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- 1. Every living organism is comprised of cells.
- 2. The cell is the smallest living unit.
- 3. Cells come from preexisting cells
- 4. Cells contain DNA
- Archaeans and bacteria
- Have few if any internal membrane & enclosed compartments
- Are the smallest and structurally simplest cells
- Protein filaments under the plasma membrane impart shape to the cell
- Protists plants fungi and animal
- Have a (true) nucleus and other membrane enclosed compartments
- They differ in internal parts and surface specializations.
Cytoskeleton key concepts
Diverse protein filaments reinforce a cell’s shape and keep its parts organized. As some filaments lengthen and shorten, they move cell structures or the whole cell.
Invented by Hans and Zacharias Janssen 1590
Examined a thinly sliced cork from a mature tree and named the tiny compartments cellulae coining the term cell.
First to identify a plant nucleus
Hypothesized a plant cell is an independent living unit
Discovered that cells divide into descendant cells
Antoni van Leeuwenhoek
The first to observe living microscopic “animalcules” and “beasties”
- The cell's outer membrane
- Selectively controls the movement of materials in and out of the cytoplasm
- It separates metabolic activities from events outside of the cell, but does not isolate the cell's interior
Double-membraned sac holding a eukaryotic cell's DNA
Region of cytoplasm where the DNA is concentrated
- Semifluid mixture of water, sugars, ions, and proteins between the plasma membrane and the region of DNA
- Cell compartments are suspended in cytoplasm
Structures on which proteins (polypeptides) are built
- Double layer of lipids organized so that their hydrophobic tails are sandwiched between their hydrophilic heads
- Forms the structural framework of all cell membranes
A physical relationship that constrains increases in cell size and shape
What are the most abundant type of lipid in cell membranes.
What are some protein cell functions? (Not all inclusive)
- -form channels through a bilayer
- -pump substances across the bilayer
- Surrounds the plasma membrane of nearly all prokaryotes
- Permeable to dissolved substances: composed of protein or peptidoglycan
- Cell walls of most bacteria consist of peptidoglycan
- Consists of proteins
Polymer of cross linked peptides and polysaccharides
- Formed of sticky polysaccharides
- Slime layer
- Helps cells adhere to many types of surfaces
- Protect cell from predators and toxins
- Slender cellular structures used for motion.
- (Organized array of microtubules - eukaryotic)
- Help cells cling to or move across surfaces
- (Sex) pilus attaches to another cell to transfer genetic material from one cell to the other
Small circles of DNA that carry a few genes that confer advantages, such as resistance to antibiotics
- Shared mass of slime composed of secreted polysaccharides and glycoproteins upon which communities of bacteria live
- May include bacteria, algae, fungi, protest, and archaeans
Benefits of the biofilm
- Serves as permanent scaffolding
- Species break down toxic chemicals allowing other, more sensitive, species to thrive
- Waste products of some species serve as building materials for others
Structure that carries out a specialized function inside a cell
Organelles of Eukaryotic Cells
- Golgi body
Protect and control access to DNA
Routing, modifying new polypeptide chains; synthesizing lipid; other tasks
Golgi body function
Modifying new polypeptide chains; sorting, shipping proteins and lipids
Transporting, storing or digesting substances in a cell; other functions
- Making ATP by sugar breakdown called aerobic respiration
- Two membrane
- Have their own DNA
- Are all Maternal
- Making sugars in plants, some protists
- Photosynthetic organelle
Assembling polypeptide chains
Anchor for cytoskeleton
Components of the Nucleus
- Nuclear envelope
Circular DNA molecule and many proteins associated with it
Pore-riddled double membrane that controls which substances enter and leave the nucleus
Semifluid interior portion of the nucleus
Rounded mass of proteins and copies of genes for ribosomal RNA used to construct ribosomal subunits
Total collection of all DNA molecules and associated proteins in the nucleus; all of the cell's chromosomes
- When a cell is not dividing - grainy
- Preparing for division - DNA in each is copied or duplicated
- During division – Condense
- A series of interacting organelles between the nucleus and the plasma membrane
- Its main function is to make lipids, enzymes, and proteins for secretion or insertion into cell membranes.
- It also destroys toxins, recycles wastes, and has other specialized functions.
Endomembrane System (Make up)
- Rough ER
- Smooth ER
- Golgi Body
- Plasma Membrane
- Contains ribosomes which synthesize polypeptide chains, which extrude into the interior of the ER.
- The proteins fold and take on their tertiary structure.
- Has no ribosomes
- Uses enzymes to make the cell membrane lipids.
- Breaks down carbohydrates, fatty acids and some drugs and poisons
- Small membrane enclosed saclike organelle.
- Transport substances from one organelle to another or to and from plasma membrane
- Sort modify and transport proteins
- Attach phosphate groups
- Cleave polypeptide chains
Vesicles that contain powerful digestive enzymes to digest the content of vacuoles carrying particles or molecules for disposal
Keeps plant cells and structures firm
- Basis of eukaryotic cell shape, internal structure and movement
- Interconnected system of many protein filaments
- Reinforce, organize and move cell structures and the whole cell
- Long hollow cylinders that consist of subunits of the protein tubulin
- For dynamic scaffolding for many cellular process, rapidly assembling when they are needed, disassembling when they are not.
- Form in the growing end of a young nerve cell support and guide its lengthening in a particular direction
- Fibers that consist primarily of subunits of the globular protein actin
- Strengthen or change the shape of eukaryotic cells
- Make up the cell cortex
- Microfilaments of myosin and actin interact in muscle cells to bring about contraction
- Strengthen and maintain cell and tissue structures
- Lamins form a layer that structurally supports the inner surface of the nuclear envelope.
A motor protein used to move chloroplasts toward or away from a light source
A motor protein used to bend a flagellum
The main constituent of a plant’s primary cell wall
Layers of firm material secreted onto the primary cell wall’s inner surface that strengthen the wall and maintain its shape
Seal abutting cells that line the outer surfaces and internal cavities of animals so no fluids can pass between them
Anchor cells to each other and to the extracellular matrix
Open channels that connect the cytoplasm of neighboring animal cells
Cytoplamic channels that cross the cell walls and join neighboring plant cells
A sticky layer in between the primary walls of adjoining cells
Substance a young plant cell first secretes onto the outer surface of its plasma membrane
The main constituent of a plant’s primary cell wall
A strong waterproof component of the secondary cell walls of older stems and roots
A protective body covering made of cell secretions
Extracellular matrix (ECM)
Nonliving mixture of fibrous proteins and polysaccharides surrounding the cells that secrete it