Transcript Zoology
A. Zoology 1. A subset of biology dealing with animals. Subsets of zoology – – Entomology – Ichthyology – Ornithology B. Cells 1. Cells are the basic organizational units of life. 2. Cells can be prokaryotic or eukaryotic. 3. Prokaryotic cells have no nucleus. 4. Eukaryotic cells have a nucleus containing DNA. 5. All eukaryoic cells have three basic parts. a. A plasma membrane b. Cytoplasm c. A nucleus C. Plasma membrane 1. Outer boundary of the cell. 2. Fluid mosaic model – a membrane has two layers of proteins and phospholipids. 3. The membrane is constantly changing shape and shifting. There may be many types of proteins dispersed through the membrane. 4. The membrane is selectively permeable. This means they let some things through while keeping others out. D. How do things cross the membrane? There are 7 ways! 1. Simple diffusion – the movement of particles from areas of high concentration to areas of low concentration. 2. Facilitated diffusion – carrier proteins help molecules get across the membrane. 3. Osmosis – the diffusion of water. Tonicity refers to the relative concentration of solutes in water inside and outside the cell. a. ISOTONIC – same concentration inside as outside the cell. (no effect on cell) b. HYPERTONIC – Concentration is higher outside the cell than inside the cell. (The cell shrinks) c. HYPOTONIC – Concentration is higher inside the cell than outside. (the cell swells) 4. Filtration – uses water pressure to force molecules across the membrane. 5. Active transport – moves molecules from areas of low concentration to high concentration.(opposite of diffusion) Requires ATP energy. 6. Endocytosis – The bulk movement of particles across the membrane INTO the cell. There are 3 types! *a. Pinocytosis – the taking in of fluids. *b. Phagocytosis – the taking in of solids. *c. Receptor-mediated endocytosis ~ uses a protein to bring molecules into the cell. 7. Exocytosis – Molecules are removed from the cell in packets called vesicles. E. Organelles 1. VACUOLE – a membrane-bound fluid filled sac within the cytoplasm of a cell. Animal cells have many small ones. 2. MITOCHONDRIA – among the largest organelles, surrounded by a double membrane, produces small energy packets that can be used by the cell. Powerhouse . 3. NUCLEUS – large round body, the most prominent structure in the cell, it is enclosed by a nuclear membrane. Chromosomes with genetic info are inside the nucleus. 4. RIBOSOMES – most numerous and smallest of the organelles, it is the site of protein synthesis. Often associated with endoplasmic reticulum. 5. ENDOPLASMIC RETICULUM – Makes proteins and hormones.Transports material throughout the cell. Comes in smooth and rough. 6. GOLGI BODIES – flattened stacked sacs, acts as a distribution center, packages and routes products throughout the cell. 7. CILIA – Short hairlike projections used for locomotion and to sense the environment 8. FLAGELLA – long thread-like structures used for locomotion. Cilia and flagella have filaments made of a protein called tubulin 9. MICROFILAMENTS – thin protein fibers in cytoplasm, helps the cell change shape. 10. MICROTUBULES – hollow cylinders of protein, provide support. 11. CYTOSKELETON – holds’ the cell upright and helps give it shape, helps it move, and holds other organelles in place. 12. LYSOSOMES – bags of enzymes, they are involved in breaking down material. “stomach” > 13. CYTOPLASM – a jelly-like substance made of proteins dissolved in water. A semifluid phase of cytoplasm where metabolic reactions occur is called the cytosol. F. Levels of Organization 1. First level – protoplasmic organization. Examples include euglena, amoeba, paramecium. 2. Second level – cellular organization, division of labor. Ex. some sponges. 3. Third level – tissue level, no organs. Ex. Jellyfish 4. Fourth level – organ level, organs composed of one or more tissues. Ex. flatworms. 5. Fifth level – system level, organs work together to form systems. Ex. most animals. G. Tissue Types A tissue is a group of similar cells specialized for a specific job. There are 4 types of animal tissue. 1. EPITHELIAL – Usually covers or lines something. – Renewable – Can be found lining the intestine, in the kidneys, the skin, etc. – Classified on the basis of shape and number of layers present. – Simple: one layer – Stratified: two or more layers – Squamous: flat – Cuboidal: cube shaped – Columnar: column shaped 2.CONNECTIVE TISSUE – Supports and binds – Loose connective tissue helps connect skin to underlying muscle. Fiberous connective tissue creates very strong cords like ligaments (connect bone to bone) and tendons (connect muscle to bones or other muscles. Adipose tissue – fat Cartilage – hard and flexible tissue for support Bone – hard. Provides protection and support. Spaces within bone or cartilage which house the living cells are called lacunae. Blood – a fluid connective tissue that transports material throughout the body. 3. Muscle tissue – Skeletal muscle attaches to bone and is used for movement – Smooth muscle creates a churning motion and helps move material around inside the body. – Cardiac muscle is found in the heart. Nervous tissue – Neurons are impulse conducting cells – Neuroglia are involved in protection, support, and nourishment – Peripheral glial cells form sheaths that protect the nervous system.