IGCSE Coordinated Science: Cell Structure

IGCSE Coordinated Science: Cell Structure Cell Structure 1. State that living organisms are made of cells. Yeah, so you have to know that all living organisms are made out of cells. This is supported by the “Cell Theory” which suggests that “cells are the basic unit of structure in every living thing 2. Identify and describe the structure of a plant cell (palisade cell) and an animal cell (liver cell), as seen under a light microscope. The one on the left is the “Animal Cell”, the one on the right is the “Plant Cell”. 3. Describe the differences in structure between typical animal and plant cells. Well, first of all, plant cells have structures that are not present in the typical animal cell. For example, only plant cells have chloroplasts and cell walls. Additionally, the vacuole is occasionally present in animal cells, but of a much smaller size as compared to the plant cell. The shape of a plant cell is also more regular, as opposed to the shape of an animal cell, which is more all over the place and irregular. The form of carbohydrate stored in each cells is different: Animal cells store carbohydrate as glycogen, where as plant cells store carbohydrates as starch. 4. Relate the structures seen under the light microscope in the plant cell and in the animal cell to their functions. This is an elaboration to point 2. 1. Nucleus: Contains DNA (genetic material) , which controls cell activities 2. Cytoplasm: Most chemical reactions take place here; controlled by enzymes 3. Cell membrane: Controls substances that moves in and out of cell. Is partially permeable-will talk about that later. The points up there apply to both animal and plant cells. The things below are only found in plant cells 1. Cell wall: strengthens and protects the cell 2. Chloroplasts: Contain chlorophyll, which absorbs light energy for photosynthesis. 3. Vacuole: Large, and filled with cell sap to help keep the cell turgid (full). *Some animal cells also have vacuoles but they are smaller 5. Relate the structure of the following to their functions ● Red blood cells – transport, ● Root hair cells – absorption. Red blood cells: These contains a protein called hemoglobin, containing iron, which binds with oxygen to carry blood around the body for respiration. They are also have a bi-concave shape to increase the surface area of the cell so that oxygen can diffuse into the cell at a quicker rate. Unlike other cells, they don’t have a nucleus so they can move around more easily. Root hair cells: They have an elongated section to its main body which maximizes the surface area to increase absorption of water. It’s also very effective for absorption because it is in contact with the soil.