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Stein: Biology Exam 2

Parts and Functions of the cell, Diffusion, Active and Passive Transport, Osmosis
STUDY
PLAY
Cell Theory
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
Types of Cells
1. Prokaryote
2. Eukaryote
Prokaryotic Cell
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
Cell Shape
1. Rod-shaped - bacillus, Escherichia ecoli
2. Spiral - Treponema pallidum, syphilis
3. Spherical - Cocci, Streptococcus pneuomoniae
Eukaryote
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)
2. Cytoskeleton
3. Plasma Membrane
4. Cytoplasm
5. Endoplasmic Reticulum
a. Rough ER
b. Smooth ER
6. Golgi Apparatus
7. Vacuoles
8. Lysosomes
9. Ribosomes
10. Mitochondria
c. Cristae
d. Matrix
11. Centrioles
12. Chloroplasts
a. Stroma
b. Grana
13. Flagella
14. Cilia
15. Plastids
16. Central vacuole
17. Nucleus
a. Nucleolus
b. Nuclear Envelope
c. Nuclear Pores
d. Chromosomes
e. Chromatin
Cell Walls
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
Chromatin
long DNA strands in nucleus
Chromosomes
DNA and protein material to keep DNA wound in tight linear paths
Nuclear Pores
small proteins that surround the perforated areas of nuclear envelope
i. Allows the passage RNA and proteins
Nuclear Envelope
double membrane with pores regulates the passage of material in and out
Nucleolus
synthesizes ribosomes
Parts of the Nucleus
1. nuclear Pores
2. nuclear envelope
3. nucleolus
4. Chromosomes
5. Chromatin
Central Vacuole
contains water and wastes, provides turgor pressure to support the cell, maintains water balance, store hazardous wastes, nutrients, pigments
Plastids
stores food, pigments
CIlia
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
Flagella
move cell through fluid, arise from plasma membrane anchored to basal body.
a. Contains 9 pairs a 2 pairs in the center of microtubules
Cytoskeleton
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
Thin microfilaments
globular pearls, allows cells to change shape and aids cytoplasmic division in animal cells.
Thick Microtubules
globular, allow movement of chromosomes during cell division, basal body, and major component of cilia or flagella.
Medium Interfilaments
fibrous
Proteins, provides supporting framework within the cell
Plasma Membrane
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.
Cytoplasm
contains fluid that houses all the organelles in the cell
a. Contains water, salts, and organic materials
b. Site of most metabolic activities
Endoplasmic Reticulum
interconnected membranes that form a labyrinth
Two Types
a. Rough ER: houses ribosomes that synthesize proteins
b. Smooth ER: synthesizes lipids like hormones, cholesterol, detoxifies drugs

7. Vacuoles:
8. Lysosomes

9. Ribosomes
10. Mitochondria
11. Centriole
12. Chloroplasts
Golgi Apparatus
modifies and packages proteins like adding carbohydrates to make glycoproteins, break s proteins, and sorts them to their destination
Vacuoles
transport secretory molecules, may contain food for phagocytosis
Lysosomes
contains intracellular digestive enzymes that digests macromolecules
a. Done through fusing with food vacuole
Ribosomes
makes proteins
Mitochondria
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 Mitochondria
c. Cristae: folded inner membrane
d. Matrix: cytoplasm of mitochondria
Centrioles
produce microtubules of cilia and flagella
Chloroplasts
performs photosynthesis
Parts of Chloroplasts
Stroma - cytoplasm of Chloroplasts
Grana - stacked Thylakoids
Thylakoids - green chlorophyll that are charged with sunlight and the electrons release energy
Cell Types
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
Receptor Proteins
trigger cellular responses upon binding of molecules such as hormones
Recognition Proteins
aka glycoproteins, ID tags for cells
Enzymatic Proteins
catalysts for cells to aid in breaking and forming molecules
Attachment Proteins
anchor cell membrane to cytoskeleton, to proteins in ECF, and other cells
Transport Proteins
regulate movement of water soluble molecules through plasma membrane
1. Two Types
- Channel Proteins
- Carrier Proteins
Channel Proteins
form channels whose central pores allow water and specific ions to pass through
i. Ie) K+ and Cl-
Carrier Proteins
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.
Selective Permeability
quality of a membrane that allows certain molecules or ion to move through it more readily than others.
Types of Attachment Proteins
a. Desmosomes
b. Tight Junctions
c. Gap Junctions
d. Plasmodesmata
Desmosomes
: 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
Tight Junctions
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
Plasmodesmata
direct communication between plant cells
i. Cells have holes that allow cytoplasmic fluid communication between cells.
Gap Junctions
direct communication between animal cells
i. Cell to cell protein channels allowing passage of hormones, ions, and nutrients
ii. Composed of proteins
Translation
is the process where mRNA decoded to attach amino acids to form polypeptide chains.
Transcription
: is the process where DNA gives its info. and is transcribed into RNA code.
Solution
: is mixture of a solute and a solvent usually with a transparent appearance.
Solvent
fluid capable of dissolving a solute.
Solute
substance that is dissolved into a solvent.
Diffusion
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
Concentration
substance that defines the amount of solute in a given amount of solvent.
Gradient
a physical difference in temp, pressure, charge, or concentration of a particular substance in a fluid between two adjoining regions of space.
Passive Transport
diffusion of substances across the membrane down concentration gradient.
1. Simple Diffusion:
2. Facilitated Diffusion:
3. Osmosis:
Simple Diffusion
substances move down their concentration gradient across the membrane, ie) CO2, water, O2, lipid soluble molecules like alcohol, vitamins A, D, E
Facilitated Diffusion
water soluble molecules like ions, amino acids, and sugars diffuse down their concentration gradients with the aid of channel (aquaporins) or carrier proteins
Osmosis
diffusion of water across a selectively permeable membrane.
Tonicity
is availability of free water molecules in solution to pass to from high concentration to low concentration
Isotonic Solution
solutions that have equal concentrations of water and dissolved substances
Hypertonic Solution
: higher concentration of solute to solvent, draws water in
Hypotonic Solution
lower concentration of solute to solvent, draws water away.
Turgor Pressure
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.
Active Transport
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
3. Endocytosis:
4. Exocytosis:
Endocytosis
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.
Pinocytosis
moves liquids into the cell
Receptor mediated Endocytosis
moves specific molecules into the cell, use special proteins that have coated pits that signal for specific molecule binding
Phagocytosis
moves large particles into the cell.
Exocytosis
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.
Types of Endocytosis
a. Pinocytosis:
b. Receptor mediated endocytosis:
c. Phagocytosis:
Sodium-Potassium Pumps
a. Pumps are used to create an electrical signal in the body for rapid fire. As Sodium and Potassium diffuse across concentration gradient to create an electrical impulse for nerve cells to fire rapidly, active transport is used to return membrane to RMP.