Flashcards
Cell Structure Flashcards
Cards in this deck (28)
- 1How much of our body weight do cells make up?About two thirds.
- 2How thick is a cell membrane?4-5nm
- 3What are cell (plasma) membranes made up of?Mainly phospholipids, but also structural proteins, receptor proteins, enzymes and antigens.
- 4What contains genetic material?DNA, chromosomes and genes.
- 5What is the nucleolus?It's a smaller body within the nucleus containing densely packed chromosomes called chromatin with protein and RNA strands. It initiates the formation of ribosomes, which are required for protein synthesis.
- 6What kind of membrane does the nucleus have?A double membrane riddled with pores involved in transporting materials between the nucleus and the rest of the cell.
- 7What is cytosol?The liquid portion of the cytoplasm
- 8What are mitochondria?Mitochondria are the sites where chemical energy contained within nutrients is trapped and stored through the formation of ATP.
- 9What is the structure of endoplasmic reticulum?A network of tubes and flattened sacs. formed by membranes, that is distributed throughout the cytoplasm.
- 10Why does rough ER have a granular appearance and what is its purpose?This is due to the attached ribosomes, that synthesise proteins for destined organelles, for cell membrane components, or for secretion to the cell exterior (e.g. hormones).
- 11What is the structure and purpose of smooth ER?Lacks attached ribosomes.
It is commonly involved in lipid metabolism, but it can also serve in detoxicification of drugs and deactivation of steroid hormones. - 12What is sarcoplasmic reticulum?This is the smooth ER in muscle cells. It sequesters large amounts of calcium, which are used to trigger muscular contraction.
- 13What is the structure and function of the Golgi Apparatus?Sets of smooth membranes forming flattened, fluid-filled sacs that are stacked, which is involved in modifying, sorting, and packaging proteins for delivery to other organelles or for secretion out of the cell.
- 14What are the numerous membrane-bound vesicles are frequently found around the Golgi Apparatus?They probably carry material between the Golgi and other organelles of the cell (e.g. receiving protein-laden vesicles from the rough ER or delivering other vesicles to the plasma membrane).
- 15What are endocytotic vesicles?In endocytosis (pinocytosis, phagocyosis) the plasma membrane infolds and engulfs extracellular material; then a membrane-bound vesicle (containing the material and surrounding fluid) buds off and is incorporated into the cell.
- 16What are exocytotic vesicles?Exocytosis (secretion) involves an actual fusion of the vesicular membrane with the plasma membrane, enabling the vesicle contents to be expelled (secreted) outside the cell.
- 17What is the structure and function of lysosymes?These membrane-bound vesicles contain many enzymes capable of digesting cellular products or damaged organelles, as well as bacteria brought into the cell by endocytosis.
- 18What disease arises from a lack of lysosomes?The fatal Tay-Sachs disease arises from a congenital lack of lysosomal enzymes that digest components of nerve cells (glycolipids). These accumulate in the cells, causing them to swell and degenerate.
- 19What is the structure and function of peroxisomes?These are membrane-bound vesicles containing digestive enzymes. They break down long-chain fatty acids as well as some toxic substances.
- 20What are example of genetic defects in peroxisome membrane transport?It can cause the fatal childhood diseases Zwellinger's syndrome and X-linked adrenoleukodystrophy.
- 21What is the structure of the cytoskeleton?Consisting of arrays of protein filaments that form networks within the cytosol, giving the cell its shape.
- 22What are the 3 major types of filament used within the cytoskeleton?Microtubules (25nm diameter), actin filaments (25nm diameter), and intermediate filaments (10nm).
- 23What is the function of microtubules?They have a 25nm diameter, and undergo frequent changes, growing or retracting by the addition or subtraction of their molecular building blocks (tubulin). They usually grow out of organising centres, e.g. centrosomes. As they extend outward, they form a system of organelles, and other cellular components to different positions within the cell.
- 24How is the movement driven for microtubules?Specialised motor molecules (dynein, kinesin). By subtle changes in shape. these motor molecules can attach, release, and then reattach to the successive positions so that the molecule 'walks' on the filament. The other end of the motor may be attached to the cargo that is moved.
- 25What is the function and structure of actin filaments?25nm in diameter. They can form stiff permanent structures, like microtubules they can also grow and retract, and hey are involved in a large array of cell movements.
- 26What ways can a actin filament move?Cell crawling, phagocytosis, and muscle contraction.
- 27What is myosin?Myosin is a motor molecule.
- 28—
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- Bachelors Degree PHYSIOLOGY (Cell Physiology) Flashcards on Cell Structure Flashcards, created by rosiewilkinson35 on 10/11/2015.
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