Unit 1 Test Flashcards
Theodor Schwann
animals are made up of cells (1839)
Matthias Jakob Schleiden
plants are made up of cells (1838)
Cell theory
1) all living organisms are made up of one more cells
2) cells are the most basic unit of life
3) al cells arise only from pre-existing cells
Who came up with cell theory?
Virchow 1855
what types of organisms have prokaryotic cells?
bacteria and archaea
example of spherical cells
streptococcus
example of rod-shaped bacteria
salmonella, escherichia coli
spiral cells
treponema pallidum
where could you find electrons in bacteria cell?
dense and light area
what captures energy form sunlight in eukaryotic cells?
chloropolasts
what is cytoskeleton responsible for?
-directed cell movement
-a network of protein filaments that can be seen criss-crossing the cytoplasm of eukaryotic cells
is cytoplasm static?
no
what is the difference between prokaryotic and eukaryotic cells?
1) intermembrane compartment
2) membrane surrounding nucleus
3) prokaryotes have no nucleus
lysosome
-low pH (5)
-waste processing center
-intracellular digestion
ribosome
where proteins are synthesized
mitochondria
-have inner and outer membrane
-inner membrane is where ATP is synthesized
-increase membrane area to house ETC
-circular DNA (its own)
what do microtubules do
pull chromosomes apart in cell division
model organisms in biology
fly, worm fish, mouse, human
what has been chosen as a model plant
arabidopsis
chromosomes
DNA when it becomes more compact before a cell divides
ER
where cell-membrane components are made (ex: proteins)
golgi apparatus
flattened membrane-enclosed discs
-modifies and packages molecules made in the ER to be shipped out
peroxisomes
provide a sequestred environment for a variety of rxn in which hydrogen peroxide is used to inactivate toxic molecules
protozoans
a class of free-living, motile, unicellular organisms
-ex: didinium- releases darts to other protozoans
what specifies the precise shape of a macromolecule?
noncovalent bonds
what allows macromolecules to bind to other selected molecules?
noncovalent bonds
hydrogen bonds
-make good solvents
-weaker than covalent and ionic bonds
-weak: 2-5 kcal/mol energy
what is bond strength determined by?
amount of energy required to break the bond
what molecules are hydrophilic?
sugar, DNA, RNA, most proteins
which have more hydrogen bonds- hydrophylic or hydrophobic molecules?
hydrophobic
properties of hydrophobic molecules
-uncharged
-few/no hydrogen bonds
-dont dissolve in water
-hydrocarbons (contain many C-H) bonds
what kind of bonding is electrostatic attraction
noncovalent bonding
what reduces strength of electrostatic attraction?
water
what is hydrophobic force?
attraction between 2 hydrophobic moleculse surrounded by water
-ex: building cell membranes from lipids with long hydrocarbon chains
acids
-release protons when dissolve in water
-weak acids are prevalent in cells (COOH)
bases
-accept protons when dissolved in water
-raise [OH-] by removing proton from water
-important in cells with NH2
-reduce [H+] by combining OH- with proton to form water
buffers
mixtures of weak acids and bases that will adjust proton [] around pH 7 by releasing protons (acids) or taking them upp (bases) when pH changs
what is the pH in stomach
4.7
why does carbon have the ability to from large molecules?
-small
-has 4 electrons and 4 vacancies in its outer shell (ready forms 4 covalent bonds)
sugar formula of monomer
(CH2O)n
n= 3,4,5,6
optical isomers
mirror pairs of molecules with the same chemical formula but different structures
sugar bond
glycosidic (covalent)
sugar functions and examples
energy storage: starch, glycogen
structural: cellulose, chitin, peptidoglycan`
condensation rxn
bond formed between OH of one molecule and OH of another
ring formation
-in an aqueous solution, aldehyde or ketone group sugar molecule tends to react with a OH group of the same molecule
-therefore closing the molecules into a ring
dissacharides
-carbon with aldehyde/ketone group reacts with OH-
-maltose, lactose, sucrose
glucose + glucose =
maltose
galactose + glucose =
lactose
fructose + glucose =
sucrose
what are lipids soluble in
-insoluble in water
-soluble in fat and organic colvents (benzene)
what groups are fatty acids made of?
hydrocarbon chain (hydrophobic)
carboxyl group (hydrophilic and chemically active)
how do fatty acids bond to other molecules?
covalently by their caboxylic acid group
where are lipids soluble?
-soluble in fat and organic solvents (like benzene)
-insoluble in water (hydrophobic nonpolar)
functions of lipids
-energy storage: fats, triglycerides
-structural: membrane phospholipids
what kind of bond is used in lipids
ester bonds
approximately how many carbons are in a chain?
even number (14-20)
typically 16 or 18
difference between saturated and unsaturated fat
-saturated has no double bonds
-unsaturated has double bonds that create kinks, interfering with ability to pack together
triacylglycerols (aka triglycerides)
-the animal fats found in meat, butter, cream
-stored in cytoplasm in form of fat droplets
-plant oils like corn and olive
-hydrophobic
difference between fatty acids and steroids
fatty acids- long hydrocarbon chains
steroids- multiple linked aromatic wings
what are phospholipids made up of
glycerol, 2 fatty acid chains, phosphate group
are phospholipids hydrophobic or hydrophilic?
amphipathic, which helps it form membranes in water
cholesterol
-mostly hydrophobic
-4-ring structure with varying side group
function: membrane components of eukaryotes that stabilize fluidity
-animal hormones: testosterone, estrogen
what is protein monomer, bond, and components
- amino acid
-covalent peptide bond
-amio group, carboxylic acid, hydrogen, R group
what gives proteins a definite directionality and what does it do?
-the difference in the 2 ends
-structural polarity
what determines how proteins bind to things?
affinity (how tightly)
specificity
binding site
what determines specificity in proteins?
affinity (ex: enzymes, antibodies)
are proteins polar or nonpolar?
polar but side groups can be polar or non-polar
what is the primary level of protein structure
-amino acid sequence determined by RNA sequence
-covalent peptide bond
-determine 3D shape
what is the secondary level of protein structure?
-2 main folded structures in a polypeptide
-has nothing to do with side chain
-forms backbone
-alpha helix and beta sheet
-depend on hydrogen bonds to stabilize them
-final folded structure
what makes up the backbone of protein?
carboxyl and amino group
what does a molecule have to be to go through the phospholipid bilayer?
nonpolar
how do proteins attach to each other in helix formation?
a stripes of hydrophobic (nonpolar) amino acids attach to each other
what is the tertiary level of protein structure?
-interactions between R groups of amino acids
-full 3D conformation formed by an entire polypeptide chain
-domains
what are domains
-amino acid+ amino acid….
-polypeptide chain that folds independently
-a functional region of a protein’s polypeptide chain that is self-stabilizing and that folds independently
all proteins assume their ________ when folded properly
lowest energy state
what is quaternary structure
-more than 1 polypeptide
what can misfolded proteins form? ex?
amyloid structure
ex: Huntington’s, prion diseases, madcow
what are prions?
-misfolded proteins that (when infected) promote the misfolding of other normal proteins
-Prp proteins don’t fold how they should
what are homodimers
have identical binding sites
What are dimers? Ex:?
-identical subunits come together due to identical binding sites
-CAP protein
What are tetramers? Ex:?
-4 identical subunits have 2 different binding sites
-Ex: hemoglobin
hemoglobin
-carries many polypeptide chains
-has 2 identical a-globin and 2 B-globin subunits
-if you don’t have one subunit (a or b), the whole thing is not functional (ex: sickle cell)
nucleic acid bonds, components and function?
-phosphodiester bonds
-pentose sugar, phosphate group, nitrogenous base
-storage and transmission of genetic info
what is a nucleoside?
base +sugar
no phosphate
(ex: ATP)
what makes a nucleotide to be negatively charged?
phosphate
difference between DNA and RNA
DNA: double-stranded, genetic info STORAGE, deoxyribose, T
RNA: single-stranded, genetic EXPRESSION, ribose, U
first law of thermodynamics
-energy released by transformations (photosynthesis, burning)
-there is a limit to amount of energy
second law of thermodynamics
-entropy
-energy goes from high to low energy states
-cells get their energy from environment (light-electromagnetic, food-chemical)
entropy
-dispersal of energy/ disorder
-increases whenever anything happens
-energy not available to do work
What is Gibbs Free Energy
-combination of 1st and 2nd law
-identifies amount of energy available for work vs. energy lost to entropy
what is free energy?
-measures energy of molecule that could do work
-the energy of movement of entire molecule
-the energy in the bonds of the molecule
what is delta G?
-change from one molecular state to another
-measures amount of disorder caused by a rxn
-measures how far away from equilibrium a rxn is (large -delta G-can speed up or slow rxn but not stop it
what does a lot of ATP mean in terms of delta G?
large -delta G because keeps a reaction a long way from equilibium
what delta G do genetically favorable reactions have?
negative
do enzymes change delta G?
no
what kinds of bonds does hydrolysis split with water?
covalent
what are coupled reactions?
-share intermediates
-product of one is reactant of another
-rxn driven by a second highly favorable rxn
what is energy of activation?
-extra energy to start a rxn
-doesn’t figure into Gibbs Free energy budget
-recovered when rxn proceeds
when does disorder increase?
-change of bonds (heat is released)
-breaking long chain
when useful energy that could be harnessed to do work is dissipated as heat
what happens when delta G = 0
-equilibrium
-no net change
-reaction will not proceed forward or backward
-no work can be done
-forward and backward reactions occur at equal rates
sequential reactions
-occurs when there is a genetically favorable and unfavorable reaction
-second reaction is more favorable and pulls first unfavorable reaction
-delta G is negative
how do molecules move through the cytoplasm?
diffusion
-still efficient
-random walk: move in random fashion but net distance (displacement) is less than distance
what does the rate at which an enzyme will encounter its substrate depend on?
-concentration of substrate
-because enzyme’s site is bombarded with random interactions until its substrate bumps into it
what does ATP carry
phosphate
what do NADH, NADPH, and FADH2 carry?
electrons and hydrogens
what does acetyl CoA carry
acetyl group
what does Carboxylated biotin carry?
carboxyl group
what does S-adenosylmethionine carry?
methyl group
what does uridine diphosphate glucose carry?
glucose
what do chaperone proteins do?
-bind to newly synthesized or partially folded chains and help them fold along most energetically favorable pathway
-requires ATP
-some can act as an isolation chamber that helps a polypeptide fold
disulfide bonds
-links together 2 -SH groups from cysteine side chains
-don’t change protein’s conformation but disrupt bacterial cell walls
what are antibodies
proteins that bind very tightly to their targets (antigens)
what are protein machines?
-individual proteins that collaborate to perform a specific task
-can carry out complex functions
what are scaffolds?
large molecules that contain binding sites recognized by multiple proteins
-can enhance the rate of a particular chemical reaction
affinity chromatography
used to isolate binding partners of protein interest
chromatography
different materials are used to separate individual components of a complex mixture into factions based on properties like size, shape, or electrical charge
what is cell cortex and what is its function?
-anchor protein
-a meshwork of filamentous proteins under the animal cell membrane
-restrain diffusion of proteins within membrane, change their own shape, and move
where is cortex particularly abundant?
actin and myosin protein
what are membrane domains?
functionally specialized regions on the surface of a cell or organelle
what is tight junction?
-barrier formed along the line where cell is sealed to adjacent cells
-helps proteins diffuse in their own membrane area and prevent from entering other areas they cant diffuse
what is glycocalyx?
-the carbohydrate layer outside the plasma membrane
-provides structural protection, helps cells move, helps in cell recognition
-give cell slimy surface (helps wbc squeeze through narrow spaces and prevents blood cells from sticking to one another or walls of blood vessels)
what are monolayer-associated proteins?
proteins only associated with inside or outside of cell. dont go through
