Cells (5078 syllabus)

Cells 1 Cells Functions: Cell membrane: 1. partially permeable membrane 2. controls substances entering and exiting the cell Cytoplasm: 1. a jelly-like substance where most cell activities and chemical reactions occur. 2. It contains enzymes and organelles Nucleus: 1. controls cell activities. 2. essential for cell division 3. repairs worn-out parts 4. contains genetic information Cell wall: 1. a fully permeable membrane. 2. It gives the plant cell its fixed shape 3. protects the cell from injury Mitochondria: 1. Aerobic respiration occurs here. 2. Food substances are oxidized to release energy Chloroplast: 1. contains chlorophyll which absorbs sunlight for photosynthesis Vacuole: 1. (Plant cell) a. helps maintain water balance by taking in water to keep the plant cell firm 2. (Animal cell)

Cells 2 a. contains water and food substances b. only exists temporarily Animal Cell VS Plant Cell In animal cell: 1. No presence of cell wall 2. No presence of chloroplast 3. There is presence of small and many vacuoles In plant cell, 1. presence of cell wall sometimes chloroplasts and a large vacuole Adaptations & Functions: Red blood cell: Adaptations: Biconcave shape increases surface area to volume ratio to take in and release oxygen at a faster rate. Red pigment haemoglobin Function: transports oxygen from lungs to all parts of the body. Xylem vessel: Adaptations: walls are thickened with lignin to prevent collapse of vessels. also provides mechanical support for plants. Function: transports water and mineral salts from surrounding

Cells 3 Root hair cell: Adaptations: long narrow feature increases surface area to volume ratio to allow the cell to absorb water and mineral salts at a faster rate Function: absorbs water and mineral salts from the surrounding Definitions: Cell: the smallest and basic unit of life. Tissue: a group of cells with a similar structure and function together as a unit Organ: a group of tissues which is typically self-contained and has a specific vital function Organ system: a group of organs working together to perform bodily functions and make up an organism.