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Cell Theory

Cell is the basic structural and functional unit of life

Cell Theory

Organismal activity depends on individual and collective activity of life

Cell Theory

Biochemical activities of cells are dictated by cellular structure

Cell Theory

Continuity of life has a cellular basis

Plasma Membrane

- separates intracellular fluids from extracellular fluids
- regulates entry and exit of materials


- cellular region between nuclear and plasma membrane
- contains cytosol (fluid), organelles, inclusions (stored nutrients, secretory products, pigment)


- double membrane structure with self-like cristae
- provide most of cells ATP via aerobic cellular respiration
- contains own DNA and RNA


- granules containing protein and rRNA
- site of protein synthesis
- free ribosomes synthesize soluble proteins
- membrane-bound ribosomes synthesize proteins to be incorporated into membranes

Endoplasmic Reticulum

- "network within the cytoplasm"
- interconnected tubes and parallel membranes enclosing cisternae (fluid-filled cavities)

Rough ER

- external surface studded with ribosomes
- ribosomes manufacture all proteins secreted from cell
- cell's "membrane factory" because responsible for the synthesis of integral proteins and phospholipids for cell membranes

Smooth ER

- Tubules arranged in a looping network
- Catalyzes the following reactions in various organs of the body: liver, testes, intestinal cells, skeletal/cardiac muscle


lipid and cholesterol metabolism; breakdown glycogen; detoxification of drugs------Smooth ER catalyzes


synthesis of steroid-based hormones------Smooth ER catalyzes

intestinal cells

absorption, synthesis, transport fats ------Smooth ER catalyzes

skeletal/cardiac muscle

storage/release of calcium ------Smooth ER catalyzes

Golgi Apparatus

- stacked and flattened membranous sacs
- functions in modification, concentration, packaging proteins
- transport vessels for ER, fuse with the cis face of the______
- Proteins that pass through the ________ to the trans face
- secretory vesicles leave the trans face of the ____ stack and move to designated parts of the cell


- spherical membranes bags contain enzymes
- digest ingested bacteria, viruses, toxins
- degrade nonfunctional organelles
- breakdown glycogen and release thyroid hormone
- secretory ______ found in white blood cells, immune cells, melanocytes

Endomembrane System

- system of organelles that function: produce, store, export biological molecules; degrade potentially harmful substances
-includes: nuclear envelope, smooth/rough ER, lysosomes, vacuoles, transport vesicles, golgi apparatus, plasma membrane


- membranous sacs have oxidases and catalases
- detoxify harmful/ toxic substance
- neutralize dangerous free radicals


- "skeleton of cell"
- consists of microtubules, microfilaments, intermediate filaments


- Dynamic, hollow tubes made of the spherical protein tubulin
- Determine overall shape of the cell and distribution of organelles


- strands of protein actin
- attached to cytoplasmic side of plasma membrane
- strength/brace cell surface
- attach to CAMs, function in edocytosis/ exocytosis

Intermediat filaments

- part of cytoskeleton
- resist pulling forces on cell and help form desmosomes


- pinwheel of 9 triplet of microtubules
- organize mitotic spindle during mitosis
- bases of cilla and flagella


- contains: nuclear envelope, nucleoli, chromatin
- Gene- containing control center of cell
- contains genetic library of all cellular proteins
- tells what proteins need to be synthesized

Nuclear Envelope

- double membrane barrier containing pores
- enclosed jellylike nucleoplasm has essential solutes
- Pore complex regulates transport of large molecules in/out of nucleus


- dark circle of body in nucleus
- site of ribosomes production


- DNA constitutes the genes
- threadlike material made of DNA/histone proteins

Fluid Mosaic Model

- Double bilayer of lipids with imbedded, dispersed proteins
- Bilayer consists of phospholipids, cholesterol, glycolipids

*see diagram


lipids which bond carbohydrate


have hydrophilic/phobic bipoles


- minute fingerlike extensions of plasma membrane
- increase plasma membrane surface area hugely

Tight Junction

- impermeable junction that encircles cells


anchoring junction scattered along sides of cells

Gap Junction

- nexus that allows chemical substances to pass between cells...junction

Passive Membrane Transport

- H20, Cl-, Fat, O2, Co2, Glucose
- energy not required-----diffusion

Active Membrane Transport

- Na+, K+, Amino Acids, steroid
- energy required---assisted by enzymes
- energy ATP
-Primary Active Transport
-Secondary Active transport

Cell Adhesion Molecules (CAMs)

- anchor cells to the extracellular matrix
- assist in movement of cell past on another
- rally protective white blood cells to injured or infected areas

Membrane receptors

Contact Signaling, Electrical signaling, chemical signaling

Contact Signaling

- important in normal development and immunity
=some bacteria use this signaling to identify target organ
-the actual coming together and touching of cells, means by which cells recognize one another
- membrane receptor

Electrical Signaling

- certain plasma membrane proteins are channel proteins that respond to changes in membrane potential by opening/close channel
- voltage-regulated "ion gates" in nerve and muscle tissue
- membrane receptor

Chemical Signaling

neurotransmitters bind to chemically gated channel-linked receptors in nerve and muscle tissue
- membrane receptor

Mitotic Phase





metabolic activity and vigorous growth....cell cycle


synthesis for DNA.........cell cycle


preparation for division......cell cycle


1st step
- centrioles move to poles
- spindle fibers start to form
- chromatin condense into chromosomes
- nuclear envelope breaks down


2nd step
- chromosomes meet in middle (equator)


3rd step
- chromosomes split and move to opposite poles (sides)


4th step
- two distinct nuclei, nuclear envelope reforms chromosomes unwind into chromatin


- carries genetic info from DNA in nucleus to ribosomes in cytoplasm


- bound amino acid base pair with codons of mRNA at the ribosome to begin process of protein synthesis

*see diagram


- a structural component of ribosomes


transfer of information from the sense strand of DNA to RNA


language of nucleic acids translated to language of proteins

Simple diffusion

- movement of molecules (driven by kinetic energy) down a concentration gradient
- Fat soluble solutes can diffuse directly through the membrane by dissolving in the lipid
*passive transport

Facilitated diffusion

-passive movement of certain solutes across the membrane either by their binding with a membrane carrier protein or by their moving through a membrane channel
-kinetic energy
*passive transport


diffusion of a solvent (water) through a selectively permeable membrane
-water diffuses through membrane pores (aquaporins) or directly through the lipid part of the membrane from a solution of lesser osmolarity to a solution of greater osmolarity
---particles move from crowded area to not crowded area
= water becomes more equal with even # particles
=more particles on 1 side higher water level
*passive transport


- water moves out of the cells


- water enters and exits the cells at the same rate


-water moves into the cells

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