/NUCLEOID: One long CIRCULAR
much smaller than Eukaryotic cells. Bacteria. Uni-cellular CHROMOSOME that controls the cells activities and replication. It
a animal cells – nucleus, cell membrane, mitochondria and floats free in the cytoplasm (not in nucleus).
ribosomes PLASMID DNA: Small loops of extra DNA not part of the
Organelles/sub-cellular structures of ANIMAL & PLANT CELLS: chromosome. Contains genes like drug/antibiotic resistance. Can
NUCLEUS: contains genetic material (DNA) that controls the be TRANSFERRED between bacteria.
activity of the cell. FLAGELLUM (pl. flagella): long, hair-like structure that rotate to
CELL MEMBRANE: Holds the cell together and controls what goes help the bacteria to move
in & out of the cell 1.2 Describe how specialised cells are adapted to their
MITOCHANDRIA: Where aerobic respiration takes place releasing function, including:
energy the cell can use Specialised cells: a cell that has a structure adapted to its
RIBOSOMES: The site of protein synthesis (where proteins are function
made) a sperm cells – acrosome, haploid nucleus, mitochondria and
CYTOPLASM: gel-like substance where most of the chemical tail
reactions happen ACROSOME: On the head that has enzymes that digest the
b plant cells – nucleus, cell membrane, cell wall, chloroplasts, membrane of the egg cell
mitochondria, vacuole and ribosomes HAPLOID NUCLEUS: contains 23 chromosomes to combine with
Additional organelles in PLANT cells ONLY: the egg and have 46 chromosomes.
CELL WALL: A rigid structure made from cellulose. It supports the MITOCHANDRIA: Contains LOTS of mitochondria in the middle
cell and strengthens it section to provide energy needed to swim
CHLOROPLASTS: Where photosynthesis happens. Contains green TAIL: Long tail to swim to the egg
substance called chlorophyll (absorbs the light energy needed)
VACUOLE: Contains cell sap (solution of sugar and salts). Used
for storage of nutrients
, RESOLUTION: The shortest distance between 2 points on an
b egg cells – nutrients in the cytoplasm, haploid nucleus and object that can still be distinguished. (A MEASURE OF HOW
changes in the cell membrane after fertilisation DETAILED THE IMAGE IS) higher resolution = more detailed
NUTRIENTS IN CYTOPLASM: Feeds the embryo in its early stage 2 types of Microscopes
CHANGES IN CELL MEMBRANE: After fertilisation, the cell LIGHT microscopes: Small, easy to use, cheap
membrane becomes impermeable to stop any more sperm cells - can be sued to see the cells, but not the sub-cellular structure as
coming in the resolution is not high enough
HAPLOID NUCLEUS ELECTRON microscope: Large size, expensive, hard to use
c ciliated epithelial cells - Use electrons which has a higher resolution than light.
Located on surface of organs/respiratory tract. They move - Thus higher magnification can be used and sub-cellular
substances. For example, in airway linings that move mucus up to structures can be identified
the throat so it can be swallowed and doesn’t reach the lungs MATHS SKILLS:
CILIA: hair-like structures that beat to move the substance in one 1.4 Demonstrate an understanding of number, size and scale,
direction including the use of estimations and explain when they should
1.3 Explain how changes in microscope technology, including be used
electron microscopy, have enabled us to see cell structures 1.5 Demonstrate an understanding of the relationship between
and organelles with more clarity and detail than in the past and quantitative units in relation to cells, including:
increased our understanding of the role of sub-cellular a milli (10−3)
structures b micro (10−6)
c nano (10−9)
d pico (10−12)
e calculations with numbers written in standard form
UNIT STANDARD FORM
Metre (m) 1
Millimetre (mm) x10-3 m
Micrometre (μm) x10-6 m
Nanometre (nm) x10-9 m
Picometre (pm) x10-12 m
,1.6 CORE PRACTICAL: MICRSCOPES d) CALCULATIONS:
a) PREPARING STAGE: Total magnification = eyepiece lens x objective lens
1) Get a very thin slice of the substance (eg. onion skin) Total magnification = image size/object size
2) Take a clean slide, add 1 drop of water (to secure specimen), OBJECT: The real object you are looking at
then use tweezers to place specimen on slide IMAGE: The image you see when looking through the microscope
3) Add 1 drop of iodine (to make specimen easier to see) 1.7 Explain the mechanism of enzyme action including the
4) Place cover slip on one end of the specimen, holding it at an active site and enzyme specificity
angle with a needle, then lower onto the specimen and press Catalyst: a substance that increases the speed of chemical
down gently (this is to ensure there are no air bubbles) reactions without being changed/used up
5) Clip slide onto stage Enzyme: Biological catalyst made up of large proteins (amino
b) VIEWING STAGE: acids)
1) Turn light on/ tilt mirror to reflect light SUBSTRATE: The molecule being acted on by the enzyme
2) Use lowest objective lens ACTIVE SITE: The part where the enzyme joins on to the substrate
3) Use course focus to bring slide up so it is just underneath the to catalyse the reaction. The active site has a high specificity with
objective lens (so you don’t crash into lens) one substrate, so it only catalyses that substrate.
4) Look into eyepiece and turn the COURSE focus downwards - The substrate fits exactly into the active sites shape like a ‘lock
until specimen is nearly into focus and key’
5) Turn the FINE focus until you get a clear image 1.8 Explain how enzymes can be denatured due to changes in
- Course & fine focus both move the stage, the course one moves the shape of the active site
it more but the fine focus very slightly moves the stage up/down. Denature: When the active site of the enzyme changes shape so it
c) SCIENTIFIC DRAWINGS OF IMAGE: is no longer complimentary to the substrate
1) Find the field of view (FOV) by placing a clear ruler onto the slide - This is irreversible
& measure the diameter of the area you can see with the eyepiece
2) Use a sharp pencil and DRAW & LABEL the main features of the
cell with NO colouring/shading
3) Include the FOV and the total magnification used in the drawing 1.9 Explain the effects of temperature, substrate
4) Repeat part b & c with a higher objective lens concentration and pH on enzyme activity
3 variables effect the rate of reaction of enzymes
, 1) TEMPERATURE 1.10 Core Practical: Investigate the effect of pH on enzyme
1) As the temperature initially activity
increases, the enzyme activity - Amylase is an enzyme that catalyses the breakdown of starch to
increases as the enzyme & maltose
substrate are moving faster -> - Iodine solution tests if starch is present and turns from browny-
more collisions orange to blue-black
2) At 37o they are working at the Boiling tube: A tube that is placed into a beaker of boiling water
fastest possible rate – optimum
HOW TO INVESTIGATE HOW pH AFFECTS AMYLASE ACTIVITY
temperature
1) Place a drop of iodine into every well of a spotting tile
3) As we increase past the
2) Heat a beaker of water till it is 35 o (optimum temp of amylase)
optimum, the activity of the
enzyme rapidly decreases to 0 3) Use a syringe to measure out into a BOILING TUBE:
and the enzyme becomes a) 3cm3 of amylase solution
denatured b) 1cm3 of a pH solution
2) pH c) 3cm3 of starch solution
- Too high/low pH will cause the 4) Immediately mix the contents and start a stopwatch
enzyme to denature 5) Use a pipette to take a sample of the boiling tube every 10
- All enzymes have an optimum seconds and drop into a well of the spotting tile
pH which is often 7 (neutral)
6) Repeat step 5 until the iodine solution remains the same colour
- Other enzymes have different
(there is no more starch left in the solution)
optimums, eg pepsin works best
7) Repeat the experiment with different pH solutions to see how
at pH 2 (acidic – stomach)
the pH affects how long it takes for the starch to be broken down
3) SUBSTRATE CONCENTRATION
1.11 Demonstrate an understanding of rate calculations for
1) Initially, the more substrates
enzyme activity
there are the higher rate of
reaction and enzymes are more Rate measures how fast the enzymes are working
likely to meet up and react with a Rate = change/Time
substrate Change: amount of: product formed OR substrate used
2) When all active sites are full, If the ‘change’ is not given then use:
more substrates will not increase Rate = 1000/time. Units are s-1
rate of reaction.
1.1 Explain how the sub-cellular structures of eukaryotic and ribosomes and flagella
prokaryotic cells are related to their functions, including: Organelles in BACTERIAL CELL
Eukaryotes: Cells that contain their genetic material in their Contains: cell membrane, ribosomes, cytoplasm & cell wall
nucleus. Plant & Animal cells. Do NOT contain: Mitochondria, Chloroplasts, nucleus
Prokaryotes: Genetic material is not enclosed in a nucleus and are CHROMOSOMAL DNA/NUCLEOID: One long CIRCULAR
much smaller than Eukaryotic cells. Bacteria. Uni-cellular CHROMOSOME that controls the cells activities and replication. It
a animal cells – nucleus, cell membrane, mitochondria and floats free in the cytoplasm (not in nucleus).
ribosomes PLASMID DNA: Small loops of extra DNA not part of the
Organelles/sub-cellular structures of ANIMAL & PLANT CELLS: chromosome. Contains genes like drug/antibiotic resistance. Can
NUCLEUS: contains genetic material (DNA) that controls the be TRANSFERRED between bacteria.
activity of the cell. FLAGELLUM (pl. flagella): long, hair-like structure that rotate to
CELL MEMBRANE: Holds the cell together and controls what goes help the bacteria to move
in & out of the cell 1.2 Describe how specialised cells are adapted to their
MITOCHANDRIA: Where aerobic respiration takes place releasing function, including:
energy the cell can use Specialised cells: a cell that has a structure adapted to its
RIBOSOMES: The site of protein synthesis (where proteins are function
made) a sperm cells – acrosome, haploid nucleus, mitochondria and
CYTOPLASM: gel-like substance where most of the chemical tail
reactions happen ACROSOME: On the head that has enzymes that digest the
b plant cells – nucleus, cell membrane, cell wall, chloroplasts, membrane of the egg cell
mitochondria, vacuole and ribosomes HAPLOID NUCLEUS: contains 23 chromosomes to combine with
Additional organelles in PLANT cells ONLY: the egg and have 46 chromosomes.
CELL WALL: A rigid structure made from cellulose. It supports the MITOCHANDRIA: Contains LOTS of mitochondria in the middle
cell and strengthens it section to provide energy needed to swim
CHLOROPLASTS: Where photosynthesis happens. Contains green TAIL: Long tail to swim to the egg
substance called chlorophyll (absorbs the light energy needed)
VACUOLE: Contains cell sap (solution of sugar and salts). Used
for storage of nutrients
, RESOLUTION: The shortest distance between 2 points on an
b egg cells – nutrients in the cytoplasm, haploid nucleus and object that can still be distinguished. (A MEASURE OF HOW
changes in the cell membrane after fertilisation DETAILED THE IMAGE IS) higher resolution = more detailed
NUTRIENTS IN CYTOPLASM: Feeds the embryo in its early stage 2 types of Microscopes
CHANGES IN CELL MEMBRANE: After fertilisation, the cell LIGHT microscopes: Small, easy to use, cheap
membrane becomes impermeable to stop any more sperm cells - can be sued to see the cells, but not the sub-cellular structure as
coming in the resolution is not high enough
HAPLOID NUCLEUS ELECTRON microscope: Large size, expensive, hard to use
c ciliated epithelial cells - Use electrons which has a higher resolution than light.
Located on surface of organs/respiratory tract. They move - Thus higher magnification can be used and sub-cellular
substances. For example, in airway linings that move mucus up to structures can be identified
the throat so it can be swallowed and doesn’t reach the lungs MATHS SKILLS:
CILIA: hair-like structures that beat to move the substance in one 1.4 Demonstrate an understanding of number, size and scale,
direction including the use of estimations and explain when they should
1.3 Explain how changes in microscope technology, including be used
electron microscopy, have enabled us to see cell structures 1.5 Demonstrate an understanding of the relationship between
and organelles with more clarity and detail than in the past and quantitative units in relation to cells, including:
increased our understanding of the role of sub-cellular a milli (10−3)
structures b micro (10−6)
c nano (10−9)
d pico (10−12)
e calculations with numbers written in standard form
UNIT STANDARD FORM
Metre (m) 1
Millimetre (mm) x10-3 m
Micrometre (μm) x10-6 m
Nanometre (nm) x10-9 m
Picometre (pm) x10-12 m
,1.6 CORE PRACTICAL: MICRSCOPES d) CALCULATIONS:
a) PREPARING STAGE: Total magnification = eyepiece lens x objective lens
1) Get a very thin slice of the substance (eg. onion skin) Total magnification = image size/object size
2) Take a clean slide, add 1 drop of water (to secure specimen), OBJECT: The real object you are looking at
then use tweezers to place specimen on slide IMAGE: The image you see when looking through the microscope
3) Add 1 drop of iodine (to make specimen easier to see) 1.7 Explain the mechanism of enzyme action including the
4) Place cover slip on one end of the specimen, holding it at an active site and enzyme specificity
angle with a needle, then lower onto the specimen and press Catalyst: a substance that increases the speed of chemical
down gently (this is to ensure there are no air bubbles) reactions without being changed/used up
5) Clip slide onto stage Enzyme: Biological catalyst made up of large proteins (amino
b) VIEWING STAGE: acids)
1) Turn light on/ tilt mirror to reflect light SUBSTRATE: The molecule being acted on by the enzyme
2) Use lowest objective lens ACTIVE SITE: The part where the enzyme joins on to the substrate
3) Use course focus to bring slide up so it is just underneath the to catalyse the reaction. The active site has a high specificity with
objective lens (so you don’t crash into lens) one substrate, so it only catalyses that substrate.
4) Look into eyepiece and turn the COURSE focus downwards - The substrate fits exactly into the active sites shape like a ‘lock
until specimen is nearly into focus and key’
5) Turn the FINE focus until you get a clear image 1.8 Explain how enzymes can be denatured due to changes in
- Course & fine focus both move the stage, the course one moves the shape of the active site
it more but the fine focus very slightly moves the stage up/down. Denature: When the active site of the enzyme changes shape so it
c) SCIENTIFIC DRAWINGS OF IMAGE: is no longer complimentary to the substrate
1) Find the field of view (FOV) by placing a clear ruler onto the slide - This is irreversible
& measure the diameter of the area you can see with the eyepiece
2) Use a sharp pencil and DRAW & LABEL the main features of the
cell with NO colouring/shading
3) Include the FOV and the total magnification used in the drawing 1.9 Explain the effects of temperature, substrate
4) Repeat part b & c with a higher objective lens concentration and pH on enzyme activity
3 variables effect the rate of reaction of enzymes
, 1) TEMPERATURE 1.10 Core Practical: Investigate the effect of pH on enzyme
1) As the temperature initially activity
increases, the enzyme activity - Amylase is an enzyme that catalyses the breakdown of starch to
increases as the enzyme & maltose
substrate are moving faster -> - Iodine solution tests if starch is present and turns from browny-
more collisions orange to blue-black
2) At 37o they are working at the Boiling tube: A tube that is placed into a beaker of boiling water
fastest possible rate – optimum
HOW TO INVESTIGATE HOW pH AFFECTS AMYLASE ACTIVITY
temperature
1) Place a drop of iodine into every well of a spotting tile
3) As we increase past the
2) Heat a beaker of water till it is 35 o (optimum temp of amylase)
optimum, the activity of the
enzyme rapidly decreases to 0 3) Use a syringe to measure out into a BOILING TUBE:
and the enzyme becomes a) 3cm3 of amylase solution
denatured b) 1cm3 of a pH solution
2) pH c) 3cm3 of starch solution
- Too high/low pH will cause the 4) Immediately mix the contents and start a stopwatch
enzyme to denature 5) Use a pipette to take a sample of the boiling tube every 10
- All enzymes have an optimum seconds and drop into a well of the spotting tile
pH which is often 7 (neutral)
6) Repeat step 5 until the iodine solution remains the same colour
- Other enzymes have different
(there is no more starch left in the solution)
optimums, eg pepsin works best
7) Repeat the experiment with different pH solutions to see how
at pH 2 (acidic – stomach)
the pH affects how long it takes for the starch to be broken down
3) SUBSTRATE CONCENTRATION
1.11 Demonstrate an understanding of rate calculations for
1) Initially, the more substrates
enzyme activity
there are the higher rate of
reaction and enzymes are more Rate measures how fast the enzymes are working
likely to meet up and react with a Rate = change/Time
substrate Change: amount of: product formed OR substrate used
2) When all active sites are full, If the ‘change’ is not given then use:
more substrates will not increase Rate = 1000/time. Units are s-1
rate of reaction.
