Enzyme Classes, Metobolic Enzymes, and Muscular/Skeletal Systems

A comprehensive set of vocabulary flashcards covering enzyme classification, metabolic regulation, DNA replication enzymes, and the musculoskeletal system based on lecture notes.

Ligase

Enzymes that join two molecules together, usually requiring ATP.

Isomerases

Enzymes that rearrange bonds within a molecule to form an isomer.

Lyases

Enzymes that break bonds without using water or oxidation, often forming a double bond or ring.

Hydrolases

Enzymes that break bonds using water.

Oxidoreductases

Enzymes that catalyze redox reactions by transferring $e^-$.

Transferases

Enzymes that move a functional group from one molecule to another.

Hexokinase/Glucokinase

Enzymes responsible for the irreversible step 1 in Glycolysis.

Phosphofructokinase-1 (PFK-1)

The rate limiting step of Glycolysis.

Pyruvate Kinase

The enzyme for the irreversible step 10 of Glycolysis.

Pyruvate Carboxylase

The Gluconeogenesis enzyme that bypasses pyruvate kinase.

Fructose-1,6-bisphosphatase

The rate limiting step of Gluconeogenesis which bypasses PFK-1.

Glucose-6-phosphatase

The Gluconeogenesis enzyme that bypasses hexokinase.

Kinase

A type of enzyme that transfers a phosphate group specifically from an ATP molecule to a substrate.

Phosphorylase

A type of enzyme that adds an inorganic phosphate group ($P_i$) to a substrate without ATP.

Phosphatase

A type of enzyme that removes a phosphate group from a substrate.

Carboxylate

An enzyme that adds a carboxyl group.

Decarboxylase

An enzyme that removes a carboxyl group, often resulting in a loss of carbon and producing $CO_2$.

Dehydrogenase

Enzymes involved in redox reactions, specifically those that produce $e^-$ carriers in the Citric Acid Cycle.

Synthase

Enzymes that join molecules together without the use of ATP.

Synthetase

Enzymes that join molecules together using a high energy molecule like ATP or GTP.

Glycogen Synthase

Enzyme responsible for attaching glucose molecules linearly ($1-4$) to form glycogen.

Branching Enzymes

Enzymes responsible for branching glucose molecules ($1-6$) to form glycogen.

Citrate Synthase

The rate limiting step of the Citric Acid Cycle.

Isocitrate Dehydrogenase

The rate limiting step of the Citric Acid Cycle that produces the first $CO_2$ and $NADH$.

$\alpha$-Ketoglutarate Dehydrogenase Complex

Enzyme complex in the Citric Acid Cycle that produces the second $CO_2$ and $NADH$.

Helicase

Enzyme that unwinds the DNA double helix during replication.

Topoisomerase (Gyrase)

Enzyme that relieves super coiling tension ahead of the replication fork.

Primase

Enzyme that synthesizes an RNA primer.

DNA Pol III

The main DNA synthesizers in prokaryotes.

DNA Pol I

Enzyme that replaces RNA primers with DNA.

DNA Ligase

Enzyme that joins Okazaki fragments together.

RNA Polymerase

Enzyme that transcribes DNA into mRNA.

Single-Stranded DNA Binding Protein

Protein that binds to each strand to prevent spontaneous reannealing of unwound DNA.

Protease

Enzyme that cleaves peptide bonds.

Lipase

Enzyme that cleaves lipids.

Nuclease

Enzyme that cleaves nucleic acids.

Skeletal Muscle

Voluntary, striated, multinucleated, non-branched muscle type.

Cardiac Muscle

Involuntary, striated, single nucleus, branched muscle type connected by intercalated disks.

Smooth Muscle

Involuntary, non-striated, single nucleus, tapered muscle type found in the respiratory, digestive, and cardiovascular systems.

Red Fibers

Slow twitch muscle fibers that utilize oxidative phosphorylation.

White Fibers

Fast twitch muscle fibers that utilize anaerobic metabolism.

Sarcomeres

The basic contractile unit of striated muscle consisting of thick myosin and thin actin.

Sarcolemma

The cell membrane of a myocyte.

Sarcoplasmic Reticulum

The storage site of $Ca^{2+}$ for muscle contraction.

T-tubules

Structures connected to the sarcolemma that carry signals for contraction.

Troponin

Protein that contains the $Ca^{2+}$ binding site in muscle cells.

Tropomyosin

Protein that moves from actin following a conformational change to reveal the myosin binding groove.

Osteoblasts

Cells that build bone.

Osteoclasts

Cells that resorb or break down bone.

Parathyroid hormone

Hormone that increases the resorption of bone and increases blood $[Ca^{2+}]$.

Vitamin D

Substance that increases resorption of bone and increases blood $[Ca^{2+}]$.

Calcitonin

Hormone that promotes bone formation and decreases $[Ca^{2+}]$ in blood.

Endochondroal ossification

The process by which fetal bones form from cartilage.

Intramembranous ossification

The process by which fetal skull bones form directly from mesenchyme.

Axial Skeleton

The portion of the skeleton consisting of the skull, hyoid, vertebrae, sternum, ribs, sacrum, and coccyx.

Appendicular Skeleton

The portion of the skeleton consisting of the limbs, pectoral girdle (clavicle, scapula), and pelvic girdle (os coxa).

BBL

Mnemonic for Bone-to-Bone: Ligament.

MBT

Mnemonic for Muscle-to-Bone: Tendon.

Compact Bone

Dense bone focused on strength, consisting of structural units called osteons.

Spongy Bone

Lattice-like bone with cavities filled with bone marrow.

Red Bone Marrow

Marrow filled with hematopoietic stem cells that help produce RBCs.

Yellow Bone Marrow

Marrow composed primarily of fat.

Lamellae

Bone layers that surround the Haversion canal.

Lacunae

Spaces between the lamellae rings where osteocytes reside.

Canaliculi

Fine channels that connect lacunae.

Cartilage

Firm and elastic tissue with a chondrin matrix, which is avascular and not innervated.

Chondrocytes

Cells that secrete the cartilage matrix.

Synovial fluid

Fluid that lubricates movable joints.