Bio/Biochem

spleen

stores blood and recycling old RBCs, lymph organ, filter

What element is required for muscles to contract?

Ca2+

Pyrimidines

Cytosine and Thymine

Purines

Adenine and Guanine

What amino acid is the only one that can form disulfide bonds?

Cysteine

Convergent evolution

process whereby distantly related organisms independently evolve similar traits to adapt to similar needs

What are gonadotropin hormones responsible for?

reproduction

helicase

separates the parent DNA strands at the origin of replication

ligase

binds two DNA fragments via phosphodiester bonds

primase

generates an RNA primer to match a fragment of DNA at the beginning of DNA replication

topoisomerase

relieves the overwinding of DNA strands ahead of the DNA replication fork by breaking, swiveling, and rejoining DNA strands.

If two genes are encoded by the same operon…

they share the same promoter and the same mRNA fragment.

digoxin effect caused by

increase in calcium

Na+K+ATPase is an example of what kind of transport?

Primary active transport because it uses ATP to move solutes against their concentration gradients

how are ketone bodies generated

from sustained oxidation of fatty acids

what branch of the peripheral nervous system does the adrenal medulla belong to?

the sympathetic nervous system of the autonomic nervous system

what supplies energy for the electron transport chain?

NADH

tubulin

a cytoskeletal protein whose expression is similar in different cells.

ETC complex 2

succinate dehydrogenase

ETC complex 1

ubiquinone oxioreductase

ETC complex 3

ubiquinol-cytochrome c oxioreductase

ETC complex 4

cytochrome c oxidase

gene imprinting

parent-specific transmission of traits

what do RNA viruses require to replicate themselves?

reverse transcriptase

what part of the nephron filters proteins?

the golermulus

what part of the nephron reabsorbs solutes and water from the filtrate?

the distal tubule

goblet cells

specialized epithelial cells that produce mucus in the respiratory tract

order in which filtrate passes thru the tubular regions of a nephron

Bowman’s capsule —> proximal tubule —> loop of Henle —> distale tubule —> collecting duct

liquid-liquid extraction

used to separate compound with disparate solubility characteristics; uses separatory funnel; take advantage of acid/base characteristics

thin-layer chromatography (TLC)

sample dabbed onto plate, then place in beaker with nonpolar solvent; capillary action draws the solvent up the plate, bringing the sample with it; nonpolar components move farther

size-exclusion column chromatography

used to separate components by physical size

cation-exchange column chromatography

trap positively charged molecules within the column; negatively charged stationary phase

anion-exchange column chromatography

positively charged stationary phase traps negative molecules

affinity chromatography

ligands designed to bind to a compound of interest are attached to the beads that make up the stationary phase

gas-liquid chromatography

time taken to move through the apparatus is measured and used to estimate its affinities for gaseous mobile and liquid/polymer stationary phases

High-performance liquid chromatography (HPLC)

passing a liquid mobile phase through an absorbent-packed column; takes place under high pressure, allowing resolution to occur more rapidly

Normal HPLC

stationary is polar, mobile is nonpolar

Reverse phase HPLC

stationary is nonpolar, mobile is polar

recrystallization

solid product place in a liquid solvent and heated, dissolving. then cooled, which forms precipitate; repeated to increase purity

filtration

used to separate solid product from unwanted fluids; only liquid can pass through filter

Distillation

separates liquids based on boiling points

simple distillation

BP > 25° apart

fractional distillation

BP < 25° apart

vacuum distillation

very high boiling points; used to lower atmospheric pressure

Hydrophobic interactions in proteins

Keep proteins stable and biologically active by decreasing surface area and reducing undesirable interactions with water. During protein folding, the hydrophobic side chains become buried in the interior of the protein.

ATP synthase

Allows passive diffusion of protons down their concentration gradient into the matrix, which provides energy for the formation of ATP from ADP and inorganic phosphate.

Active Site Model

States that the enzyme’s active site binds to the substrate. A substrate matches the site like a puzzle piece, making the enzyme specific to its substrate.

Phagocytosis

Type of endocytosis. Process by which a cell uses its plasma membrane to engulf a particle.

Active site

A location on an enzyme where binding of one or more substrate (reactant) molecules occurs, followed by the formation of products.

Competitive inhibition

Involves an inhibitor binding to the enzyme’s active site. The inhibitor is structurally and chemically similar to the substrate. It blocks the active site and thus prevents substrate binding. Its effects can be reduced by increasing substrate concentration. Increases Km.

Citric acid cycle steps

Citrate -> Isocitrate -> α-ketoglutarate -> Succinyl CoA -> Succinate -> Fumarate -> Malate -> Oxaloacetate

Vesicle

Structure consisting of liquid or cytoplasm enclosed by a lipid bilayer. Forms during the processes of secretion, uptake and transport of materials within the plasma membrane.

Uncompetitive inhibition

Involves an inhibitor interacting with the ES complex at an allosteric site. Prevents an enzyme from letting go of a substrate that it has bound. Decreases Vmax and Km.

Lyase

An enzyme that cleaves bonds through non-hydrolysis mechanisms and often facilitates the formation of a double bond.

Net energy production per molecule of glucose for glycolysis, the PDH complex, and the TCA cycle

4 ATP, 10 NADH, and 2 FADH₂ per glucose

Lipid raft

Cholesterol-rich microdomains of cell membranes. Influences membrane fluidity and membrane protein trafficking.

Phenylalanine, Phe, F, non-polar

Lysine, Lys, K, basic/positively charged.

Threonine, Thr, T, polar, the alcohol group is the target for phosphorylation in post-transcriptional modification

Arginine, Arg, R, basic/positively charged

Isomerase

An enzyme that catalyzes isomerization. It facilitates structural rearrangements.

Cofactor

A non-protein molecule that helps the enzyme carry out its biological functionality. Without these, enzymes remain within the inactive “apoenzyme” forms. Commonly in the form of a metal ion.

Gap junction

Intercellular channels that allow ions to diffuse between cells.

Beta oxidation

Process of breaking down a long-chain acyl-CoA molecule to acetyl-CoA molecules.

Triglyceride

Consists of 3 molecules of fatty acid combined with a molecule of glycerol. The major form of fat stored by the body.

Zymogen

Inactive forms of enzymes that must be cleaved to become active. e.g. trypsinongen to trypsin

Metabolism of proteins

Starts in the stomach, where enzymes break down proteins into amino acids. They are then transported into the bloodstream for circulation to the liver and cells throughout the body to create new proteins.

Tertiary protein structure

The 3D structures that result from interactions among the side chains of the amino acid residues of a protein. Many of these interactions are non-covalent charge-driven interactions.

Steroids

A category of lipid used for chemical signals and structurally supporting the cell membrane. Characterized by a 4 ring structure. Influence the membrane's fluidity.

Allosteric enzymes

Enzymes that have an additional site for an effector to bind to, as well as the active site. Binding of an effector changes the conformational ensemble.

Ketone bodies production and use

Produced from excess acetyl-CoA made during the oxidation of fatty acids. Serve as a fuel source if glucose levels are too low in the body.

Glutamate, Glu, E, acidic/negatively charged, critical component of cellular metabolism

Tight junction

Closely associated areas (similar to Velcro) of two cells whose membranes join together to form a virtually impermeable barrier to fluid.

4 steps of beta oxidation

Dehydrogenation, hydration, oxidation, and thyolisis. 

Water-soluble electron carriers

Refers to NAD⁺, FAD, NADPH, and NADP⁺. Play important roles during cellular respiration.

Pinocytosis

Type of endocytosis. Process by which liquid droplets are ingested by cells.

Adipocyte

Cells that primarily compose adipose tissue, specialized in storing energy as fat.

Effects of pH on enzyme activity

Increased or decreased pH from the optimal pH reduces enzyme activity.

Aspartate, Asp, D, acidic/negatively charged

Methionine, Met, M, non-polar, one of two amino acids with sulfur

Fatty acid activation

Process in which a CoA molecule is added to the fatty acid to produce acyl-CoA, converting ATP to AMP in the process.

Motor proteins

Include kinesins, dyneins, and myosins. Structural proteins that generate mechanical force as a result of undergoing conformational changes.

Function of enzyme

Enzymes are biological catalysts that speed up the rate of a reaction by reducing the activation energy.

Induced-Fit Model

Suggests that an enzyme, when binding with its substrate, optimizes the interface through physical interactions to form the final complex structure. Explains the protein conformational changes in the binding process.

Citric acid cycle

A cycle of reactions involved in the oxidation of acetyl-CoA and the formation of reduced soluble electron carriers and high-energy molecules (GTP).

Products of one round of the citric acid cycle

2 carbon dioxide molecules, 1 GTP or ATP, 3 NADH, and 1 FADH₂.

Exocytosis

Process in which intracellular vesicles in the cytoplasm fuse with the plasma membrane and release their contents into the extracellular space.

Protein solvation layer effect

Protein folding is largely dictated by the entropy of surrounding water.

Phospholipids

Has a hydrophillic head made of glycerol and a phosphate group, and a tail made of two fatty acids. Forms a bilayer in plasma membranes.

Electron transport chain steps

Redox of NADH at Complex I and Redox of FADH2 at Complex II -> Redox of Complex III -> Redox of Complex IV -> ATP synthase action

Oxidative phosphorylation

A transfer of electrons from soluble electron carriers (NADH and FADH₂) to oxygen; the energy released in the process is used to form ATP.

Integral protein

Protein that is permanently attached to the biological membrane. Functions include channeling or transporting molecules across the membrane and acting as cell receptors.

Squalene

The precursor of steroids. A terpene that consists of 6 isoprene subunits.

Proline, Pro, P, non-polar, has a cyclic structure in the side chain and a secondary amino group alpha to the carboxyl group.

Lipase

An enzyme that breaks down triglycerides into free fatty acids and glycerol.

Anabolism of fats

The synthesis of fatty acids from acetyl-CoA through elongation steps, increasing by two carbons each time.

Mixed inhibition

Involves an inhibitor binding the ES complex or a free enzyme at an allosteric site. Vmax is decreased. The effect on Km depends on the binding preference of a given inhibitor. If a mixed inhibitor prefers to bind the free enzyme, Km is increased. If a mixed inhibitor prefers to bind the ES complex, its overall effect can be thought of as similar to that of an uncompetitive inhibitor, and Km will be decreased.

Effect of temperature on enzyme activity

When the temperature is increased, the activity of an enzyme is increased. But an excessive rise in temperature can cause denaturation of the enzyme.

Desmosome

Adhesive protein complexes that localize to intercellular junctions and are responsible for maintaining the mechanical integrity of tissues.

Voltage gated ion channel

Channels that open or close in response to a change in membrane potential.