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THE MCAT-BIO 1

MOLECULAR BIOLOGY, CELLULAR RESPIRATION

QuestionAnswer
Phase contrast microscope view live organisms but can't focus on certain structures
electron microscope use beam of electrons to focus on dead organism in detail
In centrifugation, what types of organelles will be on top / bottom? mitochondria & lysosomes on top ribosomes on bottom
What do prokaryotes have instead of nucleus? nucleoid
What is plasmid? -small circular pieces of DNA that carry genetic info -replicate independently and can be passed from one prok to another
Do prokaryotes have cell membrane? yes
What is the benefit of membrane-bound organelles? separates bio. reactions and functions into separate compartments
What do transport proteins do? allow polar molecule and ions to move in and out of cell
What is nuclear membrane? double membrane to separate nucleus from cytoplasm?
What is nucleolus and where is it located? -rRNA synthesized here -located inside nucleus
How is genetic material organized? DNA --> genes --> wound around histone proteins --> chromatid --> chromosome
What do free ribosomes make? make proteins in cytosol
What do bound ribosomes make? -proteins that directly insert into the ER -px are used within plasma mem or expelled from cx
What does smooth ER do? -lipid & steroid synthesis -detox drugs and poison
What does rough ER do? involved in producing transmem px or secreted px
What do lysosomes do? use hydro
Where are the proteins used in peroxisomes produced? cytosol --> mature polypeptide made and then attaches to peroxisomes through a signal
Where do peroxisomes come from? ER
Where do lysosomes come from? golgi
What do lysosomes do? -breakdown cellular waste -apoptosis -digest macromolecules from phagocytosis
What do peroxisomes do? -beta-oxidation -lipid biosynthesis -catalase to convert H2O2 to water -detox rxns. in liver
What is beta-oxidation? process where fatty acids are broken down in mito to make acetyl coA
How are mito. semiautonomous? have their own genes and replicate independently of nucleus via binary fission
Where are the enzymes for cellular respiration located? mito. matrix
What are microfilaments used for and what are they made of? -muscular contraction and cytokinesis -actin
What are microtubules used for? -chromosomal separation during meiosis and mitosis -cilia and flagella -intracx transport of organelles and vesicles
What are lysosomal storage diseases? accumulation of carbs, lipids, and proteins from failure of production of an enzyme within lysosome to break down
hypotonic -conc. of solutes inside cell is higher --> gain water
hypertonic -conc. of solutes outside cell is higher --> lose water
isotonic -conc. of solutes is equal --> no net movement
What are viruses? nucleic acid surrounded by protein coat
Difference between the way bacteria and virus attack cells? Bacteria never enter cell while viruses always enter cell to replicate
What are lipids made of? -carboxylic acid + alcohol --> ester link (even number of carbons and max # is 24 in humans)
Saturated vs. unsaturated saturated has single / unsaturated has double bond
amphipathic polar and nonpolar end (that's why phospholipids are good for cell membrane)
What is glycerol? 3-carbon backbone found in lipids
Where are glucolipids found? membrane of myelinated cells in human nervous system
Formation of lipids requires what kind of bond? ester linkage
Steroids 4-ringed structures
Terpenes Vitamin A
Eicosanoids -signaling molecules involved in inflammation and immunity -include prostaglandins and leukotrienes
What does aspirin inhibit? synthesis of prostaglandins
How are lipids transported in the body? lipoproteins
Which lipoprotein has the highest lipid percentage? chylomicrons
Name all parts of an amino acid amino (NH2), carbonyl (COOH), hydrogen, R group
Can a single protein have both alpha helix and beta pleated sheet? yes!
Tertiary structure secondary structure folds upon itself
How does proline affect peptide structure? creates turns that disrupt helix and beta sheet
quaternary structure two or more polypeptides
What structures does denaturing proteins affect? secondary, tertiary, quaternary
What are 5 forces that create tertiary structure? -H-bonds -hydrophobic side chains (pushed to center) -electrostatic interactions btwn acidic and basic side chains -van der Waals -covalent disulfide bonds
cytochrome membrane bound hemopx that have a heme and carry out ETC
proteoglycans proteins that are heavily glycosylated
glycoproteins carbs covalently attached to proteins
Basic amino acids (3) histidine, lysine, arginine
acidic amino acids (2) glutamic acid and aspartic acid
How are alpha and beta glucose different? -alpha glucose has -OH on axial and equatorial -beta glucose has -OH on both axial / equatorial
If cell as enough ATP, what happens to glucose? becomes glycogen
Where is glycogen found? muscle and liver cells
How does the liver regulate blood glucose? glucose --> glycogen --> glucose
How is glucose absorbed into bloodstream? 1.) against a concentration gradient with secondary active transport with sodium 2.) facilitated diffusion (increases with insulin)
What has beta / alpha links cellulose / everything else
3 components of nucleotides -5-carbon sugar -nitrogenous base -phosphate group
Phosphodiester bond phosphate of one nucleotide and 3rd carbon of pentose of other nucleotide
What do minerals do? transport substances entering and exiting the cell through electrochemical gradient
activation energy energy required to break bonds before new bonds can form
Are enzymatic reactions reversible? yes
What do enzymes do? -lower Ea for forward and reverse rxns -increase rate of reaction (increase rate constant k) -select which reactions will occur
What don't enzymes do? -not consumed in a rxn or altered -do not start rxns that wouldn't normally occur
Induced Fit Model Enzyme and substrate change shape --> increases specificity and helps rxn proceed
Substrate squeezing in / release is endothermic / exothermic? endothermic / exothermic
Most enzymes function around which pH 7.4
Do enzymes affect Keq or delta G? NOOO --> no thermodynamics only kinetics!
Enzymes can be protein and...? RNA --> ribosome
transition state analog -resemble transition state and can act as competitive inhibitor
turnover number -when enzyme is completely saturated with substrate, number of substrate molecules converted to product
When substrate conc is small and enzyme conc is constant, velocity is proportional to substrate conc. as ______ order? first
When substrate conc. is large and velocity is independent of substrate conc as ____ order? zero
What is Km? point where 1/2 enzyme's active sites are full and rxn rate is 1/2 max value --> enzyme affinity for substrate
lysozyme -enzyme that hydrolyzes glycosidic bonds in bacterial cell walls
ribonuclease -catalyzes hydrolysis of phosphodiester in RNA
carboxypeptidase -digestive pancreatic enzyme to cleave carboxy terminal peptide bond
chymotrypsin -hydrolysis of ester and peptide bonds
peptide --> amine and acid
ester alcohol and acid
What is Vmax proportional to? enzyme concentration
What does low Km mean? high affinity for substrate
What does high Km mean? low affinity for substrate
When substrate concentration is less than Km, changes in [s] will greatly affect rxn rate T / F? True
what pH does pepsin function / pancreatic enzymes 2 and 8.5
Co-factors 1.) bind substrate to enzyme 2.) stabilize enzyme in active conformation
Apoenzyme / holoenzyme enzyme w/o cofactor & enzyme with co-factor
What are 2 types of co-factors? co-enzymes and metal ions
What are coenzymes? prosthetic groups or cosubstrates (reversibly bind to enzyme - ATP)
Irreversible inhibitors -covalently bind and permanently disrupt function at active site
Competitive Inhibitors and how to overcome? -bind reversibly with noncovalent bonds -increase conc. of substrate (Km increases)
Noncompetitive Inhibitors and how to overcome? -bind noncovalently to site other than active site -change conformation of enzyme -increase enzyme conc.
How are noncompetitive different than competitive? -do not prevent substrate from binding -do not resemble substrate so can act on more than one enzyme -bound far or near active site
What do Vmax and Km depend on? Vmax - enzyme conc Km - substrate conc
What do competitive vs. noncompetitive inhibitors do? competitive - raise Km, do not change Vmax noncompetitive - lower Vmax, do not change Km
Do noncompetitive inhibitors affect substrate binding and enzyme affinity for substrate? NO --> that's why Km stays the same
Can enzyme catalyze reaction as long as noncompetitive inhibitor is bound? NO --> substrate can still active site though
Vmax vs. Km graph: competitive shift right apparent Km increases, Vmax no effect
Vmax vs. Km graph: competitive shift left apparent Km decreases, Vmax no effect
Allosteric enzyme one active and one regulatory site where inhibitors and activators can bind
How do allosteric inhibitors / activators act? change quaternary structure
Are allosteric regulators noncompetitive inhibitors? not necessarily
Negative / positive feedback inhibition? allosteric inhibitor / activator act on reaction
Irreversible covalent modification example zymogens are irreversibly activated
Reversible covalent modification example phosphorylation
kinase vs. phosphatase enzyme that phosphorylates vs. enzyme that dephosphorylates
hexokinase phosphorylates glucose
Antitrypsin inhibits trypsin and prevents digestive enzymes from digestinb doy
Humans can synthesize NAD as long as there is what amino acid in diet? Trp
What is FAD derived from? Vitamin B2
Where does ATP energy come from? loose and covalent bonds of phosphate groups
NAD, NADPH, FAD are _____ agent and are ____ during ____ reactions oxidizing / reduced / catabolic
NADH, NADPH, FADH are _______ and are ______ during _____ reactions. reducing / oxidized / anabolic
Where does glycolysis occur and what does it produce? -cytosol -2 pyruvate and 2 NADH
substrate-level phosphorylation formation of ATP without intervention of ETC
What is the main importance for fermentation and how much ATP? -regenerate NAD+ to continue glycolysis anaerobically (aerobically, NAD+ regenerated through ETC) -2 ATP
What can pyruvate turn into with fermentation? 1.) ethanol/CO2 & 2 NAD+ 2.) lactic acid & 2NAD+
Where does pyruvate decarboxylation take place and what does it produce? -mito matrix -2 acetyl coA, 2 CO2, 2 NADH
How do pyruvate and NADH pass into mito? -pyruvate and NADH can pass through outer mem via facilitated diffusion through porin px -inner mem, pyruvate can move in but NADH may need hydrolysis of ATP
What does TCA produce for each turn of cycle? 1 ATP, 3 NADH, 1 FADH2, 2 CO2
How to begin TCA cycle? transfer 2C from acetyl coA combines with oxaloacetate (4C) to create citrate (6C)
When are ketone bodies produced? levels of acetyl coA exceed TCA capacity
Where is ETC located and what is it series of 4 large metallopx bound to inner membrane
Where is ETC and OP located for prokaryotes? Proks don't have mito so ETC and OP occurs in inner plasma mem
How are protons from inner membrane pumped to intermem? energy from ETC pumps protons through peremases
oxidative phosphorylation creation of ATP through ETC
How many ATP does NADH and FADH2 create? Why does FADH2 create less? -3 ATP / 2 ATP -electrons from FADH2 travel shorter distance
What is final electron acceptor and what is it reduced to? O2 and water
Is ATP synthase reversible T/F? TRUE - can make NADH
Is inner membrane permeable to protons? NO
Uncoupling protein -mito inner mem px that dissipates H+ gradient to block OP -energy used to generate heat instead of ATP -increase permeability of inner mito mem so protons pumped out return
Pentose phosphate pathway 1. generates NADPH --> f. a. synthesis 2. produces ribose --> nucleotide synthesis
Difference between NADP and NAD? NAD is used in catabolism while NADP is used in anabolism
What is largest class of human mutations? sex-linked deficiency in glucose-6-phosphate dehydrogenase -don't make NADPH / reduced glutathione (mosquitoes need to survive)
Gluconeogenesis lactate goes to liver and converted to glucose to return to muscle -net loss of ATP to make this happen
What are 3 steps for f.a. oxidation? transport to mito, beta oxidation, ETC
How do free fatty acids travel? bound to albumin
What activates lipases for beta oxidation? glucagon and epi
What creates ammonia? deamination of a.a.
What is chief/second nitrogenous waste of mammals and how is it excreted? urea/uric acid and kidneys
What causes kidney stones? uric acid
What is glyceraldehyde 3-P also known as? PGAL
Can glycerol backbone of fats enter glycolysis? YES --> becomes PGAL
How can amino acids be converted to TCA cycle substrate? -deaminated in liver -converted to acetyl coA
How can glycogen be converted to glycolysis intermediate? glycogen --> glucose 6-P for glycolysis
Do muscles have glucose-6-phosphatase? NO --> glycogen stored is for muscle use only
Does liver have glucose-6-phosphatase? YES --> glucose can be shared with other cells
Final products of aerobic respiration? -36-38 ATP -2 FADH2 -10 NADH
What are the irreversible reactions of glycolysis? -creation of glucose 6-P, creation of fructose 1,6-bisP, creation of pyruvate
What reaction does phosphofructokinase catalyze? fructose 6-P --> fructose 1,6-bisP
What inhibits phosphofructokinase for glycolysis regulation? -high ATP, high H+, high citrate
What promotes phosphorfructokinase activity? -low ATP, high AMP
What do prokaryotes lack? true nucleus
Why don't enzymes change the Keq of a reaction? lowers activation energy for both forward and reverse reactions
Enzymes affect the _______ of a reaction, NOT the ________. kinetics / thermodynamics
Enzymes can be specific enough to distinguish between steroisomers. True or False? True
Enzymes in the body can be _____ or ______. protein or RNA (ribosome)
Non-competitive inhibition decreases? Vmax
Does non-competitive inhibition change the amount of substrate needed for Vmax? NO
Can you overcome non-competitive inhibition by adding more substrate? NO
Where does the oxygen from the water produced in aerobic respiration come from? oxygen you breathe in
Where does carbon in glucose end up in? carbon dioxide
Where doe soxygen in glucose end up in? carbon dioxide
When electrons are passed from NADH to O2 in ETC, what is released? energy
What does FADH2 skip in the ETC which creates its lower energy? skips FMN and passes to Coenzyme Q
Energy released from ETC generates what? proton gradient which drives ATP synthesis
What inhibits ETC? antibiotics, cyanide, carbon monoxide
Where does beta oxidation occur? matrix of mitochondria
Where does ester hydrolysis occur and waht does it become? -cytosol -free fatty acids and glycerol
How is fatty acid activated for beta oxidation? -With ATP, f.a. is "activated" by CoA (becomes thioester)
What happens during beta oxidation? -breaks down fatty-coA, 2 carbons at a time, to make acetyl coA
What does beta oxidation produce? acetyl coA, FADH2, and NADH
What is nitrogen converted to in humans? in desert animals, birds, and reptiles? -urea -uric acid
For px metabolism, carbon in a.a. is converted to? pyruvate, acetyl coA, or any other metabolic intermediate depending on a.a.
What is fat for carbon products from a.a. metabolism? - go into Kreb's -starting material for gluconeogenesis
What do bacteria lack? no nuclear membrane, mitotic apparatus, golgi, ER, mito, chloroplasts
How do prok pull replicating cells apart w/o mitotic apparatus? prok cytoskeleton pulls replicated DNA apart
bacteria flagella is made of ________. eukaryotic flagella is made of ________. flagellin / microtubules
What powers bacterial flagella? Eukaryotic flagella? -proton/sodium gradient -ATP
What is motion of bacterial flagella? Eukaryotic flagella? -rotation -whip like motion
Describe fission. DNA replicates, DNA attaches to cx mem as cx elongates, cytokinesis
Defining characteristics of euks. True nucleus, membrane-bound organelles, divide by mitosis
What are 3 factors of mito according to endosymbiosis theory? self-replicate, have own DNA, have own ribosomes --> all are different than host
How do lysosomes work? Wastes gets into a vacuole by endocytosis or phagocytosis -vacuole fuses with lysosome
What is another name for smooth ER in muscles? sarcoplasmic reticulum --> stores calcium
What are the roles of smooth ER and rough ER in membrane biosynthesis? -smooth ER - makes mem lipids -rough ER - makes transmembrane px
How do transmem px / secreted px produced correctly? -have signal sequence at beginning -ribo starts to make px with signal sequence first -signal recognition particle recognizes and drags to RER
ER is connected to what? nuclear membrane
relationship between RER and golgi? RER makes px --> modified in Golgi --> buds off Golgi and exits by exocytosis
Where does glycosylation of px occur? Golgi
What does glycosylation do to px? affect's px structure, function, and protect from degradation
Fluid mosaic model protein boats floating in sea of lipids
The resting membrane potential is positive / negative? negative
gap junction connect 2 cx and allow stuff to flow through
tight jxn glues cx together to form impermeable barrier
desmosomes -connects 2 cx together by linking cytoskeleton -mechanical strength, not impermeable barrier
Microfilaments and intermediate filaments support cx shape by bearing _________. Microtubules support cx shape by bearing __________. -Tension -Compression
Where is kinetochore located? point joining two sister chromatids
What is a centrosome vs. centriole? Centrosome = centriole plus matrix and is where microtubules originate
Centrioles, microtubule organizing centers? microtubules radiate out of these barrel shaped structures which are made of microtubules
What are the stages of interphase? G0, G1, S, G2
Formula for number of peptides that contain "n" amino acids? n!
What stabilizes 3-D structure of px covalent bonds and noncovalent interactions
What is endosymbiotic theory? mito are descendents of prok engulfed by endocytosis into a vesicle lined with a euk mem.
Inne rmem of mito is analogous to ____ of prok. plasma membrane (has oxidative phos. enzymes)
During starvation, what is broken down first, second, and last? -carbs, lipids, body px
What is the major microtubule organizing center? centrosome
How are the flagella in euk and prok different in structure? -euk = 9+2 microtubules -prok = thin strand of flagellin px
ANtibiotics that block translation by prok ribo but NOT euk ribo also block translation by_____? mito ribo
Most px used by mito are coded by ________ nuclear DNA
What is most common extracx matrix px? collagen
protease enzyme involved in protein digestion
isozymes enzymes that differ in a.a. sequence but catalyze same reaction
What is main metabolic produce of CO2? TCA cycle
Primary structure of proteins linear sequence of a.a. held together by covalent peptide bonds
Secondary structure of px alpha helix or beta sheet
Which organelles replicate independently of the cx? peroxisomes and mito
WHich is the a.a. capable of forming disulfide bonds? cysteine
What are the 2 nonpolar a.a.? valine and alanine
What are the 2 acidic a.a.? glutamic acid and aspartic acid
WHat are 3 basic a.a.? arginine, histidine, lysine
What does it mean to be membrane-bound? -have double phospholipid membrane
What are membrane-bound organelles? mito, lysosome, nuclear envelope, ER, golgi bodies
What do endosomes do? intracx sorting organelles that deliver fats, px, and other materials to lysosomes fro degradation
Microfilaments are associated with _____ while Microtubules are associated with _____. -amoeboid mvmt. -phagocytosis
What most resembles the golgi apparatus? smooth ER
Is the interaction between inhibitor and enzyme permanent in competitive inhibition? NO --> transitory
Do cx walls, spore coats, or capsules have lipid bilayer? NO
What does microtubule paralysis cause? nerve degeneration and muscle weakness
autophagy lysosomes engulf and digest damaged/old intracx organelles
phagosome phagocyte + ingested material
Are sodium channels open at rest? NO --> ALWAYS CLOSED
What channel majorly determines resting potential? potassium
What determines negative resting emmbrane potential? closed Na/Cl channels and open leaky K channels
Does simple diffusion rely on channels to transport molecules? NO
What determines the resting membrane potential? leaky potassium chanels
body tissue group of similar cells
organ collection of several tissues
Where are cilia located? trachea/bronchi of respiratory tract, lumen of small intestine, fallopian tubes
obligate anaerobes absolutely unable to grow in oxygen
facultative anaerobes able to grow in presence in presence or absence of oxygen
obligate aerobes must have oxygen to survive
According to Poiseuille's Equation, what creates faster velocity conduction? increased radius, decrease in length F = r^4 / L
Can ntm diffuse across cx membrane? NO --> HYDROPHLIC
Why does the axon terminal have lots of mito? ntm exocytosis is an active process that requires a lot of ATP
What are the non-membrane bound organelles? microtubules, intermediate filaments, microfilaments, ribosomes
Are myosin and actin microfilaments or microtubules? microfilaments
Is the esophagus part of the digestive or respiratory tract? digestive
What px structure is a heterodimer? quaternary
Does the retina require ATP to function? YES
What do uncouplers do to ETC? decrease intermembrane acidity by dirupting H gradient
When is BP reached? VP is equal to atmospheric pressure
Higher vapor pressure... lower boiling point
If OP is blocked, what will the body do instead? increase ATP synthesis through glycolysis
Does hyperpolarization cause inhibition or activation? inhibition
Where are muscarinic vs. nicotinic receptors found? muscarinic - CNS nicotinic - PNS
What type of rx are nicotinic and muscarinic? What system are they a part of? cholinergic / PNS
Where are a lot of ribosomes found in a neuron? soma
prokaryotic DNA single, circular, uncoated, double stranded DNA molecule
Created by: 507935299