EXAM 2 - BIOL 1406

Cell Theory

all living organisms are composed of cells, cells are the smallest unit of life, and new cells come only from pre-existing cells

Origin of cells

life originated from inorganic molecules in the primordial ocean and inorganic molecules could be synthesized from inorganic components

Discovery of cells

In 1665, Robert Hooke observed a cork under a microscope and seeing its honeycomb like structure

Types of microscopes

Compound light, Stereo-dissecting, Scanning electron, Transmission electron

Compound Light Microscope Use

uses visible light, useful magnification up to 1000x

Stereo-Dissecting Microscope Use

for viewing larger objects utilizing a greater working distance

Scanning Electron Microscope (SEM) Use

for viewing specimen surfaces, uses beam of electrons, 30,000-50,000 X useful magnification

Transmission Electron Microscope (TEM) Use

for viewing ultrathin sections, uses beams of electrons, 100,000-250,000X useful magnification

Characteristics of Prokaryotes

lack of membrane, kernel-like appearance, simple structure

Characteristics of Eukaryotes

possess a true nucleus, exhibits extensive compartmentalization, unique structure

Organelles unique to animal cells

nucleolus, nucleus, nuclear pore, nuclear envelope, chromatin, centrosome, ribosome, lysosome, plasma membrane, rough & smooth ER, mitochondrion, cytoskeleton, peroxisome, golgi apparatus, cytosol

Organelles unique to plant cells

nucleolus, nucleus, nuclear pore, nuclear envelope, chromatin, central vacuole, ribosome, cell wall, plasma membrane, rough & smooth ER, mitochondrion, cytoskeleton, chloroplast, peroxisome, golgi apparatus, cytosol

Organelles in bacteria cell

nucleoid, plasma membrane, cell wall, glycocalyx, flagella, pili, cytoplasm, ribosomes

Functions of nucleoid

site where the DNA is found

Function of plasma membrane (bacteria)

encloses the cytoplasm

Functions of cell wall (bacteria)

provides support and protection

Functions of glycocalyx

Outer gelatinous covering

Functions of flagella

allows certain bacteria to swim

Functions of pili

allows bacteria to attach to surfaces and to each other

Functions of cytoplasm (bacteria)

site of metabolism

Function of ribosomes

synthesizes polypeptides

Functions of nucleus

area where most of the genetic material is organized and expressed

Functions of nuclear envelope

double membrane that encloses the nucleus

Function of nuclear pore

passageway for molecules into and out of the nucleus

Functions of chromatin

a complex of protein and DNA

Function of lysosome

degrade macromolecules

Function of plasma membrane (eukaryotic)

controls movement of substances into and out of the cell

Function of cytosol

pathways for metabolism

Function of peroxisome

breaks down hydrogen peroxide and other harmful molecules

Functions of cytoskeleton (eukaryotic)

provide shape and aid in movement with protein filaments

Function of mitochondrion

ATP synthesis

Functions of Rough ER

sorting and secretion of proteins

Function of Smooth ER

lipid synthesis and detoxification

Function of centrosome

growth of microtubules and staying of centrioles

Function of nucleolus

submit assembly of ribosome

Function of chloroplast

photosynthesis

Function of central vacuole

provides storage, regulation of cell volume

Function of cell wall (plants)

provides cell support

Organelles with double membrane

nucleus, mitochondria, chloroplasts

Plasma membrane properties

semi-permeable

Tay Sachs

a vital hydrolytic enzyme, found in the lysosomes, that breaks down sphingolipids

Flagellum composition

generates bends alternatively in each direction that begin at the head and more toward the tip of the flagellum

Cilium composition

same internal structure and function as flagella, but shorter and more numerous

Centriole composition

in centrosomes, an obvious pair of structures arranged perpendicularly to each other

Type of filaments in cytoskeleton

microfilaments, microtubules, intermediate filaments

Actin

a protein found in microfilaments, helps in muscular contraction

Myosin

a motor protein

Autophagy

a process where cellular material, becomes enclosed in a double membrane

Endocytosis

a process where the digestion of substances are taken up from the outside cell

Exocytosis

materials inside the cell is packaged into the vesicles and then excreted

Pinocytosis

invloves the formation of membrane vesicles from the plasma membrane

Phagocytosis

process of protits engulfing food into large food vacuoles

Endosymbiosis

a symbiotic relationship in which the smaller species lives inside the larger species

Endomembrane System

large network of membranes that enclose the nucleus

Cell evolution (mitochondria)

evolved from aerobic alpha-proteobacteria that were engulfed by an archael host cell

Cell evolution (chloroplast)

evolved from cynabobacterium that was engulfed by a non-photosynthetic eukaryotic cell

Function of extracellular matrix

provides support and helps to organize cells

Composition of extracellular matrix

water, polysaccharides, and proteins

Functions of proteoglycans

providing resistance to compression

Cellulose (polysaccharide)

a polysaccharide made of repeating molecules of glucose attached end to end

Chitin

a nitrogen-containing polysaccharide, forms the hard protective outer covering

Collagen

provides high tensile strength to many parts of an animal's body

Cellulose

the main macromolecule of the plant cell wall

Wrinkling and collagen

the amount of collagen that is synthesized in the skin significantly decreases

Functions of plant cell walls

provide rigidity for mechanical support and maintain the cell shape and growth

Components of plant cell walls

primary cell wall (thin) and secondary cell wall (thick)

Types of anchoring junctions

adherens junctions, desmosomes, hemidesmosomes, focal adhesions

Adherens Junctions

are organized into bands around cells, binds to actin filaments in the cytosol

Desmosomes

spotlike points of intercellular contact that rivet cells together, connected by intermediate filaments

Hemidesmosomes

connect cells to the extracellular matrix, they interact with intermediate filaments

Focal Adhesion

connect cells to extracellular matrix, in the cytosol, they bind to actin filaments

Transport between cells of ions

ion transport pathways across the root endodermis

Selective permeability

allows the passage of certain ions or molecules but not others

Membrane proteins

integral, peripheral, lipid-anchored

Function of Integral membrane

transports, adhesion to other cells, and signal transduction

Function of Peripheral membrane

carry signals either to a cell or inside a cell

Function of Lipid-Anchored proteins

cell signaling and regulating protein localization & interaction

Characteristics of passive diffusion

requires no energy and moves substances concentration down

Osmosis

the movement of water across a membrane to balance solute concentrations

Osmotic pressure

pressure needed to balance the concentration difference that drives water movement

Hypertonic

concentration of solutes outside a cell is higher

Hypotonic

outside of the cell have a lower concentration of solutes than the inside

Isotonic

when the concentrations of solutes on both sides of the plasma membrane are equal

Aquaporins

a transport protein in the form of a channel that allows the rapid diffusion of water across the cell membrane

Concentration gradient

situation where the concentration of a solute is higher on one side of a membrane than on the other

Facilitated diffusion

a transport protein provides a passageway for substance to cross a membrane from high to low concentrations

Active transports

moves a substance from an area of low concentration to one high concentration

Similarities of passive, facilitated, and active transport

all move substances across cell membranes and rely on its selective permeability

Differences of passive, facilitated, and active transport

passive uses no energy for transportation, active moves substances against the gradient

ATP

a molecule that is a common energy source for all cells

Sodium potassium pump

a trans-membrane protein that helps establish the resting membrane potential of cells

Ion gradients

electrical and chemical (electrochemical)

Endocytosis

plasma membrane folds inward to form a vesicle that brings substances or particles into the cell

Exocytosis

material inside the cell is packaged into vesicles and the excreted into the extracellular environment

Receptor mediated endocytosis

a receptor in the plasma membrane specific for a given cargo

LDL (low density lipoprotein)

a type of cholesterol that carries cholesterol from the liver to the arteries

HDL (high density lipoprotein)

a type of cholesterol that carries cholesterol from the arteries back to the liver for removal

first law of thermodynamics

Energy cannot be created or destroyed

Second law of thermodynamics

every energy transfer or transformation increases the entropy of the universe.

Entropy

measure of disorder