1 markThe electron micrograph below shows a plant cell.
The scale bar (measuring 45 mm in length) on this drawing represents a length of 10 μm.
Which of the following correctly identifies the magnification at which the micrograph is viewed?
x45000
x4.5
x4500
x450
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Which changes can occur when a cell differentiates from a stem cell into a specialised cell?
I. The size of the cell can change
II. The number and type of proteins in the cell changes
III. Enzymes cut out the DNA that is no longer needed
I and II only
II and III only
I and III only
I, II and III
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Which row correctly compares the magnification and resolution of an electron microscope with a light microscope?
| Magnification | Resolution |
A. | Lower | Higher |
B. | Higher | Lower |
C. | Higher | Higher |
D. | Lower | Lower |
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The diagram shows a bacterium.
Which three structures are found in both an animal cell and this bacterial cell?
Cell membrane, cell wall and DNA
Cell membrane, DNA and ribosome
Capsule, DNA and ribosome
Capsule, cell membrane and cell wall
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Which of the following can not be viewed using a light microscope?
Nucleus
Cell wall
Chloroplasts
Ribosomes
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The table shows some possible units for measuring alveoli, white blood cells and cell walls.
Which of the rows show the most suitable units for measuring each of these structures?
| Diameter of alveoli | Diameter of white blood cells | Width of cell walls |
A. | mm | µm | µm |
B. | mm | µm | nm |
C. | µm | nm | µm |
D. | µm | µm | nm |
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The diagram shows a typical plant cell.
Which of the cell components would be present in prokaryotes?
I only
II only
II and III
I and IV
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Which row correctly describes the features of prokaryotic chromosomal DNA?
A. | Associated with histone proteins | Circular |
B. | Not associated with histone proteins | Linear |
C. | Not associated with histone proteins | Circular |
D. | Contains a few hundred genes | Circular |
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1 markWhen preparing a temporary mount with which to view specimens under a light microscope, what is the main purpose of gently pressing onto the cover slip once it is in place?
To increase the magnification.
To remove air bubbles.
To remove excess stain.
To kill the specimen.
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A prokaryotic cell has a diameter of 1 µm. The cell is magnified ×50 000 by an electron microscope.
In the electron micrograph that is produced by the electron microscope, what is the diameter of the prokaryotic cell?
5 x 100 mm
5 x 10-1 mm
5 x 102 mm
5 x 101 mm
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The electron micrograph shows the organelles in a leaf cell. A student uses their ruler to measure the length of the scale bar, which they find to be 1.5 cm.
What is the magnification of the micrograph?
×7000
×7.5
×3000
×300
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The electron micrograph below shows a root vascular system. The magnification of the image is ×200. A student uses a ruler to measure distance X and finds it to be 10 mm.
What is the diameter of the cell labelled Y?
100 µm
50 µm
10 µm
5 µm
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The electron micrograph of the plant cell has a 2 cm scale line labelled 5 µm.
What is the magnification?
×5000
×4000
×2000
×1000
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Erythrocytes (red blood cells) have a diameter of 7 000 nm. Pancreatic cells have a diameter of 35 µm.
Which of these statements about the relative sizes of these cells is correct?
The erythrocytes are 5 times smaller
The erythrocytes are 50 times smaller
The erythrocytes are 5 times larger
The erythrocytes are 50 times larger
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Which of the following ideas are part of cell theory?
Cells are the smallest unit of life
Cells show great variety in shape and structure
Cells are derived from other cells (pre-existing cells) by division
I only
II only
I and III only
II and III only
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The role of exocrine gland cells in the pancreas is to secrete digestive enzymes into the pancreatic duct.
Which of the following organelles does not directly help it to achieve this task?
Rough endoplasmic reticulum
Golgi apparatus
Lysosomes
Mitochondria
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Which of the following is not a correct description of a light microscope or an electron microscope?
An electron microscope can resolve specimens as small as 0.5 nm in diameter
A light microscope has a maximum resolution of 0.2 µm
An electron microscope has a maximum resolution of 0.05 nm
A light microscope can resolve specimens as small as 200 nm in diameter
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The list below contains structures that are all features of eukaryotic cells.
Nucleus
Endoplasmic reticulum
Lysosome
Chloroplast
Mitochondrion
Which of these structures contain(s) a double membrane?
I, II and III
I, III and IV
I, IV and V
II, III and IV
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Which set of observations would indicate that a student is observing a eukaryotic cell?
| Cytoplasm contains endoplasmic reticulum | Protein molecules are associated with the DNA | Diameter <1 µm |
A | X | ✓ | X |
B | X | X | ✓ |
C | ✓ | ✓ | X |
D | ✓ | X | X |
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Which of the following is evidence for the endosymbiotic theory?
70S ribosomes can be found in prokaryotic cells
Mitochondria contain their own DNA
Meteorites have been found that contain organic molecules
In certain cases, gene transfer from prokaryotic cells to eukaryotic cells via plasmids has been found to occur
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The image below shows an electron micrograph of a specialised cell.
Which of the following correctly identifies the function of this specialised cell?
This is a cell found in a gland that secretes enzymes for digestion
This is a cell that carries out photosynthesis in the leaf of a plant
This is a cell that transports oxygen around the body in the blood
This is a cell that absorbs nutrients from digested food and transports them into the small intestine
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Which statements best describe ribosomes?
I. | They are composed of protein and ribosomal RNA |
II. | They are found in both eukaryotes and prokaryotes |
III. | Ribosomal RNA provides structure |
IV. | They consist of two equal-sized subunits |
I only
I and II
I, II and III
I, II and IV
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In prokaryotes, the processes of transcription and translation are said to be coupled, which means they can proceed simultaneously.
Which is the key cellular feature of prokaryotes that allows this to happen?
Circular chromosomal DNA
Free ribosomes
The lack of a nucleus
The presence of introns in prokaryotic DNA
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John Cairns carried out a study in which he kept E. coli bacteria in a solution containing radioactive thymine.
What was he able to conclude from the results of his study?
Prokaryotes have a circular chromosome.
E. coli have a circular chromosome.
Autoradiography does not produce clear enough results to determine whether bacteria have one chromosome or many.
Bacteria replicate their DNA using a structure called a replication fork.
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Which of the following statements about eukaryotic chromosomes are correct?
Chromosomes are long, linear molecules that can be condensed for compact storage.
After DNA replication, the two strands of DNA are held together at the centromere.
DNA wraps around histone proteins to form chromatids.
I and II only
II only
II and III only
I, II, and III
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1 markA stage micrometer with small divisions of 0.1 mm was used to calibrate an eyepiece graticule, as shown in the diagram below.
A slide containing a plant cell was placed on the stage in place of the stage micrometer.
What is the width of one of the chloroplasts below?
100 µm
50 µm
10 µm
0.5 mm
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A giant bacterium, Epulopiscium fishelsoni was discovered in 1985.
Which cell structure(s) would enable biologists to classify Epulopiscium as prokaryotic?
Circular DNA and 70S ribosomes occurring freely in the cytoplasm, and a cell wall made of murein
A pair of centrioles close to a nuclear pore, and 70S and 80S ribosomes occurring freely in the cytoplasm
Smooth endoplasmic reticulum throughout the cytoplasm, and a cell wall made of murein
A cellulose cell wall outside the plasma membrane, 70S ribosomes, and circular DNA occurring freely in the cytoplasm
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A cell which is actively growing is supplied with radioactive amino acids.
Which cell component will show an increase in radioactivity first?
Mitochondria
Golgi apparatus
Rough endoplasmic reticulum
Nucleus
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The image below is an electron micrograph of part of an animal cell.
Which of the following options (A to D) would be the site of protein modification and packaging?
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The electron micrograph below shows a small section of a palisade mesophyll cell.
Which structure controls the exchange of substances into and out of the cell?
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