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define macromolecules. name them
large molecules composed of thousands of covalently connected atoms
define polymers? monomers
polymers- long molecule consisting of many similar building blocks
monomers- small building-block molecules
what is dehydration reaction
occurs when 2 monomers bond together through the loss of a water molecules
hydrolysis
polymers are disassembled to monomers; reaction that is essentially the reverse of dehydration reaction
what are carbohydrates? what is a monosaccharide? what is its use to a cell
carbs- serve as fuel and building material (1st thing body goes to)
monosaccharide- simplest/single sugars; glucose is the most common
what is the general molecular formula for a monosaccharide
CH2O
what is a disaccharide? glycosidic linkage. know sucrose examples
disaccharide- formed when a dehydration and reaction joins 2 monosaccharides
glycosidic linkage- covalent bond
what are polysaccharides? know starch, glycogen, cellulose, and chitin
polysaccharides- polymers of sugars (many), have storage and structural roles
starch- plants store gluslose (bread, pasta rice, potatos)
glycogen- animals store glucose
cellulose- makes up the cell wall of plants
chitin- found in the exoskeleton of arthropods
how are polymers with glucose different from B glucose
polymers with a glucose are helical
polymers with B are straight
-form microfibrils, which form strong building materials for plants
what compounds makes up the diverse groups, liquids
fats & oils
phospholipids
steroids
waxes
what are fats constructed of? what is an ester linkage? triacylglyerol?
fats- glycerol and fatty acids
fatty acids- consists of a carboxyl group attached to a long carbon skeleton
What are saturated fats? Unsaturated fats? What are the properties of each? Where are they found? Which are healthier?
satured fats- maximum number of hydrogen atom possible and no double bonds; fiybd ub bytter
unsaturated fatty acids- have one or more double bonds; found in plant/fish oils; healthier
what is meant by trans fats
more than saturated fats to cardiovascular disease
define essential fatty acids. examples
include the meta-e fatty acids, required for normal growth
what is the major function of fats
energy source
what makes up phospholipids? what are they the major component of
two fatty acids and a phosphate group are attached to glycerol
-two fatty acids tails are hydrophobic but the phosphate group and its attachements form a hydropilic head
major component of all cell membranes
what are steroids? why is cholesterol important
sterioids- lipids characterized by a carbon skeleton consisting of four fused rings
cholesterol- found in animal cell membrane, importatnt steroid, high level in the blook may contribute to cardiovascular disease
how much of a cell is protein? what are some functions
accounts for more than 50% of the dry mass of most cells
functions- structural support, storage, transport, cellular communications, movement, defese
define enzymes
type of protein that acts as a catalyst to speed up chemical reactions
what is the relationship between proteins and polypeptides
polypeptides- unbranched polymers build from the same set of 20 amino acids
protein- biologically functions molecule that consists of one or more polypeptides
what are amino acids? what is the significance of the R group? how many amino acids are there
amino acids= organic molecules with carboxyl and amino groups
-R group- differ in their properties due to differing sides chains (cariable group)
how many- 20
what is peptide bond? Significance of carboxyl and amino groups
amino acids are liked by these
polypeptide is a polymer of amino acids
each polypeptide has a unique linear sequence of amino acids
what determines the function of a protein
shape -> structure -> function
what are the 4 levels of protein structure? describe them. example
1. primary structure of a protein is its unique sequence of amino acids
2. secondary structure found in most proteins, consists of coids and fold int he polypeptide chain (H bonds)
3. tertiary structure determined by interactions amoung various side chains (R groups)
4. quaternary structure results when a protein consists of multiple polypeptide chains
how is hemoglobin affected in sickle-cell disease
globular protein consisting of 4 polypeptides: 2 alpha and 2 beta chains
sickle-cell disease
define denaturation? what factors cause it
loss of a protein natives structure
-denautres protein is biologically inactive
what role do chaperonins play
proteins molecules that assist the proper folding of other proteins
how is X-ray crystallography used
determine proteins structure
what are nucleic acids? what is nucleotide? what are its 3 parts
nucleic acid- genes are made of DNA, made of monomers called nucleoides store infor and help transmit it
nucletoides- polynucleotide is made of monomers; consists of nitrogenous base, pentose sugar, one of mroe phosphate groupf
what are the 2 types of nucleic acids?
deoxyribonucleic acid (DNA)
-provides info for replication
-will direct synthesis of proteins
ribonucleic acid (RNA)
describe the plasma membrane as a fluid mosaic
boundary that separates living cell from its surroundings
who is credited the fluid mosaic models
S. J. Singer & G. Nicolson
what did freeze-fracture studies reveal
splits a membrane along the middle of the phopholipid bilayer
describe the fluidity oft the plasma membrane
phospholipids in the plasma membrane can move within the bilayer, most of the lipids, and some proteins, drift laterally
what role does temperature play
cool- membranes switch fro fluid to solid
difference between unsaturated and saturated fatty acids
saturated- solid at room temp
unsaturated- liquid at room temp; double bonded
what is the role of cholesterol
vital role in secretion of several other vital enzymes and hormones
what accounts for variation in lipid composition
what is the role of proteins
catalyse reactions in our bodies, transport molecules such as oxygen, keep us healthy as part of the immune system and transmit messages from cell to cell
describe peripheral and integral proteins
peripheral- bound to the surface of membrane
integral- penetrate hydrophobic core
what that the 6 major functions of membrane proteins
transport
enzymatic activity
signal transduction
cell-cell recognition
intercellular jointing
attachement to the cytoskeleton and ECM
what is the role of membrane carbohydrates
bonded to lipids
what is the responsible for selective permeability
membrane structure
what molecules are permeable through the membrane
small polar molecules
describe transport proteins
allow passage hydrophilic substances across the membrane
what are aquaporins
facilitate passage of water
describe passive transport. diffusion.
substance across a membrane with no energy investment
what is a concentration gradient
regions along which the density of chemical substance increases or decreases
what is osmosis? what does it have to do with solute concentration
diffusion of water across a selectively permeable membrane; does this until concentration is equal on both sides
describe tonicity
ability of a surrounding solution to cause a cell to gain or lose water
define isotonic, hypertonic, and hypotonic solutions
isotonic- no net water movement across plasma membrane
hypertonic- cell loses water
hypotonic- cell gain water
what is osmoregulation? the paramecium contractile vacuole
control of solute concentrations and water balance
paramecium- vacuole that acts as a pump
describe plant cells that are turgid, flaccid
turgid- plant cell in a hypnotic solution sells until wall opposes uptake
flaccid- no net movement of water into the cell; plant wilts
what happens to a plant cell during plasmolysis
lose water; membrane pulls away from wall
what is facility diffusion? role of channel proteins
transport proteins speed the passive movement of colecules across the plasma membrane
provide corridors that allow a specific molecule or ion to corss the membrane
what is the role of ion channels
open or close in response to a gated channels
what is active transport? sodium-potassium pump example
uses energy to move solutes against their gradients
allows cells to maintain concentration gradients that differ from surroundings
define exocytosis & endocytosis
exocytosis- transport vesicles migrate to the membrane, fuse with it, release their contents
endocytosis- cells take in macromolecules by forming vesicles from the plasma membrane
what the the 3 types of endocytosis
phagocytosis
-cellular eating
pinocytosis
-cellular drinking
receptor
-mediated endocytosis
how are cells the fundamental units of life
all organisms are made of cells
how does the light microscope work/ what re the limits
first microscope to visualize cells, (LM),light transmitted thorught the image and then throught the glass lenses, len then bend and the image is magnified; only allows 1,000 times
define magnification, resolution & constract in microscopy
magnification- how long image made
reolution- measure of the clarity of the image
contrast- visible difference in parts of the sample
how do electron microscopes work? what are the differences between SEM & TEMs
(EMs), sub cellar study structures
(SEMs). bean of electrols onto the surfact of a specimen, images look 3D
what is cell fractionation and how is it used
takes cells apart and separates the major organelles from one another
Compare basic features of prokaryotic and eukaryotic cells. Know terms cytosol, nucleoid, nucleus, cytoplasm
cytosol- semifluid substance (fluid part)
prokaryotic cells- no cucleus, DNA is unbounded relgion called the nucleoid, no membrane-bound organelles, cytoplasm bound by the plasma membrane
rukarytoic cells- DNA in a nucleus that is bounded by a membranouse, membrane bound organelles, crtoplams, larger than prokaryotic
what does the plasma membrane do? what is it made up of
selective barrier that allows sufficient passage of oxygen, nutrients, and wste to service the volume of every cell; is a doulb layer of phosholipids
what limits cells size
Fragility of cell membrane
describe the nucleus, nuclear membrane, chromosomes, chromatin, nucleolus
nucleus- contains most of the cells genes, usually the most conspicuous organelle
nuclear membrane- double membrane; each membrane consists of a lipid bilayer
chromosomes- DNA is organized into discrete units
chromatic- DNA and proteins of chromosomes
nucleolus- locat4ed within the nucleus and is the site of RNA synthesis
what do ribosomes do and where are they found
carry out protein synthesis in 2 locations; found in the cytosol (free ribosomes), outside of the endoplasmic reticulum or nuclear envelope (bound ribosomes)
what are the components of the endomembrane system and what do they do
do- regulates protein traffic and performs metalbolic functions in the cell
comonents: nuclear envelope, endoplasmic reticulum, golgi apparatus, lysosomes, vacuoles, plasma membrane
what does the endoplasmic reticulum make
responsible for the assembly of many proteins
how are the rough and smooth ER different
smooth- lacks ribosomes
rough- studded with ribosomes
what are the functions of the smooth ER
synthesizes lipids, metabolized carbohydrates, detoxifies drugs & poisons, stores calcium ions
what are the functions of the rough ER? transport cesicles
has bound ribosomes with secrete proteins bonded to carbs, distributes proteins surrounded by membranes, membrane factory for the cell
describe the Golgi apparatus and its functions
function: shipping & receiving center ( modifies products of the ER, manufactures certain macromolecules, sorts and packages materials into transport vesicles
describe: consists of flattened membranous sacs called cisternae
what do lysosomes do? role in phagocytosis?
lysosomes- digestive compartments , can hydrolyze proteins, fats, polysaccharides, nucleci acids
phagocytosis- food vacuole and digests the molecules, recycle cells own organelles and macromolecule
describe vacuoles. food, contractile, and central
vacuoles- plant & fungal cells; derived from of reticulum and Golgi apparatus
food vacuoles- formed by phagocytosis
contractile vacuoles- found in many freshwater protists, pump excess water out of cells
central vacuoles- found in many mature plant cells, hold organic compounds and water
what is the relationship between the mitochondria and the chloroplasts
change energy from one form to another
describe the origin of them. explain the endosymbiont theroy
mitochondria and chloroplasts have similarities with bacteria; enveloped by a double membrane, contain free ribosomes, and circular DNA molecules, grow and reproduce somewhat independently in cells
endosymbiont theory- eukaryotic cells engulfed a nonphotosynthetic prokaryotic cell, host cell, and endosymbiont merged into a single organism with mitochondrion, one cell may take up photosynthetic prokaryotic
know mitochondria structure, cristae, mitochondrial matrix and their role
cristae- smooth outer membrane, inner membrane folded
mitochondrial matrix-inne membrane creates 2 compartments
catalyzed in the mitochondrial matrix, large surface area for enzymes that synthesize ATP
know chloroplasts structure, thylakoids, geranum, storma, term plastid
Chloroplahts- capture light energy, found in leaves and green organs
thylakoids- membranous sacs
gernum- thylakoids are stacked to form you
stoma- internal fluid
plastids- one of a group of plant organelles
what role do peroxisomes play
produce hydrogen peroxide and convert it to water
describe the role of the cytoskeleton. what 3 fibers make it up
network of fibers that organizes structures and activities in the cell
fibers: microtubules (thickest), microfilaments (thinnest), intermediate filaments (diameters in a middle range)
function of microtubules. centrosome, centrioles
microtubuels- hollow rods; functions: shaping cells, guiding movement of organelles, separate chromosomes during cell division
describe cilia and flagella. how do they move? role of basal body, dynein protein
microtubules control the beating of cilia and flagella locomotor appendages of come cells; they differ in their beating patterns
basal body- anchors cilium or flagellum (9+0)
dynein- dirives the bending movements of cilium or flagellum
What makes up microfilaments. Their role in cell. Muscles with myosin? In pseudopodia? Cytoplasmic streaming?
microfilaments- solid rods built as a twisted double chain; bear tension/ resisting pulling forces within the cell
myosic- function in cellular motility contain this protein
pseudopodia= cellular extensions
cytoplasmic streaming- circular flow of cytoplasm within cells
role of intermediate filaments
support cell shape and fix organelles in place
know extracellular structures
cell wall of plants, extracellular matrix of animals cells, intercellular junctions
role of cell wall. what organisms have it? what makes it up
plant cells only
-prokaryotes, fungi and some protists also have thins
-cell wall, middle lamella, secondary cell wall
role of plasmodesmata
channels between adjacent plant cells
describe the ECM in animals. protein names
bind to receptor proteins in the plasma membrane (called integrins)
function of EMS: support, adhesion, movement, regulation
know 4 cell junctions. and their roles in plants and animals
plasmodesmata
-perforate plant cell walls
tight junctions
-preventing leakage of extracellular fluid desmosomes
-fasten cells together into strong sheets
gap junctions
-provide cytoplasmic channels between adjacent cells
What are the bases in DNA & RNA? what is meant by complementary base pairing
In DNA, there are four different bases: adenine (A) and guanine (G) are the larger purines. Cytosine (C) and thymine (T) are the smaller pyrimidines. ... Three of these are the same as in DNA: adenine, guanine, and cytosine. RNA contains uracil (U) instead of thymine (T).
pairing; DNA(=) A=T; G=C RNA(=) A=U; G=C