Salters-Nuffield Advanced Biology Resources Activity 3.
1 Student Sheet
CELL STRUCTURE AND FUNCTION
Purpose
To describe the ultrastructure of a typical eukaryotic animal cell.
To recognise organelles from electron micrograph images.
To make measurements from electron micrograph images.
3D cell structure
In this activity you will look at the 3D structure of cells and at how structures in cells are related to
their functions. Use the Student Book and the interactive cell to help you complete this activity.
Questions
Q1 For each of the 2D shapes in Figure 1 below, decide which of the 3D shapes could be
sectioned (cut through) to produce that 2D shape. Write the letters of the appropriate 3D
shapes beside the 2D shapes. You may find you have more than one letter for some of the
shapes.
Figure 1 2D and 3D shapes.
Q2 Look at the three electron micrographs of mitochondria in the interactive cell. Describe and
explain any differences that you observe between these three micrographs.
Q3 Here are five features associated with membranes in cells:
(1) contains pores
(2) selective permeability
(3) may be stacked or folded
(4) fluid
(5) may surround organelles.
a Write the appropriate number (1–5) beside each characteristic below to show which of
the characteristics are associated with the features above.
Provides large surface area for attachment of enzymes
Determines which molecules enter or leave the cell
Allows passage of large molecules through the membrane
Can fuse with itself
Can change shape and fold
Forms an extensive channel system
Forms a separate compartment within a cell
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© 2015 University of York, developed by University of York Science Education Group.
This sheet may have been altered from the original. Page 1 of 4
Salters-Nuffield Advanced Biology Resources Activity 3.1 Student Sheet
b Which of the features 1–5 above are associated with the following functions of cell
membranes?
The balance of ions inside and outside a cell can be controlled
Membrane can pinch off sections and reseal itself
Enzymes can be isolated for specific chemical reactions at a particular
location in the cell
mRNA can pass out of the nucleus
Large molecules can be directed and transported quickly about the cell
Components of ribosomes can pass to the cytoplasm from the
nucleolus
c Which of the features 1–5 above are important for the following components and
activities of cells? (More than one feature may be important for each.)
Nucleus
Mitochondria
Chloroplasts
Vesicle formation
Exocytosis and endocytosis
Endoplasmic reticulum
Cell surface membrane
Look at the microscope images of organelles in the interactive cell before trying to identify the
organelles in the electron micrograph photographs shown in Figures 2, 3 and 4.
Q4 Identify the organelles A to E in the frog white blood cell (Figure 2).
Figure 2 Electron micrograph of a frog white blood cell. Magnification ×12 300.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© 2015 University of York, developed by University of York Science Education Group.
This sheet may have been altered from the original. Page 2 of 4
Salters-Nuffield Advanced Biology Resources Activity 3.1 Student Sheet
Q5 Figure 3 shows a bat pancreas cell. Identify the organelles A to C. A colour version of this
figure is available in the mediabank on SNAB Online.
Figure 3 Electron micrograph of bat pancreas cell. Magnification ×12 300.
Q6 Identify the organelles labelled A to C. A colour version of this figure is available in the
mediabank on SNAB Online.
Figure 4 Electron micrograph of part of a cell.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© 2015 University of York, developed by University of York Science Education Group.
This sheet may have been altered from the original. Page 3 of 4
Salters-Nuffield Advanced Biology Resources Activity 3.1 Student Sheet
Calculating the size of electron micrograph images
To calculate the size of an electron micrograph image, you need to:
measure the length of the image in mm
convert this length to µm (×1000)
calculate the actual size of the image by dividing the length of image in µm by the magnification.
To calculate the magnification of an electron micrograph image using a scale bar, you need to:
measure the length of the scale bar in mm
convert the length into µm
Work out the magnification by dividing the measured length of the scale bar by the number
written on the scale bar.
Q7 Calculate:
a the width of the nucleus in Figure 2 (horizontally across the centre)
b the mean width of the mitochondria in Figure 2.
Q8 Calculate the length of the mitochondrion shown in Figure 3.
Q9 a Work out the magnification of Figure 4.
b Using the scale bar, work out the length of the organelle labelled B in Figure 4.
All users will need to review the risk assessment information and may need to adapt it to local circumstances.
© 2015 University of York, developed by University of York Science Education Group.
This sheet may have been altered from the original. Page 4 of 4
