What does cell theory state?
All organisms consist of cells
What do all cells have?
- Proteins—perform most of the cell’s functions
2. Nucleic acids—store, transmit, and process information
3. Carbohydrates—provide chemical energy, carbon, support, and identity
4. Plasma membrane—serves as a selectively permeable membrane barrier
How are cells grouped/divided?
Based on Morphology or phylogeny (evolutionary history)
What are the 2 cell groups?
- Eukaryotes have membrane-bound nucleus
- Prokaryotes lack membrane-bound nucleus
What are the 3 domains that organisms are divided into?
- Bacteria—prokaryotic
- Archaea—prokaryotic
- Eukarya—eukaryotic
How are bacteria classified?
According to their basic shape.
What are the 5 groups that Bacteria are classified into
according to their basic shapes?
- spherical (cocci)
- rod (bacilli)
- spiral (spirilla)
- comma (vibrios)
- corkscrew (spirochaetes).
They can exist as single cells, in pairs, chains or clusters.
Describe Prokaryotic structure.
All prokaryotes lack a membrane-bound nucleus. Two types:
1. Archaeal cell structure is still relatively poorly understood
2. Bacterial cells vary greatly in size and shape. Most bacteria contain several structural similarities: Plasma membrane, a single chromosome, ribosomes (which synthesize proteins), & Stiff cell wall.
What shape or structure is the form of a prokaryotic DNA?
The long strand of DNA is in the form of one supercoiled circular chromosome. Also has a few supportive proteins. Basically the DNA double helix coils on itself with the aid of enzymes to form a compact, “supercoiled” structure”
Where is DNA located in a prokaryote?
In the nucleoid region of a prokaryotic cell.
What are plasmids?
Many bacteria contains these. Are small, supercoiled, circular DNA molecules. Usually contain genes that help the cell adapt to unusual environmental conditions. Are physically independent of the cellular chromosome
What structures does a prokaryotic cell have in their cytoplasm?
- Ribosomes: Consist of RNA molecules and protein. Used for protein synthesis.
- Cytoskeleton: The inside of the cell is supported by a network of long, thin protein filaments, which also assist with cell division in bacteria
What are internal photosynthetic membranes?
Many prokaryotes and photosynthetic species have this.
They convert energy in sunlight to chemical energy. Multiple membranes passing through the internal region of cell observed in photosynthetic bacteria. Develop as infoldings of plasma membrane. Contain enzymes and pigment molecules required for reactions to occur
What are organelles?
Certain Species Have Organelles for Specialized Functions.
Some bacteria have organelles.
They are membrane-bound compartments that perform specialized tasks:
1. Store calcium ions
2. Concentrate enzymes for building organic compounds
3. Hold magnetite crystals: This serves as a compass and helps cells sense a magnetic field and swim in a directed way
What are the protective layers on a prokaryotic cell?
- Plasma Membrane- phospholipids
- Cell wall- a tough fibrous layer that surrounds the plasma membrane and forms a protective “exoskeleton”. The primary structural component of the cell wall is polysaccharide peptidoglycan
- Capsule- Outermost layer found in SOME bacteria for protection. Usually made from polysaccharides.
What is a flagella?
An external structure that enable movement
They are long filaments that rotate to propel cell
What is a fimbriae?
They are needlelike projections that promote attachment to other cells or surfaces.
Many prokaryotes interact with their environment via structures that grow from their plasma membrane.
What are the categories of eukaryotic?
- Protists
- fungi
- plants
- animals
May be multicellular or unicellular. Most eukaryotic cells are larger than most prokaryotic cells
What are the benefits of Organelles?
- The relatively large size of the eukaryotic cell makes it difficult for molecules to diffuse across the entire cell. This problem is partially solved by breaking up the large cell volume into several smaller membrane-bound organelles
- Compartmentalization offers two advantages: Separation of incompatible chemical reactions & increasing efficiency of chemical reactions.
Cell component structure correlates with its …
FUNCTION
What is the nucleus?
Large, highly organized membrane bound compartment. Are
surrounded by a double-membrane nuclear envelope.
It has a distinct region called nucleolus, which is the location where ribosomal RNA is synthesized and ribosome subunits are assembled.
What is the primary function(s) of the nucleus?
- Information Storage and Processing
- Ribosomal RNA Synthesis (nucleolus)
What are ribosomes?
Are complex molecular machines that manufacture proteins. Are non-membranous so they are considered to be NOT organelles.
Have large and small subunits
Both contain RNA molecules and protein
Can be attached to the rough ER or can be free in the cytosol, the fluid part of the cytoplasm
