1. Bio 101 Medgar Evers College Fall 2017
The Cell
Bio 101
Medgar Evers College
Fall 2017

2. The History of Eucaryotes
They first appeared approximately 2 billion years ago.
Evidence suggests evolution from procaryotic organisms by symbiosis.
Organelles originated from procaryotic cells trapped inside them.

3. The Cell Theory All living things are made up of cells
Cells are the functional units of life
Cells are the structural units of life
All cells come from previous cells

4. Prokaryote vs Eukaryote cell
Primitive cells
1-10 µm in size
Bacteria/ archaea
No nucleus
No membrane bound organelles
Advanced cells
µm in size
Found in Eukarya domain of life
Nucleus
Membrane bound organelles

5. 3 Domains

7. External Structures Locomotor appendages function in motility
Flagella, whip like structure
function in motility
cilia
similar in overall structure to flagella, but shorter and more numerous
function in motility, feeding and filtering.

9. External Structures Glycocalyx
an outermost boundary that comes into direct contact with environment
usually composed of polysaccharides
functions in adherence, protection, and signal reception

10. External Boundary Structures
Cell wall
rigid, provides structural support and shape

11. External Boundary Structures
Cytoplasmic (cell) membrane
typical bilayer of phospholipids and proteins
sterols confer stability
serves as selectively permeable barrier in transport
Eucaryotic cells also contain membrane-bound organelles that account for 60-80% of their volume.

13. Internal Structures Nucleus
compact sphere, most prominent organelle of eucaryotic cell
nuclear envelope composed of two parallel membranes separated by a narrow space and is perforated with pores
contains chromosomes
nucleolus – dark area for rRNA synthesis and ribosome assembly

15. Internal Structures Endoplasmic reticulum – two types:
Rough endoplasmic reticulum (RER)– originates from the outer membrane of the nuclear envelope and extends in a continuous network through cytoplasm; rough due to ribosomes; proteins synthesized and shunted into the ER for packaging and transport; first step in secretory pathway
Smooth endoplasmic reticulum (SER)– closed tubular network without ribosomes; functions in nutrient processing, synthesis and storage of lipids, etc.

16. Internal Structures Golgi apparatus
consists of a stack of flattened sacs called cisternae
closely associated with ER
Transitional vesicles from the ER containing proteins go to the Golgi apparatus for modification and maturation.
Condensing vesicles transport proteins to organelles or secretory proteins to the outside.

19. Internal Structures Lysosomes
vesicles containing enzymes that originate from Golgi apparatus
involved in intracellular digestion of food particles and in protection against invading microbes

20. Internal Structures Mitochondria
consists of an outer membrane and an inner membrane with folds called cristae
Cristae hold the enzymes and electron carriers of aerobic respiration.
divide independently of cell
contain DNA and procaryotic ribosomes
function in energy production

22. Internal Structures Chloroplast found in algae and plant cells
outer membrane covers inner membrane folded into sacs, thylakoids, stacked into grana
larger than mitochondria
contain photosynthetic pigments
convert the energy of sunlight into chemical energy through photosynthesis
primary producers of organic nutrients for other organisms

24. Internal Structures Ribosomes composed of rRNA and proteins
40S and 60S subunits form 80S ribosomes
larger than procaryotic ribosomes
function in protein synthesis

25. Internal Structures Cytoskeleton
flexible framework of proteins, microfilaments and microtubules form network throughout cytoplasm
involved in movement of cytoplasm, amoeboid movement, transport, and structural support

27. Vacuoles
Membrane bound structures that store food, water, or waste.

28. Centrioles
Cylindrical shaped organelles involved in cell division.

29. Differences between a plant and animal cell
1- Plant cells have a cell wall
2- Plant cells are rectangular in shape
3- Plant cells have no centrioles
4- Plant cells have chloroplast
5- plant cells have a central vacuole.

30. Difference between plant and animal cell
Plant cells have a cell wall 2- Plant cells are rectangular in shape 3- Plant cells have no centrioles 4- Plant cells have chloroplast 5- plant cells have a central vacuole.