Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Cell Structure Chapter 7 7-1: Introduction to Cells The Discovery of Cells In 1665, Robert Hooke, an English scientist, used a simple microscope (which magnified objects 30 times their normal size) to observe “little boxes” in thin slices of cork. He called the boxes “cells” because they reminded him of the small rooms in which monks lived. The Discovery of Cells In 1675, Anton van Leeuwenhoek, a Dutch scientist, used a stronger microscope (that could magnify objects 300-fold) He named pond water creatures “animalcules” or “tiny animals”. First to observe living cells Cell Theory 1. 2. 3. All living things are made up of one or more cells. Cells are the basic units of structure and function in organisms. All cells arise from existing cells. Similarities and Differences in Prokaryotic and Eukaryotic Cells Average Cell Size Cell Wall Cell Membrane Nucleus Cytoplasm DNA Prokaryotic 1-10 µm Eukaryotic 10-100 µm YES YES NO YES YES, in cytoplasm SOMETIMES YES YES YES YES, in nucleus Continuation on next slide Similarities and Differences in Prokaryotic and Eukaryotic Cells Ribosomes Membrane Enclosed Organelles Mode of Locomotion Found in -- Prokaryotic YES Eukaryotic YES NO YES One or more flagella Bacteria only One or two flagella or cilia Fungi, protists, plants, animals 7-2: Inside the Eukaryotic Cell Directing Cellular Activity Nucleus – membrane bound structure that contains the cell's hereditary information and controls the cell's growth and reproduction The nucleus (nuclei – plural) houses deoxyribonucleic acid (DNA) Genetic material in cells Directing Cellular Activity Ribosomes – Organelles that help in the synthesis of proteins Directing Cellular Activity Cytoplasm – the gel-like substance found between the cell membrane and the nucleus Directing Cellular Activity Centriole – one of a pair of organelles that are found in animal cells that function in the formation of spindle fibers during cell division Protein Processing The endoplasmic reticulum and the Golgi apparatus are organelles that prepare proteins for extracellular export Endoplasmic reticulum (ER) – a network of membranes throughout the cytoplasm of the cell Protein Processing Two types of ER Rough ER – proteins are made in ribosomes and then packaged into vesicles Smooth ER – makes lipids (fats) and helps in cleaning harmful substances in the cell Protein Processing Golgi complex – responsible for sorting and correctly shipping the proteins produced in the ER Resembles a post office in cells Storage and Maintenance Lysosome – a vesicle that contains specific enzymes that breaks down large molecules They also help recycle materials in the cell by digesting old, damaged, or unused organelles Lysosomes are in animal cells Storage and Maintenance Mitochondrion (mitochondria = plural) – an organelle that uses energy from organic compounds to make ATP Storage and Maintenance Vacuole – an organelle that stores water, ions, nutrients, and wastes; it can also store toxins and pigments Storage and Maintenance Chloroplast – an organelle that uses light energy to make sugar from carbon dioxide and water Plant Cell vs. Animal Cell Cell wall – provides additional support for certain cells; they have cellulose which aids in its structure Plant Cell vs. Animal Cell Organelles that are exclusively found in plant cells Cell wall Central vacuole Chloroplast Organelles that are exclusively found in animal cells Lysosome Centriole Picture of animal cell vs. plant cell Cellular Movement Flagella – long finger-like projections that push cells forward by snakelike wriggling Cellular Movement Cilia – short hair-like projections of certain cells that beat in a regular fashion to create currents that sweep materials along 7-3: From Cell to Organism Levels of Organization Cell – the smallest unit of life Tissue – group of cells that work together and have a common function Organ – group of tissues that work together… Organ system – group of organs… Organism – group of organ systems… Cellular Differentiation Cellular differentiation – The normal process by which a less specialized cell develops or matures to possess a more distinct form and function