Ethiopian Health Research Institutions Overview
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Questions and Answers

What is the primary function of muscles in animals?

  • To store nutrients
  • To perform photosynthesis
  • To produce energy
  • To facilitate movement (correct)

What distinguishes plant cells from animal cells?

  • Presence of ribosomes
  • Presence of mitochondria
  • Presence of a cell membrane
  • Presence of chloroplasts (correct)

Which of the following cell structures is essential for controlling all cell activity?

  • Mitochondria
  • Ribosomes
  • Cell membrane
  • Nucleus (correct)

Why is reproduction important for living organisms?

<p>To ensure the survival of the species (C)</p> Signup and view all the answers

What is the process by which organisms respond to changes in their environment called?

<p>Irritability (C)</p> Signup and view all the answers

What is used to stain the onion epidermis cells for better visibility under a microscope?

<p>Iodine (A)</p> Signup and view all the answers

What aspect of cells is highlighted when using dark-field illumination?

<p>Internal tiny structures (D)</p> Signup and view all the answers

What major limitation exists when using light microscopes to observe cells?

<p>Cells appear flat and two-dimensional (D)</p> Signup and view all the answers

Which type of microscope uses an electron beam instead of light to form images?

<p>Scanning electron microscope (C), Transmission electron microscope (D)</p> Signup and view all the answers

Why is the resolving power of an electron microscope greater than that of a light microscope?

<p>It uses electrons which have smaller wavelengths. (D)</p> Signup and view all the answers

At what minimum detail size can an electron microscope resolve?

<p>0.3 nm (C)</p> Signup and view all the answers

What should you use when making a drawing of cells observed under a microscope?

<p>Pencil (D)</p> Signup and view all the answers

What happens to living cells when they are observed through conventional light microscopy?

<p>They appear flat and distorted. (C)</p> Signup and view all the answers

What substance primarily makes up the cell wall of plant cells?

<p>Cellulose (D)</p> Signup and view all the answers

What role does chlorophyll play in plant cells?

<p>Absorbs light energy to make food (D)</p> Signup and view all the answers

How does the permanent vacuole contribute to the plant's structure?

<p>Keeps the cells rigid and supports the plant (B)</p> Signup and view all the answers

What characterizes the cell wall's permeability?

<p>It is freely permeable (B)</p> Signup and view all the answers

Which of the following activities would show the presence of chloroplasts?

<p>Studying pondweed cells such as Elodea (B)</p> Signup and view all the answers

In what part of the plant are chloroplasts typically found?

<p>Green parts of the plant (B)</p> Signup and view all the answers

Which component of a plant cell is responsible for storing cell sap?

<p>Permanent vacuole (B)</p> Signup and view all the answers

What is a common feature of both plant and animal cells?

<p>Nucleus (C)</p> Signup and view all the answers

What is the main purpose of adding stains to biological specimens in microscopy?

<p>To make it easier to see specific cells or organelles (D)</p> Signup and view all the answers

Which type of microscope allows you to view living material directly?

<p>Light microscope (C)</p> Signup and view all the answers

What happens to cells when they are treated with stains for microscopic analysis?

<p>The cells become more vibrant but are dead (C)</p> Signup and view all the answers

What is the primary color of nuclei stained with Haematoxylin?

<p>Brown or purple (B)</p> Signup and view all the answers

Which type of cells can be stained with Methylene blue?

<p>Animal cells only (C)</p> Signup and view all the answers

Why is it important to slice biological material very thinly for microscopy?

<p>To allow better penetration of light and stains (C)</p> Signup and view all the answers

What type of staining does Acetocarmine perform in plant and animal cells?

<p>Staining the chromosomes in dividing nuclei (D)</p> Signup and view all the answers

What potential drawback can occur when preparing stained cell samples?

<p>Cells may be damaged or changed during the process (C)</p> Signup and view all the answers

What is the main advantage of using an electron microscope compared to a light microscope?

<p>Specimens are examined in a vacuum and must be dead. (A)</p> Signup and view all the answers

Which of the following organisms is classified as a single-celled organism?

<p>An amoeba (C)</p> Signup and view all the answers

What is the significance of the cell theory?

<p>It explains that cells are the basic units of life. (C)</p> Signup and view all the answers

Which structure is NOT typically found in plant cells?

<p>Centrioles (A)</p> Signup and view all the answers

Why is it essential to compare plant and animal cells?

<p>To identify similarities and differences in cellular structures. (D)</p> Signup and view all the answers

Which of the following statements is false regarding cells?

<p>Cells can only be multicellular. (C)</p> Signup and view all the answers

What is a characteristic feature of multicellular organisms?

<p>They are made up of multiple interdependent cells. (D)</p> Signup and view all the answers

Which of the following statements best describes the function of the cell wall?

<p>It supports and protects the cell. (D)</p> Signup and view all the answers

What is the primary limitation of a light microscope compared to an electron microscope?

<p>It has a limited resolving power that restricts detail. (C)</p> Signup and view all the answers

What defines the resolving power of a microscope?

<p>The ability to distinguish between two separate points. (A)</p> Signup and view all the answers

How does the resolving power of an electron microscope compare to that of a light microscope?

<p>It is significantly better than that of a light microscope. (C)</p> Signup and view all the answers

What is the limit of resolution for the optical light microscope?

<p>200 nanometres (D)</p> Signup and view all the answers

What is the resolving power of an electron microscope?

<p>0.3 nm (A)</p> Signup and view all the answers

What causes the increase in resolving power in an electron microscope compared to a light microscope?

<p>The smaller wavelength of the beam used. (B)</p> Signup and view all the answers

Which statement about the human eye's resolution is accurate?

<p>It cannot resolve details smaller than 0.1 mm. (D)</p> Signup and view all the answers

Why is it necessary to use an electron microscope for viewing certain details?

<p>The details are smaller than the light microscope's limit of resolution. (C)</p> Signup and view all the answers

Flashcards

Irritability

The ability of an organism to detect and respond to changes in its environment.

Movement

The movement of an organism in response to a stimulus.

Reproduction

The process by which living organisms produce offspring.

Nucleus

The control center of a cell, containing genetic material (chromosomes).

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Cell membrane

The outer layer of a cell that controls what enters and leaves.

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Resolution

The ability of a microscope to distinguish between two closely spaced points.

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Limit of Resolution

The minimum distance between two objects that allows them to be seen as separate.

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Wavelength and Resolution

The wavelength of light determines how much detail a light microscope can show.

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Electron Microscope

A microscope that uses a beam of electrons to create an image.

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Light Microscope

A microscope that uses a beam of light to create an image.

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Magnification

The ability to increase the apparent size of an object.

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Detail and Resolving Power

The ability to see more detail, determined by the resolving power of the microscope.

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Electron vs Light Microscopes

Electron microscopes have much greater resolving power than light microscopes, allowing us to see much smaller objects with greater detail.

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Slides

Thin slices of biological material prepared for viewing under a microscope.

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Stains

Chemicals used to stain biological specimens, making them easier to see under a microscope.

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Fixing (cells)

A process that kills and preserves cells, preventing them from decomposing.

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Haematoxylin

A type of stain that colors the nucleus of animal and plant cells blue or purple.

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Methylene blue

A type of stain that colors the nucleus of animal cells blue.

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Acetocarmine

A type of stain that colors chromosomes in dividing nuclei red.

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Cell Theory

All living organisms are made up of one or more cells.

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Multicellular

Organisms that contain more than one cell.

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Cell Structures

Structures found within a cell that have specific functions.

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Plant vs. Animal Cells

The main difference between plant and animal cells is that plant cells have a cell wall, chloroplasts, and a large vacuole, while animal cells do not.

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Types, Shapes, and Sizes of Cells

Cells can vary in size, shape, and function depending on their role in the organism.

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Unicellular

A single-celled organism, like a bacterium.

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Resolving Power

The ability of a microscope to distinguish between two closely spaced objects.

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Wavelength

The distance between two successive crests or troughs of a wave, such as a light wave.

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Dark-field illumination

A technique that illuminates the specimen while keeping the background dark, making tiny structures inside cells easier to see.

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Scanning electron microscope

A type of electron microscope that scans a beam of electrons across the surface of a specimen to create a 3D image.

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Cell wall

The thin outer layer of a plant cell that provides support and protection.

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Cellulose

A type of carbohydrate that makes up the cell wall, giving it strength and rigidity.

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Chlorophyll

A green pigment found within chloroplasts responsible for absorbing light energy for photosynthesis.

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Chloroplasts

Organelles found in plant cells containing chlorophyll, where photosynthesis takes place.

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Photosynthesis

The process by which plants use sunlight, water, and carbon dioxide to create their own food (sugars).

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Vacuole

A large fluid-filled sac within plant cells that stores water, sugars, and other substances. It also helps maintain cell shape.

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Cell sap

The liquid found within the vacuole of a plant cell. It contains dissolved substances like sugars and minerals.

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Free permeability

The process of movement across a cell membrane that allows substances to pass through freely without any energy input.

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Study Notes

Armauer Hansen Research Institute (AHRI)

  • Founded in 1969, initially focused on leprosy research
  • Expanded research in 1996 to include tuberculosis (TB), leishmaniasis, malaria and HIV/AIDS in addition to leprosy
  • Located near a hospital dedicated to leprosy patients

Aklilu Lemma Institute of Pathobiology (ALIPB)

  • Renamed department of pathobiology at Addis Ababa University
  • Aims to be a center of excellence for biomedical research and training
  • Research in five major areas: microbiology of infectious diseases, disease vectors, human parasitic diseases, animal health, and investigation of plant-based medicines as potential treatments.
  • Offers a master's degree in tropical and infectious diseases

Ethiopian Health and Nutrition Research Institute (EHNRI)

  • Conducts research on health and nutrition issues affecting Ethiopia
  • Focuses on identifying problems and awareness to improve public health
  • Well-equipped laboratory facilities for immunology and viral diseases, including HIV/AIDS research
  • Long-term study (since 1994) following the progression of HIV/AIDS in factory workers
  • Involved in TB research and diagnosis, and nutritional state of mothers and babies.

Ethiopian Institute of Agricultural Research (EIAR)

  • Works to improve agriculture and support Ethiopian farmers
  • Five main research areas: crop technology, livestock management, soil and water management, forestry, and mechanization of farming.
  • Research aimed at food security and nutritional quality, specifically focusing on crops like maize, teff, and sorghum.
  • Also involved in restoring and conserving forest ecosystems.

Institute of Biodiversity Conservation (IBC)

  • Conserves Ethiopia's biodiversity, focusing on plant, animal and microorganism genetics and ecosystem management.
  • One of the leading gene banks in Africa, with over 300 plant species represented.
  • High priority due to the unique biodiversity, especially plants native to Ethiopia.

Activity 1.2: Discovering more about research in Ethiopia

  • Students should investigate local biology departments or research institutions
  • Investigate an additional Ethiopian research institution
  • Gather information from resources such as books, reports, magazines, and any available on-line resources
  • Provide a presentation to classroom

Activity 1.3: Making a table of research institutions

  • Create table summarizing research institutions. List the institution, and its focus of research.

End of unit questions

  • Name two Ethiopian biologists who have made internationally recognized contributions. Describe their main work and why it is important
  • What are the advantages of using Endod in the battle against bilharzia?
  • Why is Professor Yalemtsehay Mekonnen internationally renowned?
  • What is rinderpest?
  • Why is the work of Dr Gebissa Ejeta so important?
  • Why are scientific institutions important to biological research? +Name three Ethiopian research institutions involved in different types of biological research Summarize the areas of biological research carried out by each institution

Cell Biology

  • The Microscope: Different types, magnification, resolution, techniques (like staining), and preparation methods for light and electron microscopes are discussed.
  • The Cell: This section delves into the cell theory, cellular structures (like nucleus, cell membrane, cytoplasm, mitochondria, ribosomes) and their functions, including their roles in diffusion, osmosis, and active transport.
  • Cell and its Environment: Explains concepts like permeability and how substances move across the cell membrane (diffusion, osmosis), and active transport. Discusses the importance of these processes in living organisms, and experiments to demonstrate these phenomena.

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Unit 1: Biology and Technology PDF

Description

Explore the key research institutions in Ethiopia, including the Armauer Hansen Research Institute, Aklilu Lemma Institute of Pathobiology, and the Ethiopian Health and Nutrition Research Institute. Learn about their focus areas, historical context, and contributions to public health and biomedical research in the country.

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