Cell structures
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Cell structure |
Features(characteristics) |
Functions |
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Nucleus |
Contain DNA, the genetic material, carries the genetic information |
Controls the activities of the cell |
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There are pores in the nuclear membrane |
Allow the exchange of materials between the nucleus and the cytoplasm |
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- Spherical - Bounded by double membrane(nuclear membrane) |
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Cytoplasm |
- Jelly-like fluid - Contains enzymes - Mainly made up of water and proteins |
Holds many organelles |
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Site for many chemical reactions |
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Allows the movement and transport of materials inside the cell |
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Cell membrane |
- Is a membrane, mainly made up of phospholipid |
Encloses the cell and separates the cell contents from the outside |
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- Differentially permeable (only allow certain substances to pass through) - Made of up specific proteins |
Controls the movement of substances into and out of the cells |
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- Flexible |
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Cell wall |
- Fully permeable |
Allow water and dissolved substance to pass through |
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- Thick, rigid outermost layer - Mainly made up of cellulose |
Protect, supports and give shape to the plant cells |
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Endoplasmic reticulum(ER) |
- Continuous with outer nuclear membrane and extends throughout the cytoplasm - Two types |
Efficiently transport of materials withing the cell |
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Rough endoplasmic reticulum |
- With ribosomes attached on the surface |
Site of synthesis of protein |
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Smooth endoplasmic reticulum |
- Without ribosomes |
Site of synthesis of lipids |
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Ribosomes |
- Small particles, - No membrane - Some are lying free in the cytoplasm |
Involved in the synthesis of proteins |
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Mitochondrion |
- With related enzymes |
Main site of respiration - Converts chemical energy in food into energy that the cell use |
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- Bounded by double membrane - Inner membrane is highly folded |
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Chloroplast |
- Contain chlorophyll (a green pigment) |
Carry out photosynthesis - Captures light energy and converts into chemical energy in food |
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- Present in green plant cells - Bounded by a double membrane, with a network of membrane inside - Starch grains are often present |
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Vacuole |
- The membrane is flexible |
When become turgid (the central vacuole is full of water), provide support to the plant |
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- Fluid-like sac surrounded by a single membrane - Contains water and dissolved substances, such as glucose, pigments and wastes |
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Test yourself
1. List the names of all cell structures that need to be known within the scope of the DSE curriculum.
2. What are the functions and related characteristics (or structures) of the following cellular structures?
(1) cell wall
(2) cell membrane
(3) Cytoplasm
(4) rough endoplasmic reticulum
(5) smooth endoplasmic reticulum
(6) Endoplasmic reticulum
(7) Ribosomes
(8) Vacuole
(9) Chloroplasts
(10) nucleus
3. Which of the above structures are double-layer membranes?4. Which of the above structures only exist in plant cells, but not in animal cells?5. Which types of cells in the human body contain more mitochondria? What are the common needs of these types of cells?6. Which types of cells in the human body contain more rough endoplasmic reticulum? What are the common functions of these types of cells?7. What is the main component of plant cell wall?8. Which components on the cell membrane can control the movement of substances into and out of the cell membrane?9. Which of the above cell structures can only be observed under an optical microscope?10. Which cells in the human body do not have nuclei?11. Which cells in the human body do not have mitochondria? What is the significance of it?12. Which living cells in plants do not have chloroplasts?13. Which of the above structures do prokaryotic cells (such as bacteria, etc.) lack?
Advanced Questions:1. Viruses must enter cells to replicate themselves, but some viruses cannot enter human cells. what is the reason?2. The functions of the rough endoplasmic reticulum and the free ribosomes in the cytoplasm are the same. What is that? But where the product goes is a little different. What's the difference?3. How do substances of different properties move in and out of cells?
