a. Every living organism is made of one or more cells
b. The smallest organism are single cells, and cells are the functional units of multicellular organisms
c. All cells arise from pre-existing cells
Physical Attributes of a Cell
a. Cell size= 1-100um
b. Volume and surface area are limited in order for the cell to function efficiently
less than 5um, that contain a simple internal structure with no membrane bound nucleus or organelles, with some internal structures that capture light
Parts of a Prokaryotic Cell
1. cell wall (not all) - protective covering
2. cytoplasm - intracellular fluid that contains ribosomes, food granules, and plasmids
3. plasma membrane - phospholipid bilayer that is selectively permeable
4. ribosomes - protein synthesis
5. nucleoid - long strands of DNA that carried essential info. in haploid form
6. Plasmids - small rings of DNA that contain useful non-essential information
7. Flagella - protein extension that allows the cell to move
8. Pilli - protein strands that can transfer plasmids to other cells or further enhance adhesion
9. Slime Layer or Capsule - polysaccharide membrane on the outside of cell wall that allows it to adhere to stuff.
Types of Prokaryotes
1. Bacteria - single celled organisms found everywhere
2. Archaea - single celled organisms found in extreme environments
1. Rod-shaped - bacillus, Escherichia ecoli
2. Spiral - Treponema pallidum, syphilis
3. Spherical - Cocci, Streptococcus pneuomoniae
larger cells that make single and multicellular organisms, contain membrane bound organelles and a nucleus
Parts of Eukaryotic Cell
1. Cell Wall (may or may not)
3. Plasma Membrane
5. Endoplasmic Reticulum
a. Rough ER
b. Smooth ER
6. Golgi Apparatus
16. Central vacuole
b. Nuclear Envelope
c. Nuclear Pores
protects and supports cell
a. Plant cells are composed of cellulose and another polysaccharide
b. Fungi are composed of chitin and polysaccharides
c. are porous to allow small molecules to pass through ie) Oxygen, CO2 , Water
Types of Eukaryotic Cell
1. Animals - multicellular, heterotrophs
2. Plants - multicellular, autotrophs
3. Fungi - single and multicellular, Heterotrophs
4. Protists - single cellular, autotroph and heterotroph
small proteins that surround the perforated areas of nuclear envelope
i. Allows the passage RNA and proteins
contains water and wastes, provides turgor pressure to support the cell, maintains water balance, store hazardous wastes, nutrients, pigments
move cell through fluid or moves fluid past cell, arise from plasma membrane anchored to basal body.
a. Contains 9 pairs a 2 pairs in the center of microtubules
move cell through fluid, arise from plasma membrane anchored to basal body.
a. Contains 9 pairs a 2 pairs in the center of microtubules
maintains changing of cell shape, provides movement within and outside of cell, and facilitates in mitosis
a. Composed of proteins
i. Organelles attach to protein fibers
ii. 3 Types - hold cells together
1. Thin microfilaments
2. Medium sized intermediate filaments
3. Thick microtubules
globular pearls, allows cells to change shape and aids cytoplasmic division in animal cells.
globular, allow movement of chromosomes during cell division, basal body, and major component of cilia or flagella.
communication with other cells (glycoproteins), regulates exchange and reactions between essential substances (carrier proteins), creates attachments within/between cells (fibrous and globular proteins), and isolates cell's contents from external environment (bilayer)
a. Composed of a phospholipid bilayer, polar heads pointed away from each other, and non-polar tails that point towards each other.
b. All phospholipids bond together.
c. Some phospholipids have kinks and those kinks regulate the amount of fluidity in the cell. # of kinks allows the cell to live in different temperature climates.
d. Cholesterol is present in animal membranes stabilizes, affecting and reducing permeability.
e. Small, usually non-polar molecules can diffuse through cell like water, CO₂, O₂, and larger lipid soluble molecules. Ions, amino acids, and sugars cannot easily pass through.
f. Considered to have a fluid mosaic model: the bilayer has the ability to move while the proteins suspend like patchwork. Allows the membrane to be dynamic and structural at the same time. Allows for cellular shape change.
contains fluid that houses all the organelles in the cell
a. Contains water, salts, and organic materials
b. Site of most metabolic activities
interconnected membranes that form a labyrinth
a. Rough ER: houses ribosomes that synthesize proteins
b. Smooth ER: synthesizes lipids like hormones, cholesterol, detoxifies drugs
modifies and packages proteins like adding carbohydrates to make glycoproteins, break s proteins, and sorts them to their destination
contains intracellular digestive enzymes that digests macromolecules
a. Done through fusing with food vacuole
produces energy in the cell
a. Extracts energy from food molecules and chloroplasts to produce energy in the form of ATP
b. Energy extraction methods involve anaerobic and aerobic reactions
Parts of Chloroplasts
Stroma - cytoplasm of Chloroplasts
Grana - stacked Thylakoids
Thylakoids - green chlorophyll that are charged with sunlight and the electrons release energy
1. Unicellular - organisms that contain only 1 cell ie) protists
2. Multicellular - organisms that contain more than 1 cell ie) humans
Role of Proteins
mosaic portion of the fluid mosaic model of plasma membranes
a. Proteins are embedded within lipid bilayer
Types of Proteins
i. Receptor Proteins
ii. Recognition Proteins
iii. Enzymatic Proteins
iv. Attachment Proteins
v. Transport Proteins
regulate movement of water soluble molecules through plasma membrane
1. Two Types
- Channel Proteins
- Carrier Proteins
form channels whose central pores allow water and specific ions to pass through
i. Ie) K+ and Cl-
have binding sites that can temporarily attach to specific molecules and then move them through the membrane to the other side.
i. Uses a ligand or substrate to bind to active site to open gates for molecules to pass through. Ie) insulin
Differences between Animal and Plant Cells
a. Special Plant Cell Organelles - cell wall, large central vacuole, chloroplasts, plastids
b. Special Animal Cell Organelles - vesicles, lysosomes, small vacuoles, centrioles, and cilia, contains no cell wall.
quality of a membrane that allows certain molecules or ion to move through it more readily than others.
: attach cell together
i. Strongest of cell attachments
ii. Contains tensile strength
iii. Composed of protein filaments that anchor to cytoskeleton
iv. Ie)bladder, skin, intestine
make cell attachments
i. Found where tubes and sacs hold contents without leaking
ii. Series of seals
iii. Blocks water or water soluble molecules from passing
iv. Composed of globular proteins
direct communication between plant cells
i. Cells have holes that allow cytoplasmic fluid communication between cells.
direct communication between animal cells
i. Cell to cell protein channels allowing passage of hormones, ions, and nutrients
ii. Composed of proteins
movement of molecules from a high concentration to a low concentration or along its concentration gradient.
c. Does not require energy.
d. Molecules naturally collide in solution therefore molecules will diffuse to get away from each other.
e. Purpose is to equalize the difference in concentration from one area to another.
f. Mainly used for energy harvesting.
g. 2 Types of Transport
- Passive Transport
- Active Transport
a physical difference in temp, pressure, charge, or concentration of a particular substance in a fluid between two adjoining regions of space.
diffusion of substances across the membrane down concentration gradient.
1. Simple Diffusion:
2. Facilitated Diffusion:
substances move down their concentration gradient across the membrane, ie) CO2, water, O2, lipid soluble molecules like alcohol, vitamins A, D, E
water soluble molecules like ions, amino acids, and sugars diffuse down their concentration gradients with the aid of channel (aquaporins) or carrier proteins
is availability of free water molecules in solution to pass to from high concentration to low concentration
water pressure within the large central vacuole, in hypertonic solution, water draws out and in hypotonic solution, water is drawn in pushing chloroplasts toward cell surface.
movement of molecules across the membrane using energy, usually going against its concentration gradient.
1. Active transport proteins usually contain a ligand binding site and an ATP binding site.
2. Usually referred to as pumps
engulfed particles are transported within the cell inside vesicles. ATP binds to site breaks off releasing ADP and P and the energy left is used to fuel action.
Receptor mediated Endocytosis
moves specific molecules into the cell, use special proteins that have coated pits that signal for specific molecule binding
moves material out of the cell, uses energy to dispose waste or secrete substances into ECF for use.
a. Vesicles carrying material attach to lipid membrane and create an opening for substances to disperse.