Chapter 4 Honors and Lab Biology
Quick Write : ◦ Why do we need to learn about cells?
Healing time is radically reduced and scarring almost eliminated by bioartificial skin!
Cells that do NOT contain membrane bound organelles. (unicellular)
Cells that DO contain membrane bound organelles.
Cells were discovered due to microscopes in the early 17 th century ROBERT HOOKE 1665 (english scientist) examined a slice of cork, he saw “little boxes” they reminded him of small rooms….cells! These were dead plant cells. ANTON VAN LEEUWENHOEK (dutch microscope maker) first to observe living cells
Is the smallest unit of matter that can carry out all the processes of life. Organelle: parts within a cell!
1. All living things are composed of one or more cells 2. Cells are the basic unit of structure and function in an organism 3. Cells come from the reproduction of existing cells.
Matthias Schleiden (1838) botanist, all plants are composed of cells Theodor Schwann (1839) zoologist, all animals are composed of cells Rudolf Virchow (1855) physician, cells come ONLY from other cells.
Not all cells are alike! They vary in… ◦ A) size ◦ B) shape ◦ C) internal organization SIZE: range from.2m – 0.2um (most are 10-50um) -not all are microscopic (most are) ex: giraffe’s nerve cells extend 6.5 ft. down it’s leg!! Cells are limited in size by the ratio between their outer surface area and their volume
Organelles: parts of a cell, have specific jobs Tissues: groups of cells that have a similar function
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Organ systems- a group of organs that work together to perform a set of related tasks. Digestive system includes: the stomach, esophagus, intestines and mouth. Cells → Tissues → Organs → Organ Systems
Cell Membrane – separates cell from external environment, gives shape and flexibility to cell, selectively permeable
Cytoplasm: ◦ gelatin like aqueous fluid called cytosol ◦ Cytoplasmic streaming ◦ Mostly water but also salts and organic molecules
Mitochondia: power house of the cell! Where cellular respiration occurs, production of ATP, has it’s own DNA ◦ Cristae: inner membrane creating many folds to increase surface area
Ribosomes: where proteins are made, ◦ Free Floating Ribosome: make proteins for the cell ◦ Ribosomes attached to ER: make proteins to be exported from the cell
Endoplasmic Reticulum: (ER) acts as a highway for molecules to move around the cell. ◦ Smooth ER: does NOT contain ribosomes ◦ Rough ER: does contain ribosomes
Golgi Apparatus (bodies) processes, packages, and secretes a) product is assembled (moves from ER to golgi, where it is put together and adjusted) b) product is packaged (in new sacs) c) product is mailed out (sent out of cell)
Cilia: short hair like projections beat together to move an organism ex: humans trachea cilia move fluids and mucus! YUM
Flagella: long, whiplike projections, single or in pairs, rapid movement, ex: sperm
Nucleus: brains! Control center of cell, DNA & RNA are made here! ◦ Nuclear envolope: double membrane with pores ◦ Chromatin: fine strands of DNA & protein ◦ Nucleolus: inside nucleus where ribosomes are made
Lysosome: digestive enzymes, digest food, disease causing bacteria, old organelles, ex: lysosomes eat up tissue between fingers in embryos, usually only in animal cells
Cytoskeleton- helps shape & support cells ◦ Microtubules: long slender protein tubes form spindle fibers during mitosis ◦ Microfilaments: fine protein threads
Centrioles: cell reproduction Centrosome: cell reproduction
Cell Wall: rigid covering made of cellulose, protects cell, goes OUTSIDE cell membrane
Central Vacuole: huge structure which may take up 90% of the space in plant cell
Plastids ◦ a) chloroplasts : site for photosynthesis ◦ b) chromoplasts: stores red and yellow pigment ◦ c) leucoplasts: non pigmented