Cell Structure Object: to study the general structure of the cell, morphological variation (shapes) and size of cells through the light microscope.
History In the 1600s, Anton Van Leevwenhoek used a single lens microscope to view bacteria
Leevwenhoek’s microscope
2- Robert Hook (1635 – 1703): discovered small “rooms” called CELLS under a piece of cork
Robert Hook’s Microscope:
3 – Scientists (Schwann, Schleiden and Virchow) put the CELL THEORY in (1882) a – Cells are basic unit of living things b – All living things are made up of cells c – New cells come from pre-existing cells
Classification of Cells Eukaryotes Prokaryotes e.g., Bacteria Free Cells Cells as a unit Amoeba Euglena Reproductive cells Somatic cells Paramecium Trypanosoma eggs sperms
But, what are the characteristics of prokaryotes and eukaryotes? Types of Cells: Prokaryotes Ex. Bacteria and Blue green Algae Eukaryotes Ex. Plants, Animals, Fungi, and Protists But, what are the characteristics of prokaryotes and eukaryotes?
Differences between prokaryotic & eukaryotic cells No nucleus [nucleoid instead] Nucleus with envelope DNA circular and not complexed with protein DNA linear and with protein to form chromatin Smaller than eukaryotes larger than prokaryotes No membrane bound organelles Many membrane bound organelles Simple cells highly specialized.
Typical prokaryotic structures
Typical shapes of bacteria
Characteristic grouping (or not grouping)
Cocci do not have flagella
Cell Shapes
Cell Sizes frog or fish egg are the largest individual cells easily visible, approx. 1mm diameter human or sea urchin egg, approx. 100 m diameter typical somatic cell, approx. 20 - 70m plant cells are larger, approx. 10 -100 m bacteria are smaller, approx. 1- 5 m
Cell Size
Levels of Organization Cell tissue organ organ system The levels of organization in a multicellular organism are individual cells, tissues, organs, and organ systems. In this example, muscle cells make up smooth muscle tissue, which, along with other tissues, makes up the stomach, an organ. The stomach, in turn, is part of an organ system, the digestive system.
Different types of cells: Protists: single eukaryotic cells: such as: 1- Amoeba 2- Paramecium 3- Euglena 4- Trypanosomes
1- Amoeba proteus
2 – Paramecium caudatum
3 – Euglena Viridis
4 – Trypanosoma spp.
Representative Animal Cell
Representative Plant Cell
Components of Blood Blood is a mixture of cellular components suspended in plasma: 1. Erythrocytes (RBCs) 2. Leukocytes (WBCs) 3. Thrombocytes (platelets) Total Blood Volume: 8 % of body weight 2.75 / 5.5 liters of blood is plasma (remaining is the cellular portion)
Centrifuged Blood Sample
Separation of Components Plasma = Less Dense Platelets / WBC’s RBC’s More Dense
WBC’ s RBC’s
Microscopic Views Fish Blood Bird Blood Horse Blood Frog Blood Cat Blood Dog Blood Fish Blood Frog Blood Snake Blood Microscopic Views Human Blood Horse Blood