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Questions and Answers
The maximum useful magnification of an electron microscope is about ______.
The maximum useful magnification of an electron microscope is about ______.
1,500,000
The basic types of electron microscopes are Transmission Electron Microscope (TEM) and ______.
The basic types of electron microscopes are Transmission Electron Microscope (TEM) and ______.
Scanning Electron Microscope (SEM)
TEMs use ______ to focus a beam of electrons.
TEMs use ______ to focus a beam of electrons.
electromagnets
Scanning electron microscopes create images by scanning a beam of electrons over the ______.
Scanning electron microscopes create images by scanning a beam of electrons over the ______.
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The densest parts of the specimen in TEMs appear ______ because they absorb more electrons.
The densest parts of the specimen in TEMs appear ______ because they absorb more electrons.
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SEM images often give a ______ resolution image compared to TEMs.
SEM images often give a ______ resolution image compared to TEMs.
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For light microscopy, specimens are typically prepared by ______ and/or staining.
For light microscopy, specimens are typically prepared by ______ and/or staining.
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To prepare a temporary mount of a specimen on a slide, one should add a drop of ______ first.
To prepare a temporary mount of a specimen on a slide, one should add a drop of ______ first.
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Optical microscopes use ______ to form the image.
Optical microscopes use ______ to form the image.
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Electron microscopes have a higher ______ than optical microscopes.
Electron microscopes have a higher ______ than optical microscopes.
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The maximum resolution of optical microscopes is about ______ micrometres (μm).
The maximum resolution of optical microscopes is about ______ micrometres (μm).
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You can see the ______ in optical microscopy but details of smaller organelles may not be clear.
You can see the ______ in optical microscopy but details of smaller organelles may not be clear.
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Electron microscopes can achieve a maximum resolution of about ______ micrometres (μm).
Electron microscopes can achieve a maximum resolution of about ______ micrometres (μm).
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Ribosomes and the endoplasmic reticulum cannot be viewed using optical microscopes because they are smaller than ______ micrometres (μm).
Ribosomes and the endoplasmic reticulum cannot be viewed using optical microscopes because they are smaller than ______ micrometres (μm).
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The ______ is crucial for maintaining cell shape and facilitating movement within the cell.
The ______ is crucial for maintaining cell shape and facilitating movement within the cell.
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When preparing slides for use in light microscopy, the use of ______ can enhance the visibility of certain structures.
When preparing slides for use in light microscopy, the use of ______ can enhance the visibility of certain structures.
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The three main monosaccharides are glucose, fructose, and ______.
The three main monosaccharides are glucose, fructose, and ______.
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Disaccharides are formed by joining two monosaccharides with a ______ bond.
Disaccharides are formed by joining two monosaccharides with a ______ bond.
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Maltose is formed from two molecules of ______.
Maltose is formed from two molecules of ______.
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The bond between carbon 1 of one glucose molecule and carbon 4 of another is called a ______ glycosidic bond.
The bond between carbon 1 of one glucose molecule and carbon 4 of another is called a ______ glycosidic bond.
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Cellulose is a polymer made up of long chains of ______ glucose.
Cellulose is a polymer made up of long chains of ______ glucose.
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The chains of cellulose are linked by ______ bonds to provide structural support.
The chains of cellulose are linked by ______ bonds to provide structural support.
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Plants store excess glucose as ______.
Plants store excess glucose as ______.
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Cellulose provides tensile strength and prevents plant cells from ______ under high pressure.
Cellulose provides tensile strength and prevents plant cells from ______ under high pressure.
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Starch is a mixture of two polysaccharides of alpha-glucose - amylose and ______.
Starch is a mixture of two polysaccharides of alpha-glucose - amylose and ______.
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Amylose is a long, unbranched chain of ______.
Amylose is a long, unbranched chain of ______.
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The angle of the glycosidic bonds gives amylose a coiled, ______-like structure.
The angle of the glycosidic bonds gives amylose a coiled, ______-like structure.
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Glycogen is the main energy storage material in ______.
Glycogen is the main energy storage material in ______.
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This polymer consists of repeating ______ sub-units.
This polymer consists of repeating ______ sub-units.
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Glycogen has a similar structure to amylopectin but has a lot more ______.
Glycogen has a similar structure to amylopectin but has a lot more ______.
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Lipids are a mixed group of hydrophobic compounds composed of ______, hydrogen and oxygen.
Lipids are a mixed group of hydrophobic compounds composed of ______, hydrogen and oxygen.
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The stored glucose in animals is typically found in the ______ and some muscles.
The stored glucose in animals is typically found in the ______ and some muscles.
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If the test is positive, it will form a coloured ______ (solid particles suspended in the solution).
If the test is positive, it will form a coloured ______ (solid particles suspended in the solution).
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The higher the concentration of reducing sugar, the further the change of ______ goes.
The higher the concentration of reducing sugar, the further the change of ______ goes.
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To test for a non-reducing sugar, you first need to break them down into ______.
To test for a non-reducing sugar, you first need to break them down into ______.
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You can neutralise it with sodium ______.
You can neutralise it with sodium ______.
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If the test is negative, the solution stays ______ and it means the solution does not contain any sugar.
If the test is negative, the solution stays ______ and it means the solution does not contain any sugar.
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Whenever you want to experiment on the digestion of ______ and need to know if there is any left, you need the iodine test.
Whenever you want to experiment on the digestion of ______ and need to know if there is any left, you need the iodine test.
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If there is starch present, the sample changes from ______ to a dark blue-black colour.
If there is starch present, the sample changes from ______ to a dark blue-black colour.
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Iodine is dissolved in potassium ______ solution to create the iodine test.
Iodine is dissolved in potassium ______ solution to create the iodine test.
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Non-competitive inhibitors can bind to a region away from the ______ site.
Non-competitive inhibitors can bind to a region away from the ______ site.
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High temperatures can cause ______ due to breaking of bonds holding the tertiary structure together.
High temperatures can cause ______ due to breaking of bonds holding the tertiary structure together.
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As enzyme concentration increases, the rate of reaction also ______.
As enzyme concentration increases, the rate of reaction also ______.
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Deviations from the optimum ______ cause a decrease in enzyme activity.
Deviations from the optimum ______ cause a decrease in enzyme activity.
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Enzyme activity can be prevented by enzyme ______.
Enzyme activity can be prevented by enzyme ______.
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At higher substrate concentrations, enzyme molecules become ______ with substrate.
At higher substrate concentrations, enzyme molecules become ______ with substrate.
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The breaking of hydrogen and ionic bonds can lead to enzyme ______.
The breaking of hydrogen and ionic bonds can lead to enzyme ______.
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Competitive inhibitors bind to the ______ site or other similar molecules.
Competitive inhibitors bind to the ______ site or other similar molecules.
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Study Notes
Biological Molecules
- Key biological molecules are carbohydrates, proteins, and lipids.
- These molecules are composed of monomers that are joined together.
- Condensation reactions join the monomers and produce water.
- Hydrolysis reactions break down the polymers by using water.
Water as a Solvent
- Water is a polar molecule due to its uneven charge distribution.
- The polarity of water allows it to dissolve many substances.
- Water molecules form hydrogen bonds with each other, resulting in high surface tension, viscosity, heat capacity, and density.
- These properties of water are crucial to life.
Monosaccharides
- Monosaccharides are simple sugars, such as glucose, fructose, and galactose.
- Glucose is the most common monosaccharide and is a major energy source.
- All monosaccharides have an identical molecular formula (CH₂O)ₙ
- The arrangements of atoms within a monosaccharide affects its structure and function.
Disaccharides
- Disaccharides are formed when two monosaccharides combine through a glycosidic bond.
- Common disaccharides include sucrose, lactose, and maltose.
Polysaccharides
- Polysaccharides are polymers made of many monosaccharides.
- Examples include starch, glycogen, and cellulose.
- The structure and properties of polysaccharides affect their function within living organisms.
- Starch is a storage polysaccharide in plants, formed of amylose and amylopectin.
- Glycogen is a storage polysaccharide in animals.
- Cellulose is a structural polysaccharide in plants, forming plant cell walls.
Lipids
- Lipids are a diverse group of hydrophobic molecules.
- They include triglycerides, phospholipids, and steroids.
- Triglycerides are composed of glycerol and three fatty acids.
- They are important for energy storage, insulation, and protection.
- Phospholipids have a hydrophilic head and two hydrophobic tails, and are essential components of cell membranes.
- Steroids, such as cholesterol, have a complex ring structure and are involved in various functions, like structural support, and hormone production.
Proteins
- Proteins are polymers made of amino acids.
- Twenty different amino acids are commonly found in proteins.
- The sequence of amino acids determines the protein's primary structure.
- Interactions between amino acids cause folding, creating secondary, tertiary, and quaternary protein structures.
- Protein structure affects their function including enzymatic activity, structural support and transportation.
Enzymes
- Enzymes are biological catalysts that speed up biochemical reactions.
- Enzymes have specific active sites for binding substrates.
- Factors, including temperature, pH and substrate concentration, influence enzyme activity.
- Enzyme activity can be inhibited by various molecules, affecting reaction rates.
Nucleotides and Nucleic Acids
- Nucleotides are the monomers of nucleic acids (DNA and RNA).
- Nucleotides have a pentose sugar, a nitrogenous base, and a phosphate group.
- DNA is a double helix structure composed of two polynucleotide chains held together by hydrogen bonds between the bases.
- DNA carries genetic information and is responsible for the synthesis of proteins.
- RNA is typically a single-stranded structure that assists in protein synthesis.
Cell Membranes
- Cell membranes separate the interior from the exterior of the cell.
- The fluid mosaic model describes the cell membrane's structure composed of a phospholipid bilayer, proteins, and cholesterol.
- Cell membranes are selectively permeable, allowing specific substances to pass through.
- Various mechanisms including simple diffusion, osmosis, facilitated diffusion, and active transport, regulate the movement of substances across the membrane.
- Cotransport simultaneously moves two substances across the membrane.
Cell Cycle
- The cell cycle is a series of events that lead to cell growth and duplication.
- Regulation of the cell cycle involves internal and external checkpoints to ensure proper division.
- Mitosis is a process that divides a single cell into two genetically identical daughter cells, essential for growth, repair, and asexual reproduction.
- Meiosis involves two divisions that produce four genetically different haploid cells, critical for sexual reproduction.
Specialised Cells
- Cells in multicellular organisms can differentiate into various specialized types, each with specific functions.
- Examples include epithelial cells, muscle cells, and nerve cells.
- Specialised cells work together to form tissues, organs, and organ systems, maintaining and carrying out complex bodily activities.
- Understanding specialized cell function is crucial to understanding human and other complex biological systems.
- Plant cells display specialization too; the root hair cells absorb water and minerals whilst the guard cells control stomata opening and closing. .
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Description
Test your knowledge on the principles of electron microscopy including the types, uses, and preparation techniques of specimens. This quiz covers key concepts related to Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM). See how well you understand the differences between optical and electron microscopes.
