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Description
Flashcards by Risa Kunii, updated more than 1 year ago
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Created by Risa Kunii
over 5 years ago
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| Question | Answer |
| State the 3 principles of cell theory | The cell theory states that: 1. All living things are composed of cells 2. The cell is the smallest unit of life 3. All cells arise from pre-existing cells |
| List 3 atypical examples that question cell theory. | Certain types of cells/tissues do not conform to a standard notion of what constitutes a cell: 1. Striated muscle cells 2. Aseptate fungal hyphae 3. Giant algae |
| Discuss how Striated Muscle Cells differ from typical cells. | - Muscle cells fuse to form fibres that may be very long (>300mm). (Much larger than a typical cell) - Have multiple nuclei despite being surrounded by a single, continuous plasma membrane. - Challenges the idea that cells always function as autonomous units & that cells have one nucleus. |
| Discuss how Aseptate Fungal Hyphae differ from typical cells. | - Aseptate fungal hyphae are long threads (hyphae) w/ many nuclei, but no dividing cell walls (septa/septum) - Challenges the idea that cells are a single unit, as it is multinucleate, very large, & possesses a continuous cytoplasm. |
| Discuss how Giant Algae differ from typical cells. | - Gigantic size (b/n 0.5 - 10cm in length) - Has complex parts (3 parts: bottom rhizoid, stalk, & top umbrella that may fuse into a cap). - Challenges the idea that cells are simple in structure & small in size. |
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List & explain the functions of life.
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MR SHENG - Metabolism: Enzyme-catalysed chemical reactions that take place w/i the cells of living organisms. - Reproduction: The production of offspring, either asexually/sexually, to pass on genetic information to the next generation. Reproduction ensures the survival of the species. - Sensitivity/Response (to a stimulus): Living things respond to changes in their internal & external environment. - Homeostasis: Maintenance of a constant internal environment by regulating internal cell conditions. - Excretion: Removal of waste products from metabolism & other toxic materials. - Nutrition: Living things exchange materials & gases with the environment. - Growth: Living things can move & change shape or size |
| Describe the Paramecium | - Eukaryotic organism - Unicellular - Heterotroph |
| State & explain the functions of life in a Paramecium (referring to its structures). | - Metabolism (food vacuole/cytoplasm): Food particles are enclosed w/in small vacuoles that contain enzymes for digestion. Most metabolic pathways occur in the cytoplasm. - Reproduction (macronucleus & micronucleus): Paramecia often divides asexually (fission) to form two new daughter cells. Macronucleus splits by a type of amitosis, & micronuclei undergo mitosis. - Sensitivity/Response (cilia): Paramecia are surrounded by small hairs called cilia which allow it to move towards food. - Homeostasis (cell membrane): Essential gases enter (e.g. O2) and exit (e.g. CO2) the cell via diffusion. - Excretion (: Solid wastes are removed via an anal pore, while liquid wastes (e.g water) are pumped out via contractile vacuoles. - Nutrition (cell mouth/cytostome): Paramecia engulf food via the cytostome. - Growth: After consuming food, the Paramecium will get larger until it divides. |
| Contrast Unicellular & Multicellular organisms w/ examples of both. | Unicellular: An organism composed of a single cell. e.g. Paramecium, Amoeba, etc. Multicellular: An organism composed of multiple cells. e.g Turtle, Oak tree, Human |
| Describe the Chlorella | - Eukaryotic cell - Unicellular - Autotroph |
| State & explain the functions of life in a Chlorella (referring to its structures). | - Metabolism (chloroplast): Chlorophyll pigments allow organic molecules to be produced via photosynthesis. - Reproduction: The nucleus divides to support cell division via mitosis. - Sensitivity/Response: Cilia move the chlorella in response to changes in the environment e.g. towards light - Homeostasis: Essential gases enter (e.g. CO2) & exit (e.g. O2) the cell via diffusion. - Excretion: Gases & other essential materials exchange via diffusion. - Nutrition: " " - Growth: The org. will grow until it divides asexually. |
| State the function of a cell's mass/volume. | A cell's rate of metabolism bc larger cells need more energy to carry out processes. |
| State the function of a cell's surface area. | The cell's rate of material exchange bc large membrane surface = more material movement. |
| Explain what occurs to the volume & surface area of a cell as it grows. State what effect it has on the SA:Vol ratio. | As a cell grows, volume (units3) increases faster than surface area (units2), leading to a decreased SA:Vol ratio. |
| Explain why cells divide. | If metabolic rate exceeds the rate of exchange of vital materials and wastes (low SA:Vol ratio), the cell will eventually die. Therefore, growing cells tend to divide & remain small to maintain a high SA:Vol ratio suitable for survival. |
| State examples of tissues that specialize in gas/material exchange. | Intestinal tissue of the digestive tract may form a ruffled structure (villi) to increase the SA of the inner lining. Alveoli w/in the lungs have microvilli, which function to increase the total membrane surface. |
| State the formula to calculate magnification in drawings/on a micrograph. | Magnification = Image size (with ruler) ÷ Actual size (according to scale bar) |
| Describe the function of a light microscope. | - Uses visible light & a combination of lenses to magnify images of specimens. - Live specimens can be viewed in their natural colour. - Stains may be applied to resolve specific structures. |
| State what should be included when drawing microscopic structures. | - A title to identify the specimen (e.g. name of organism, tissue or cell). - A magnification/scale to indicate relative size. - Identifiable structures should be clearly labelled (drawings should only reflect what is seen, not idealised versions). |
| State what is meant by Emergent Properties | When the interaction of components parts produce new functions that individual cells would be unable to perform on its own. "The whole is greater than the sum of its parts" - Aristotle |
| State the organization of an organism in multicellular organisms. Note: Emergent properties | Cells (basic unit of life) --> Tissue (group of cells working together to perform a specific function) --> Organ (group of tissues working together to perform a specific function) --> Organ system (group of organs working together to carry out the life functions of the complete organism) --> Organism Overall: Cells --> Tissue --> Organ --> Organ System --> Organism |
| Define Differentiation | The process during development whereby newly formed cells become specialized by expressing some genes & not others in a cell’s genome. |
| State what causes cells to differentiate. | The activation of different instructions (genes) w/in a given cell by chemical signals will cause it to differentiate |
| Compare how Active & Inactive Genes are packaged in the nucleus. State the names of the form in which they are packaged. | Active genes are usually packaged in an expanded form called euchromatin that is accessible to transcriptional machinery. Inactive genes are typically packaged in a more condensed form called heterochromatin (saves space, not transcribed). |
| Describe the relationship b/n euchromatin & heterochromatin in differentiated cells. | Differentiated cells will have different regions of DNA packaged as euchromatin & heterochromatin according to their specific function. Genes which help w/ the cell's function will be in the form of euchromatin & expressed, whereas, genes that do not aid in the cell's specialized function will be in the form heterochromatin. |
| State the properties of Stem Cells. | Stem cells are unspecialized/undifferentiated cells. Properties: 1. They can continuously divide & replicate. 2. They have the capacity to differentiate into specialized cell types. |
| Describe the 4 main types of stem cells. | 1. Totipotent (e.g zygote): Can differentiate into any cell type including placental tissue. 2. Pluripotent (e.g embryonic stem cells): Can differentiate into any cell type. 3. Multipotent (e.g. haematopoeitic adult stem cells): Can differentiate into a number of closely related cell types. 4. Unipotent (e.g muscle stem cells & skin cells): Cannot differentiate, but are capable of self renewal. |
| State the function of Stem Cells. | Stem cells can be used to replace damaged/diseased cells with healthy, functioning ones. |
| Describe the general process of using stem cells for therapeutic use. | - Use of biochemical solutions to trigger the differentiation of stem cells into the desired cell type. - Surgical implantation of cells into the patient’s own tissue. - Suppression of host immune system to prevent rejection of cells (if stem cells are from foreign source). - Careful monitoring of new cells to ensure they do not become cancerous |
| Describe Stargart's |
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