Module 2: Section 1 - Cell structure
The following list describes a number of features of mitochondria and chloroplasts. Select the three
statements that could be used as evidence for the endosymbiotic theory.
- mitochondria contain ribosomes that are smaller than those in the cell cytoplasm
- chloroplasts contain chlorophyll and other photosynthetic pigments
- mitochondria are a similar size to bacteria
- the inner membrane of a mitochondrion is folded to form cristae
- chloroplasts contain many disc-shaped membranes called thylakoids
- chloroplasts have their own circular DNA
Name two features of plant cells that are not features of animal cells.
- Cellulose cell wall
- Chloroplasts
- Starch grains/ amyloplasts
- Large/ permanent vacuole
Name one structure present in animal cells that is not present in plant cells.
- Centriole
- Lysosome
- Cilia
- Flagella
The cytoskeleton in cells consists of microtubules and microfilaments. Describe the roles of the
cytoskeleton.
- Support whole cell/ maintain shape
- Use of cilia/ flagella/ undulipodium to move cell
- Changing shape of cell/ cytokinesis/ phagocytosis/ exocytosis/ endocytosis/ muscle
contraction
- Movement of chromosomes. chromatids/ mRNA
The pancreas is an organ that secretes protease enzymes. Outline how the organelles in pancreatic
cells work together to produce and release these protein molecules from the cells.
- Nucleus contains gene for protein/ site of transcription/ produces mRNA
- Ribosomes/ rough endoplasmic reticulum is the site of protein synthesis/ translation
- Vesicles for transport of protein
- Golgi apparatus processes and modifies proteins
- Vesicles fuse with cell surface membrane
A student suggested that the details of the mitochondrion could be seen clearly with a very good light
microscope. Explain why the student is not correct.
- Mitochondrion/ cristae is too small
- Resolution of light microscope is not high enough (only 0.2μm)
- Wavelength of light too long
Staining is a process often used in microscopy. Describe the advantages of staining specimens to be
viewed under a microscope.
- Makes visible/ easier to see more details
, - Staining increases contrast to identify organelles/ different parts of the cell
Mitochondria provides ATP which is a source of energy. Suggest one stage during the secretion of a
protein that requires energy.
- Transport vesicles to cell surface membrane
- Fusing vesicles to membrane/ exocytosis
Outline the role of the Golgi apparatus.
- Receives proteins from the rough ER/ ribosomes
- Modify and repackages proteins into vesicles
- Eg. make glycoproteins/ add carbohydrate groups/ sugar
- Make lysosomes
- Replenishes cell surface membrane/ make glycolipids
- Lipid synthesis
Identify two features in a eukaryotic cell which would not be present in a prokaryotic cell.
- Nucleus
- Mitochondria
- Rough/ smooth ER
- Glogi apparatus
- Secretory vesicles
Name one feature that would be present in the cytoplasm of a prokaryotic cell that is not found in a
eukaryotic cell.
- Free/ circular DNA
- Plasmid
- Smaller ribosomes
A student wanted to observe some red blood cells under the microscope. The student placed a small
sample of blood onto a microscope slide and added a drop of distilled water. When viewed at high
power, the student observed that the red blood cells had burst. In a similar procedure using plant
epidermis, the student observed that the plant cells did not burst. Explain these observations.
- Cell cytoplasm has a lower water potential that distilled water
- Water moves into cells down the water potential gradient
- Water enters the cell by osmosis
- Plasma membrane of blood cell will burst/ cannot withstand pressure/ haemolyses
- Plant cell wall is strong and provides support, and thus does not burst/ can withstand pressure
- Plant cell becomes turgid, which reduces water uptake
Suggest how the student could modify the procedure to observe red blood cells without them bursting.
- Use a salt/ sugar solution OR add solute to water
- Use a solution with the same/ similar/ lower water potential as blood cells
Oxygen enters red blood cells as they pass through the capillaries in the lungs. Name the mechanism
by which oxygen enters the red blood cells.
- Diffusion
,The cells in the epidermis of a plant root are specialised to absorb minerals from the surrounding soil.
State the process by which root epidermal cells absorb minerals from the soil and describe how these
cells are specialised to achieve absorption.
- Active transport
- Cell have extensions/ hairs
- Thin cell wall
- Increased surface area
- More mitochondria
- Many carrier proteins in cell surface membrane
The following figure shows a representation of part of a carbohydrate molecule called agarose. One of
the subunits of agarose is a sugar called galactose. Starch contains a carbohydrate called amylose.
Amylose does not contain galactose.
Using the information in the figure, identify one similarity and one further difference in structure
between agarose and amylose.
- Similarity: unbranched chain/ glycosidic bonds/ contain hexose/ O in each ring
- Difference: agarose has: two types of glycosidic bond/ two different sugar/ monosaccharides/
residues are alternately rotated/ straight chain (while amylose is coiled)
Agarose forms part of a more complex carbohydrate called agar, which is used as a growth medium
for bacteria. Bacteria cannot break down the agarose in agar. Suggest why bacteria cannot break down
agarose.
- Bacteria do not have correct enzyme to digest agarose
- Agarose is not complementary to the active site of bacterial enzymes
- Bacteria unable to transport substrate/ enzyme across membrane
The student did not have access to a colorimeter when testing solutions for the presence of reducing
sugar. Describe how the student could carry out a chemical test for reducing sugar and suggest how he
could estimate the amount of reducing sugar in the sample from tube A.
- Add Benedict's reagent
- Heat up/boil the solution
- Forms precipitate
- Colour changes from blue to brick red/ orange
- Concentration estimated from
- EITHER - degree of colour change/ different colours, and comparison of final colour
with standard/ known solution
- OR - filter/ centrifuge and weigh precipitate, greater mass means more sugar present/
use of a standard curve
- OR - centrifuge, size or mass of pellet/ colour of supernatant (liquid) indicates
concentration
Another student suggested that the agarose may have been broken down to a non-reducing sugar.
Describe how the test for reducing sugar could be modified to investigate this hypothesis.
, - Add hydrochloric acid and boil
- Add sodium carbonate/ sodium hydrogencarbonate
- Then carry out reducing sugar test again
Explain the difference between magnification and resolution.
- Magnification is the number of times larger the image is compared to the object
- Resolution is the ability to distinguish between two separate points/ the level of detail that
can be seen
State the resolution that can be achieved by each of the following types of microscope.
- Light microscope: 50-200nm
- Transmission electron microscope: 0.05-1.0nm
A student states that an image was taken using a scanning electron microscope. What evidence
supports the student's statement?
- 3 dimensional/ 3D image
- Can see surface details
State the function of the nuclear pores.
- Allow communication between nucleus and cytoplasm
- Allow molecules to enter/ leave the nucleus
State two features of an eukaryotic cell, other than nuclear pores, that would not be visible using
medium power of a light microscope.
- Membranes/ phospholipid bilayer
- Ribosomes
- Golgi apparatus
- Endoplasmic reticulum/ RER/ SER
- Cytoskeleton/ microtubules/ microfilaments
- Centrioles
- Vesicles/ lysosomes
- Mitochondria
State two features of a cell that indicate it is eukaryotic.
- Nucleus/ nuclear envelope/ nucleolus
- Membrane bound organelles
- Ribosomes larger
- Large cell size/ 20μm wide
Suggest two roles of the cytoskeleton in eukaryotic cells.
- Provides strength/ stability/ support cell
- Determines shape/ change shape/ moves membrane for endo/exocytosis
- Movement of organelles/ RNA/ protein/ chromosomes/ chromatids
- Attachment to/ hold organelles in place
- Make up centrioles/ spindle fibres
Name the process in which a cell becomes specialised.
- Differentiation
The following list describes a number of features of mitochondria and chloroplasts. Select the three
statements that could be used as evidence for the endosymbiotic theory.
- mitochondria contain ribosomes that are smaller than those in the cell cytoplasm
- chloroplasts contain chlorophyll and other photosynthetic pigments
- mitochondria are a similar size to bacteria
- the inner membrane of a mitochondrion is folded to form cristae
- chloroplasts contain many disc-shaped membranes called thylakoids
- chloroplasts have their own circular DNA
Name two features of plant cells that are not features of animal cells.
- Cellulose cell wall
- Chloroplasts
- Starch grains/ amyloplasts
- Large/ permanent vacuole
Name one structure present in animal cells that is not present in plant cells.
- Centriole
- Lysosome
- Cilia
- Flagella
The cytoskeleton in cells consists of microtubules and microfilaments. Describe the roles of the
cytoskeleton.
- Support whole cell/ maintain shape
- Use of cilia/ flagella/ undulipodium to move cell
- Changing shape of cell/ cytokinesis/ phagocytosis/ exocytosis/ endocytosis/ muscle
contraction
- Movement of chromosomes. chromatids/ mRNA
The pancreas is an organ that secretes protease enzymes. Outline how the organelles in pancreatic
cells work together to produce and release these protein molecules from the cells.
- Nucleus contains gene for protein/ site of transcription/ produces mRNA
- Ribosomes/ rough endoplasmic reticulum is the site of protein synthesis/ translation
- Vesicles for transport of protein
- Golgi apparatus processes and modifies proteins
- Vesicles fuse with cell surface membrane
A student suggested that the details of the mitochondrion could be seen clearly with a very good light
microscope. Explain why the student is not correct.
- Mitochondrion/ cristae is too small
- Resolution of light microscope is not high enough (only 0.2μm)
- Wavelength of light too long
Staining is a process often used in microscopy. Describe the advantages of staining specimens to be
viewed under a microscope.
- Makes visible/ easier to see more details
, - Staining increases contrast to identify organelles/ different parts of the cell
Mitochondria provides ATP which is a source of energy. Suggest one stage during the secretion of a
protein that requires energy.
- Transport vesicles to cell surface membrane
- Fusing vesicles to membrane/ exocytosis
Outline the role of the Golgi apparatus.
- Receives proteins from the rough ER/ ribosomes
- Modify and repackages proteins into vesicles
- Eg. make glycoproteins/ add carbohydrate groups/ sugar
- Make lysosomes
- Replenishes cell surface membrane/ make glycolipids
- Lipid synthesis
Identify two features in a eukaryotic cell which would not be present in a prokaryotic cell.
- Nucleus
- Mitochondria
- Rough/ smooth ER
- Glogi apparatus
- Secretory vesicles
Name one feature that would be present in the cytoplasm of a prokaryotic cell that is not found in a
eukaryotic cell.
- Free/ circular DNA
- Plasmid
- Smaller ribosomes
A student wanted to observe some red blood cells under the microscope. The student placed a small
sample of blood onto a microscope slide and added a drop of distilled water. When viewed at high
power, the student observed that the red blood cells had burst. In a similar procedure using plant
epidermis, the student observed that the plant cells did not burst. Explain these observations.
- Cell cytoplasm has a lower water potential that distilled water
- Water moves into cells down the water potential gradient
- Water enters the cell by osmosis
- Plasma membrane of blood cell will burst/ cannot withstand pressure/ haemolyses
- Plant cell wall is strong and provides support, and thus does not burst/ can withstand pressure
- Plant cell becomes turgid, which reduces water uptake
Suggest how the student could modify the procedure to observe red blood cells without them bursting.
- Use a salt/ sugar solution OR add solute to water
- Use a solution with the same/ similar/ lower water potential as blood cells
Oxygen enters red blood cells as they pass through the capillaries in the lungs. Name the mechanism
by which oxygen enters the red blood cells.
- Diffusion
,The cells in the epidermis of a plant root are specialised to absorb minerals from the surrounding soil.
State the process by which root epidermal cells absorb minerals from the soil and describe how these
cells are specialised to achieve absorption.
- Active transport
- Cell have extensions/ hairs
- Thin cell wall
- Increased surface area
- More mitochondria
- Many carrier proteins in cell surface membrane
The following figure shows a representation of part of a carbohydrate molecule called agarose. One of
the subunits of agarose is a sugar called galactose. Starch contains a carbohydrate called amylose.
Amylose does not contain galactose.
Using the information in the figure, identify one similarity and one further difference in structure
between agarose and amylose.
- Similarity: unbranched chain/ glycosidic bonds/ contain hexose/ O in each ring
- Difference: agarose has: two types of glycosidic bond/ two different sugar/ monosaccharides/
residues are alternately rotated/ straight chain (while amylose is coiled)
Agarose forms part of a more complex carbohydrate called agar, which is used as a growth medium
for bacteria. Bacteria cannot break down the agarose in agar. Suggest why bacteria cannot break down
agarose.
- Bacteria do not have correct enzyme to digest agarose
- Agarose is not complementary to the active site of bacterial enzymes
- Bacteria unable to transport substrate/ enzyme across membrane
The student did not have access to a colorimeter when testing solutions for the presence of reducing
sugar. Describe how the student could carry out a chemical test for reducing sugar and suggest how he
could estimate the amount of reducing sugar in the sample from tube A.
- Add Benedict's reagent
- Heat up/boil the solution
- Forms precipitate
- Colour changes from blue to brick red/ orange
- Concentration estimated from
- EITHER - degree of colour change/ different colours, and comparison of final colour
with standard/ known solution
- OR - filter/ centrifuge and weigh precipitate, greater mass means more sugar present/
use of a standard curve
- OR - centrifuge, size or mass of pellet/ colour of supernatant (liquid) indicates
concentration
Another student suggested that the agarose may have been broken down to a non-reducing sugar.
Describe how the test for reducing sugar could be modified to investigate this hypothesis.
, - Add hydrochloric acid and boil
- Add sodium carbonate/ sodium hydrogencarbonate
- Then carry out reducing sugar test again
Explain the difference between magnification and resolution.
- Magnification is the number of times larger the image is compared to the object
- Resolution is the ability to distinguish between two separate points/ the level of detail that
can be seen
State the resolution that can be achieved by each of the following types of microscope.
- Light microscope: 50-200nm
- Transmission electron microscope: 0.05-1.0nm
A student states that an image was taken using a scanning electron microscope. What evidence
supports the student's statement?
- 3 dimensional/ 3D image
- Can see surface details
State the function of the nuclear pores.
- Allow communication between nucleus and cytoplasm
- Allow molecules to enter/ leave the nucleus
State two features of an eukaryotic cell, other than nuclear pores, that would not be visible using
medium power of a light microscope.
- Membranes/ phospholipid bilayer
- Ribosomes
- Golgi apparatus
- Endoplasmic reticulum/ RER/ SER
- Cytoskeleton/ microtubules/ microfilaments
- Centrioles
- Vesicles/ lysosomes
- Mitochondria
State two features of a cell that indicate it is eukaryotic.
- Nucleus/ nuclear envelope/ nucleolus
- Membrane bound organelles
- Ribosomes larger
- Large cell size/ 20μm wide
Suggest two roles of the cytoskeleton in eukaryotic cells.
- Provides strength/ stability/ support cell
- Determines shape/ change shape/ moves membrane for endo/exocytosis
- Movement of organelles/ RNA/ protein/ chromosomes/ chromatids
- Attachment to/ hold organelles in place
- Make up centrioles/ spindle fibres
Name the process in which a cell becomes specialised.
- Differentiation
