IB Biology
Required Practicals
The table overleaf lists the seven required practicals on the syllabus for Higher Level. Questions
specifically related to these (or some of them) will feature in Paper 3. This does not mean questions about
them will not also be asked in other papers.
Any other practical work done (e.g. as per applications sections of the syllabus) may be asked about in
Papers 1 and 2.
Note that in addition you may be asked about statistical analysis including significance tests.
It would be worth completing a summary table (or a set of revision cards) along the lines of the one
over the page to make sure that you fully know and understand the nature of the required
practicals.
, Required Topic Area Name of Syllabus Details Basics of method (include a Outcomes (Results Other relevant Possible questions (add your own
Practical Practical small diagram if helpful) and conclusions) information ideas)
Number
1 Cell Biology Microscopy Skill: Use of a light 1. Place the cells on a slide in a layer Attempts can be made to Transmission electron Questions requiring magnifications to be
microscope to no more than 1 cell thick deduce cell function based microscopes (TEM) generate calculated or interpreted.
investigate the 2. Add a drop of water or stain on the relative abundance of high resolution cross-sections Image size/ actual size (in same
structure of cells and 3. Carefully lower a cover slip onto various organelles: of objects
tissues, with drawing the drop Mitochondria – Cells with Scanning electron microscopes
measurement)
of cells. Calculation 4. Remove excess fluid or stain by many mitochondria typically (SEM) display enhanced depth Questions requiring organelles to be
of the magnification putting the slide inside a folded piece undertake energy- to map the surface of objects in identified.
of drawings and the of paper towel and press lightly on consuming processes (e.g. 3D Determination of mitotic index
actual size of cover slip neurons, muscle cells) Outline process of focusing a light
structures and ultra- ER – Cells with extensive Electron microscopes have two microscope
structures shown in Focusing: ER networks undertake key advantages compared to
drawings or 1. place the object on the stage secretory activities (e.g. light microscopes:
micrographs. «centred» below the objective plasma cells, exocrine gland They have a much higher
lens/above the light cells) range of magnification (can
2. focus by moving the objective lens Lysosomes – Cells rich in detect smaller structures)
and specimen apart rather than lysosomes tend to They have a much higher
towards each other undertake digestive resolution (can provide clearer
3.use coarse/ large focusing first/to processes (e.g. phagocytes) and more detailed images)
find areas of interest and then Chloroplasts – Cells with
fine/small focusing «knob» chloroplasts undergo Resolution- distinguishing
4. use low power first to find areas of photosynthesis (e.g. plant between different parts of a
interest /use high power first to look leaf tissue but not root structure
in detail tissue)
5. Adjust light intensity
2 Membrane Osmosis Skill: Estimation of 1. Create stock solutions of certain Plants that store the most Osmolarity is a measure Questions in which data or a graph is
Transport and osmolarity in tissues concentrations of solution water and the least solutes of solute concentration, as used to determine the osmolarity of
Osmolarity by bathing samples 2. Obtain plant tissue samples that (lowest osmolarity) will loose defined by the number different tissues.
in hypotonic and are similar in terms of osmolarity the most mass, for example of osmoles of a solute per litre
hypertonic solutions. 3. Ensure surface of tissue samples xerophytes such as cacti. of solution (osmol/L)
Adaptions of plants for water storage
are dry when finding mass
4. Leave tissues long enough for Uncontrolled osmosis will have
mass change to take place, but not negative effects with regards to
long enough for other factors such as cell viability:
deposition to have an effect In hypertonic solutions, water
5. Calculate % mass change will leave the cell causing it to
shrivel (crenation)
Constant variables: In hypotonic solutions, water
Time left in solution will enter the cell causing it to
How the tissues are dried swell and potentially burst
Balance used to weigh samples (lysis)
Surface area of sample
In plant tissues, the effects of
uncontrolled osmosis are
moderated by the presence of
an inflexible cell wall
In hypertonic solutions, the
cytoplasm will shrink
(plasmolysis) but the cell wall
will maintain a structured shape
In hypotonic solutions, the
cytoplasm will expand but be
unable to rupture within the
constraints of the cell wall
(turgor)
3 Enzymes Rate of Skill: Experimental Factors affecting enzyme activity: Heat- increase up to a point Questions relating to the different factors
Enzyme investigation of a 1. Temperature then denaturation. Optimum that can affect the rate of an enzyme-
Required Practicals
The table overleaf lists the seven required practicals on the syllabus for Higher Level. Questions
specifically related to these (or some of them) will feature in Paper 3. This does not mean questions about
them will not also be asked in other papers.
Any other practical work done (e.g. as per applications sections of the syllabus) may be asked about in
Papers 1 and 2.
Note that in addition you may be asked about statistical analysis including significance tests.
It would be worth completing a summary table (or a set of revision cards) along the lines of the one
over the page to make sure that you fully know and understand the nature of the required
practicals.
, Required Topic Area Name of Syllabus Details Basics of method (include a Outcomes (Results Other relevant Possible questions (add your own
Practical Practical small diagram if helpful) and conclusions) information ideas)
Number
1 Cell Biology Microscopy Skill: Use of a light 1. Place the cells on a slide in a layer Attempts can be made to Transmission electron Questions requiring magnifications to be
microscope to no more than 1 cell thick deduce cell function based microscopes (TEM) generate calculated or interpreted.
investigate the 2. Add a drop of water or stain on the relative abundance of high resolution cross-sections Image size/ actual size (in same
structure of cells and 3. Carefully lower a cover slip onto various organelles: of objects
tissues, with drawing the drop Mitochondria – Cells with Scanning electron microscopes
measurement)
of cells. Calculation 4. Remove excess fluid or stain by many mitochondria typically (SEM) display enhanced depth Questions requiring organelles to be
of the magnification putting the slide inside a folded piece undertake energy- to map the surface of objects in identified.
of drawings and the of paper towel and press lightly on consuming processes (e.g. 3D Determination of mitotic index
actual size of cover slip neurons, muscle cells) Outline process of focusing a light
structures and ultra- ER – Cells with extensive Electron microscopes have two microscope
structures shown in Focusing: ER networks undertake key advantages compared to
drawings or 1. place the object on the stage secretory activities (e.g. light microscopes:
micrographs. «centred» below the objective plasma cells, exocrine gland They have a much higher
lens/above the light cells) range of magnification (can
2. focus by moving the objective lens Lysosomes – Cells rich in detect smaller structures)
and specimen apart rather than lysosomes tend to They have a much higher
towards each other undertake digestive resolution (can provide clearer
3.use coarse/ large focusing first/to processes (e.g. phagocytes) and more detailed images)
find areas of interest and then Chloroplasts – Cells with
fine/small focusing «knob» chloroplasts undergo Resolution- distinguishing
4. use low power first to find areas of photosynthesis (e.g. plant between different parts of a
interest /use high power first to look leaf tissue but not root structure
in detail tissue)
5. Adjust light intensity
2 Membrane Osmosis Skill: Estimation of 1. Create stock solutions of certain Plants that store the most Osmolarity is a measure Questions in which data or a graph is
Transport and osmolarity in tissues concentrations of solution water and the least solutes of solute concentration, as used to determine the osmolarity of
Osmolarity by bathing samples 2. Obtain plant tissue samples that (lowest osmolarity) will loose defined by the number different tissues.
in hypotonic and are similar in terms of osmolarity the most mass, for example of osmoles of a solute per litre
hypertonic solutions. 3. Ensure surface of tissue samples xerophytes such as cacti. of solution (osmol/L)
Adaptions of plants for water storage
are dry when finding mass
4. Leave tissues long enough for Uncontrolled osmosis will have
mass change to take place, but not negative effects with regards to
long enough for other factors such as cell viability:
deposition to have an effect In hypertonic solutions, water
5. Calculate % mass change will leave the cell causing it to
shrivel (crenation)
Constant variables: In hypotonic solutions, water
Time left in solution will enter the cell causing it to
How the tissues are dried swell and potentially burst
Balance used to weigh samples (lysis)
Surface area of sample
In plant tissues, the effects of
uncontrolled osmosis are
moderated by the presence of
an inflexible cell wall
In hypertonic solutions, the
cytoplasm will shrink
(plasmolysis) but the cell wall
will maintain a structured shape
In hypotonic solutions, the
cytoplasm will expand but be
unable to rupture within the
constraints of the cell wall
(turgor)
3 Enzymes Rate of Skill: Experimental Factors affecting enzyme activity: Heat- increase up to a point Questions relating to the different factors
Enzyme investigation of a 1. Temperature then denaturation. Optimum that can affect the rate of an enzyme-
