Chapter 3 Cytology Part 1 Biology Mr. Cobb
Cytology The study of cells First observed and noted by Robert Hooke in Cork cells Named cells because it looked like rooms in a monastery.
Original Microscope
Other people noticing cells Leeuwenhoek saw living organisms in 1674 Robert Brown found the nucleus in Protoplasm – the “stuff” inside the cell.
Cell Theory The cell is the basic unit of life Cells perform all the functions of living things. Cells come from pre-existing cells
Levels of Cellular Organization Unicellular – one – cell organisms Colonial organism – a collection of similar cells living together. Multi-cellular tissues organs organ system
Cell Jobs Absorb Digestion Excrete Egestion Secretion Synthesis Respiration
Animal Cell
Plant Cell Anatomy
Two Types of Cells Eukaryotic Cells Has a membrane bound nucleus Membrane bound organelles in the cytoplasm Organelles - a structure that performs special functions in the cell. Prokaryotic Cells Bacteria and Blue-green algae Lack a membrane around nucleus Contains only non-membrane bound organelles
Plasma Membrane Separates the cell from the environment. Regulates what comes in and out of the cell. Contains lipids, because lipids do not dissolve in H 2 O Phospholipids in a lipid bilayer. Membrane proteins throughout the membrane with different functions.
Plasma Membrane
Cell Wall Only in plant cells outside the plasma membrane Made of cellulose and rigid 2 of them Primary Secondary Has pores for transport and communication.
Cell Wall
Cytoplasm Everything inside the cell except the nucleus. Cytoplasmic streaming is moving the organelles around inside the cell.
Mitochondria “Powerhouse” Bean shaped Turn chemical energy in sugar into usable energy Two membranes Cristae – inner membrane with many folds for more surface area. Have their own DNA (directly from maternal lineage)
Mitochondria
Ribosome Non-membrane bound organelle found in prokaryotes and Eukaryotes Used to make proteins Free floating or on the ER Made of 2 parts (we will discuss this later)
Endoplasmic Reticulum (ER) Around the nucleus Rough ER has ribosomes on it, smooth ER does not. Rough ER produces proteins. Smooth ER produces lipids and hormones.
Endoplasmic Reticulum
Rough ER
Golgi Final processing and packaging of produced compounds. UPS of the cell, packaging compounds into sacs.
Golgi Body
Lysosomes W hat does “lys” mean? L ys means to break down. B reak down invaders, food, old cell components.
Cytoskeleton Tiny fibers inside the cell. Shape Strength Move structures around the cell.
Cytoskeleton
Flagella and Cilia Flagellum is a long tail. Cilia are short hairs that cover the cell
Plastids Found in cells of plants, algae and few others. Storage containers 2 types: Leukoplasts – contain starch or oil for the plant Chromoplasts – contain pigments Best known is chloroplasts.
Chloroplasts Converts light energy into chemical energy. “football shaped” Have their own DNA (like the mitochondria)
Chloroplast structure Thylakoids – sacks Granum – stacks of thylakoids Stroma – fluid Chlorophyll – green pigments Function – making sugar
Chloroplast
Nucleus “control center” DNA replication and RNA transcription Nuclear Envelope is a double membrane that surrounds the nucleus. Nuclear pores or openings Chromatin material – DNA and other proteins Nucleolus – center part of nucleus
Nucleus
Vacuoles Membrane-bound sac Function: storage Food Waste Secretion Pinocytic Central vacuole in plants
Cytoskeleton 3 Types: Microfilaments – support network inside cell Intermediate filaments – strength Microtubules – internal framework for transportation