Biochemistry Flashcards Flashcards by Dack Punke

_______________
- fundamental subunit of polypeptides/proteins

Amino acid
(AA)

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There are ____ amino acids that are coded for by the DNA & there are ____ essential amino acids and ____ nonessential amino acids

20
9
11

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Amino Acid Structure includes :
____________ bonded to a hydrogen
____________ group
____________ group
____________ group

Central a-carbon bonded to a hydrogen
Amine group (-NH2)
Carboxyl group (-COOH)
Variable functional group (R-group)

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All amino acids are chiral except ____________

Glycine

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_______________
- 4 different distinct groups bound to an α-Carbon resulting in non-superimposable mirror-images
- a form of isomer with different configuration around a chiral center (forms 2 isomers)

Enantiomers

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Amino acids form __________ at low pH
Amino acids form __________ at high pH
Amino acids form __________ at intermediate pH

Cations
Anions
Neutral zwitterions (contains both positive and negative electrical charges, but the net charge on the molecule is zero COO- & NH3+)

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R-group chemical properties :
____________ - aliphatic or aromatic
____________ - pH neutral, acidic, alkaline, 3 with sulfur, or selenium

Non-polar
Polar

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____________
- amino acids form peptide bonds by dehydration synthesis between the amino group of 1 amino acid & the carboxyl group of another amino acid

Polypeptide synthesis

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Polypeptide synthesis is facilitated by ribosomes during ____________ of mRNA

translation

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Proteins are composed of 1 or more long ____________ molecules

polypeptide

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Other bonds formed in the synthesis & activation of proteins include __________ linkages between cysteine R-groups and __________ bonds between polar R-groups

Disulfide linkages
Hydrogen Bonds

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In protein digestion, the protease or peptidase enzymes break peptide bonds via ____________

Hydrolysis

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____________ structure
- actual sequence of amino acids in the protein due to peptide bonds

Primary structure

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____________ structure
- 2 common configurations
- a-helix & B-pleated sheet are due to Hydrogen bonds between amine hydrogens and carbonyl oxygen of amino acids
- especially prevalent in fibrous structural proteins

Secondary structure

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____________ structure
- 3D shape of entire polypeptide due to interaction among hydrophobic R-groups & hydrophilic R-groups, hydrogen bonds, ionic bonds, & disulfide bridges between cysteine R-groups

Tertiary structure

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Structural proteins usually have ________ tertiary structures

Fibrous

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Enzymes usually have ________ tertiary structures

Globular

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____________ structures
- 2 or more polypeptides combine to form a functional protein or incorporation of ligands
- ex : Fe containing heme groups of hemoglobin

Quaternary structures

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Long sequences of (non-polar OR polar) amino acids are found in membrane-bound proteins or membrane-embedded proteins & attach protein to lipid bilayer or folded into the interior to stabilize the 3D structure of proteins dissolved in water

Non-polar

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____________
- disruption of protein/polypeptide folding & activity by changes in pH, Temperature, or presence of hydrophobic solvents

Denaturation

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____________
- correct refolding of denatured protein

Renaturation

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____________
- dissolved proteins are surrounded by water molecules oriented according to the charges of the amino acids in that particular surface of the folded protein
- have properties key to binding of substrates to protein active sites

Solvation layer

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____________
- proteins are forced by electric current to pass through a medium that sorts molecules by size, charge, and/or other chemical properties

Electrophoresis

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__________________
- proteins have unique combinations of R-groups charged positive or negative
- at a specific pH then a particular protein acquires neutral charge (therefore stops moving due to no electromagnetic field force)
- proteins then separated along a pH gradient gel with cathode & anode charges at either end

Isoelectric focusing

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____________ chromatography - mixtures of proteins dissolved in a solvent pass by gravity or under pressure through a medium that binds with varied affinity to substances in the mixture - more soluble (lower binding affinity) molecules pass through the column fastest & others lag behind so each can be collected as it passes through the column

Column chromatography

_________________ - different molecules' mass-to-charge ratios detected by bombarding them with beams of electrons - magnetic field separates charged molecules by mass & charge

Mass spectrometry

X-ray crystallography & computer modeling can help determine _______________

3D protein folding

True or False Protein function is due to conformational strength, stability, & binding specificity

True

Functions of ___________ - enzymes, providing structure, facilitating movement, transport, or storage of substances & communication - membrane bound, dissolved, or suspended in organelles or cytosol or are secreted out of cells

proteins

____________ proteins - collagen (cartilage, bone, tendon) - keratin (nails, hair, horn) - histones (DNA supercoiling) - cytoskeleton - bacterial/fungal cell walls

Structural

____________ - catalysts of biochemical reactions - suffix : -ase

Enzymes

Proteins that help facilitate ____________ - muscle function (actin, myosin, tropomyosin) - kinesins - flagella - cilia

Movement

__________ & _________ proteins - membrane pumps - membrane channels - hemoglobin - myoglobin

Transport & Storage proteins

___________ & __________ proteins - peptide hormones (insulin, adrenalin) - neurotransmitters - antigens (surface markers) - antibodies (target non-self antigens)

Communication & Identification proteins

____________ - proteins that catalyze biochemical reactions - production, activation, & regulation determine the complex biochemical dynamics in living organisms - not reactants & can catalyze the same reaction repeatedly - highly substrate specific & enzymes specificity includes stereochemistry - do not influence the thermodynamics (just kinetic reaction rate)

Enzymes

Energy consumed in ____________ enzyme catalyzed reactions are usually obtained when the enzyme activity is coupled with the __________ catalysis of the reaction ATP --> ADP + Pi

endergonic exergonic

Enzyme-catalyzed reactions are linked sequentially to form ________________

Biochemical pathways

____________ - series of gradual chemical changes in a reactant to form a particular product

Biochemical pathways

____________ - biochemical reactions/pathways break down complex molecules into simpler molecules or release potential chemical energy stored in chemical bonds - associated with digestion, hydrolysis, oxidation, & exergonic processes

Catabolism

____________ - biochemical reactions/pathways that synthesize complex macromolecules from simpler subunits and/or form bonds that help store chemical energy - associated with polymerization, dehydration synthesis, reduction, & endergonic processes

Anabolism

____________ reactions - anabolic reactions & catabolic reactions together - dephosphorylation of PEP --> pyruvate coupled with substrate-level phosphorylation of ADP to ATP in glycolysis

Coupled reactions

__________ bond with substrates (reactants) at substrate-specific active sites

Enzymes

____________ - change conformation to form enzyme-substrate complex (lowers the activation energy of reactions that create or break substrate bonds by several ways)

Induced fit

The ____________ lowers activation energy of reactions that create or break substrate bonds by : - conformationally straining bonds so they break more readily - placing substrates together in an orientation that causes a chemical reaction - creating an active site microenvironment that induces a reaction - forming temporary bonds with the substrate as a step toward formation of the product

enzyme-substrate complex

True of false: Enzymes function within a limited optimal range of temperature & pH conditions

True

Apoenzymes may require cofactors (metal ions or organic molecules) to become activated ____________

Holoenzymes

Cofactors that are permanently incorporated into the enzyme are called _____________

Prosthetic groups

Cofactors that are temporarily bind to enzymes are called ____________

Coenzymes (ATP, NAD+, coenzyme A)

Enzyme catalysis involves 2 steps: 1. 2.

1. Binding of enzyme to substrate to form E-S complex 2. formation of product

The ______________________ (aka the Km value) is the substrate concentration at which the reaction rate is half of the maximum rate & it is a measure of how well an enzyme binds to its substrate

Michaelis-Menten constant

A (low OR high) Km = high affinity for enzyme to substrate & low rate of catalysis

Low Km

A (low OR high) Km = low enzyme-substrate affinity & high rate of catalysis

High Km

True or false: The rate of an enzyme reaction or non-enzyme protein binding (antigen/antibody) is a function of substrate concentration [S], Km value, & maximum catalysis rate Vmax

True

True or false: Temperature & pH affect conformational stability of enzymes (ability to bind or catalyze substrate declines)

True

Enzyme activity is regulated __________ & __________ control of genes coding for those enzymes

transcription translation

Activation of enzymes by modification of the inactive forms, which are called ____________

zymogens

True or false: The activation of enzymes occurs by change in the environment (secretion into stomach acid), addition of organic or inorganic covalently bonded groups (phosphorylation), & presence of inhibitors or activators

True

____________ may be products of enzyme catalysis or products farther down the biochemical pathway, or may be substances not directly related to the enzyme-catalyzed reaction

inhibitors

____________ enhance enzyme activity

activators

_______________ - in multi-polypeptide enzymes the substrate binding to 1 subunit enhances binding to others

Positive cooperativity

_______________ - substrate binding to 1 subunit reduces binding to others

Negative cooperativity

______________ inhibition - inhibitor to substrate that binds to the same active site as the substrate - formation of enzyme-substrate complex is reduced and therefore Km increases while Vmax stays the same because higher substrate concentration still increases catalysis

Competitive inhibition

______________ inhibition - inhibitor that binds to the enzyme but not at the active site (allosteric change to enzyme conformation) - prevents enzyme-substrate complex from completing catalysis - enzyme still binds to substrate so Km stays the same but Vmax decreases

Non-competitive inhibition

______________ inhibition - inhibitor binds to enzyme-substrate complex and prevents enzyme-substrate binding & prevents catalysis - Km increases and Vmax decreases

Uncompetitive inhibition

The inverse of the _______________ rate yields a linear equation that when graphed it clarifies the effects of enzyme inhibitors on Km or Vmax

Michaelis-Menten

______________ - subunit of nucleic acids - contains a phosphate, a 5-Carbon Sugar, & a Nitrogenous base (A, G, C, T, or U)

Nucleotide

________ : nitrogenous bases bound to ribose ________ : nitrogenous bases bound to deoxyribose

RNA DNA

The DNA molecule forms a double helix (twisted ladder structure) : "Rails" are alternating __________ & __________ "Rungs" are the __________

deoxyribose & phosphate subunits base pairs

Bonds between the base pairs in DNA molecules are ___________

H bonds

Bonds between alternating deoxyribose & phosphate subunits in DNA molecules are ____________

Phosphodiester bonds

In DNA the phosphodiester linkage is highly stable and the helical structure is maintained by ____________ between nonadjacent sugar molecules as the molecule twists

H bonds

Base pairing : between a purine & a pyrimidine A pairs to _____ C pairs to _____

A to T C to G

The base pairing between A & T contains a ________ H bond The base pairing between C & G contains a ________ H bond

Double Triple

______________ rule - equal concentrations of A & T also same for C & G

Chargaff's rule

DNA strands are ____________ - sequence of 1 strand can be known from the other strand

complementary

DNA strands are ____________ - the 5' carbon of the sugar molecules & phosphate on 1 strand are in opposite directions on the other complementary strand - the 3' carbons of each sugar are opposite the 5' ends - because of the orientation of the 2 strands, 1 end of each strand is designated the 5' end & the other is the 3' end

antiparallel

True or False : In DNA molecules there are thousands to several hundred million base pairs and the hydrogen bonds are weak but the cumulative effect makes the double strand stable

True

The denaturation of DNA molecules can be caused by Heat, Acid, or Enzymes can disrupt the __________ holding the strands together

H bonds

DNA _______ denaturation is the first step in a variety of techniques including DNA hybridization & PCR

Heat

In DNA heat denaturation the more A-T pairs there are then the (lower OR higher) the temperature required to cause denaturation

Lower - due to A-T only having 2 H bonds than compared to C-G having 3 H bonds

DNA ____________ - cooling process after heat denaturation so the DNA strands restore base pairing

Annealing

DNA ____________ - denatured DNA from different sources are combined and allowed to reanneal (similar sequences bind together) - used to help locate or mark specific sequences or genes or measure similarity of 2 DNA molecules

DNA Hybridization

In RNA, the pyrimidine __________ replaces Thymine as the base complementary to Adenine

Uracil

True or False : RNA molecules are much smaller and more mobile than to their parent DNA molecules in chromosome

True

DNA has 2 functions : ____________ ____________

Heredity Genes

______________ - responsible for carrying traits from 1 generation to the next generation

Heredity

______________ - information to make protein and RNA

Genes

______________ RNA - is a transcribed gene - prokaryotes : contains all the info to synthesize a single polypeptide - eukaryotes : primary transcript introns are spliced out to form secondary transcript

mRNA - messenger RNA

______________ RNA - most transfer RNA molecules carry 1 of the 20 amino acids to ribosomes which are creating a polypeptide - contains a 3-base anticodon which pairs with a mRNA codon

tRNA - transfer RNA

______________ - a component of ribosomes in which catalyzes peptide bond formation

rRNA - ribosomal RNA

RNA's that contribute to __________ regulation - miRNA, siRNA, snRNA, snoRNA, Xist RNA, CRISPR RNA

Gene regulation

____________ systems are inherently physical & chemical systems

Biological systems

Gibbs free energy incorporates the 2 components of thermodynamics in chemical systems ____________ & ____________

Enthalpy (H) & Entropy (S)

In Gibbs free energy, if the G > 0 then the process is ______________

Endergonic (consumes energy)

In Gibbs free energy, if the G < 0 then the process is _____________

Exergonic (releases energy)

____________ - biological systems convert light energy into chemical energy

Photosynthesis

______________ - biological systems convert chemical energy into other forms of chemical energy

Cellular respiration

____________ affect the rate at which biochemical reactions reach equilibrium but do not affect the final equilibrium concentrations

Catalysts

Increasing concentration of either of the __________ increases the forward reaction until equilibrium concentrations are reestablished

reactants

Increasing concentration of either of the __________ increases the reverse reaction until equilibrium is reestablished

products

______________ - the ribonucleoside Adenosine bound to a trimer of 3 phosphates linked by high-energy phosphodiester bonds

ATP

ATP & GTP act as __________ in many endergonic enzyme-catalyzed reactions so when the enzyme, motor protein, or membrane pump binds to its substrate then it also binds to an ATP at a different site

coenzyme

In the ATP molecule, hydrolysis of the phosphodiester bond between the 2nd and 3rd phosphates cause a release of ______ Kcal/mol.

7.3 Kcal/mol.

Enzyme : ____________ - remove a -COOH group

Carboxylases

Enzyme : _______/__________ - catalyze oxidation reactions - use electron carriers (NAD+ & FAD) and other flavonoids as cofactors - some reactions also decarboxylate the substrate

Oxidase / dehydrogenases

Enzyme : ____________ - transfer phosphate groups to substrates

Kinases

Enzyme : ____________ - remove a phosphate

Phosphatases

Enzyme : ____________ - reconfigure the molecule to an isomer

Isomerases

Enzyme : ____________ - add an electron (accompanied by an H+ from NADH + H+ or from FADH2)

Reductases

Enzyme : ________/_________ - responsible for anabolic formation of macromolecules

Polymerases / Synthases

Digestive / Catabolic enzymes are named for the substrate they break down : ________ - break down protein ________ - break down lipids ________ - break down lactose ________ - break down maltose ________ - break down nucleic acids

Proteases Lipases Lactase Maltase Nucleases

____________ - the 1st step in cellular respiration - oxidizes food molecules (glucose) and uses energy released to catalyze ADP + Pi --> ATP - occurs in cytoplasm of all cells

Glycolysis

Glycolysis summary : - the 1st 3 reactions consume _____ ATP molecules to convert glucose to fructose biphosphate (the negatively charged phosphates help split the Hexose to form _____ 3-Carbon glyceraldehyde phosphates - in a series of oxidative reactions, _____ G3P are converted to 2 pyruvate and these steps produce 4 ATP as well as 2 molecules of reduced electron carrier NADH + H+

2 2

Glycolytic intermediates are precursors for many __________ processes

anabolic

____________ - anaerobically recycles NAD+ to glycolysis

Fermentation

____________ fermentation - anaerobic bacteria & yeast - 2 pyruvate --> 2 ethanol + 2 CO2 - coupled with NADH + H+ --> NAD+

Ethanol fermentation

____________ fermentation - muscle cells that are O2 stressed (anaerobic) - 2 pyruvate --> 2 lactate - coupled with NADH + H+ --> NAD+

Lactic acid fermentation

____________ - synthesizes glucose from simpler molecules including lactate, glycerol, glutamine, & alanine - these molecules converted to pyruvate which is then reduced to form glucose - "essentially reverse glycolysis"

Gluconeogenesis

Gluconeogenesis derives its energy by consuming _____ ATP molecules and _____ GTP molecules

4 ATP 2 GTP

Gluconeogensis occurs mainly in ________ cells and is regulated by production of glucagon in the pancreas when blood sugar is too low

Liver cells

____________ - an alternative pathway in which energy from glucose is used to synthesize NADPH (a reduced electron carrier/coenzyme in many anabolic processes - also used as an antioxidant to reduce cell damage by free radicals - pathway yields ribose (nucleotide synthesis) & erythrose (aromatic amino acid synthesis)

Pentose Phosphate Pathway (PPP)

The Pentose Phosphate Pathway takes place predominantly in the __________

Liver

Aerobic Respiration : 4 steps 1. 2. 3. 4.

Glycolysis Pyruvate Oxidation Citric Acid Cycle Oxidative Phosphorylation (ETC)

Acetyl-CoA is transported into the _______________

Mitochondrial Matrix

All 6 carbons from glucose during aerobic respiration are converted to __________

CO2

True or False : Intermediate substrates of Citric Acid cycle are involved in other pathways

True

____________ - final pathway in aerobic respiration - yields additional 26-28 ATP per glucose - NADH + H+ & FADH2 in the mitochondrial matrix give their electrons to a series of protein complexes in the inner mitochondrial membrane - as electrons pass between the protein complexes the H+ are pumped from matrix to intermembrane space

Electron transport chain (ETC)

In Electron Transport Chain, the accumulation of protons (H+) is called _______________

Chemiosmotic Potential

True or False: Protons (H+) pass through ATP synthase complexes embedded in inner membrane, the positive charge helps neutralize repulsion between phosphates, allows new phosphodiester bonds to form, & the protons (H+) passing through ATP synthase and the electrons from the ETC react with O2 to form H2O

True

Anaerobic respiration net yield of ATP is _____ Aerobic respiration net yield of ATP is _____

2 ATP 30-32 ATP

Carbohydrate homeostasis combines __________ enzyme control of respiratory pathways with hormonal regulation

Allosteric

In glycolysis, enzymes that phosphorylate or dephosphorylate substrates act as sites of control : - high concentration of ______ inhibits phosphofructokinase which stops the production of fructose diphosphate

ATP

Reactions in the Citric Acid Cycle are : - inhibited by high concentrations of ____________ & ________ - stimulated by high concentrations of _________

NADH + H+ & ATP ADP

High or Low glucose stimulates either production or oxidation of __________

Lipids High glucose --> production of lipids Low glucose --> oxidation of lipids

The hormone ____________ causes glycogen formation, gluconeogenesis, and production of gastrin & CCK

Glucagon

__________ hormones control basal metabolic rates

Thyroid

____________ - damage to biomolecules/cells/tissues due to reactivity of oxygen-free radicals & peroxides - reactive oxidizers are necessary to the electron transport chain, immune system function, and cell-signaling mechanisms - overabundance of reactive oxidizers can trigger cell apoptosis or necrosis at the tissue level - degenerative, developmental, cardiovascular diseases, & cancer are associated

Oxidative stress

Apoptosis - enzyme-controlled cell death that is mediated in part by mitochondrial exposure to oxidative stress then the mitochondria release cytochrome C and several enzyme activators that stimulate activity of ____________ enzymes (trigger the cascade leading to apoptosis

Caspase enzymes

__________ factors that affect metabolism & body mass regulation - diet (caloric intake & food type), physical activity, sleep patterns, pollutants/toxins, medications, & cultural/economic factors

Environmental factors

__________ factors that affect metabolism & body mass regulation - levels of thyroid hormones, liver function, & specific genetic conditions

Genetic factors

Gut flora, pathogens, & parasites can influence body mass and __________ uptake

Nutrient

High body mass creates a positive feedback and hormones that enhance appetite (leptin & CCK) are produced by __________ tissue

Adipose (fat)

__________ - pathological syndrome associated with increased affluence in developing countries & poverty in developed countries

Obesity

__________ synthesis - if ATP demand is low & glucose levels are high then acety-CoA diverts from respiration to FA synthesis - fatty acid synthases form a growing hydrocarbon chain using NADPH as a reducing agent - primarily in liver, adipose, & mammary tissue

Fatty acid synthesis

The energy yield from fat oxidation is ______ kcal/g compared to the energy yield from carbohydrates or proteins of 4 kcal/g

9 kcal/g

Ingested or stored fats are digested by __________

Lipases

Fatty acids are transported bound to ____________

albumin

Inside mitochondria, fatty acids undergo ____________ which cleaves off 2 carbons at a time from the fatty acid and forming acetyl-CoA which enters the Krebs cycle

Beta-Oxidation

__________ bodies - are 3 biochemicals when food is not available or energy demands exceeds carbohydrate supply - 2 can become acetyl-CoA but the 3rd (acetone) is excreted but can reach toxic levels (leading to ketoacidosis)

Ketone bodies

__________ - breakdown of proteins into its component amino acids

Proteolysis

__________ synthesis is accomplished by ribosomes

Protein synthesis

The digestive system has __________ enzymes that catabolize proteins so amino acids can be absorbed and then transported to cells to be used in gene expression/protein synthesis

protease enzymes

Low carb & low fat causes dietary or cellular __________ to be used as energy sources (broken down in the liver by transamination to alpha-keto acids & converted to acetyl-CoA for oxidation in the Krebs cycle)

proteins

__________ - causes glycogen to be broken down into glucose to be used as an energy source - causes fat catabolism to ketone bodies to provide energy to the brain - causes protein to be catalyzed

Starvation

__________ - a diverse group of hydrophobic biochemicals with a wide range of functions - fats, oils (acylglycerols) waxes, steroids, & terpenes

Lipids

__________ functions - long-term energy storage, cell membranes (phosphodiglycerides & cholesterol), thermal & electrical insulation, waterproofing (waxes), buoyancy, padding, hormones (steroids), plant defenses (terpenes), and communication (pheromones)

lipid functions

Fats & oils are a glycerol with ________ bonds to 1-3 fatty acids (termed -glycerides)

ester bonds

__________ - a carboxyl group & a long hydrocarbon polymer

Fatty acids

__________ fatty acids - single bonds between pair of carbons

Saturated fatty acids

__________ fatty acids - 1 or more double bonds between carbons in the hydrocarbon chain

Unsaturated fatty acids

True or False: Fats & oils vary in the number of fatty acids, fatty acid hydrocarbon chain length, & if the fatty acids are saturated or unsaturated

True

Short-chain fatty acids contain _______ carbons Medium-chain fatty acids contain _______ carbons Long-chain fatty acids contain _______ or more carbons

4-6 8-12 14-40

Short chain fatty acids are (less OR more) hydrophobic than longer chain fatty acids

Less

__________ unsaturated fatty acids - contain double bonds between 1 or more carbons - are straight

trans-unsaturated fatty acids

__________ unsaturated fatty acids - contain double bonds between 1 or more carbons - have bends in them that reduce hydrophobicity

cis-unsaturated fatty acids

__________ - synthesized from fatty acids but rearranged to form 4 hydrocarbon rings

Steroids

Carotenoids & Lipophilic vitamins are derived from __________

fatty acids

__________ - phospholipid bilayer - stable : insoluble in cell's aqueous environment - selectively permeable : retains vital ions & biochemicals inside the cell - fluid : flexible, grow and engulf/discharge substances - complex mosaic : proteins, sterols, other biochemicals (complex are embedded in, penetrating, or extending from membrane)

Plasma membrane

__________ - contain C, H, & O - basic formula : (CH2O)n

Carbohydrates

Monosaccharides ________ : 3-C sugars such as glyceraldehydes ________ : 5-C sugars such as ribose & deoxyribose ________ : 6-C sugars such as glucose, fructose, etc.

Trioses Pentoses Hexoses

__________ - contain 2 or more monosaccharides connected via dehydration synthesis to form a glycosidic linkage

Disaccharides

__________ - composed of many sugar monomers connected by glycosidic linkages

Polysaccharides

__________ - short term easily transported energy sources - enter glycolysis as glucose or an intermediate further down the pathway

Monosaccharides

Disaccharides are __________ in the digestive tract before absorption

hydrolyzed

__________ - intermediate length - often cell surface molecules involved in communication, transport, & recognition - glycolipids or glycoproteins

Oligosaccharides

__________ - structural (cellulose) or for longer-term energy storage (starches or glycogen)

Polysaccharides

__________ constitutes dietary fiber and is indigestible by animals

Cellulose

__________ - certain genes that when activated & expressed may promote or cause cancer - may be triggered by mutation, chromosomal translocations, carcinogens, or viruses - may cause cancer if there is a loss of gene regulation, duplication of the gene, or translocation of the oncogene to a region of higher transcription promotion - many function by disrupting apoptosis, cause accumulation of a certain type of cell which would normally undergo stable turnover, new cells form to replace old ones that self-destruct via apoptosis - form proteins that disrupt normal cell differentiation or increase rates of cell proliferation

Oncogenes

True of False: Many chemotherapy drugs target the oncoprotein products of oncogenes, binding them or allosterically competing with them

True

__________ - complex transmembrane proteins - when stimulated by membrane voltage potential depolarization or by ligand binding, open & passively facilitate diffusion of a particular ion along a concentration or charge gradient

Gated ion channel

__________ - transmembrane proteins that when activated by binding of an external ligand then catalyze a reaction on the inner membrane surface, often initiating a pathway involved in cell growth or other cell activity

Receptor enzymes

__________ - large complex transmembrane proteins - receptor component on the cell surface binds to a ligand such as a hormone or neurotransmitter or to a sensory stimulus then a conformational change in the receptor occurs which stimulates a G protein on the interior membrane surface - uses energy from hydrolysis of GTP where the G protein initiates a cAMP cascade by stimulating adenylate cyclase or comparable pathway to trigger cell specific functions

G protein-coupled receptors