MaChp 1

Would he have been able to see any of the structures shown in the figure below? The figure shows an animal cell, a plant cell, and a bacterium. The animal cell has a diameter of about 20 micrometers. It contains large nucleus and small mitochondria. The plant cell is slightly larger and contains huge vacuole besides mitochondria and nucleus. The bacterial cell is cylindrical with a diameter of about 1 micrometer and a length of about 2 micrometers.

yes he would

Palade, Porter, and Sjøstrand each develop techniques for fixing and sectioning biological tissue for electron microscopy (1952-1953). cytological biochemical genetic

cytological

Claude isolates the first mitochondrial fractions from rat liver (1940). Select the two correct answers. cytological biochemical genetic

cytological and biochemical

Define limit of resolution. -The limit of resolution of a microscope is the shortest distance between four separate points in a microscopes field of view that can still be distinguished as distinct entities. -The limit of resolution of a microscope is a measure of how close together two points can be and still be distinguished from one another when viewed through the microscope. -The limit of resolution of a microscope is the minimum distance or angular separation between two point objects which allows them to be resolved according to the Rayleigh criterion. -The limit of resolution of a microscope is the clearance distance between the closest surface of the cover glass and the objective front lens.

-The limit of resolution of a microscope is a measure of how close together two points can be and still be distinguished from one another when viewed through the microscope.

define bright field, fluorescence, phase-contrast-confocal, transmission electron microscopy, scanning electron microscopy

-light passes directly through a specimen -shows specific molecules -amplifies variations in density -uses a laster to view a single plane of a specimen -detects electrons passing through a specimen -detects electrons deflected form the surface of the specimen

What was the limit of resolution Leeuwenhoek's microscope? 0.83 μm 8.3 μm 83 μm 830 μm

0.83 μm

1 mm = ________ nm 1/1000 10 1,000,000 1/1,000,000 1000

1,000,000

Which of the following accurately details the relationship between wavelength of illumination, lens quality, magnification, and the limit of resolution for light microscopy? -As shorter wavelength illumination and better quality lenses are used, magnification will decrease and the limit of resolution will decrease. -As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will decrease. -Magnification and limit of resolution are independent of wavelength of illumination and lens quality for light microscopy. -As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will increase.

As shorter wavelength illumination and better quality lenses are used, magnification will increase and the limit of resolution will decrease.

Suggest one advantage that scanning electron microscopy has over transmission electron microscopy. -Scanning electron microscopy makes it possible to only visualize cells and tissues as if in two dimensions. -Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in two dimensions. -Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions. -Scanning electron microscopy makes it possible to only visualize cells and tissues as if in three dimensions.

Scanning electron microscopy makes it possible to visualize subcellular structures and macromolecules as if in three dimensions.

Which ones? animal cells plant cells bacteria cells

animal and plant cells

Which ones?

animal, plant, and bacteria cells

What would Hooke and van Leeuwenhoek be able to see

any animal and plant cell as a whole

What would only van Leeuwenhoek be able to see

any organelles or bacteria structures under 10um

Avery, MacLeod, and McCarty demonstrate that bacterial transformation is attributable to DNA, not protein (1944). cytological biochemical genetic

genetic

Haeckel postulates that the nucleus is responsible for heredity (1868). cytological biochemical genetic

genetic

Muller discovers that X-rays induce mutations (1927). cytological biochemical genetic

genetic

Beadle and Tatum formulate the one gene-one enzyme hypothesis (1940). Select the two correct answers. cytological genetic biochemical

genetic and biochemical

Which organelle stores most of the DNA in plant and animal cells? Golgi complex nucleus chloroplast lysosome mitochondrion

nucleus

The scientific work that established DNA, rather than protein, as the molecule of heredity was performed prior to -the formation of the chromosome theory of heredity. -Mendel's work on heredity. -the elucidation of the double helix structure of DNA. -the description of the enzymatic steps of glycolysis. -Antonie van Leeuwenhoek's observation of internal cell structures.

the elucidation of the double helix structure of DNA.

What are the approximate dimensions of the smallest structure that a contemporary cell biologist should be able to observe with a modern light microscope? 400-500 nm 100-200 nm 200-350 nm 50-100 nm

200-350 nm

What was the limit of resolution of Hooke's microscope? 0.83 μm 8.3 μm 83 μm 830 μm

8.3 μm

Which of the following statements is false? -All cells have a membrane-bound nucleus. -All cells arise from preexisting cells. -The cell is the basic unit of structure for all organisms. -Cells come in a wide variety of sizes and shapes. -All organisms consist of one or more cells.

All cells have a membrane-bound nucleus.

What can no biologists see

DNA helix, a microfilament, a ribosome, or any structures under 1 um (measured in nanometers)

Suggest one advantage that DNA sequencing has over nucleic acid hybridization. -DNA sequencing makes it possible to identify species present in a sample of water, sewage, dirt, debris filtered from the air, or swab samples of organisms. -DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand. -DNA sequencing can assess whether there is enough sequence complementarity to allow two strands to adhere to one another under specified conditions. -DNA sequencing makes it possible to determine the tertiary and quaternary structure of a DNA strand.

DNA sequencing makes it possible to determine the order of individual nucleotides along a DNA strand.

Suggest one advantage that the electron microscopy has over the light microscopy. -Electron microscopy uses complex mathematical algorithms to increase the contrast and resolution of digital images. -Electron microscopy is capable of much greater limit of resolution and hence much less resolving power. -Electron microscopy uses video cameras to collect digital images for computer storage. -Electron microscopy is capable of much greater resolution and hence much higher useful magnification.

Electron microscopy is capable of much greater resolution and hence much higher useful magnification.

Suggest one advantage that electrophoresis has over chromatography. -Electrophoresis separates molecules based on differences in chemical properties, thereby making it possible to separate molecules that undergo similar chemical reactions. -Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density. -Electrophoresis separates molecules based on differences in solubility, thereby making it possible to separate molecules that are similar in mass and size. -Electrophoresis separates molecules based on mass differences, thereby making it possible to separate molecules that are similar in molar mass.

Electrophoresis separates molecules based on charge differences, thereby making it possible to separate molecules that are similar in size, shape, and density.

Suggest one advantage that bioinformatics has over sequencing of a genome. -Sequencing of a genome simply provides a large amount of data about the DNA present on a chromome, whereas bioinformatics provides a large amount of data about the DNA present in the entire genome. -Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics techniques such as image and signal processing allow extraction of useful results from small amounts of raw data. -Sequencing of a genome uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression, whereas bioinformatics simply provides a large amount of data about the DNA present in the genome. -Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression.

Sequencing of a genome simply provides a large amount of data about the DNA present in the genome, whereas bioinformatics uses computer analysis to aid in understanding and interpreting those data in terms of gene numbers and expression.

Suggest one advantage that ultracentrifugation has over centrifugation. -Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation. -Ultracentrifugation allows to separate mixtures containing charged molecules, whereas conventional centrifugation separates neutral biomolecules only. -Ultracentrifugation allows to separate biomolecules based on their size, shape, and/or density, whereas separation in a conventional centrifugation is based on molecular mass only. -Ultracentrifugation allows to separate biomolecules with different physical properties, whereas conventional centrifugation precipitates all the biomolecules.

Ultracentrifugation is capable of much higher speeds and hence much greater centrifugal force than conventional centrifugation.

Which of the following is INCONSISTENT with the cellular basis of life? -Cellular function is intimately linked to cellular structure. -Viruses are living, acellular parasites. -The nuclear and mitochondrial DNA of a cell contains all of the information necessary for cellular reproduction. -All anatomical structures and physiological processes of an organism are consequences of emergent properties of cellular structures and cellular processes.

Viruses are living, acellular parasites.

Hoppe-Seyler isolates the protein hemoglobin in crystalline form (1864). cytological biochemical genetic

biochemical

Lehninger demonstrates that oxidative phosphorylation depends for its immediate energy source on the transport of electrons in the mitochondrion (1957). cytological biochemical genetic

biochemical

Lipmann postulates the central importance of ATP in cellular energy transactions (1940). cytological biochemical genetic

biochemical

Ostwald proves that enzymes are catalysts (1893). cytological biochemical genetic

biochemical

Cell biology emerged from which of the following fields of biology? -biochemistry, cytology, and genetics -cytology -biochemistry -cytology and biochemistry -genetics

biochemistry, cytology, and genetics

Early microscopes did not allow clear visualization of cells because they were limited by magnification. refraction. resolution. number of kernels. both magnification and resolution.

both magnification and resolution

Davson and Danielli postulate a model for the structure of cell membranes (1935). cytological biochemical genetic

cytological

Ko¨llicker describes "sarcosomes" (now called mitochondria) in muscle cells (1857). cytological biochemical genetic

cytological