MCAT — Biology & Biochemistry Review

Enzyme active site

Region where substrate molecules bind and undergo a chemical reaction

Role of ribosomes

Protein synthesis

What is glycolysis?

The breakdown of glucose by enzymes, releasing energy and pyruvic acid

Function of lysosomes

Digestive organelle for waste processing and recycling

Phagocytosis

The process by which a cell engulfs particles to form an internal compartment

Structure of DNA

Double helix composed of nucleotides with sugar-phosphate backbone and nitrogenous bases

What is the Bohr effect?

The physiological phenomenon where low pH and high CO₂ concentration decrease hemoglobin's oxygen affinity

Function of the Golgi apparatus

Modifies, sorts, and packages proteins and lipids for storage or transport out of the cell

What is the role of NAD⁺ in cellular respiration?

Acts as an electron carrier in redox reactions

What is the Michaelis-Menten equation?

$v = \frac{V_{max}[S]}{K_m + [S]}$

Role of tRNA

Transfers specific amino acids to the ribosome during protein synthesis

What is osmosis?

The movement of water across a semipermeable membrane from a region of low solute concentration to high solute concentration

Function of the rough endoplasmic reticulum

Synthesis of proteins destined for the cell membrane or secretion

What is chemiosmosis?

The movement of ions across a semipermeable membrane, down their electrochemical gradient

What does the term 'allosteric regulation' mean?

Regulation of an enzyme by binding an effector molecule at a site other than the enzyme's active site

What is a kinase?

An enzyme that catalyzes the transfer of phosphate groups

What is the significance of the lac operon?

An operon required for the transport and metabolism of lactose in E. coli and many other enteric bacteria

Role of the spleen

Filters blood, recycles old red blood cells, and houses white blood cells

What is the function of hemoglobin?

Transport oxygen from the lungs to the body's tissues and return carbon dioxide from the tissues back to the lungs

What occurs during the S phase of the cell cycle?

DNA replication

Describe the fluid mosaic model

A model that describes the structure of cell membranes as a mosaic of components that gives the membrane a fluid character

What is a plasmid?

A small DNA molecule within a cell that is physically separated from chromosomal DNA and can replicate independently

What is the role of acetylcholine?

Acts as a neurotransmitter at neuromuscular junctions, causing muscle contraction

Function of B cells in the immune system

Produce antibodies against antigens

What is apoptosis?

Programmed cell death involving a cascade of specific cellular events leading to the death and elimination of the cell

What is the significance of the Hardy-Weinberg equilibrium?

A principle stating that genetic variation in a population will remain constant in the absence of disturbing factors

What is the role of the lymphatic system?

Maintains fluid levels in our body tissues by removing all fluids that leak out of our blood vessels

What is the role of myelin?

Insulates axons, increasing the speed at which impulses propagate along the myelinated fiber

What is a karyotype?

A photograph of an individual's chromosomes arranged by size and shape

What is the role of insulin?

Regulates blood glucose levels by facilitating the uptake of glucose into tissues

What is a telomere?

The region of repetitive nucleotide sequences at each end of a chromosome, which protects the end of the chromosome from deterioration

What is the purpose of PCR (Polymerase Chain Reaction)?

A technique used to amplify small segments of DNA

What is the role of the hypothalamus?

Regulates body temperature, hunger, thirst, and other homeostatic systems, and is involved in sleep and emotional activity

What is the difference between competitive and non-competitive inhibition?

Competitive inhibition occurs when a molecule similar to the substrate competes for the active site. Non-competitive inhibition occurs when an inhibitor binds to an enzyme at a site other than the active site, altering the enzyme's function.

Role of macrophages

Engulf and digest cellular debris, foreign substances, microbes, and cancer cells

What is the function of the pancreas in digestion?

Produces enzymes that break down carbohydrates, proteins, and lipids in the small intestine

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a nucleus and membrane-bound organelles, while eukaryotic cells have both.

What are the main phases of the human menstrual cycle?

Follicular phase, ovulation, luteal phase, and menstruation

What is the function of serotonin?

Regulates mood, appetite, and sleep